Intraplate brittle deformation and states of paleostress constrained by fault kinematics in the central German platform

    Intraplate brittle deformation and states of paleostress constrained by fault kinematics in central German platform Payman Navabpour, Alexander Malz, Jonas Kley, Melanie Siegburg, Norbert Kasch, Kamil Ustaszewski PII: DOI: Reference:

S0040-1951(16)30557-1 doi:10.1016/j.tecto.2016.11.033 TECTO 127335

To appear in:

Tectonophysics

Received date: Revised date: Accepted date:

9 June 2016 12 October 2016 21 November 2016

Please cite this article as: Navabpour, Payman, Malz, Alexander, Kley, Jonas, Siegburg, Melanie, Kasch, Norbert, Ustaszewski, Kamil, Intraplate brittle deformation and states of paleostress constrained by fault kinematics in central German platform, Tectonophysics (2016), doi:10.1016/j.tecto.2016.11.033

This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

ACCEPTED MANUSCRIPT

T

Intraplate brittle deformation and states of paleostress constrained by fault kinematics in central German platform

IP

Payman Navabpoura*, Alexander Malzb, Jonas Kleyc, Melanie Siegburgd, Norbert Kascha,

SC R

Kamil Ustaszewskia

University of Jena, Institute of Geosciences, Burgweg 11, 07749 Jena, Germany.

b

Geological Survey of Saxony-Anhalt, Köthenerstraße 38, 06118 Halle, Germany.

c

University of Göttingen, Geoscience Center, Goldschmidtstraße 1-3, 37077 Göttingen,

NU

a

Germany.

University of Southampton, Ocean and Earth Science Department, Southampton

MA

d

SO14 3ZH, England.

Corresponding author, e-mail: [email protected]

TE

D

*

CE P

Abstract

The structural evolution of Central Europe reflects contrasting tectonic regimes after the Variscan orogeny during Mesozoic – Cenozoic time. The brittle deformation related to each

AC

tectonic regime is localized mainly along major fault zones, creating complex fracture patterns and kinematics through time with diverging interpretations on the number and succession of the causing events. By contrast, fracture patterns in less deformed domains often provide a pristine structural inventory. We investigate the brittle deformation of a relatively stable, wide area of the central German platform using fault-slip data to identify the regional stress fields required to satisfy the data. In a non-classical approach, and in order to avoid local stress variations and misinterpretations, the fault-slip data are scaled up throughout the study area into subsets of consistent kinematics and chronology for sedimentary cover and crystalline basement rocks. Direct stress tensor inversion was 1

ACCEPTED MANUSCRIPT performed through an iterative refining process, and the computed stress tensors were verified using field-based observations. Criteria on relative tilt geometry and indicators of

T

kinematic change suggest a succession of events, which begins with a post-Triassic normal

IP

faulting regime with σ3 axis trending NE-SW. The deformation then follows by strike-slip

SC R

and thrust faulting regimes with a change of σ1 axis from N-S to NE-SW, supposedly in the Late Cretaceous. Two younger events are characterized by Cenozoic normal and oblique thrust faulting regimes with NW-SE-trending σ3 and σ1 axes, respectively. The fracture

MA

NU

patterns of both the cover and basement rocks appear to record the same states of stress.

AC

CE P

TE

D

Keywords: Brittle tectonics; Fault kinematics; Intraplate deformation; Paleostress

2

ACCEPTED MANUSCRIPT

Introduction

T

1

IP

It is a fundamental tenet of plate tectonics that deformation of the Earth’s lithosphere is

SC R

strongly localized along plate margins. Still so, weaker deformation also affects plate interiors. Central Europe has been located within a plate interior since the Variscan orogeny, and its tectonic evolution is commonly interpreted to be related to events at distant plate

NU

margins (e.g., Sissingh, 2006; Ziegler, 1987). During the Mesozoic and Cenozoic, a distant

MA

northwestern plate margin evolved from rifting to the fully developed North Atlantic midocean ridge. At the same time, a southern plate margin evolved from rifting over the formation of Alpine Tethys Ocean to subduction and collision (Handy et al., 2010;

TE

D

Rosenbaum et al., 2002; Stampfli and Borel, 2002). Both the Atlantic divergent and Tethyan convergent margins are active today, but neither is closer than 1400 km to our study area

CE P

(Fig. 1a).

There is a broad consensus about the general post-Variscan tectonic evolution of Central

AC

Europe, as reviewed in recent books. A long Permian – Early Cretaceous period of weak extension is followed by contraction in the Late Cretaceous and then again by extension related to the European Cenozoic Rift System (Doornenbal and Stevenson, 2010; Littke et al., 2008; McCann, 2008). However, diverging opinions persist about the number and timing, the kinematics and the causes of tectonic events. Detailed paleostress reconstructions in other regions of the world have revealed links between local deformation and far-field stress in different extensional and contractional settings (e.g., Angelier et al., 1990; Bergerat and Angelier, 2000; Gudmundsson et al., 1996; Navabpour, 2009; Navabpour and Barrier, 2012; Navabpour et al., 2014). A couple of brittle tectonics studies were conducted in Central 3

ACCEPTED MANUSCRIPT Europe, but results often disagree. Some studies find many discrete events, e.g. ten distinct stress fields from Late Variscan to Cenozoic time (Peterek et al., 1997) and six (Vandycke,

T

2002) or eight (Coubal et al., 2015) successive stress fields since the Late Cretaceous. Other

IP

studies interpret only a few tectonic regimes, e.g. two (Lamarche et al., 2003) or three

SC R

(Franzke et al., 2007) events throughout the Mesozoic to Cenozoic time. Possible reasons for these divergent interpretations include different completeness of stratigraphy, temporal and spatial variations in actual stress fields, over interpretation of limited data or poor

NU

preservation. For instance, Sippel et al. (2009) did not find evidence of Mesozoic extension

MA

along the southern rim of the Central European Basin and concluded that much evidence must have been lost to overprinting by younger events.

D

Furthermore, there is still no consensus on the kinematics of intraplate deformation. Large-

TE

scale structural and basin geometries were interpreted to indicate bulk dextral transtension

CE P

with an E-W stretching axis during the Mesozoic extension, and bulk dextral transpression with a N-S shortening axis during the following contraction(s) (e.g., Betz et al., 1987; Doornenbal and Stevenson, 2010; McCann, 2008). By contrast, brittle tectonics studies have

AC

repeatedly found evidence for extension and contraction approximately perpendicular to the main NW-SE-striking faults. The question of kinematics has important implications for the causes of intraplate deformation. The European intraplate shortening has been commonly interpreted to be foreland deformation resulting from a N-directed push exerted by the Alpine collision (e.g., Ziegler and Dèzes, 2006; Ziegler, 1987; Ziegler et al., 1995). Even with dextral transpressive deformation, intraplate kinematics in this scenario only loosely matches plate boundary kinematics. Kley and Voigt (2008) instead proposed that this event has a regionally uniform NNE-SSW shortening direction that closely reflects the convergence of Africa, Iberia and Europe in Late Cretaceous time. 4

ACCEPTED MANUSCRIPT In the present paper, we address the issues listed above by analyzing fault-slip data from a relatively stable, wide area of the central German platform. We stayed away from major fault

T

zones to avoid stress variations related to differential fault block rotations. A systematic

IP

attempt was made to identify the minimum number of regional stress fields required to satisfy

SC R

the data by inverting consistent fault kinematics of the entire area together rather than analyzing individual outcrops separately. Finally, we discuss age constraints for the identified

2

MA

NU

stress fields and correlate them with deformation sequences from surrounding areas (Fig. 1b).

Geological setting

D

After the end of the Variscan orogeny, a Basin-and-Range type wide rift created the fault-

TE

bounded Latest Carboniferous to Early Permian ―Rotliegend‖ basins filled with volcanic and clastic rocks (Lützner, 1988). Following the demise of the rift, the Latest Permian Zechstein

CE P

transgression overstepped the Rotliegend basins. The Mesozoic – Cenozoic structural evolution of Central Europe comprises contrasting tectonic regimes (Littke et al., 2008;

AC

McCann, 2008). A protracted phase of thermal subsidence with intermittent, low-magnitude extension and transtension from the Latest Permian to the early Late Cretaceous was punctuated by more pronounced extension with graben and salt diapir formation in the Late Triassic and Late Jurassic to Early Cretaceous (Betz et al., 1987; Ernst, 1989; Franzke et al., 2007; Kockel, 2002; Tröger and Schubert, 1993). This long period of subsidence was terminated by a phase of contraction, which began and peaked in the Late Cretaceous and persisted into the Early Cenozoic involving inversion of many extensional faults (Clausen and Pedersen, 1999; Danišík et al., 2012; Kley and Voigt, 2008; Kockel, 2002; Malz and Kley, 2012; Otto, 2003; Scheck et al., 2002; Ziegler, 1987). The end of intraplate contraction 5

ACCEPTED MANUSCRIPT was followed by the formation of the European Cenozoic Rift System, which was coeval with Alpine orogeny farther south (Dèzes et al., 2004; Ziegler and Dèzes, 2006; Ziegler, 1992).

T

The present-day deformation across large areas of Central Europe is characterized by a NW-

IP

SE maximum horizontal shortening (Fig. 1a) (Gölke and Coblentz, 1996; Grünthal and

SC R

Stromeyer, 1992; Heidbach et al., 2007; Hinzen, 2003). This requires a substantial change in the state of stress, as documented for segments of the Cenozoic Rift System such as the Upper Rhine Graben (Schumacher, 2002), but poorly constrained in less deformed areas of

NU

the European plate interior such as the central German platform.

MA

The study area is located between the Rhenish Massif to the west and the Bohemian Massif to the southeast (Fig. 1b) and mainly covers the Thuringian domain of the central German

D

platform (Fig. 2). Over much of its history, this domain was located on the southern rim of

TE

the Central European Basin (Fig. 1b). During the Late Cretaceous shortening event it became

CE P

separated from surrounding basins through uplift of the Harz Mountains and Thuringian Forest (Thomson and Zeh, 2000; Voigt et al., 2004). These mountains expose low- to highgrade metamorphic rocks of the Variscan orogeny and the associated late- to post-orogenic

AC

Carboniferous – Permian granite intrusions (Toloczyki et al., 2006). Both the granites and the country rocks are intruded by NW-SE-striking Permian rhyolitic dykes in the Thuringian Forest and discontinuously overlain by locally thick Rotliegend volcanic and clastic rocks (e.g., Franzke and Rauche, 1991; Lützner, 1988; Rieke et al., 2001; Schröder, 1987; Zeh and Brätz, 2004; Zeh et al., 2000). The continuous sedimentary cover of the study area begins with as much as 700 m of Upper Permian Zechstein (Karnin et al., 1996). The Zechstein succession consists of evaporite and carbonate cycles of laterally variable thickness across the central German Platform (Doornenbal and Stevenson, 2010; Reinhardt, 1993). These strata mark the transition to a relatively uniform subsidence that continues into the Mesozoic. The 6

ACCEPTED MANUSCRIPT Mesozoic rocks of the study area consist of an about 1000 m thick succession of limnic, eolian and fluvial sandstone, shale and evaporite of the Lower Triassic Buntsandstein,

T

shallow marine carbonate and evaporite of the Middle Triassic Muschelkalk, and shale, marl,

IP

sandstone and evaporite of the Upper Triassic Keuper (Beutler and Schubert, 1987; Feist-

SC R

Burkhardt et al., 2008). The youngest Mesozoic strata preserved are small remnants of Lower Jurassic open marine shale and sandstone. The Mesozoic stratigraphic succession is locally intruded by NNE-SSW-striking basaltic dykes of Late Oligocene – Early Miocene age

NU

(Abratis et al., 2007; Lippolt, 1983; Rauche and Franzke, 1990) to the south and west of the

MA

Thuringian Forest (Fig. 2).

The entire association of pre-Zechstein rocks defines a mechanically competent basement, the

D

structures of which are traceable up into the cover rocks in the Thuringian Basin (Malz, 2014;

TE

Malz and Kley, 2012). However, where thick evaporites are present, the Zechstein strata form

CE P

a potential detachment layer on top of the basement rocks (Holländer, 2000; Nachsel and Franz, 1983). The dominant structures in the Mesozoic cover rocks of the study area are a few map-scale narrow NW-SE-striking faults separated by less deformed, essentially flat-

AC

lying terrains with horizontal strata (Fig. 2) (Ellenberg, 1992; von Bubnoff, 1953). The NW-SE-striking faults exhibit graben-like down faulted strips of Middle to Upper Triassic strata, suggesting NE-SW extension (Betz et al., 1987; Ernst, 1989; Franzke et al., 2007; Kockel, 2002; Malz, 2014; Malz and Kley, 2012; Tröger and Schubert, 1993). Some of these faults are locally associated with outcrop-scale tight and inclined drag folds, indicating tectonic inversion and contraction superimposed along the same NE-SW direction (Bankwitz et al., 1993; Franzke et al., 1986; Malz, 2014; Malz and Kley, 2012). No map-scale fold structures are associated with the NW-SE-striking faults. The faulted Mesozoic cover rocks are disrupted by the basement uplifts of the Harz Mountains, Thuringian Forest and Slate 7

ACCEPTED MANUSCRIPT Mountains to the north, south and southeast of the Thuringian Basin, respectively (Fig. 2). Minor NNE-SSW-striking faults including those of the Leinetal Graben delimit our study

Inventory of brittle structures

NU

3

SC R

IP

T

area to the west.

MA

For a comprehensive paleostress reconstruction, fault-slip data including spatial orientation of fault planes and associated striae were collected from 93 sites across the study area (Fig. 2).

D

Owing to the widespread vegetation cover, data acquisition sites were mainly located in

TE

active and abandoned quarries and along road cuts. Most of the fault-slip data were collected from sub-horizontal micritic to bioclastic limestone of the Middle Triassic Muschelkalk in the

CE P

cover rocks. Fault-slip data from natural rock exposures are particularly rare. A small number of fault-slip data could be collected from the granitic rocks to evaluate the response of pre-

AC

existing fracture patterns to the events that postdate the Carboniferous – Permian time, hence approximating the states of stress that affected the Triassic rocks. The criteria used for the sense of slip mostly include calcite slickenfibers and slickolites in the cover rocks, and Riedel shear fractures in the basement rocks. An average magnetic north correction of N002° is applied to the orientation data collected by compass, according to the International Geomagnetic Reference Field (Finlay et al., 2010) for the center of the study area during the data acquisition period. Stereoplots of the fault-slip data are given as supplementary material in the online repository to this article.

8

ACCEPTED MANUSCRIPT A common difficulty in interpreting the measurements within the framework of polyphase brittle deformation is related to the heterogeneity of fault-slip data, in terms of their diversity

T

in type, spatial orientation and temporal reactivation. This heterogeneity demands appropriate

IP

means for classification of data into both kinematically and chronologically consistent

SC R

subsets (e.g., Angelier, 1984; Hippolyte et al., 2012; Madritsch, 2015; Navabpour et al., 2007, 2008, 2010, 2011; Saintot and Angelier, 2002; Ustaszewski and Schmid, 2006). The criteria that could help in data separation were relative geometry of fault planes with respect

NU

to tilted strata and kinematic change indicators on the same fault slickensides. Because the

MA

study area comprises mostly flat-lying horizontal strata, the relative tilt geometries could be only verified at a limited number of sites where outcrop-scale folded strata were visible.

D

Measurement of the bedding planes at these sites yields an azimuth of N121° as the average

TE

fold axis for the entire study area (Fig. 2, inset). This axis suggests an azimuth of N031° for the orientation of first-order shortening, which we refer to as folding event (fl) hereinafter.

CE P

The kinematic changes were evidenced by several instances of successive striae at many sites. We describe some of the key examples observed in the study area in the following

AC

paragraphs.

3.1

Relative tilt geometries

At some outcrops, where the strata were locally folded, it was possible to determine the relative pre-, syn- and post-tilt geometries between the faults and bedding planes, based on the Anderson’s theory of faulting (Anderson, 1951). The pre-tilt geometry mainly includes normal and strike-slip faults that have specific angular relationships with respect to tilted strata. The syn-tilt geometry includes bedding-parallel reverse kinematics that form in 9

ACCEPTED MANUSCRIPT flexural slip folding. The post-tilt geometry mostly includes normal and strike-slip faults that have no specific angular relationship with respect to the previously folded strata.

T

Examples of pre-tilt geometry can be given for sites 40 and 76. Site 40 provides data of tilted

IP

normal faults along the Eichenberg-Gotha-Saalfeld Fault Zone (Fig. 2). In the present-day

SC R

orientation, the faults appear as a system of crosscutting low-angle normal and high-angle reverse faults (Fig. 3a). The intersection line of the faults is sub-parallel to the bedding plane,

NU

suggesting that they are tilted conjugate-like normal faults. The stress field obtained from these fault-slip data indicates inclined σ1 and σ3 axes deviated from vertical and horizontal

MA

orientations, respectively. Back tilting the fault-slip data around the strike of tilted strata reconstructs the initial geometry and yields a normal faulting regime with vertical σ1 axis.

D

Site 76 provides data of tilted strike-slip faults to the southeast of the Finne Fault Zone (Fig.

TE

2). At this site, there are folded strata containing sub-vertical oblique sinistral strike-slip

CE P

faults with striae parallel to the tilted bedding planes (Fig. 3b). The stress field obtained from these fault-slip data indicates inclined stress axes with σ2 axis deviated from vertical in the present-day orientation. Back tilting the fault-slip data around the strike of the bedding plane

axis.

AC

reconstructs their initial geometry and yields a strike-slip faulting regime with vertical σ2

An example of syn-tilt geometry can be given for site 21. This site represents overturned flank of a local fold across the Finne Fault Zone (Fig. 2) with bedding-parallel slip planes indicating normal senses of motion (Fig. 3c). The stress field obtained from these fault-slip data is a normal faulting regime with vertical σ1 axis in the present-day orientation. Back tilting the fault-slip data around their strikes to a non-overturned, moderately tilted attitude of the strata reconstructs their typical syn-fold geometry. These back-tilted fault-slip data indicate a thrust faulting regime with vertical σ3 axis. 10

ACCEPTED MANUSCRIPT Examples of post-tilt geometry can be given for sites 40 and 42. At site 40, along the Eichenberg-Gotha-Saalfeld Fault Zone (Fig. 2), a separate set of conjugate-like normal faults

T

cut through locally folded strata (Fig. 3d). These faults appear in their typical Andersonian

IP

geometry (Anderson, 1951) with a horizontal intersection line, regardless the inclination of

SC R

bedding plane. The stress field obtained from these fault-slip data indicates a normal faulting regime with vertical σ1 axis. At site 42, along the northern rim of the Thuringian Forest (Fig. 2), sub-vertical sinistral strike-slip faults with sub-horizontal striae cut through locally folded,

NU

deeply tilted strata (Fig. 3e). The stress field obtained from these fault-slip data suggests a

Kinematic change indicators

TE

3.2

D

MA

strike-slip faulting regime with vertical σ2 axis.

CE P

Kinematic changes are evidenced by successive striae on the same fault planes at several sites. The successive striae are of different types in terms of relative chronology. The best instances of successive striae are those that clearly show relative binary chronologies. These

AC

striae either crosscut or overprint each other with different senses of slip. Some striae twist from one to another, evidencing continuous kinematic change between faulted blocks, which need cautious consideration in paleostress reconstructions. Other instances of striae exhibit disparate kinematics on different parts of the same fault plane with unclear relative chronology.

Instances of successive striae with relative binary chronology mostly include strike-slip and reverse reactivation of pre-existing NW-SE-striking normal faults. A kinematic change from normal to dextral sense of slip was observed at site 17 (Fig. 4a) through slickolites crosscutting calcite slickenfibers on a tilted normal fault plane. At site 52, a fault slickenside 11

ACCEPTED MANUSCRIPT indicates reverse reactivation of a normal fault by calcite slickenfibers crystallized over older slickolites (Fig. 4b). These sites suggest that a NE-SW extension was replaced by contraction.

T

Sites 04 and 22 reveal successive striae on fault slickensides sub-parallel to the pre-existing

IP

normal faults. At site 04, calcite slickenfibers overprinting slickolites indicate sinistral

SC R

reactivation of a thrust fault (Fig. 4c). At site 22, twisted slickolites indicate a kinematic change from dextral to reverse sense of slip (Fig. 4d). These successive striae suggest a reorientation of contraction from N-S to NE-SW, possibly in a continuum of events. This

NU

interpretation can be confirmed by observation of successive horizontal stylolites in sub-

MA

horizontal strata at site 73 (Fig. 4e), as well as site 77. These sites are spatially located far from each other to the north and south of the Finne Fault Zone (Fig. 2), respectively. The

D

horizontal stylolites independently indicate similar clockwise change in the direction of

TE

contraction.

CE P

Nevertheless, other instances of kinematic change suggest contrasting reorientation of contraction. At site 08, twisted striae on SW-dipping, steep bedding planes indicate a change from reverse to oblique dextral sense of slip (Fig. 4f). This kinematic change suggests

AC

counterclockwise reorientation of contraction towards NW-SE. If this interpretation is correct, the change should postdate the folding event because steeply tilted strata are affected by this kinematic change (see also Fig. 3e).

Instances of successive striae with unclear relative chronology exhibit contrasting normal and strike-slip fault slickensides. Site 31 indicates disjunctive normal and sinistral senses of slip on a NE-SW-striking high-angle fault plane (Fig. 4g). The relative chronology is not well understood between these two senses of slip. However, these fault-slip data seem to be geometrically consistent with the pre- and post-tilt orientation of sub-parallel faults observed elsewhere at sites 76 and 40 (Fig. 3b and d, respectively). Hence, the normal component 12

ACCEPTED MANUSCRIPT suggests a NW-SE extension that should postdate both the strike-slip component and the folding event. At site 75, opposite dextral and sinistral strike-slip motions are evidenced by

T

slickolites on the same sub-vertical fault planes striking NNW-SSE (Fig. 4h). The stress

IP

fields obtained from the collected fault-slip data indicate orthogonal NE-SW and NW-SE

SC R

directions of contraction. The relative chronology could not be reliably verified between these fault-slip data. The only observation was that the striae indicating sinistral sense of slip prevail and that sub-parallel sinistral faults appear in post-tilt geometry elsewhere at site 42

NU

(Fig. 3e). Hence, the sinistral sense of slip should postdate the dextral one.

MA

In the case of basement rocks, we could find two instances of successive striae. At site 34, there are calcite slickenfibers crystallized on incongruous steps of Riedel shear fractures on a

D

SW-dipping fault plane cutting through the granites (Fig. 5a). The calcite slickenfibers

TE

indicate a reverse sense of slip opposite to that of the Riedel shear fractures. This observation

CE P

suggests inversion of a normal fault under a NE-SW contraction. Another change in fault kinematics is evidenced by twisted striae on sub-vertical NNW-SSE-striking fault planes showing dextral senses of slip within the rhyolites at site 62 (Fig. 5b). The twisted striae

AC

could be interpreted either as a change of kinematics or as successive increments of strikeslip displacements associated with progressive fault block rotation towards south. The structural location of the outcrop along a map-scale NW-SE-striking fault in southwestern foothills of the Thuringian Forest is in favor of the latter.

3.3

Distribution of deformation

As already explained, the study area widely consists of flat-lying strata (Fig. 2) away from surrounding major deformational zones of the Elbe Fault, Leinetal Graben and Franconian 13

ACCEPTED MANUSCRIPT Lineament (Fig. 1b). This structural configuration limited the possibility to use relative tilt geometries in data separation for every outcrop. The stratigraphy of the study area is such that

T

almost all the fault-slip data of the cover rocks are collected from the Middle Triassic

IP

Muschelkalk (see supplementary material). This uniform lithology made it impossible to

SC R

separate data based on the age of affected rock, except between the limestone of the cover and the granite of the basement. Furthermore, many outcrops provided us with few fault-slip data of different kinematics, which could not be used in stress tensor inversion individually.

NU

The interpretation of kinematic changes can also be ambiguous, because they might be

MA

related to either change in stress or differential fault block rotation. However, we should emphasize that most of the successive striae were collected from outcrops with horizontal

D

strata where the rocks were not distorted by a local fault zone. While we avoided collecting

TE

ambiguous data from the narrow fault zones, it was indispensable to verify the relative tilt

CE P

geometries close to these faults.

In order to evaluate the regional significance of the field-based observations and establish the links between the relative tilt geometries and kinematic changes, the fault-slip data are

AC

separated based on relative chronology and kinematic consistency. The stress axes are calculated for individual outcrops (Table 1) through the right dihedra method of Angelier and Mechler (1977). The orientations of maximum and minimum principal stress axes, σ1 and σ3 respectively, are plotted on separate paleostress maps (Fig. 6). On these maps, the data of the cover strata for which the relative tilt geometry is known are categorized into pre-, syn- and post-tilt geometries (Fig. 6a, b and c). The data obtained from horizontal cover strata, as well as the data from the basement granite, are plotted as ―not tilted‖ stress axes (Fig. 6d, e and f), and categorized based on consistent kinematics with the pre-, syn- and post-tilt geometries.

14

ACCEPTED MANUSCRIPT Where available, the relative chronology between two stress axes is given based on the kinematic change indicators of the corresponding fault-slip data (Table 1).

T

According to the paleostress maps (Fig. 6), the stress axes of pre- and syn-tilt geometries are

IP

approximately perpendicular to the map-scale NW-SE-striking faults (Fig. 6a and b) and

SC R

most of the stress axes of post-tilt geometry are parallel to these faults (Fig. 6c). These stress axes have comparable orientations to those obtained from horizontal cover strata, as well as

NU

from the basement granite (Fig. 6d, e and f). The paleostress maps indicate a homogeneous distribution of the stress axes and do not characterize a specific stress axis to belong to a

MA

distinct location or lithology. The pre-tilt data (Fig. 6a) mostly include normal and strike-slip faults (Fig. 3a and b). A succession of first NE-SW σ3 then NNE-SSW σ1 is obvious at

D

several sites (Fig. 6d), based on the successive striae on the same fault planes (Fig. 4a and b).

TE

The syn-tilt geometry (Fig. 6b) characterizes a NE-SW orientation for σ1, reconstructed based

CE P

on the bedding-parallel reverse kinematics (Fig. 3c). A succession of first N-S then NE-SW σ1 is observed at several sites (Fig. 6e), based on the successive reactivations on the preexisting normal faults (Fig. 4c, and d). A clockwise change in the orientation of σ1 towards

AC

NE-SW may be inferred. However, the presence of twisted slickolites (Fig. 4d), as well as the successive horizontal stylolites (Fig. 4e), likely suggest a gradual kinematic change in a continuum of events. In the post-tilt geometry, horizontal σ1 and σ3 axes are mostly oriented NW-SE (Fig. 6c). The corresponding fault-slip data include normal and strike-slip faults, respectively, that cut through previously folded strata (Fig. 3d and e). The relative chronology between these two horizontal stress axes could not be constrained. However, successive striae (Fig. 4f, g and h) suggest that they should postdate the NE-SW-trending σ1 axis (Fig. 6f).

15

ACCEPTED MANUSCRIPT 4

States of paleostress

For accurate computation of the states of paleostress that might belong to distinct tectonic

T

events, we adopted the direct stress tensor inversion method of Angelier (2002), using

IP

Angelier’s Tector 2000 software. Briefly, the stress tensor inversion is based on maximizing

SC R

the sum of slip shear stress components, i.e. shear stress in the direction of actual slip, for the entire dataset. This sum is calculated as a function of four independent variables of the

NU

reduced stress tensor, i.e. three angular parameters for orientation of the principal axes of stress  1   2   3 , as well as the ratio of the principal stress magnitude differences

MA

calculated as    2   3  /  1   3  , giving the orientation and shape of the stress ellipsoid. Hence, to formulate the stress tensor inversion, at least four consistent fault-slip data

D

belonging to the same stress field must be available. For a given dataset, the best fitting stress

TE

tensor is reached by retaining consistent and rejecting inconsistent data through an iterative

CE P

refining process, which minimizes the misfit angle, , between the slip shear stress component and the maximum resolved shear stress on the fault planes (Angelier, 2002).

AC

A synoptic view of the stereoplots of fault-slip data (see supplementary material) points out that the consistent data for individual fault sets at many sites are very few and less than the minimum threshold needed for the inversion. The direct inversion based on the slip shear stress could not be performed for these individual data. Additionally, at many outcrops of the cover rocks, the data are collected from sub-horizontal Middle Triassic strata (Table 1) with no further evidence for separation based on either the relative geometry or the age of affected rock, but the kinematic consistency. This provides a situation similar to the outcrops of Carboniferous – Permian granite with comparable orientations of stress axes (Fig. 6d, e and f). Therefore, we arrived at scaling up the data to be able to proceed with stress tensor 16

ACCEPTED MANUSCRIPT inversion for the following reasons. First, in order to evaluate the states of stress between the cover and basement rocks, the entire study area is regarded as a single measuring site. The

T

fault-slip data of the cover and basement rocks are categorized into separated datasets of

IP

consistent kinematics. Where applicable, a tilt correction was performed to reconstruct the

SC R

initial orientation of data in the cover rocks before scaling up the data. Second, in order to compute regional stress tensors for the uniform brittle deformation distributed throughout the study area, the separated fault-slip data of the cover rocks are combined together into

NU

chronologically consistent subsets. In essence, this approach eliminates the effect of

MA

unsystematic variations of stress axes that may result from local fault block rotations, measurement errors and/or misinterpretations. The reason to this elimination is that

D

unsystematic data would be rejected in the refining process, if they do not satisfy the criteria

4.1

CE P

TE

of a best fitting stress tensor (Angelier, 2002).

Kinematic consistency

AC

Examination of the entire data and separation into consistent kinematics reveals three general best-fitting stress tensors of normal, strike-slip and thrust faulting regimes for the basement and cover rocks, individually (Fig. 7, top box). Details of the computed stress tensors are given in Table 2.

For the basement rocks, the normal faulting regime includes dominant NW-SE-striking dipslip and oblique-slip components. The stress tensor indicates moderate value of ϕ and a horizontal σ3 axis trending N230° (Fig. 7a). The strike-slip faulting regime consists of NWSE- and NE-SW-striking high-angle fault planes with dextral and sinistral components, respectively. These faults yield a stress tensor with moderate value of ϕ and a horizontal σ1 17

ACCEPTED MANUSCRIPT axis trending N183° (Fig. 7b). The thrust faulting regime consists of mostly WNW-ESEstriking low-angle fault planes with dip-slip and oblique-slip components. These faults yield

T

a stress tensor with moderate value of ϕ and a horizontal σ1 axis trending N042° (Fig. 7c).

IP

Unlike the cover rocks, there are no clear geometrical criteria to evaluate the succession of

SC R

events in the basement rocks. However, we know that the thrust faulting postdates the normal faulting, based on our observation of relative chronologies at site 34 (Fig. 5a). Residual faultslip data, which could not fit with the best fitting stress tensors, result in computation of a

NU

stress tensor with horizontal σ1 axis trending N318° and low value of ϕ indicating

MA

permutation of σ2 and σ3 axes (Fig. 7d). The stereoplot of the corresponding data shows that the faults have mostly E-W-striking inclined planes with oblique thrust and strike-slip

D

components.

TE

For the cover rocks, the stereoplots related to the best-fitting stress tensors reveal conjugate-

CE P

like normal, strike-slip and thrust fault patterns. The normal faulting regime consists of dominant NW-SE-striking dip-slip faults. The stress tensor indicates moderate value of ϕ and a horizontal σ3 axis trending N036° (Fig. 7e). The strike-slip faulting regime consists of sub-

AC

vertical NNW-SSE- and ENE-WSW-striking fault planes with dextral and sinistral components, respectively. The stress tensor computed for these faults has a moderate value of ϕ and a horizontal σ1 axis trending N211° (Fig. 7f). The thrust faulting regime has dominant NW-SE-striking low-angle fault planes. These faults yield a stress tensor of moderate ϕ value and horizontal σ1 axis trending N029° (Fig. 7g). Residual fault-slip data, which could not fit with the best fitting stress tensors, result in computation of a stress tensor with horizontal σ1 axis trending N125° and low value of ϕ indicating permutation of σ2 and σ3 axes (Fig. 7h). The stereoplot of the fault-slip data indicates scattered distribution of the slickensides. There

18

ACCEPTED MANUSCRIPT is no obvious systematic pattern for the strike and dip direction of the fault planes and

Chronological consistency

SC R

4.2

IP

T

associated striae. Most of the slickensides indicate strike-slip and oblique thrust kinematics.

Examination of the separated fault-slip data for the cover rocks and scaling up the consistent

NU

geometries and chronologies throughout the study area reveals six major subsets. These subsets include pre-tilt normal and strike-slip faults, dextral reactivation of normal faults,

MA

syn-tilt bedding-parallel reverse faults, and post-tilt normal faults and strike-slip reactivations

D

(Fig. 7, bottom box).

TE

The pre-tilt normal faulting subset indicates NW-SE-striking conjugate-like faults. Inversion of the fault-slip data of this subset yields a stress tensor with moderate value of ϕ and a

CE P

horizontal σ3 axis trending N214° (Fig. 7i). This stress tensor is very close to that of the entire normal faulting regime (Fig. 7e). The pre-tilt strike-slip faults consist of sub-vertical NW-SE-

AC

and NE-SW-striking conjugate-like fault planes with dextral and sinistral components, respectively. The stress tensor computed for this subset has a moderate value of ϕ and a horizontal σ1 axis trending N189° (Fig. 7j). This N-S orientation of σ1 is slightly different to that of the entire strike-slip faults of the cover rocks (Fig. 7f). The dextral reactivation of NW-SE-striking normal faults (Fig. 4a) reconstructs a consistent subset for the study area. Inversion of these fault-slip data yields a stress tensor with low value of ϕ and a horizontal σ1 axis trending N013° (Fig. 7k). This low value of ϕ indicates permutation of σ2 and σ3 axes between vertical and horizontal orientations and suggests an interchange between strike-slip and thrust faulting regimes. The syn-tilt fault-slip data reveal conjugate-like NW-SE-striking thrust faults. Inversion of the fault-slip data of this subset yields a stress tensor with moderate 19

ACCEPTED MANUSCRIPT value of ϕ and a horizontal σ1 axis trending N030° (Fig. 7l). This NE-SW orientation of σ1 is parallel to that of the entire thrust faults of the cover rocks (Fig. 7g) and coherent with the

T

first-order shortening (Fig. 2). The post-tilt normal faulting subset reveals conjugate-like NE-

IP

SW-striking fault planes. This subset yields a stress tensor with moderate value of ϕ and a

SC R

horizontal σ3 axis trending N292° (Fig. 7m). The post-tilt fault reactivations constitute a subset of strike-slip faults. Most of these faults belong to the residual subset of the entire dataset (Fig. 7h) and yield a similar stress tensor with horizontal σ1 axis trending N129° (Fig.

MA

Succession of events

D

4.3

NU

7n).

TE

Based on the relative chronologies obtained from the brittle structures of the cover rocks (Fig.

CE P

3 and Fig. 4), we used a chronological matrix analysis to establish and illustrate the best possible succession of events (Fig. 8). Briefly, each cell of the matrix denotes a binary chronology between the first and second event for the corresponding row and column,

AC

respectively. The best solution could be reached when the numbers of binary chronologies accumulate in the compatible area at the upper right half of the matrix, through manual consecutive permutation of the events (Angelier, 1991). One advantage of this matrix analysis is that inconsistent binary chronologies will be filtered out in the incompatible area, statistically. Therefore, any misinterpretations of relative tilt geometry and/or random kinematic changes that may result from differential fault block rotations do not vitiate the prevailing succession. The matrix solution presented here is obtained based on 48 individual binary chronologies between the fault-slip data, as well as between the fault planes and the folded strata, identified at 33 sites and includes 5 incompatible binary chronologies. The 20

ACCEPTED MANUSCRIPT succession of events refers to the stress tensors reconstructed based on the chronologically consistent datasets of the cover rocks (Fig. 7i-n). It starts with the NE-SW extension then

T

changes to the N-S and NE-SW contractions and follows by the NW-SE extension and NW-

IP

SE contraction. The incompatible chronologies of the solution possibly arose from our choice

SC R

to plot the folding event separated from the N-S and NE-SW contractions in the matrix. The solution also shows that the succession of the NW-SE extension and NW-SE contraction is not constrained because of a lack of binary chronology between the corresponding fault-slip

MA

Discussion

D

5

NU

data.

TE

The relative chronology of events found in our study area can now be compared to the

CE P

tectonic history deduced from isotopic ages, and to the earlier paleostress studies from surrounding regions. We also discuss the relationships between the stress fields found in the

style.

5.1

AC

cover and basement rocks and the implications for mechanical stratigraphy and structural

Relative versus absolute chronology

The oldest brittle deformation recorded by the fault-slip data is the normal faulting regime with a NE-SW-trending σ3 axis that was in vigor after deposition and before folding of the Triassic strata (Fig. 7i). The normal faults are tilted wherever the strata are folded (Fig. 3a). We could not find any convincing outcrop-scale evidence for a possible Triassic syn-tectonic deposition associated with this brittle deformation. A lower age limit of extension for some 21

ACCEPTED MANUSCRIPT fault zones of the study area is given by normal faults affecting Lower Jurassic strata (Ernst, 1989). In one locality, an upper age limit is indicated by Upper Cretaceous (Cenomanian)

T

strata sealing normal faults (Tröger and Schubert, 1993). A Late Jurassic – Early Cretaceous

IP

age is well established for the main phase of extension in the NW-SE-trending Lower Saxony

SC R

Basin (Betz et al., 1987; Kockel, 2002), about 200 km northwest of our study area (Fig. 1b). Extensional regimes in the Harz Mountains are attributed to Late Triassic – Early Jurassic and Early Cretaceous at about 226-180 and 125-90 Ma, respectively (Franzke et al., 2007),

NU

based on K-Ar and Rb-Sr isotopic ages of authigenic hydrothermal vein and fault gouge

MA

mineralization (Franzke et al., 1996; Haack and Lauterjung, 1993; Hagedorn and Lippolt, 1993; Schneider et al., 2003). Taken together, these data suggest that the oldest extension

D

event we observe is bracketed between the (Late Triassic to) Early Jurassic and Early

TE

Cretaceous.

CE P

The next states of stress revealed by fault-slip data are the strike-slip and thrust faulting regimes (Fig. 7j and l, respectively). The strike-slip event occurred before the folding event with a N-S-trending σ1 axis (Fig. 3b) and reactivated the pre-existing NW-SE-striking normal

AC

faults with dextral components (Fig. 4a and Fig. 7k). Zulauf (1992, 1993) reconstructed a NS-trending σ1 axis at the western border of the Bohemian Massif to be of Early Cretaceous age, based on K-Ar dating of fault gouge. The state of stress then switched to the thrust faulting regime evidenced by kinematic change from dextral to reverse on the NW-SEstriking normal faults (Fig. 4b and d) and by bedding-parallel flexural slip (Fig. 3c). This change was associated with clockwise rotation of the σ1 axis to the NE-SW orientation during the folding event (Fig. 4e). Stratigraphic data constrain a Coniacian – Paleocene age for the tectonic inversion across the Lower Saxony and Subhercynian Cretaceous basins (Betz et al., 1987; Otto, 2003; Voigt et al., 2004; Voigt et al., 2006; von Eynatten et al., 2008). According 22

ACCEPTED MANUSCRIPT to fission track analyses (Danišík et al., 2010; Thomson et al., 1997; Thomson and Zeh, 2000; Vamvaka et al., 2014), a Late Cretaceous age (ca. 110-70 Ma) can be attributed to

T

exhumation of the basement rocks and, by inference, to inversion resulting from the NE-SW

IP

contraction (Franzke et al., 2007; Kley and Voigt, 2008).

SC R

The two younger states of stress that appear in post-fold geometry (Fig. 3d and e) are associated with reactivation of the earlier fracture patterns. A normal faulting regime with

NU

NW-SE-trending σ3 axis (Fig. 7m) is possibly characterized by reactivation of pre-existing tilted strike-slip faults (Fig. 4g). An oblique thrust faulting regime with NW-SE-trending σ1

MA

axis (Fig. 7n) is documented by strike-slip reactivation of pre-existing fault planes (Fig. 4f and h). Considering the Coniacian – Paleocene age for the folding event, these states of stress

D

should represent brittle tectonic events of Cenozoic age. The NW-SE extension is

TE

perpendicular to the general strike of Tertiary basaltic dykes (Fig. 2) that are integral parts of

CE P

the Cenozoic Rift System (Fig. 1b). According to K-Ar and Ar-Ar ages reported from southwest of the Thuringian Forest, the basaltic rocks belong to the Late Oligocene – Early Miocene, ca. 26-10 Ma (Abratis et al., 2007; Lippolt, 1983). NW-SE contraction is reported

AC

to have affected the Late Cretaceous strata (Sippel et al., 2009) to the northwest of our study area and has the same orientation of the maximum horizontal shortening as the present-day stress field (Fig. 1a). This youngest stress field should have been established after emplacement of the basaltic dykes described above. It is possibly coeval with successive basaltic dyke intrusion and syn-sedimentary tectonic activity within the Rhine Graben during the Miocene – Pliocene (Illies, 1975; Rauche and Franzke, 1990; Schumacher, 2002).

23

ACCEPTED MANUSCRIPT 5.2

Local versus regional paleostress

The NE-SW extension affecting the Triassic strata of Thuringia is regionally reported from

T

surrounding areas such as the northern border of the Harz Mountains, southwest of the

IP

Thuringian Forest and the western border of the Bohemian Massif (Fig. 9a) (Franzke et al.,

SC R

2007; Peterek et al., 1997; Rauche and Franzke, 1990). According to our paleostress reconstruction, this event is evidently characterized by the pre-fold normal faulting regime

NU

with moderate value of ϕ and vertical σ1 axis (Fig. 7i). Nevertheless, contrasting deformation and interpretation also exist. For example, Sippel et al. (2009) obtained a local normal

MA

faulting regime with NW-SE-trending σ3 axis and low value of ϕ that has affected only the Middle Triassic rocks along a major zone of deformation at the northern tip of the Leinetal

D

Graben (Fig. 9a). Although the low value of ϕ indicates possible permutation between

TE

horizontal σ2 and σ3 axes, i.e. bidirectional extension here, but the authors did not document

CE P

brittle structures that clearly indicate the NE-SW extension. The Late Cretaceous – Paleocene inversion and folding has been attributed to the NE-SW

AC

contraction, as recorded in fault-slip data from the Harz Mountains, southwest of the Thuringian Forest and the Bohemian Massif (Fig. 9b) (Coubal et al., 2015; Franzke et al., 2007; Peterek et al., 1997; Rauche and Franzke, 1990). This orientation is coherent with orientation of one generation of horizontal tectonic stylolites of presumably Late Cretaceous age (Kley, 2013; Kley and Voigt, 2008; Kurze and Necke, 1979). However, a distinct prefold N-S shortening of strike-slip and oblique thrust faulting was reported from the Lower Rhine Graben and the Osning Thrust bordering the Lower Saxony Basin in the south (Saintot et al., 2013; Vandycke, 2002). This pre-fold strike-slip faulting could not be reconstructed along the major thrust fault of the northern Harz Mountains. Sippel et al. (2009) obtained a general N-S- to NE-SW-trending horizontal σ1 axis for a state of stress with low value of ϕ, 24

ACCEPTED MANUSCRIPT denoting permutation of σ2 and σ3 axes along the Elbe Fault Zone (Fig. 9b). Our observations suggest reorientation of σ1 axis from N-S to NE-SW through a change from strike-slip to

T

thrust faulting regime (Fig. 7j and l, respectively), possibly in a continuum of events through

IP

an intervening stress state characterized by low value of ϕ (Fig. 7k). We found little evidence

SC R

of post-fold strike-slip faulting indicating NE-SW contraction. This corroborates the observation that the Late Cretaceous – Paleocene inversion occurred in a predominantly thrust faulting regime. A similar reorientation and sequential change in the state of stress is

NU

also reported from the Holy Cross Mountains in the Carpathian foreland of southeastern

MA

Poland (Lamarche et al., 2002). Hence, both the change in stress regime and reorientation of σ1 axis from N-S to NE-SW seem to be of regional scale, either due to clockwise rotation of

D

the far-field stress or readjustment of shortening to an optimum orientation perpendicular to

TE

the strike of pre-existing structures.

CE P

The stress fields attributed to the Cenozoic Rift System represent horizontal σ3 axes of various orientations (Fig. 9c). Post-inversion normal faulting regimes with N-S-trending σ3 axes are reported from the Osning Thrust of the Lower Saxony Basin and from the Lusatian

AC

Thrust of the Bohemian Massif (Coubal et al., 2015; Saintot et al., 2013). Our fault-slip data indicate a post-fold normal faulting regime with NW-SE-trending σ3 axis (Fig. 7m). This stress axis is close to the σ3 axis of Miocene normal faulting reported from southwest of the Thuringian Forest (Rauche and Franzke, 1990). By contrast, Vandycke (2002) obtained a normal faulting regime with NE-SW-trending σ3 axis along the Lower Rhine Graben, and Sippel et al. (2009) measured an oblique normal faulting regime with low value of ϕ at northern tip of the Leinetal Graben, indicating permutation between NE-SW- and NW-SEtrending σ3 and σ2 axes, respectively. Farther south, fault-slip data along the Upper Rhine Graben indicate a normal faulting regime with an E-W-trending σ3 axis (Bergerat, 1987; 25

ACCEPTED MANUSCRIPT Villemin and Bergerat, 1987). Apart from the relatively stable area of Thuringia, the various orientations of horizontal σ3 axis seem to be consistent with and approximately perpendicular

T

to the local structural trends (Fig. 9c). Nevertheless, Lopes Cardozo and Behrmann (2006)

IP

argue for a transtensional opening of the Upper Rhine Graben under a NW-SE-trending

SC R

horizontal σ1 axis, which is more likely coherent to the present-day states of stress (Fig. 1a and Fig. 9d).

NU

The structural setting of the Rhine Graben within the regional intraplate stress field is already interpreted as passive rifting in response to the build-up of Alpine collision associated with

MA

counterclockwise rotation of the horizontal σ1 axis from NE-SW to NW-SE (Ahorner, 1975; Dèzes et al., 2004; Illies, 1975; Peterek et al., 1997; Rauche and Franzke, 1990). Coubal et al.

D

(2015) reconstructed the stress reorientation in oblique thrust and strike-slip faulting regimes

TE

along the Lusatian Thrust of the Bohemian Massif. Our post-fold NW-SE-trending horizontal

CE P

σ1 axis belongs to a stress tensor with moderate to low value of ϕ (Fig. 7n), indicating a strike-slip to oblique thrust faulting regime (Fig. 9d). This state of stress is consistent with the results of Sippel et al. (2009) from the Lower Saxony Basin. According to in-situ stress

AC

measurements and earthquake focal mechanisms (Grünthal and Stromeyer, 1992; Heidbach et al., 2010), the present-day Central Europe is characterized by a NW-SE-trending horizontal σ1 axis (Fig. 1a), with deformation mainly localized along major fault zones (Ahorner, 1975; Illies, 1975). However, in contrast to our findings in the central German platform, inversion of earthquake fault plane solutions indicate that the state of stress is mainly strike-slip along the Upper Rhine Graben with permutation between σ1 and σ2 axes, i.e. oblique normal faulting, towards the Lower Rhine Graben (Fig. 9d) (Hinzen, 2003; Homuth et al., 2014).

26

ACCEPTED MANUSCRIPT 5.3

Cover versus basement deformation

Surveys on the inherited basement structures in the central German platform reveal two

T

prominent orthogonal NW-SE- and NE-SW-striking fault sets that have been active in

IP

Carboniferous – Permian times (Fielitz, 1992; Matte, 1991; Rieke et al., 2001; Scheck et al.,

SC R

2002; Schröder, 1987; Wilson et al., 2004). Our fault-slip data collected from a small number of granite outcrops in the Thuringian Forest indicate that fault sets parallel to these strikes

NU

have dextral and sinistral strike-slip components, respectively, with the NW-SE-striking fault set indicating additional normal and reverse components on inclined fault planes. We do not

MA

have any age criteria for the fault-slip data. However, correlation of the data between the basement and cover rocks (Fig. 7a-h) indicates similar fault patterns and kinematics. This

D

similarity in brittle deformation implies that the fault patterns of the cover rocks could be

TE

induced by reactivation of pre-existing basement structures under the subsequent stress fields.

CE P

This could be the case where the map-scale NW-SE-striking faults of the basement displace the Zechstein layer and the corresponding fault can be traced up into the cover rocks in the Thuringian Basin (Fig. 2) (Malz, 2014; Malz and Kley, 2012). Seismic profiles across the

AC

Lower Saxony Basin confirm the involvement of pre-Permian basement in both the extension and inversion of the Mesozoic structures (Baldschuhn et al., 2001; Betz et al., 1987).

The structural style observed in the Thuringian Basin differs from that described by Otto (2003) for the Elbe Fault Zone, across which a thick-skinned deformation with vertical basement displacements in the central part changes to a thin-skinned deformation where Zechstein detaches the cover from an unaffected basement farther north. Franzke et al. (2007) argue that the Zechstein evaporites act as a detachment layer and provide mechanical decoupling between the basement and cover rocks north of the Harz Mountains. The change from an exclusively thick-skinned structural style in Thuringia to a mixed thick- and thin27

ACCEPTED MANUSCRIPT skinned style farther north is very likely due to the northward increasing thickness of Zechstein evaporites. Local to regional observations suggest that the presence of salt-related

T

structures strongly depends on distribution of different Zechstein cycles (e.g., Doornenbal

IP

and Stevenson, 2010; Reinhardt, 1993). The first cycle of Zechstein, the Werra cycle, is

SC R

mostly flat-lying and thicker in our study area than to the north, with minor extent of salt structures that retrace the underlying basement structures (Hoppe, 1960). The second cycle of Zechstein, the Stassfurt cycle, which is extremely ductile (Nachsel and Franz, 1983) and

NU

acted as the main decoupling horizon for detached structures in northern central German

MA

platform (Holländer, 2000), roughly dwindles towards south across our study area. Hence, the contradictory results could be partly explained by the differences in mechanical stratigraphy.

D

Nevertheless, we would rather interpret the similar fracture patterns of the basement and

TE

cover in terms of local versus regional aspects of deformation. Whereas the evolution of local

CE P

structures strongly depends on the mechanical stratigraphy, the regional stress fields affect the entire stratigraphy regardless of lithological contrasts (Gunzburger and Magnenet, 2014). Hence, scaling up the consistent fault-slip data of the Triassic cover strata across a wide area

AC

fades out local variations in fracture patterns and results in computation of comparable stress tensors to that of the underlying Carboniferous – Permian basement (Fig. 7). The normal faulting stress tensors of the basement and cover (Fig. 7a and e) have very close orientations of stress axes and values of ϕ (Table 2). The strike-slip faults of the basement (Fig. 7b) yield a stress tensor close to that of the pre-tilt strike-slip faults of the cover (Fig. 7j), indicating a N-S-trending σ1 axis. The thrust faults of the basement and cover provide similar stress tensors with NE-SW-trending σ1 axes (Fig. 7c and g). We interpret that these observations likely reflect the reorientation of σ1 concomitant with the change from strike-slip to reverse kinematics rather than synchronous different shortening directions in the basement and cover 28

ACCEPTED MANUSCRIPT rocks (Hecht et al., 2003). The residual fault-slip data that did not fit with other best fitting stress tensors result in similar stress tensors for both the basement and cover (Fig. 7d and h).

T

In the regional scale, these data characterize fault reactivations under the post-tilt NW-SE-

IP

trending σ1 axis (Fig. 7n). Although the states of stress of the basement could be attributed to

SC R

the Late Variscan crustal deformation (Zulauf, 1993), we assume that the Mesozoic –

Conclusions

MA

6

NU

Cenozoic events may have overprinted the earlier brittle deformation.

In this study, we analyzed the post-Triassic brittle deformation of a relatively stable area of

D

the central German platform to reconstruct the changes in far-field stress through time. In a

TE

non-classical approach, we scaled up the fault-slip data collected throughout the study area

CE P

into large subsets of consistent kinematics and chronology. This approach minimized the role of local fault block rotations and misinterpretations, thus allowing us to deduce regional states of stress. Our results reveal a succession of events whose chronology is constrained by

AC

relative tilt geometries and kinematic change indicators obtained from the Triassic strata. The oldest event recorded represents a normal faulting regime with NE-SW-trending σ3 axis. This event was followed by strike-slip and thrust faulting regimes concomitant with reorientation of σ1 axis from N-S to NE-SW, supposedly during the Late Cretaceous inversion. Two younger events postdate the inversion and involve reactivation of pre-existing fractures by a normal faulting regime with NW-SE-trending σ3 axis and an oblique thrust faulting regime with NW-SE-trending σ1 axis. The succession of events is coherent with the general Mesozoic – Cenozoic tectonic evolution of Central Europe. The fracture patterns of the basement rocks appear to record the same states of stress as the cover strata. This observation 29

ACCEPTED MANUSCRIPT suggests uniform stress transmission throughout the brittle upper crust, despite the presence of rheologically ductile rocks of Zechstein, which have locally acted as detachment layer

T

between the basement and cover. A correlation of the brittle deformation between the

IP

surrounding structural domains confirms that the state of stress is variable and/or overprinted

SC R

by younger events in the vicinity of major zones of deformation. The numerous discrete states of stress reconstructed in some researches along major faults seem unlikely to evidence distinct tectonic events separated in time, unless dating of syn-kinematic fault minerals is

MA

NU

provided.

D

Acknowledgements

TE

This study was accomplished through financial support of the German Research Foundation

CE P

(DFG) under the research grant no. NA1165/2-1 ―Stress Field Evolution in a Plate Interior‖. The fieldwork was partly covered by projects INFLUINS no. 03IS2091 and OPTIRISS no. 2012FE9080, funded by the German Federal Ministry of Education and Research (BMBF)

AC

and by the Thuringian Development Bank (TAB), respectively. We thank TLUG Weimar, especially A. Nestler, and LAGB Sachsen-Anhalt, K. Stedingk, for their kind and prompt support in accessing the visited quarries. J.-F. Groth, D. Turner and T. Knörrich assisted during the fieldwork. Detailed comments by D. Delvaux and an anonymous reviewer, as well as constructive remarks by the editor Ph. Agard, contributed towards improving this manuscript.

30

ACCEPTED MANUSCRIPT References

IP

T

Abratis, M., Mädler, J., Hautmann, S., Leyk, H.-J., Meyer, R., Lippolt, H.J., Viereck-Götte, L., 2007. Two distinct Miocene age ranges of basaltic rocks from the Rhön and Heldburg areas (Germany) based on 40 Ar/39 Ar step heating data. Chem ErdeGeochem 67, 133-150.

SC R

Ahorner, L., 1975. Present-day stress field and seismotectonic block movements along major fault zones in Central Europe. Tectonophysics 29, 233-249. Anderson, E., 1951. The dynamics of faulting: Oliver and Boyd, Ltd. Edinburgh, 206p.

NU

Angelier, J., 1984. Tectonic analysis of fault slip data sets. Journal of Geophysical Research: Solid Earth (1978–2012) 89, 5835-5848. Angelier, J., 1991. Chronological matrix analysis and regional succession of tectonic events. Comptes Rendus de l'Academie des Sciences Serie II 312, 1633-1638.

MA

Angelier, J., 2002. Inversion of earthquake focal mechanisms to obtain the seismotectonic stress IV—a new method free of choice among nodal planes. Geophysical Journal International 150, 588-609.

TE

D

Angelier, J., Bergerat, F., Hao-Tsu, C., Teh-Quei, L., 1990. Tectonic analysis and the evolution of a curved collision belt: the Hsüehshan Range, northern Taiwan. Tectonophysics 183, 77-96.

CE P

Angelier, J., Mechler, P., 1977. Sur une methode graphique de recherche des contraintes principales egalement utilisables en tectonique et en seismologie: la methode des diedres droits. Bulletin de la Société géologique de France, 1309-1318.

AC

Baldschuhn, R., Binot, F., Fleig, S., Kockel, F., 2001. Geotektonischer Atlas von NordwestDeutschland und dem deutschen Nordsee-Sektor. Geologisches Jahrbuch, Reihe A 153, 1-88. Bankwitz, P., Gross, U., Bankwitz, E., 1993. Krustendeformation im Bereich der FinneKyffhäuser-Gera-Jachymov-Zone. Zeitschrift für Geologische Wissenschaften 21, 3-3. Bergerat, F., 1987. Stress fields in the European platform at the time of Africa‐Eurasia collision. Tectonics 6, 99-132. Bergerat, F., Angelier, J., 2000. The South Iceland Seismic Zone: tectonic and sismotectonic analyses revealing the evolution from rifting to transform motion. Journal of Geodynamics 29, 211-231. Betz, D., Führer, F., Greiner, G., Plein, E., 1987. Evolution of the Lower Saxony basin. Tectonophysics 137, 127-170. Beutler, G., Schubert, J., 1987. Facial development of the middle clay Keuper in the Thuringian Basin. Zeitschrift für Geologische Wissenschaften 15, 475-484. 31

ACCEPTED MANUSCRIPT Clausen, O.R., Pedersen, P.K., 1999. Late Triassic structural evolution of the southern margin of the Ringkøbing-Fyn High, Denmark. Marine and Petroleum Geology 16, 653-665.

T

Coubal, M., Málek, J., Adamovič, J., Štěpančíková, P., 2015. Late Cretaceous and Cenozoic dynamics of the Bohemian Massif inferred from the paleostress history of the Lusatian Fault Belt. Journal of Geodynamics 87, 26-49.

SC R

IP

Danišík, M., Migoń, P., Kuhlemann, J., Evans, N.J., Dunkl, I., Frisch, W., 2010. Thermochronological constraints on the long-term erosional history of the Karkonosze Mts., Central Europe. Geomorphology 117, 78-89.

NU

Danišík, M., Štěpančíková, P., Evans, N.J., 2012. Constraining long‐term denudation and faulting history in intraplate regions by multisystem thermochronology: An example of the Sudetic Marginal Fault (Bohemian Massif, central Europe). Tectonics 31. DeMets, C., Gordon, R.G., Argus, D., Stein, S., 1990. Current plate motions. Geophysical journal international 101, 425-478.

MA

Dèzes, P., Schmid, S., Ziegler, P., 2004. Evolution of the European Cenozoic Rift System: interaction of the Alpine and Pyrenean orogens with their foreland lithosphere. Tectonophysics 389, 1-33.

TE

D

Doornenbal, J., Stevenson, A., 2010. Petroleum Geological Atlas of the Southern Permian Basin Area: Houten. Netherlands, European Association of Geoscientists & Engineers.

CE P

Ellenberg, J., 1992. Recent fault tectonics and their relations to the seismicity of East Germany. Tectonophysics 202, 117-121. Ernst, W., 1989. Revision der stratigraphischen Einstufung rätoliassischer Sedimente im Creuzburger Graben bei Eisenach. Wiss Z Univ Greifswald, math-nat 38, 79-84.

AC

Feist-Burkhardt, S., Götz, A.E., Szulc, J., Borkhataria, R., Geluk, M., Haas, J., Hornung, J., Jordan, P., Kempf, O., Michalík, J., 2008. Triassic. The geology of central Europe 2, 749-821. Fielitz, W., 1992. Variscan transpressive inversion in the northwestern central Rhenohercynian belt of western Germany. Journal of structural geology 14, 547-563. Finlay, C., Maus, S., Beggan, C., Bondar, T.N., Chambodut, A., Chernova, T., Chulliat, A., Golovkov, V., Hamilton, B., Hamoudi, M., 2010. International geomagnetic reference field: the eleventh generation. Geophysical Journal International 183, 1216-1230. Franzke, H., Ahrendt, H., Kurz, S., Wemmer, K., 1996. K-Ar Datierungen von Illiten aus Kataklasiten der Floßbergstörung im südöstlichen Thüringer Wald und ihre geologische Interpretation. Zeitschrift für Geologische Wissenschaften 24, 441-456. Franzke, H., Heise, G., Rauche, H., 1986. Analyse der strukturellen Entwicklung der FinneStörung und der Naumburger Mulde. Hall Jahrbuch Geowiss 11, 77-94.

32

ACCEPTED MANUSCRIPT Franzke, H., Müller, R., Voigt, T., Eynatten, H., 2007. Paleo-stress paths in the Harz mountains and surrounding areas (Germany) between the Triassic and the Upper Cretaceous. Zeitschrift für Geologische Wissenschaften, Berlin 35, 141-156.

IP

T

Franzke, H., Rauche, H., 1991. Ablauf der rupturellen Deformationen an der Fränkischen Linie im Bereich des nordwestlichen Thüringer Waldes. KTB Report, BGR Hannover 91, 21-39.

SC R

Gölke, M., Coblentz, D., 1996. Origins of the European regional stress field. Tectonophysics 266, 11-24. Grünthal, G., Stromeyer, D., 1992. The recent crustal stress field in central Europe: trajectories and finite element modeling. J. geophys. Res 97, 11805-11820.

NU

Gudmundsson, A., Bergerat, F., Angelier, J., 1996. Off-rift and rift-zone palaeostresses in Northwest Iceland. Tectonophysics 255, 211-228.

MA

Gunzburger, Y., Magnenet, V., 2014. Stress inversion and basement-cover stress transmission across weak layers in the Paris basin, France. Tectonophysics 617, 44-57.

TE

D

Haack, U., Lauterjung, J., 1993. Rb/Sr dating of hydrothermal overprint in Bad Grund by mixing lines. Formation of hydrothermal vein deposits—a case study on the Pb–Zn, barite and fluorite deposits in the Harz Mountains. Monogr Ser Mineral Deposits 30, 103-114.

CE P

Hagedorn, B., Lippolt, H., 1993. Isotopic age constraints for epigenetic mineralizations in the Harz Mountains (Germany) from K–Ar, 40 Ar/39 Ar and Rb–Sr data of authigenic Kfeldspars. Formation of hydrothermal vein deposits—a case study of the Pb–Zn, barite and fluorite deposits of the Harz Mountains. Monogr Ser Mineral Deposits 30, 87-102.

AC

Handy, M.R., M. Schmid, S., Bousquet, R., Kissling, E., Bernoulli, D., 2010. Reconciling plate-tectonic reconstructions of Alpine Tethys with the geological–geophysical record of spreading and subduction in the Alps. Earth-Science Reviews 102, 121-158. Hecht, C.A., Lempp, C., Scheck, M., 2003. Geomechanical model for the post-Variscan evolution of the Permocarboniferous–Mesozoic basins in Northeast Germany. Tectonophysics 373, 125-139. Heidbach, O., Reinecker, J., Tingay, M., Müller, B., Sperner, B., Fuchs, K., Wenzel, F., 2007. Plate boundary forces are not enough: second‐and third‐order stress patterns highlighted in the World Stress Map database. Tectonics 26. Heidbach, O., Tingay, M., Barth, A., Reinecker, J., Kurfeß, D., Müller, B., 2010. Global crustal stress pattern based on the World Stress Map database release 2008. Tectonophysics 482, 3-15. Hinzen, K.-G., 2003. Stress field in the Northern Rhine area, Central Europe, from earthquake fault plane solutions. Tectonophysics 377, 325-356.

33

ACCEPTED MANUSCRIPT Hippolyte, J.-C., Bergerat, F., Gordon, M.B., Bellier, O., Espurt, N., 2012. Keys and pitfalls in mesoscale fault analysis and paleostress reconstructions, the use of Angelier's methods. Tectonophysics 581, 144-162.

T

Holländer, R., 2000. Vom Salzkeil zur Decke: Struktur und Entwicklungsgang der VoglerHomburgwald-Decke (Südniedersachsen).

SC R

IP

Homuth, B., Rümpker, G., Deckert, H., Kracht, M., 2014. Seismicity of the northern Upper Rhine Graben—Constraints on the present-day stress field from focal mechanisms. Tectonophysics 632, 8-20. Hoppe, W., 1960. Die Kali-und Steinsalzlagerstätten des Zechsteins in der Deutschen Demokratischen Republik. Akademie-Verlag.

NU

Illies, J., 1975. Recent and paleo-intraplate tectonics in stable Europe and the Rhinegraben rift system. Tectonophysics 29, 251-264.

MA

Karnin, W., Idiz, E., Merkel, D., Ruprecht, E., 1996. The Zechstein Stassfurt carbonate hydrocarbon system of the Thuringian Basin, Germany. Petrol Geosci 2, 53-58.

D

Kley, J., 2013. Saxonische Tektonik im 21. Jahrhundert [―Saxonian tectonics‖ in the 21st century]. Zeitschrift der Deutschen Gesellschaft für Geowissenschaften 164, 295-311.

TE

Kley, J., Voigt, T., 2008. Late Cretaceous intraplate thrusting in central Europe: Effect of Africa-Iberia-Europe convergence, not Alpine collision. Geology 36, 839-842.

CE P

Kockel, F., 2002. Rifting processes in NW-Germany and the German North Sea sector. Geologie en Mijnbouw - Netherlands Journal of Geosciences 81, 149-158. Kurze, M., Necke, G., 1979. Horizontalstylolithen als regional-geologische Druckspannungsindizien. Zeitschrift für Geologische Wissenschaften 7, 633-639.

AC

Lamarche, J., Bergerat, F., Lewandowski, M., Mansy, J., Świdrowska, J., Wieczorek, J., 2002. Variscan to Alpine heterogeneous palaeo-stress field above a major Palaeozoic suture in the Carpathian foreland (southeastern Poland). Tectonophysics 357, 55-80. Lamarche, J., Lewandowski, M., Mansy, J.-L., Szulczewski, M., 2003. Partitioning pre-, synand post-Variscan deformation in the Holy Cross Mountains, eastern Variscan foreland. Geological Society, London, Special Publications 208, 159-184. Lippolt, H.J., 1983. Distribution of volcanic activity in space and time, Plateau Uplift. Springer, pp. 112-120. Littke, R., Bayer, U., Gajewski, D., Nelskamp, S., 2008. Dynamics of Complex Intracontinental Basins: The Central European Basin System. Springer Science & Business Media. Lopes Cardozo, G.G., Behrmann, J.H., 2006. Kinematic analysis of the Upper Rhine Graben boundary fault system. Journal of Structural Geology 28, 1028-1039.

34

ACCEPTED MANUSCRIPT Lützner, H., 1988. Sedimentology and Basin Development of Intramontane Rotliegend Basins in Central-Europe. Zeitschrift für Geologische Wissenschaften 16, 845-863.

T

Madritsch, H., 2015. Outcrop-scale fracture systems in the Alpine foreland of central northern Switzerland: kinematics and tectonic context. Swiss Journal of Geosciences 108, 155-181.

SC R

IP

Malz, A., 2014. Inversionsstrukturen und abgescherte Überschiebungssysteme: Strukturinventar und strukturelle Analyse einengender Deformation in Mitteleuropa am Beispiel der Thüringer Mulde und des Schweizer Faltenjura.

NU

Malz, A., Kley, J., 2012. The Finne fault zone (central Germany): structural analysis of a partially inverted extensional fault zone by balanced cross-sections. International Journal of Earth Sciences 101, 2167-2182. Matte, P., 1991. Accretionary history and crustal evolution of the Variscan belt in Western Europe. Tectonophysics 196, 309-337.

MA

McCann, T., 2008. The Geology of Central Europe: Mesozioc and cenozoic. Geological Society of London.

D

Nachsel, G., Franz, E., 1983. Zur Ausbildung der Wippertal-Störungszone im Bereich der Grubenfelder des Kaliwerks "Glückauf" Sondershausen. Z. geol. Wiss. 11, 1005-1021.

CE P

TE

Navabpour, P., 2009. Brittle tectonics and palaeostress reconstructions in the Zagros: passive palaeo-margin and continental collision. PhD Thesis, University of Nice—Sophia Antipolis, France, 333. Navabpour, P., Angelier, J., Barrier, E., 2007. Cenozoic post-collisional brittle tectonic history and stress reorientation in the High Zagros Belt (Iran, Fars Province). Tectonophysics 432, 101-131.

AC

Navabpour, P., Angelier, J., Barrier, E., 2008. Stress state reconstruction of oblique collision and evolution of deformation partitioning in W-Zagros (Iran, Kermanshah). Geophysical Journal International 175, 755-782. Navabpour, P., Angelier, J., Barrier, E., 2010. Mesozoic extensional brittle tectonics of the Arabian passive margin, inverted in the Zagros collision (Iran, interior Fars). Geological Society, London, Special Publications 330, 65-96. Navabpour, P., Angelier, J., Barrier, E., 2011. Brittle tectonic reconstruction of palaeoextension inherited from Mesozoic rifting in West Zagros (Kermanshah, Iran). Journal of the Geological Society 168, 979-994. Navabpour, P., Barrier, E., 2012. Stress states in the Zagros fold-and-thrust belt from passive margin to collisional tectonic setting. Tectonophysics 581, 76-83. Navabpour, P., Barrier, E., McQuillan, H., 2014. Oblique oceanic opening and passive margin irregularity, as inherited in the Zagros fold‐and‐thrust belt. Terra Nova 26, 208-215. 35

ACCEPTED MANUSCRIPT Nocquet, J.-M., Calais, E., 2004. Geodetic measurements of crustal deformation in the Western Mediterranean and Europe. Pure and Applied Geophysics 161, 661-681.

T

Otto, V., 2003. Inversion-related features along the southeastern margin of the North German Basin (Elbe Fault System). Tectonophysics 373, 107-123.

SC R

IP

Peterek, A., Rauche, H., Schröder, B., Franzke, H.-J., Bankwitz, P., Bankwitz, E., 1997. The late-and post-Variscan tectonic evolution of the Western Border fault zone of the Bohemian massif (WBZ). Geologische Rundschau 86, 191-202. Rauche, H., Franzke, H., 1990. Stress field evolution at the northern part of the South German Block on the territory of the GDR. Gerlands Beitr Geophysik 99, 441-461.

NU

Reinhardt, H.-G., 1993. Structure of Northeast Germany: Regional depth and thickness maps of Permian to Tertiary intervals compiled from seismic reflection data, Generation, Accumulation and Production of Europe’s Hydrocarbons III. Springer, pp. 155-165.

MA

Rieke, H., Kossow, D., McCann, T., Krawczyk, C., 2001. Tectono‐sedimentary evolution of the northernmost margin of the NE German Basin between uppermost Carboniferous and Late Permian (Rotliegend). Geological Journal 36, 19-37.

D

Rosenbaum, G., Lister, G.S., Duboz, C., 2002. Relative motions of Africa, Iberia and Europe during Alpine orogeny. Tectonophysics 359, 117-129.

CE P

TE

Saintot, A., Angelier, J., 2002. Tectonic paleostress fields and structural evolution of the NWCaucasus fold-and-thrust belt from Late Cretaceous to Quaternary. Tectonophysics 357, 1-31. Saintot, A., Kozakovski, A., Pascal, C., 2013. Paleostress analysis of the Osning Thrust, Germany, EGU General Assembly Conference Abstracts, p. 13744.

AC

Scheck, M., Bayer, U., Otto, V., Lamarche, J., Banka, D., Pharaoh, T., 2002. The Elbe Fault System in North Central Europe—a basement controlled zone of crustal weakness. Tectonophysics 360, 281-299. Schneider, J., Haack, U., Stedingk, K., 2003. Rb-Sr dating of epithermal vein mineralization stages in the eastern Harz Mountains (Germany) by paleomixing lines. Geochimica et Cosmochimica Acta 67, 1803-1819. Schröder, B., 1987. Inversion tectonics along the western margin of the Bohemian Massif. Tectonophysics 137, 93-100. Schumacher, M.E., 2002. Upper Rhine Graben: role of preexisting structures during rift evolution. Tectonics 21. Sippel, J., Scheck-Wenderoth, M., Reicherter, K., Mazur, S., 2009. Paleostress states at the south-western margin of the Central European Basin System—application of fault-slip analysis to unravel a polyphase deformation pattern. Tectonophysics 470, 129-146. Sissingh, W., 2006. Kinematic sequence stratigraphy of the European Cenozoic Rift System and Alpine Foreland Basin: correlation with Mediterranean and Atlantic plate36

ACCEPTED MANUSCRIPT boundary events. Netherlands Journal of Geosciences/Geologie en Mijnbouw 85, 77129.

T

Stampfli, G.M., Borel, G.D., 2002. A plate tectonic model for the Paleozoic and Mesozoic constrained by dynamic plate boundaries and restored synthetic oceanic isochrons. Earth and Planetary Science Letters 196, 17-33.

SC R

IP

Tesauro, M., Hollenstein, C., Egli, R., Geiger, A., Kahle, H.-G., 2006. Analysis of central western Europe deformation using GPS and seismic data. Journal of Geodynamics 42, 194-209. Thomson, S., Brix, M., Carter, A., 1997. Late Cretaceous denudation of the Harz Massif assessed by apatite fission-track analysis. Schriftenr der Dt Geol Ges 2, 115.

NU

Thomson, S., Zeh, A., 2000. Fission-track thermochronology of the Ruhla Crystalline Complex: New constraints on the post-Variscan thermal evolution of the NW SaxoBohemian Massif. Tectonophysics 324, 17-35.

MA

Toloczyki, M., Trurnit, P., Voges, A., Wittekindt, H., 2006. Geowissenschaftliche Karte der Bundesrepublik Deutschland 1: 1.000.000. Geologie, Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover.

TE

D

Tröger, K.-A., Schubert, J., 1993. Bemerkungen zur Ausbildung und Biostratigraphie des Oberkreide-Profils im nördlichen Teil des Holunger Grabens (Thüringer Becken). Zeitschrift für Geologische Wissenschaften 21, 403-403.

CE P

Ustaszewski, K., Schmid, S.M., 2006. Control of preexisting faults on geometry and kinematics in the northernmost part of the Jura fold‐and‐thrust belt. Tectonics 25.

AC

Vamvaka, A., Siebel, W., Chen, F., Rohrmüller, J., 2014. Apatite fission-track dating and low-temperature history of the Bavarian Forest (southern Bohemian Massif). International Journal of Earth Sciences 103, 103-119. Vandycke, S., 2002. Palaeostress records in Cretaceous formations in NW Europe: extensional and strike–slip events in relationships with Cretaceous–Tertiary inversion tectonics. Tectonophysics 357, 119-136. Villemin, T., Bergerat, F., 1987. Tectonique cassante et paléocontraintes tertiaires de la bordure nord-est du fossé rhénan. Oberrhein. Geol. Abh 14, 63-87. Voigt, T., von Eynatten, H., Franzke, H.-J., 2004. Late Cretaceous unconformities in the Subhercynian Cretaceous Basin (Germany). Acta Geologica Polonica 54, 673-694. Voigt, T., Wiese, F., von Eynatten, H., Franzke, H.-J., Gaupp, R., 2006. Facies evolution of syntectonic Upper Cretaceous deposits in the Subhercynian Cretaceous Basin and adjoining areas (Germany)[Faziesentwicklung syntektonischer Sedimente der Oberkreide im Subherzynen Kreidebecken und benachbarten Gebieten]. Zeitschrift der Deutschen Gesellschaft für Geowissenschaften 157, 203-243. von Bubnoff, S., 1953. Der geotektonische Charakter Thüringens. Abh. Akad. Wiss. Berlin Kl. Math. u. Naturwiss 3, 5-18. 37

ACCEPTED MANUSCRIPT von Eynatten, H., Voigt, T., Meier, A., Franzke, H.-J., Gaupp, R., 2008. Provenance of Cretaceous clastics in the Subhercynian Basin: constraints to exhumation of the Harz Mountains and timing of inversion tectonics in Central Europe. International Journal of Earth Sciences 97, 1315-1330.

IP

T

Wilson, M., Neumann, E.-R., Davies, G.R., Timmerman, M., Heeremans, M., Larsen, B.T., 2004. Permo-Carboniferous magmatism and rifting in Europe: introduction. Geological Society, London, Special Publications 223, 1-10.

SC R

Zeh, A., Brätz, H., 2004. Timing of Upper Carboniferous-Permian horst-basin formation and magmatism in the NW Thuringian Forest, central Germany: a review. Geological Society, London, Special Publications 223, 319-334.

NU

Zeh, A., Cosca, M., Brätz, H., Okrusch, M., Tichomirowa, M., 2000. Simultaneous horstbasin formation and magmatism during Late Variscan transtension: evidence from 40 Ar/39 Ar and 207 Pb/206 Pb geochronology in the Ruhla Crystalline Complex. International Journal of Earth Sciences 89, 52-71.

MA

Ziegler, P., Dèzes, P., 2006. Crustal evolution of western and central Europe. Geological Society, London, Memoirs 32, 43-56.

D

Ziegler, P.A., 1987. Late Cretaceous and Cenozoic Intraplate Compressional Deformations in the Alpine Foreland - a Geodynamic Model. Tectonophysics 137, 389-420.

TE

Ziegler, P.A., 1992. European Cenozoic rift system. Tectonophysics 208, 91-111.

CE P

Ziegler, P.A., Cloetingh, S., van Wees, J.-D., 1995. Dynamics of intra-plate compressional deformation: the Alpine foreland and other examples. Tectonophysics 252, 7-59. Zulauf, G., 1992. Late to post-Variscan deformation phases and palaeostresses in the KTB pilot research well (Bohemian Massif, Germany). Tectonophysics 202, 1-21.

AC

Zulauf, G., 1993. Brittle deformation events at the western border of the Bohemian massif (Germany). Geologische Rundschau 82, 489-504.

38

CE P

TE

D

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

AC

Fig. 1. Location of the study area within the regional tectonic framework. (a) Plate kinematics affecting Western Eurasia. Nubia – Eurasia plate convergence in Eurasia-fixed reference frame after Nocquet and Calais (2004). North America – Eurasia plate divergence after DeMets et al. (1990). SHmax is average orientation of the present-day maximum horizontal shortening for central German platform (after Heidbach et al., 2010; Tesauro et al., 2006). Shaded relief map is based on digital elevation data of USGS-EROS Centre (http://eros.usgs.gov). (b) Main structural elements of Central Europe, simplified after Kley and Voigt (2008) and Dèzes et al. (2004). Abbreviations: CEB, Central European Basin; EFZ, Elbe Fault Zone; FL, Franconian Lineament; HM, Harz Mountains; LG, Leinetal Graben; LRG, Lower Rhine Graben; LSB, Lower Saxony Basin; LT, Lusatian Thrust; OT, Osning Thrust; TF, Thuringian Forest; URG, Upper Rhine Graben.

39

CE P

TE

D

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

AC

Fig. 2. Geological map of the study area in central German platform, simplified after Toloczyki et al. (2006), illustrating distribution of measurement sites for fault-slip data collection. EGS, Eichenberg-Gotha-Saalfeld Fault Zone. Stereoplot indicates lower hemisphere equal area projection of best-fitting great circle (gray girdle) through the poles of bedding planes indicated by solid dots (n, number of data). Convergent black arrows indicate deduced first-order shortening perpendicular to b-axis of local folds. Orientations are given as dip/azimuth in degrees. Details on geographic coordinates, lithology and orientation of strata for the measurement sites, as well as stereoplots of the collected fault-slip data are given as supplementary material in the online repository to this article.

40

AC

CE P

TE

D

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

Fig. 3. Tilt correction for the fault-slip data of cover rocks. (a) Tilted conjugate-like normal faults on a flank of folded strata. (b) Tilted strike-slip fault plane, characterized by striae parallel to the bedding plane. (c) Overturned limb of a local anticline, with marked bedding-parallel flexural slip. (d) Conjugate-like normal faults cutting through previously tilted strata. (e) Sub-vertical strike-slip fault plane cutting through steeply tilted, folded strata. Stereoplots indicate selected fault-slip data of each outcrop and are equal area projection of the lower hemisphere, including magnetic north (marked by small M). Numbers at top left corner of stereoplots refer to locality of measurement site indicated in Fig. 2. Faults are shown by great circles, including striae as solid dots and slip arrows with double arrows referring to relative strike-slip component and single arrows referring to relative motion of the hanging-wall. Dashed great circles are 41

ACCEPTED MANUSCRIPT

AC

CE P

TE

D

MA

NU

SC R

IP

T

bedding planes. Isolated solid and open dots are poles to the bedding and fault planes, respectively. Back tilting is performed by rotation of the fault planes around a horizontal axis parallel to the strike of local bedding plane. Stress axes are determined based on right dihedra method of Angelier and Mechler (1977), and marked as 5-, 4and 3-tined stars for σ1, σ2 and σ3, respectively.

42

AC

CE P

TE

D

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

Fig. 4. Fault kinematic change in the cover rocks. (a) Successive normal and dextral striae evidenced by slickolites overprinting calcite slickenfibers. (b) Successive normal and reverse striae characterized by calcite slickenfibers overprinting slickolites. (c) Successive reverse and sinistral striae indicated by calcite slickenfibers overprinting tectonic groove marks, possibly on a tilted normal fault (shown in gray). (d) Successive striae evidencing kinematic change from dextral to reverse, possibly on a 43

ACCEPTED MANUSCRIPT

AC

CE P

TE

D

MA

NU

SC R

IP

T

pre-existing normal fault (shown in gray). (e) Successive horizontal stylolites indicating clockwise change in the direction of contraction. (f) Successive striae evidencing kinematic change from reverse to dextral on steeply tilted bedding plane. (g) Normal striae on a tilted sinistral fault slickenside. (h) Contrasting dextral and sinistral slickolites on a sub-vertical fault plane. Single white and black arrows on the pictures refer to the 1st and 2nd relative chronologies, respectively, indicated by the corresponding numbers on the stereoplots. Convergent and divergent double arrows refer to direction of contraction and extension, respectively, determined based on right dihedra method of Angelier and Mechler (1977). Other description of stereoplots as in Fig. 3.

44

TE

D

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

AC

CE P

Fig. 5. Fault kinematic changes in the basement rocks. (a) Reverse reactivation of a normal fault evidenced by calcite slickenfibers crystallized on incongruous steps of Riedel shear fractures. Note that, in this case, the white and black arrows respectively refer to the 1st and 2nd chronology of slip of the footwall, as the picture is taken from underside of the hanging-wall. (b) Twisted striae on a sub-vertical fault plane suggest successive increments of dextral strike-slip motion and fault block rotation under the same contraction. The 1st and 2nd chronologies on the stereoplots refer to relative motion of the hanging-wall in both cases. Other descriptions of stereoplots as in Fig. 3 and Fig. 4.

45

AC

CE P

TE

D

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

Fig. 6. Paleostress maps for the study area. Horizontal maximum and minimum principal stress axes, σ1 and σ3, are given based on right dihedra method of Angelier and Mechler (1977). The data for which a relative tilt geometry could be reconstructed 46

ACCEPTED MANUSCRIPT

AC

CE P

TE

D

MA

NU

SC R

IP

T

(Fig. 3) are categorized as pre-, syn- and post-tilt geometries (a, b and c). The data obtained from horizontal strata, as well as the basement granite, are categorized into consistent kinematics with and presented in parallel to the relative tilt geometries as ―not tilted‖ stress axes (d, e and f). Numbers next to the stress axes indicate relative binary chronology based on successive striae of the corresponding fault-slip data (Fig. 4). Details of the stress tensors are given in Table 1. Background geology as in Fig. 2.

47

AC

CE P

TE

D

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

Fig. 7. Stress tensors for consistent fault-slip datasets. The top box indicates stereoplots of the fault-slip data separated from the entire datasets of the basement and cover rocks based on kinematic consistency. The bottom box indicates stereoplots of the fault-slip data of the cover rocks separated based on consistent chronology and kinematics. Stress tensors are computed based on direct inversion method of Angelier (2002) and given as the orientation of σ1, σ2 and σ3 axes, with 60, 75 and 90% confidence ellipses, 48

ACCEPTED MANUSCRIPT

AC

CE P

TE

D

MA

NU

SC R

IP

T

azimuthal confidences in gray curves and the ratio of stress magnitude differences ϕ. Other descriptions of stereoplots as in Fig. 3 and Fig. 4. Details of the stress tensors are given in Table 2.

49

D

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

AC

CE P

TE

Fig. 8. Chronological matrix analysis of events, based on Angelier (1991). Rows and columns refer to the first and second binary chronology, respectively. Numbers are counts of each binary chronology observed throughout the study area. Compatible area characterizes the binary chronologies that are consistent with the given order of the events. Letters refer to the corresponding stress tensors of the cover rocks given in Fig. 7 (i, j, k, l, m, n); ―fl‖ refers to the folding event (Fig. 2). Simplified stereoplots are given for visual appraisal of the events.

50

AC

CE P

TE

D

MA

NU

SC R

IP

T

ACCEPTED MANUSCRIPT

Fig. 9. Post-Triassic stress field evolution in Central Europe. (a) Early Jurassic – Early Cretaceous normal faulting prior to folding of strata. (b) Late Cretaceous – Paleocene strike-slip and thrust faulting before and during inversion of earlier normal faults. (c) Oligocene – Early Miocene normal faulting after folding. (d) Late Miocene – Quaternary stress fields. States of stress and approximate age of events are compiled after: Be, Bergerat (1987); Ra, Rauche and Franzke (1990); Pe, Peterek et al. (1997); Va, Vandycke (2002); Hi, Hinzen (2003); Lo, Lopes Cardozo and Behrmann (2006); Fr, Franzke et al. (2007); Si, Sippel et al. (2009); Sa, Saintot et al. (2013); Ho, Homuth et al. (2014); Co, Coubal et al. (2015); Pr, present study (bold arrows). Background structures as in Fig. 1b. 51

ACCEPTED MANUSCRIPT Table 1. Stress tensors for separated fault-slip data of individual sites. Stress tensors

Long. E

Lithology

Bedding

Fault-slip n

03

50.94192

11.54044

Muschelkalk

Bh

Nr

03

04

51.05900

11.70806

Muschelkalk

Bn 105/22N

Ss

13

Ss

04

Chronology σ1

Pre-tilt 1st

σ2

σ3

ϕ

005/76

184/14

274/00

0.55

195/09

053/79

286/07

0.54

2nd

035/19

206/70

304/03

0.46

10

51.11917

10.01889

Muschelkalk

Bn 139/24E

Ss

SC R

Site Lat. N

T

Geology

IP

Location

05

Pre-tilt

175/01

275/84

085/05

0.50

11

51.11667

10.02167

Muschelkalk

Bn 108/48N

Nr

05

Pre-tilt

011/75

121/05

213/14

0.49

14

51.11389

10.04250

Muschelkalk

Bi 106/80S

Ss

05

Syn-tilt

218/30

101/39

334/37

0.49

15

51.11306

10.05778

Muschelkalk

Bn 115/13S

Ss

05

252/18

038/68

158/11

0.50

16

51.05972

09.98806

Muschelkalk

Bn 119/28S

Nr

02

025/86

128/01

218/04

0.50

Ss

05

187/06

040/83

278/04

0.50

Nr

17

Pre-tilt 1st

121/85

302/05

212/00

0.48

Ss

04

Pre-tilt 2nd

203/02

304/78

112/12

0.50

Iv

03

Syn-tilt

208/05

117/11

323/78

0.50

196/14

051/73

288/09

0.50

05

50.83750

10.91472

Muschelkalk

Bn 030/36E

Ss

08

51.07750

09.95806

Muschelkalk

Bn 130/50S

Iv

09.95111

Muschelkalk

MA

D

51.06389

Bn 121/33S

TE

17

Syn-tilt

222/42

106/26

354/37

0.49

06

Syn-tilt 1st

212/01

122/11

308/79

0.52

298/24

043/31

177/49

0.55

06

2nd

NU

Ss

06

Pre-tilt

51.05667

11.71083

Muschelkalk

Bn 097/16S

Ss

03

21

51.22889

11.30000

Muschelkalk

Bi 117/64N

Ss

02

Pre-tilt

203/07

007/83

113/02

0.50

Iv

09

Syn-tilt 1st

015/12

284/07

164/76

0.50

Iv

02

057/06

324/31

157/59

0.50

Nr

02

091/82

297/07

207/03

0.50

Ss

07

1st

019/04

278/69

111/20

0.51

Iv

09

2nd

212/03

302/06

093/83

0.48

Ss

07

1st

203/03

300/65

112/25

0.58

Iv

04

2nd

218/05

308/05

081/83

0.50

215/22

359/64

119/14

0.49

026/57

173/29

272/15

0.51

23

51.01553

51.10911

AC

22

CE P

19

11.70011

11.70514

Muschelkalk

Muschelkalk

Bh

Bh

2nd

24

51.11128

11.71308

Muschelkalk

Bh

Ss

03

26

51.11194

09.86000

Muschelkalk

Bn 012/54E

Nr

03

Iv

21

035/05

302/33

134/57

0.58

012/76

129/07

221/13

0.50

Post-tilt

27

51.06111

10.00056

Muschelkalk

Bh

Nr

02

29

50.57194

10.51861

Muschelkalk

Bn 104/32S

Iv

08

Syn-tilt

023/29

119/11

229/58

0.50

31

50.45556

10.44806

Muschelkalk

Bn 117/22S

Ss

17

Pre-tilt 1st

018/02

115/79

287/11

0.50

Iv

05

Syn-tilt

226/03

135/08

338/82

0.50

52

ACCEPTED MANUSCRIPT

33

50.67139

50.62707

10.66306

10.71105

Lithology

Granite

Granite

Bedding

-

-

Fault-slip n

Chronology σ1

σ2

σ3

ϕ

Nr

03

Post-tilt 2nd

140/65

039/05

306/24

0.50

Ss

07

168/16

284/56

069/29

0.49

Iv

03

045/25

139/09

248/63

0.51

Ss

10

160/13

292/72

067/13

0.51

Nr

05

325/08

056/07

0.47

06

326/79

135/11

225/02

0.48

05

316/01

053/80

226/10

0.54

06

221/04

128/33

318/57

0.50

186/79

Ss

10

230/02

338/82

140/07

0.50

Iv

18

221/03

311/04

097/85

0.54

Nr

03

213/82

015/08

105/02

0.49

Nr

12

064/81

324/02

234/09

0.50

Ss

10

195/11

344/77

103/06

0.52

02

285/03

020/58

193/32

0.54

215/02

102/84

305/05

0.51

261/84

125/04

034/04

0.46

130/04

229/65

038/25

0.49

34

50.63037

10.71425

Granite

-

Nr

35

50.52792

10.67708

Granite

-

Ss

10.69840

Muschelkalk

Granite

Bh

-

MA

50.63215

10.45083

50.62028

10.43582

Muschelkalk

Bh

Ss

32

40

50.92972

10.73694

Muschelkalk

Bn 124/39N

Nr

08

Ss

08

Nr

10

Post-tilt

258/86

016/02

106/04

0.49

Iv

08

Syn-tilt

251/00

341/29

160/61

0.53

Ss

02

Post-tilt

121/10

013/60

217/27

0.50

Iv

04

032/23

302/00

211/67

0.49

Nr

07

130/84

303/06

033/01

0.51

Ss

06

040/03

267/85

129/03

0.50

Ss

04

331/05

208/80

062/08

0.50

174/04

287/79

084/10

0.50

50.79278

CE P

43

50.77000

10.77083

10.88472

AC

42

TE

Ss

39

D

37

50.58722

NU

Iv 36

T

32

Long. E

Stress tensors

IP

Site Lat. N

Geology

SC R

Location

Muschelkalk

Muschelkalk

Bn 139/67E

Bh

Pre-tilt 1st 2nd

44

50.49640

10.60185

Muschelkalk

Bh

Ss

03

46

50.55236

10.63193

Muschelkalk

Bf

Iv

07

Syn-tilt

242/05

152/01

051/85

0.45

47

50.55360

10.63305

Muschelkalk

Bf

Iv

15

Syn-tilt

208/04

117/19

309/71

0.53

48

50.66833

10.68452

Granite

-

Iv

06

034/23

300/10

187/64

0.52

Nr

03

089/60

334/14

237/26

0.50

001/04

222/84

091/04

0.49

50

50.64338

10.69451

Granite

-

Ss

04

52

51.18092

10.34109

Muschelkalk

Bh

Nr

04

1st

053/82

297/03

206/07

0.49

Iv

07

2nd

201/05

110/09

322/80

0.51

53

ACCEPTED MANUSCRIPT

51.34485

10.49187

Lithology

Muschelkalk

Bedding

Bh

Fault-slip n

230/73

128/04

0.48

Ss

02

126/11

279/78

035/05

0.49

Iv

09

1st

188/00

098/39

278/51

0.50

Ss

04

040/01

302/81

130/09

0.50

04

129/06

281/84

0.49

188/03

278/03

058/86

0.43

Muschelkalk

Bh

Iv

57

51.06704

10.27026

Muschelkalk

Bn 148/14E

Iv

58

50.91328

11.21780

Muschelkalk

Bh

Nr

Nr

05

Pre-tilt

063/87

268/02

178/01

0.52

Iv

04

Pre-tilt

001/11

093/10

224/75

0.50

03

Syn-tilt

209/12

300/07

056/75

0.50

03

50.31306

10.51856

Muschelkalk

Bh

1st

141/75

307/15

038/03

0.50

05

2nd

012/08

279/16

128/72

0.49

Nr

04

1st

192/75

291/02

021/15

0.50

Iv

12

2nd

003/04

272/05

134/84

0.49

07

217/03

353/86

127/03

0.49

51.49552

10.38614

Muschelkalk

Bn 018/29E

Ss

07

221/19

056/71

313/05

0.49

62

50.51756

10.68438

Rhyolite

-

Iv

02

038/07

308/01

212/82

0.49

Ss

03

215/09

316/53

118/36

0.50

Nr

03

101/43

279/47

010/01

0.57

Iv

06

170/15

079/02

341/75

0.50

Nr

05

340/83

091/03

182/07

0.51

Ss

18

024/05

283/64

116/26

0.46

Iv

05

206/09

296/04

048/80

0.49

Ss

03

211/05

013/84

121/02

0.50

Ss

03

272/03

026/82

182/07

0.50

213/18

119/11

359/69

0.50

66

51.12507

51.09367

CE P

65

50.64378

11.48074

11.70657

AC

63

TE

Ss

61

D

60

MA

Iv

02

NU

Bn 134/43N

2nd

039/03

Iv Muschelkalk

ϕ

037/16

10.31443

11.10458

σ3

07

51.20324

50.74185

σ2

Ss

55

59

Chronology σ1

T

53

Long. E

Stress tensors

IP

Site Lat. N

Geology

SC R

Location

11.64241

Zechstein

Muschelkalk

Muschelkalk

Bh

Bn 112/12S

Bn 112/20S

71

51.12100

11.55956

Muschelkalk

Bn 117/80S

Iv

02

72

51.20839

11.67153

Muschelkalk

Bn 072/12S

Ss

02

114/02

013/80

204/10

0.50

73

51.19906

11.59680

Muschelkalk

Bn 172/15E

Ss

06

210/05

011/85

120/02

0.50

74

50.99357

11.82502

Muschelkalk

Bh

Ss

14

014/02

278/70

105/19

0.53

Iv

03

238/04

328/02

080/86

0.47

Ss

03

1st

015/01

274/82

105/08

0.50

Ss

05

2nd

118/07

309/83

208/01

0.50

Ss

07

185/02

082/84

275/06

0.50

75

76

50.93801

50.95144

12.03288

11.97187

Zechstein

Bh

Buntsandstein Bf

Post-tilt

Pre-tilt

54

ACCEPTED MANUSCRIPT Location

Geology

Stress tensors

Long. E

Lithology

Bedding

Fault-slip n

Chronology σ1

σ2

σ3

ϕ

77

10.63671

Muschelkalk

Bn 137/20S

Nr

08

Pre-tilt 1st

287/81

154/06

063/07

0.51

Ss

03

2nd

172/10

072/43

273/45

0.50

Ss

10

1st

017/18

253/60

115/23

0.52

Iv

12

210/02

308/77

0.52

04

292/06

063/80

0.50

51.35243

10.57243

Muschelkalk

Bh

Iv

81

51.24872

10.23531

Muschelkalk

Bh

Nr

IP

78

120/13

05

1st

098/88

312/02

222/01

0.50

02

2nd

036/13

129/14

265/70

0.50

136/01

266/89

046/01

0.45

Syn-tilt 2nd

201/07

82

51.15563

10.28585

Muschelkalk

Bf

Ss

SC R

51.40684

T

Site Lat. N

85

50.70506

11.23834

Muschelkalk

Bh

Ss

04

027/01

133/84

297/05

0.50

87

50.79847

11.30925

Muschelkalk

Bh

Nr

08

073/80

328/02

238/09

0.50

Iv

02

222/02

312/05

108/84

0.48

Iv

03

208/12

298/00

029/78

0.50

Iv

03

186/10

089/30

293/58

0.50

02

Post-tilt

MA

NU

Iv

50.83196

11.22312

Muschelkalk

Bh

89

50.82264

11.46522

Muschelkalk

Bh

90

50.79982

11.60964

Muschelkalk

Bh

Ss

02

109/02

224/85

019/05

0.50

91

50.80273

11.60465

Muschelkalk

Bh

Nr

08

223/78

131/00

041/12

0.50

Iv

03

208/03

299/02

064/87

0.50

Bn 138/55W Iv

15

223/13

315/07

074/75

0.49

Nr

11

1st

126/81

295/09

025/02

0.50

Ss

04

2nd

007/11

266/44

107/44

0.49

Nr

04

099/62

290/28

198/05

0.50

Iv

07

214/09

305/04

057/80

0.50

50.88012

TE

11.51573

Muschelkalk

CE P

93

50.89175

11.53530

AC

92

D

88

Muschelkalk

Bh

Syn-tilt

Bedding is given as strike/dip: Bh, horizontal; Bn, tilted; Bf, folded; Bi, overturned. Fault-slip: Nr, normal; Iv, reverse; Ss, strikeslip. n, number of fault-slip data. Orientation of stress axes (σ1≥σ2≥σ3) is given as azimuth/plunge in degrees. ϕ, ratio of stress magnitude differences defined as ϕ=(σ2−σ3)/(σ1−σ3).

55

ACCEPTED MANUSCRIPT

n

σ1

σ2

σ3

ϕ

α

a

30

018/77

139/07

230/11

0.35

26±24

b

46

183/18

326/68

089/12

0.44

T

Table 2. Stress tensors for consistent fault-slip datasets.

c

22

042/12

133/06

250/77

0.36

d

12

318/03

215/74

049/15

0.13

e

138

126/85

306/05

036/00

0.38

16±13

f

251

211/04

348/85

121/04

0.48

12±13

g

261

029/03

299/01

194/87

0.49

17±16

h

69

125/01

221/77

035/13

0.20

24±24

i

115

117/85

304/05

214/01

0.48

15±11

j

61

189/05

023/85

279/01

0.49

09±09

k

30

013/04

281/26

112/63

0.18

23±17

l

163

030/01

300/00

209/89

0.53

13±10

m

23

158/76

024/10

292/10

0.47

16±10

n

47

233/85

038/05

0.34

23±24

Basement

MA

D

TE 129/01

NU

Cover Fig. 7

IP

23±14

SC R

Fig. 7

21±12 34±17

AC

CE P

n, number of fault-slip data. Orientation of stress axes (σ1≥σ2≥σ3) is given as azimuth/plunge in degree. ϕ, ratio of stress magnitude differences defined as ϕ=(σ2−σ3)/(σ1−σ3). α, average misfit angle between actual slip and maximum resolved shear stress in degrees (acceptable for α<25°).

56

ACCEPTED MANUSCRIPT Highlights

Fault kinematic changes are documented for the central German platform.



Structural binary chronologies unravel the succession of tectonic events.



Analysis of the entire fault-slip dataset reconstructs regional states of stress.



The basement rocks and cover strata indicate the same states of stress.

CE P

TE

D

MA

NU

SC R

IP

T



AC

7

57