Quartz cementation and related sedimentary architecture of the Triassic Solling Formation, Reinhardswald Basin, Germany

Sedimentary Geology 175 (2005) 459 – 477 www.elsevier.com/locate/sedgeo

Research paper

Quartz cementation and related sedimentary architecture of the Triassic Solling Formation, Reinhardswald Basin, Germany Jutta Webera,T, Werner Rickenb a European and Global Geopark, Bergstrasse-Odenwald, Nibelungen Str. 41, D-64653 Lorsch, Germany Department of Geology and Mineralogy, University of Cologne, Zuelpicher Str. 49, D-50674 Cologne, Germany

b

Received 30 March 2004; received in revised form 8 December 2004; accepted 8 December 2004

Abstract The Olenekian Solling Formation of the Reinhardswald Basin was studied with the aim to examine the dependency of the degree of silica diagenesis on the sedimentary architecture. The Solling Formation is composed of stacked sandstone/clay– siltstone cycles deposited by braided (i.e., subarkoses) and meandering (i.e., subarkosic wackes) river systems. The sanddominated braided rivers of the Lower Solling Formation are characterized by channels and downstream accretion, whereas mixed load meandering rivers of the Upper Solling Formation are represented by lateral accretion and laminated sands. Diagenetic processes which modified the sandstone–siltstone successions include compaction, feldspar alteration, and cementation. Sandy, clay-poor successions are highly quartz cemented (i.e., silica importers), whereas clay- and mica-rich successions are more compacted (i.e., silica balanced or silica exporters). Three quartz cement generations with a total volume of up to 18% indicate that silica from several different sources cemented the sandy fluvial architectural elements of the Lower Solling Formation. Cementation includes silica supply from internal and external to the sandstone layers, which are silica from grain margin dissolution, from feldspar alteration, silica released from clay–siltstones and silica precipitated from basinal brines. This cementation history is supported by cathodoluminescence observations and fluid inclusion studies, and a consistent burial history was successfully modeled by simulation of the thermal subsidence. In contrast to the Lower Solling Formation, the fluvial architectural elements of the mixed load systems of the Upper Solling Formation contain only one quartz cementation phase with a total volume up to 8%. The Reinhardswald Basin shows a dependency of the fluvial architecture and the diagenetic features. For that we define the term bdiagenetic architectureQ. D 2005 Elsevier B.V. All rights reserved. Keywords: Sandstone fluvial architecture; Diagenetic architecture; Quartz cementation; Silica sources and importers; Burial history

1. Introduction T Corresponding author. Tel.: +49 6254 943835; fax: +49 6254 943848. E-mail address: [email protected] (J. Weber). 0037-0738/$ - see front matter D 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.sedgeo.2004.12.019

Ancient lithified clastic sediments are the result of numerous diagenetic processes. Initial textures, compositions and volumes are modified by compac-

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tion, dissolution and transformation of detrital phases. Transformed and dissolved phases are often reprecipitated as authigenic phases (Barnes et al., 1992; Dutton, 1993; Gaupp et al., 1993; Bjbrlykke, 1994; Oelkers et al., 1996; Marfil et al., 2000; Chuhan et al., 2001). The interrelationship between diagenesis, the depositional system and basin fill facies, however, has been addressed in a more limited number of studies (Burley and McQuaker, 1992; Cord, 1995; Lynch, 1996). The emphasis of our investigation was the relationship between silica diagenesis and the distribution of depositional systems on a basin-wide scale. In order to reach this goal one 3rd-order cycle of a siliciclastic basin fill that is composed of stacked fluvial sandstone cycles was analyzed. The investigated sequence belongs to the Solling Formation and is part of the Triassic Middle Buntsandstein, a well-known sandstone interval of the German Basin. The German Basin comprises several smaller subbasins, including the Reinhardswald Basin, where the Solling Formation is well exposed. Here the diagenetic processes that modify initial textures, compositions, and volumes by mechanical and chemical compaction, and the cementation of the lithified sandstone layers are described. The following specific issues are addressed in this paper: (i) The depositional architecture of braided versus meandering rivers and their related diagenetic history; (ii) the estimated degree of silica transfer between sandstone layers; (iii) the diagenetic architecture in the Reinhardswald Basin; and finally (iv) the burial history and fluid evolution of the Solling Formation. A close relationship between the different fluvial architectural elements is observed in the Solling Formation of the Reinhardswald Basin. We define the word bdiagenetic architectureQ to show a predictive relationship between the fluvial lithologic variation and the diagenetic overprint. During diagenesis the depositional architecture in the basin is sensitively translated into the degree and type of silica transfer.

Section 5.5. does refer to the term diagenetic architecture.

2. Geological setting The Solling Formation belongs to the Buntsandstein, the lowermost part of the classical Germanic Triassic. The Olenekian Buntsandstein is dominated by epicontinental clastic sequences of fluvial, aeolian and evaporite to lacustrine origin (Wycisk, 1984; Bindig, 1991; Aigner and Bachmann, 1992; Lepper and Ro¨hling, 1998). Sediment transport under generally semi-arid climate conditions was perennial, suggesting rare events of heavy rain periods in the crystalline source areas to the south. The clastic sediments were transported into a major playa system located in the northern part of the German Basin (Bindig, 1991). The Reinhardswald Basin, a smaller subbasin of the entire Mid European Basin (Fig. 1a), is located between the source area in the south and the northern playa facies. It is 50 km in diameter and has a length of 100 km. The Solling Formation in the Reinhardswald Basin is characterized by massive sandstone layers and covers one interval of the Upper Olenekian. As one of the most characteristic formations of the Middle Buntsandstein (Fig. 1b), the Solling Formation represents one 3rd-order filling cycle of the Reinhardswald Basin (Wright and Marriot, 1993). Paleocurrent measurements of cross bedded units indicate a dominantly south to north transport along the former basin axis (Fig. 2). During deposition of the Solling Formation, the fluvial environment changed from braided to meandering river systems (Bindig, 1991). Changing deposition style may be governed by climatic and tectonic influences, which indicate a rise in base level (Wright and Marriot, 1993; Weber, 2000). In the depocenter of the Reinhardswald Basin, the Solling Formation reaches a maximum thickness of 120 m, whereas in paleohigh positions (i.e., the Eichsfeld Altmark Swell), condensed thicknesses of 10–30 m are observed (Fig. 2). From Triassic to Jurassic times the Reinhardswald Basin was subjected to about 2 km of subsidence. Later, during the Cretaceous, the rate of subsidence decreased and the basin fill was

J. Weber, W. Ricken / Sedimentary Geology 175 (2005) 459–477

a

461

Fenno Scandia OSLO

EDINBURGH COPENHAGEN

Anglia WARSAW BERLIN LONDON

AMSTERDAM study area

Bohemia PARIS MUNICH

Armorica

Te t h y s 0

Mid basin, fine-grained

Basin margin, coarse-grained

251

PERMIAN

Subgroup

Formation

Upper Bundsandst.

Muschelkalk Roet Formation

Solling Formation

Middle Buntsandstein

Buntsandstein

Induan

TRIASSIC

241

Olenekian

Anisian

Stage Group

Hardegsen Formation

Seq.Strat.

1 5 4

3

Detfurth Formation Volpriehausen

Formation

Lower Buntsandst.

b

100 200 300km

Bernburg Formation

2

1

Calvoede Formation

Fig. 1. German Basin stratigraphy. (a) Olenekian German Basin paleogeography with study area after Ziegler (1990). (b) Stratigraphy and sequences of the Lower German Triassic, modified from Aigner and Bachmann (1992).

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HE

Germany

Bodenwerder

EC

NB3 WÜ2 WÜ1

FB

KH

BB SH

SP

LL AM

HC

20

120

80

100

40

60

NP

Kassel

EAS Cologne

REINHARDSWALD BASIN (RB)

RB

rf sfS

Marburg

Rhenish Massif

North part of the RB

20

HE

Frankfurt

NB3

KH

EC

50 km SP FB SH BB LL WÜ2 WÜ1 HC KH AM NP NB3 EC HE

= Spindler quarry = Frohrieper Berg quarry = Sohnreyhöhe quarry = Blockholzer Berg quarry = Lug ins Land quarry = Willeke quarry = Würgassen quarry = Hannoverian cliffs = Niemeyer quarry = Amelith quarry = Nienover-Polier quarry = Negenborntal quarry = Eckberg quarry = Helmer quarry

SH

WÜ2

SP

FB

LL

BB NP WÜ1

AM

HC

Fig. 2. Isopach map of the Solling Formation. RB, Reinhardswald Basin; EAS, Eichsfeld Altmark Swell. Stratigraphic column of the Solling Formation in the basin center with location of investigated exposures. sfS, Stammen Beds; rf, Roet Formation. Isopaches after Bindig (1991).

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uplifted during the Upper Cretaceous and Lower Tertiary. Diapirism of underlying Zechstein salt modified the subsidence history (Lepper, 1976) and influenced the present anticlinal structure of the Reinhardswald Basin.

463

ification of the methods of Houseknecht (1984, 1987, 1991). One-dimensional thermal modeling was done using the program PetroMod (IES, Aachen). Fluid inclusion homogenization temperatures were measured with a Reynolds modified USGS gas flow at the Department of Fysico-Chemische Geologie, Leuven, Belgium.

3. Materials and methods The sedimentology of 14 outcrops representing both braided and meandering river systems was investigated. These outcrops include all important stratigraphic levels of the Solling Formation and are distributed over 2500 km2, forming a nearly threedimensional network of exposures (Fig. 2). They were investigated on the basis of high-resolution photomosaics using the fluvial architectural element method of Miall (1985, 1996). Third-, fourth- and fifth-order bounding surfaces were used to characterize genetically different sediment units and sequence boundaries. A total of 66 drill core samples were taken from selected outcrops with well-defined architectural elements in order to characterize the petrography and diagenesis of the sandy architectural elements. Standard petrographic and cathodoluminescence (CL) analyses of thin sections utilised an HC2-LM hot CL-microscope as described by Neuser (1997), with a beam acceleration voltage of 14 kV, and cathode current of 15 AA mm 2. The quantification of detrital and authigenic phases is based on point counting under transmitted light, crossed polar light and cathodoluminescence (Marshall, 1988; Ramseyer et al., 1988) microscopy with a total of 2580 points per thin section (i.e., 6 photographs, each with 425 points counted on average). Additionally, the grain size, grain interrelationship, and clay morphology was investigated by image analysis using VIDAS 25 (Zeiss) and a scanning electron microscope (SEM). Highly polished thin sections were prepared from oriented drill core samples from the sandy fluvial architectural elements CH, DA, LA and LS in order to investigate the sediment petrography. Only welllithified sandstones and the small transition zones to silt–claystones (FF) were investigated by thin section analysis, because most of the silt–claystone beds (FF) were too fine grained to be sampled and prepared. Silica diagenesis was investigated by using a mod-

4. Observations and results 4.1. Stratigraphic setting and depositional architecture The major stratigraphic pattern of the 3rd-order cycle of the Solling Formation in the Reinhardswald Basin is characterized by fining-upward succession (Fig. 2). The base of the Solling Formation is generally erosive to the underlying Hardegsen Formation and pass into the Stammen Beds, a floodplain-dominated system. The Solling Formation is unconformably overlain by the Roet Formation, which is the uppermost unit of the Buntsandstein. The lithological trend of the sequence is interpreted as an effect of base level rise. During deposition of the Lower Solling Formation, sandy braided rivers dominated the succession (Olsen, 1988; Bindig, 1991; Weber, 2000; Fig. 3). In the central basin, braided river deposits reach a maximum thickness of about 75 m (i.e., Wilhelmshausen and Trendelburg beds). The major fluvial architectural element consists of sandy channel fill (CH) cycles of different hierarchies. These contain stacked sets of sandstone cycles, with channel deposits at the base followed by downstream accretion (DA). The top of the cycles consists of laminated sands (LS) with intercalated clay–siltstones of floodplain fines (FF), initial paleosoil calcretes, and heterogeneous crevasse splays (CS). Amalgamated complexes of channel fill show vertical and lateral stacking patterns, indicating changing accommodation space (Wright and Marriot, 1993). In the central portion of the Reinhardswald Basin, braided river deposits of the Lower Solling Formation are overlain by a few meters thick transitional unit. This zone is characterized by laminated sand sheets with low-angle point bar

464 J. Weber, W. Ricken / Sedimentary Geology 175 (2005) 459–477 Fig. 3. Fluvial pattern of the Solling Formation in the Reinhardswald Basin, RB, with typical fluvial architectural elements. Braided river systems (BR) of the Lower Solling Formation with channels (CH), downstream accretion (DA), and laminated sands (LS). The trend from lateral to vertical stacking (ls, vs) indicates increasing accommodation space (Wright and Marriot, 1993). Meandering rivers (MR) of the Upper Solling Formation with lateral accretion (LA), laminated sands (LS), and vertical stacking. Examples of the fluvial architecture: (A) Hanoverian cliffs, sequence boundary between Hardegsen Formation (hf) and Solling Formation (sf) with H-unconformity, Wilhelmshausen beds (sfW). (B) Abandoned Wqrgassen quarry, Trendelburg Beds (sfT), Lower Solling Formation. (C) Niemeyer quarry, Karshafen Beds (sfK), Upper Solling Formation. (D) Abandoned Negenborntal quarry (sfK), Upper Solling Formation. Open circles: drill core samples for diagenetic investigations.

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75%

F

ite

TR IX MA

e A r co s Lithic

Arco s

e

Sublitharenite

nite are Lith

Sandstones of the Lower Solling Formation, i.e., the sandy braided river deposits, are medium grained and grayish colored. In river channel positions with the elements CH and DA, low clay and mica contents and a grain-supported fabric predominates. The main components are detrital and authigenic quartz (65–85%), K-feldspars (15–35%), and minor clays and mica (2–12%). The grain shape is subangular to subrounded; grain contacts are dominantly point-shaped, elongated and subordinately concavo-convex. In proximal floodplain positions, with the fluvial architectural element LS, the clay and mica content increases to 20–28%. Therefore, sandstones of the Lower Solling Formation are classified as medium grained subarkoses and arkoses. Only a few clay-rich sandstones are subarkosic wackes. Sandstones of the Upper Solling Formation with the elements LA and LS, deposited in mixed load meandering river systems, are classified as subarkosic wackes (Fig. 4). They are fine grained and reddish stained. The main components are detrital and authigenic quartz (60–80%), K-feldspars (15–25%), and clay and mica (up to 30%). Grain shape is

95% Subarcose

n ithare par-L

4.2. Sediment petrography

Quartz Arenite Q

Felds

deposits. It trends from laminated sands towards pure clay and mica-rich sandstones and thus indicates the transition to a meandering river system (Olsen, 1988). The Upper Solling Formation is characterized by mixed load meandering river deposits with a thickness of about 45 m (i.e., Karlshafen and Stammen Beds). Meandering river systems are indicated by stacked cycles of point bars, including lateral accretion deposits (LA) with low inclination, laminated sandstones (LS), floodplain fines (FF), crevasse splays (CS) and oxbow lakes (FF ox). Single point bar fining-upward accretion events are composed of sand to clay couplets. The upper flow regime, as indicated by the presence of upper plain beds, is well developed in the sandstone layers (see Fig. 3). This suggests vigorous, perennial water flow under semiarid conditions. In marginal positions of the meander belts, laminated sandstones and clay-rich floodplain fines are the dominant elements.

465

15%

L

Fig. 4. Sandstone classification after Folk (1974). Subarkoses of braided river systems (open circles, Lower Solling Formation). Subarkosic wackes of meandering rivers (solid circles, Upper Solling Formation).

subangular to subrounded with elongated to concavoconvex grain contacts. Floodplain fines (FF) of both the braided and meandering river systems, which contain high clay and mica contents (N45%), classify as claystones to siltstones (Weber, 2000). 4.3. Pattern of silica diagenesis The degree of diagenesis depends on both the facies and spatial distribution of primary depositional architectures and their closely related petrographic compositions (Weber and Lepper, 2002). Thus, subarkosic braided river sandstones followed different pathways of diagenesis than subarkosic wackes in meandering river deposits (Fig. 5). In particular, subarkoses from braided river deposits were compacted mechanically from initial porosities of about 40% down to an intergranular volume (IGV) of about 26%. Thereafter, chemical compaction and silica precipitation took place resulting in IGVs of around 20%. During the early and late mesogenetic stages, two main quartz precipitation phases, which can be distinguished by different cathodoluminescence colors, stabilized the grain framework. Phase 1 (1%) is relatively minor and did not significantly inhibit compaction. This was followed by phase 2, which is the dominant phase. A maximum of 18% quartz cement is observed. In the remaining pore space,

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J. Weber, W. Ricken / Sedimentary Geology 175 (2005) 459–477 Upper Solling Formation

Lower Solling Formation

meandering rivers: subarcosic wackes

braided rivers: subarcoses

EOGENESIS IGV 60 %

initial sediment

mechanical compaction

IGV 40 %

MESOGENESIS 20 %

13 %

RP = 5 - 10 %

QC 1 mechanical compaction feldspar-alteration quartz-dissolution

precipitation of QC QC 2

QC 3 authigenic clay minerals and/or carbonate cement

26 %

20 %

RP = 5 - 10 %

maximum burial: 1800 - 2000 m. Fig. 5. Diagenetic history of the Reinhardswald Basin sandstones. Subarkoses of the Lower Solling Formation (i.e., braided rivers, main detrital components quartz and feldspar) are characterized by moderate mechanical compaction during eogenesis, followed by mesogenetic polyphase quartz cementation (i.e., QC 1, QC 2, QC 3), which stopped further compaction at moderate IGV volumes of 15–22%. Subarkosic wackes of the Upper Solling Formation (i.e., meandering rivers, main detrital components quartz, feldspar, mica, and clay matrix) are much more mechanically compacted down to IGV volumes of 8–13% and quartz cemented by only one generation.

minor authigenic clays and/or minor carbonate cements occur that reach volumes of about 5% (Fig. 5). Subarkosic wackes from meandering river sandstones, which had estimated initial porosities of 60% (Houseknecht, 1988), were compacted to IGV values of approximately 13%, which is a result of the higher

clay mineral content. Compaction was dominantly mechanical, with a small degree of chemical compaction. In contrast to the subarkoses of braided rivers only one phase of quartz cementation is observed by cathodoluminescence which is supposed to be analogue to the dominant quartz cement phase 2 of subarcoses. Quartz cement volumes of 2–8% were

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precipitated during the mesogenetic stage. The remaining pore space of approximately 5% is occasionally coated with authigenic clays and/or carbonates. During burial and uplift, diagenesis of the subarkoses and subarkosic wackes was influenced by changing pore waters of varying compositions. The early burial history with likely meteoric pore waters was accompanied by feldspar alteration. Alteration products of potassium feldspar, dominantly kaolinite, are commonly found in the rock record. Quartz cementation significantly reduces the primary pore space in the fluvial sandstones. Therefore, the timing of quartz cementation and the sources of the precipitated silica are of major interest. Quartz cement occurs as syntaxial overgrowth on detrital quartz grains. An authigenic origin is confirmed by cathodoluminescence observations and by fluid inclusions trapped at grain boundaries. Detrital quartz grains generally show luminescence colors between blue and purple, whereas quartz cement generally appears non-luminescent to dark blue/brown. In the subarkoses of the Lower Solling Formation, quartz cement luminescence colors indicate at least three cementation phases (i.e., dark brown, dark blue to brownish, and dark blue to nonluminescent). In subarkosic wackes of the Upper Solling Formation, however, only one phase of quartz can be distinguished (i.e., dark brown to non-luminescent).

5. Discussion: sources and transfer of silica 5.1. Importers and exporters and silica release from feldspar alteration As this study addresses the diagenetic pattern in sandstone layers and not in intercalated floodplain fines, sources of silica are described relative to the sandstone beds. Two types of silica sources are discussed: an internal and an external source relative to the sandstone beds themselves. Silica sources internal to sandstones include grain margin dissolution and feldspar alteration processes within a sandstone layer, whereas external silica sources include intercalated siltstones or silica carried in solution by basinal brines (Weber, 2000; Worden and Morad, 2000).

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According to Houseknecht (1984, 1987, 1991), the conventional silica import–export diagram compares the amounts of quartz cement to the silica source. The silica source, detrital quartz dissolved at grain contacts, is identified by concavo-convex grain boundaries. The Houseknecht diagram is generally applicable to uniform quartz arenites. However, in sandstones with a more varied mineralogical assemblage, higher amounts of silica may be generated internally within the clastic beds. Therefore, we have modified the silica import–export diagram to account for the effect of additional silica supply from feldspar alteration in the subarkoses and subarkosic wackes of the Lower and Upper Solling Formations. Both lithologies are kaolinite-bearing. Therefore, feldspar alteration (i.e., kaolinitization) can be considered as an additional sandstone-internal silica source. Using the reaction equation, a maximum of 44% volume silica can be generated from 100% leached K-feldspar (De Ros, 1998), which is then available for reprecipitation. To assume that all feldspar-derived silica remains within the sandstone beds as quartz cement requires that it is not transported away in solution. Support for a silica source from feldspar dissolution comes from microprobe analysis of quartz cements, which shows Al content in the authigenic phase (Weber, 2000). In Fig. 6, the classic import–export relationship from Houseknecht (1991) is compared to the modified import–export relationship with additional silica supply from feldspar alteration (Weber, 2000). Point counting results of the photomicrographs that were converted with respect to the volume of altered feldspar into the volume of released silica using the reaction equation. Based on the major lithologies investigated here, separate diagrams for braided and meandering rivers were generated to illustrate their different silica balance relationships. Compared to the classic Houseknecht relationship, each sample shifts towards a more balanced silica budget as a result of the additional supply of silica from feldspar alteration. This shift varies from sample to sample, depending on the specific content of altered feldspar. The content of altered feldspar was determined by cathodoluminescence microscopy. Non-altered potassium feldspar is bright blue (i.e., fresh plagioclase is green), whereas altered grains have ochre luminescence colors. In principle, two scenarios with different end members in the silica budget can be envisaged. In

(0.44 x Falt + overlap quartz)/detrital quartz overlap quartz/detrital quartz

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MR

0.30

0.20

0.10

0.00 0.00

0.10

0.20

0.30

(0.44 x Falt + overlap quartz)/detrital quartz overlap quartz/detrital quartz

quartz cement/detrital quartz

0.30

BR

0.20

0.10

0.00 0.00

0.10

0.20

0.30

quartz cement/detrital quartz Fig. 6. Import–export plot for subarkoses of braided river systems (BR, lower diagram) and subarkosic wackes of meandering river systems (MR, upper diagram). Solid triangles: import–export characterization after Houseknecht (1991). Open triangles: modified import–export characterization including the silica supply from altered feldspar in the investigated sandstone beds; shifting to a more balanced silica budget, depending on the amount of altered feldspar in each single sample. Subarkoses of the Lower Solling Formation are predominantly importers, subordinately balanced or exporters of silica, whereas subarkosic wackes of the Upper Solling Formation are predominantly balanced to exporters of silica. Falt=altered feldspar.

the first scenario, equivalent to Houseknecht’s diagram, there was no additional cementation of silica through feldspar alteration. In the second scenario, however, silica released from feldspar alteration was

reprecipitated in the sandstone beds as quartz cement. Based on our modifications of Houseknecht’s import–export diagram, subarkoses from braided river systems in the Lower Solling Formation are dominantly silica importers. They contain high quantities of quartz cement of up to 18%. However, subarkosic wackes from meandering rivers in the Upper Solling Formation are dominantly silica balanced or silica exporters. They contain only small amounts of quartz cement, from 2% to 8% (Fig. 6). Subarkoses and subarkosic wackes from the Solling Formation underwent porosity loss during burial diagenesis. The various diagenetic pathways for porosity loss, characterized by compaction and/or cementation, can be expressed by the interrelationship between the cement content and two characteristic types of volumes, the intergranular volume (IGV) and the remnant porosity (RP) (Houseknecht, 1984, 1987, 1988). For the initial porosities of the primary sediment, two commonly used values were assumed, 40% for the subarkoses and 60% for the subarkosic wackes with a higher clay content (Houseknecht, 1988). The subarkoses of the Lower Solling Formation braided river systems underwent a combination of compaction and precipitation of up to 18% quartz cement. Both processes caused porosity loss, resulting in final IGV values of 22% and a remnant porosity of approximately 5–10% (Fig. 7, arrow C). Although a higher initial primary porosity was assumed compared to the subarkoses, subarkosic wackes from the meandering river systems suffered a greater reduction in pore space. Their porosity loss, however, was caused dominantly by compaction. The amount of quartz cement is low at only 2–8%. Final IGV values are around 13% and the remnant porosity is approximately 5–10% (Fig. 7, arrow B). Subarkoses and subarkosic wackes show different degrees of diagenesis that reflect their different clay contents. Subarkoses poor in clay and mica show little evidence for chemical compaction. Quartz cementation of up to 18% is the major porosity reducing process. In the clay and mica-rich subarkosic wackes, however, concavo-convex grain contacts are more commonly observed. IGVs are lower, and only minor amounts of quartz cement (2 to 8%) are present. As seen in Fig. 8, there is an inverse relationship between the amount of quartz cement and the clay and

J. Weber, W. Ricken / Sedimentary Geology 175 (2005) 459–477

10

20

30

40

60

50

40

IGV (%)

30 20

30 10

C

0 R P

(% )

20

10

B

0 Fig. 7. Intergranular volume (i.e., IGV) versus quartz cement content. Open triangles: subarkoses of braided rivers (i.e., Lower Solling Formation) underwent porosity loss predominantly by a combination of quartz cementation and compaction (C). Solid triangles: subarcosic wackes of meandering rivers (i.e., Upper Solling Formation) underwent porosity loss predominantly by compaction (B) and subordinately by cementation.

mica contents. This is caused by mechanical and micro-chemical effects, which influence the dissolution–precipitation properties of silica. Thin clay rims surrounding detrital quartz grains contaminate the crystal surfaces and inhibit nucleation of authigenic quartz (Dewers and Ortolewa, 1991; Pittman et al., 1992). Additionally, micas in contact with detrital quartz grains influence the chemical micro-environment by causing a catalyzing effect. Other factors, such as increasing pH caused by partial dissolution of the mica surface, and changes in ion composition led to enforced quartz dissolution (Weyl, 1959; Boles and Johnson, 1983; Bjbrkum, 1996; Dove and Nix, 1997). The dissolution properties of quartz are, therefore, not only a function of the pressure between grains caused by overburden, but also a result of the mineralogical composition, and pore water chemistry

(Brady and Walther, 1989; Canals and Meunier, 1995). Quartz to quartz dissolution does occur frequently in the arkosic wackes and was enhanced by surface films of micaeous material which catalyze the dissolution process (Aase et al., 1996). To understand the distribution of quartz cements in the sandstone beds in the Solling Formation, silica sources must be considered as either internal or external to the sandstone beds themselves. Internal silica sources include grain pressure dissolution and feldspar alteration. External silica sources may include intercalated siltstones or rising basinal brines. These sources and the quantification of internal and external sources of silica has been intensively investigated (e.g., McBride, 1989; Gaupp et al., 1993; Bjbrlykke, 1994; Lynch, 1996; Stone and Siever, 1996; Macaulay, 1997; Williams et al., 1997; Worden and Morad, 2000; and others). We focus here on the different sources of silica in the Reinhardswald Basin in relation to the sandstone layers. In the Reinhardswald Basin sandstones, feldspar alteration is the most important internal silica source (Fig. 6). During early burial the subarkoses and subarkosic wackes of the Solling Formation were flushed by acidic meteoric pore waters, causing kaolinitization of K-feldspars (Bjbrlykke and Aagaard, 20

quartz cement (%)

quartz cement (%) 0

469

10

0 0

10

20

30

clays and mica (%) Fig. 8. Quartz cement versus clay and mica content. Subarkoses of braided rivers (open triangles) contain high quartz cement contents and minor clay and mica minerals. Subarkosic wackes of meandering rivers (solid triangles) contain less quartz cement and higher clay and mica contents.

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1992; Huang, 1992; De Ros, 1998). Evidence for this can be seen by the trace element contents in the quartz cement/altered feldspar pattern (Weber, 2000). On average, the relatively high proportion of one third of the total quartz cement, a maximum of approximately 6% relative to total rock volume, was potentially available for precipitation as a result of feldspar dissolution. 5.2. Corrosion of detrital quartz grains by grain margin dissolution Silica derived from dissolution of quartz in the sandstone beds in subarkoses of the Lower Solling Formation is only 1% of the total rock volume. Subarkosic wackes from the Upper Solling Formation may have generated around 2% quartz cement from grain margin dissolution. Stylolites were not observed in Solling Formation sandstones. Thus, in the sandstones analyzed, the volume of silica supplied by grain margin dissolution was relatively small. 5.3. Silica transfer from intercalated clay–siltstones Several authors (Fu¨chtbauer, 1978; McBride, ´ rla et al., 1996; Stone and 1989; Lynch, 1996; O Siever, 1996; Surdam et al., 1996; and others) have suggested that a potential source of silica could be clay–siltstones. In the Reinhardswald Basin, clay– siltstones of floodplain fines (FF) alternate with sandstone beds. Silica derived from clay–silt beds can be characterized as an external source relative to the sandstone layers. By analogy with the subarkosic wackes, the higher amounts of clay and mica minerals in the floodplain fines forced dissolution of the silt-sized detrital quartz grains. Quantification of quartz dissolution processes in clay–siltstones of the Solling Formation is based on observations by Fu¨chtbauer (1978), who estimated a maximum quartz dissolution volume of up to 35% quartz in various silt beds. In the clay–siltstones themselves quartz cementation is suppressed, because the kinetics of quartz precipitation do not allow nucleation in highly oversaturated solutions (Coleman, 1996); furthermore, the surface coatings of fines do not allow homoaxial quartz precipitation. Land and Milliken (2000) suggested potassium–silica transfer processes between clay–siltstones and sandstones. In the

Reinhardswald Basin, clay–siltstones from the underlying Hardegsen Formation and the overlying Roet Formation may have acted as sinks for potassium from sandstones, whereas silica from clay–siltstones was probably transported to the more porous interbedded sandstones (Mullis, 1992). The sandy braided river deposits of the Lower Solling Formation have b 10% floodplain fines, whereas the mixed load meandering rivers of the Upper Solling Formation contain approximately 30%. The total volume of detrital quartz inside the clay– siltstones (40%) has also been considered in this calculation. If a value of 35% (Fu¨chtbauer, 1978) for the maximum dissolution in clay–silt layers is presumed, only low values of quartz cement were generated. Maximum silica values from the total rock volume indicate a possible 3% quartz cement for the Lower and 6% for the Upper Solling Formation. 5.4. Silica derived from supersaturated basinal brines Silica supply from the deeper parts of a sedimentary basin (e.g., supersaturated hot basinal fluids) requires open pathways and/or open fractures for ascending pore waters. The amount of silica from hot fluids can be roughly estimated by considering all of the various above mentioned silica sources, including those inside and outside a sandstone layer. If the amount of quartz cement is higher than that possible from the local sources, other sources for the remaining amount of silica must be considered. They may be derived from basinal brines which are connected with the fracturing and opening of pathways for ascending pore waters during inversion and updoming in Late Cretaceous to Early Tertiary times (see burial history). The subarkosic wackes of the Upper Solling meandering river systems show a balanced silica budget, therefore, additional silica sources are not required. However, the Lower Solling subarkoses from braided river systems are importers of silica. Calculations of the amount of silica generated inside the sandstone beds from feldspar dissolution (maximum 6%) and silica derived from intercalated clay–siltstones (maximum of 3%) indicate that half of the total 18% quartz cement must have been drawn from other sources. To test the possible contribution of hot basinal brines, homogenization temperature measurements were made on fluid inclusions in definitively authi-

J. Weber, W. Ricken / Sedimentary Geology 175 (2005) 459–477

Fig. 9. Histogram showing homogenization temperatures of twophase aqueous inclusions from Lower Solling Formation arkoses.

genic quartz from six samples. These samples represent the highly quartz cemented subarkoses of the Lower Solling Formation and indicate at least two major temperature ranges during quartz cementation. Singlephase inclusions that were observed near the grain boundaries indicate homogenization temperatures b60 8C (Goldstein and Reynolds, 1994; Munchez et al., 1992). Two-phase inclusions more related to the grain margin area, however, suggest a second quartz cementation phase at temperatures of around 120 8C (Fig. 9). Due to the small size (b3 Am) of the inclusions no salinity measurements were possible. 5.5. Diagenetic architecture A relatively close coherence between diagenetic patterns and depositional architecture is observed in the Reinhardswald Basin. Consequently, the various sandy fluvial architectural elements of the Lower and Upper Solling Formation can be distinguished by their characteristic diagenetic properties (Fig. 10). We use

471

the term bdiagenetic architectureQ (Weber, 2000) to describe a predictive relationship between the depositional processes and the resulting diagenetic regime. During diagenesis, the depositional architecture in the basin is sensitively translated into the degree and type of silica transfer. At least for the studied Reinhardswald Basin, this is observed on a basin-wide scale. The depositional regime depends on both the fluvial dynamics and the distribution of associated mineral assemblages (e.g., the ratio between quartz and clay content). The diagenetic regime, on the other hand, depends on the subsidence history and the pore water evolution. The diagenetic regime also depends on lithologies and mineral assemblages. The diagenetic architecture of the Lower Solling braided rivers architectural elements CH and DA (i.e., silica importers) is characterized by intense quartz cementation and medium degrees of compaction. CH and DA elements show the highest degree of cementation observed in the entire Reinhardswald Basin. Cementation is controlled by two factors, the relatively low clay and mica content in the channel systems and the relatively large grain size of dominantly medium grained sandstones. As shown in the present study, both factors allow quartz cement to precipitate. Cementation is also controlled by the stacking pattern of CH and DA elements, which form amalgamated sandstone units. Porous beds of amalgamated sandy elements were major migration pathways for pore fluids and therefore were the preferred zones for reprecipitation of authigenic phases (Lynch, 1996). Consequently, the architectural elements with the highest initial porosity and lowest clay content show the strongest cementation (i.e., up to 18% of the total rock volume; Lynch, 1996; Weber, 2000). Within the Lower Solling Formation the fluvial architectural element LS varies from silica importer to exporter and shows a higher compaction rate than CH and DA elements. Variations in quartz cement content depend on the different clay and mica contents of each LS unit (Fig. 10). Upper Solling subarkosic wackes from mixed load meandering systems with the fluvial architectural elements LA and LS are dominantly characterized by compacted beds. Minor degrees of quartz cement up to 8% of the total rock volume are observed. The silica import–export pattern is, on average, balanced. LA shows a uniformly balanced silica budget, whereas LS has both balanced units and exporters of silica, depend-

10

0.10

DA

0.20

10

0.10

0.00 0 0 10 20 0.00 0.10 0.20 0.30 30 quartz cement/detrital quartz clays and mica (%) quartz cement (%)

50

50

50

50

40

40

40 30

30

30

20 10

20

20 MC + CC

B

0

20

(0.44 x Falt + overlap quartz)/ detrital quartz

20

IGV (%)

) (% P

20

10

10

0

0

30

40

MC + CC

20

LS-BR

0.20

10

0.10

0.00 0 0 10 20 0.00 0.10 0.20 0.30 30 quartz cement/detrital quartz clays and mica (%) quartz cement (%)

MC 40

0

10

20

30

40

40

30

10

20

30

40

30

20 10

20

0

MC

30

MC + CC

10

MC

C B

0

IGV (%)

(% P

20

)

0

0.00 0 0 10 20 0.00 0.10 0.20 0.30 30 quartz cement/detrital quartz clays and mica (%) quartz cement (%) 0 10 20 30 40 0 10 20 30 40 60 60

C

20

0.30

0

30 10

)

C

IGV (%)

0.00 0 0 10 20 0.00 0.10 0.20 0.30 30 clays and mica (%) quartz cement/detrital quartz quartz cement (%) 20 40 10 0 10 20 30 40 0 30 40 40 30 MC 30 20 30

10

(%

0.10

10

P

0.20

0.10

R

CH

quartz cement (%)

0.30

0.20

40

20

30

20

LS-MR

IGV (%)

20

0.30

)

0

quartz cement (%)

(0.44 x Falt + overlap quartz)/ detrital quartz

B

R

IGV (%)

(0.44 x Falt + overlap quartz)/ detrital quartz

0

40

quartz cement (%)

MC + CC 10

30

A

R

(%

C

10

20

30

LS-BR

20

R

0

IGV (%)

20

P

10

10

(%

30

20

CH

IGV (%)

30

LS-MR

0

R P

30

40

MC

IGV (%)

40

40

IGV (%)

50

40

)

IGV (%)

50

MC + CC

10

10

10

10

10

10

0

0

0

0

0

0

Fig. 10. Diagenetic architecture expressed as characteristic patterns for the quartz cementation/compaction potential of the various architectural elements of braided rivers (i.e., CH, DA, LS-BR) versus meandering rivers (i.e., LA, LS-MR) from the Solling Formation in the Reinhardswald Basin.

J. Weber, W. Ricken / Sedimentary Geology 175 (2005) 459–477

0.00 0 0 10 20 0.00 0.10 0.20 0.30 30 quartz cement/detrital quartz clays and mica (%) quartz cement % 0 10 20 30 40 0 10 20 30 40 60 60

20

DA

0.30

quartz cement (%)

0.20

LA

(0.44 x Falt + overlap quartz)/ detrital quartz

LA

quartz cement (%)

(0.44 x Falt + overlap quartz)/ detrital quartz

472

20 0.30

J. Weber, W. Ricken / Sedimentary Geology 175 (2005) 459–477

center of the Reinhardswald Basin. We used the 1D simulation program bPetroModQ from IES (Juelich), to model the thermal and burial history of the area since the Permian, which was a new depositional cycle above the folded Variscan basement. Results indicate the relative timing of different cementation phases during subsidence, and show the possible source of the suggested hot fluids during silica cementation. For the sedimentary units between the Zechstein and the Quaternary, subsidence and uplift phases were modeled based on commonly used values of heat flow and thermal conductivity in North Germany. Modelling is based on the well-known stratigraphy in the center of the Reinhardswald Basin, but upsection the stratigraphy is partially extrapolated because of erosion of the upper strata (Fig. 11). From

ing on the clay and mica contents in each unit. In mixed load systems with relatively more floodplain fines, the sandy architectural elements are more isolated and are separated by intercalated clay–siltstone successions that reduced pore fluid mobility. Furthermore, the sandy sediments themselves contain more clay and mica, which inhibit cementation and promote compaction. Silica supply from outside the sandstone beds was relatively low, but compaction rates were higher. 5.6. Burial history, controlling factors of fluid development and timing of quartz cementation The relationship between diagenesis and the subsidence and uplift history of the study area was evaluated by modeling the Solling Formation in the

EOGENESIS 250

230

TELOGENESIS

JURASSIC 210

190

170

CRETACEOUS 150

130

TERTIARY

90

70

50

30

Q 10

ol/mi

jo/ku jm QC1

ju

1000

QC(Fault)

QC3

70-105

su 3000

z

7000 m

LEGEND

ju

Lower Jurassic

k

Keuper

ol/mi

Oligocene - Miocene

su

Solling Formation Middle Buntsandstein (without sf) Lower Buntsandstein

m

Muschelkalk

jo/ku

U.Jurassic - L.Cretaceous

z

Zechstein

so

Upper Buntsandstein

sf sm

jm

140-175 175-210 >210

subsidence maximum: sandstone external silica supply from claysiltstones

5000

6000

uplift: sandstone external silica supply from hot Zechstein fluids

105-140

subsidence: sandstone internal silica supply from feldspar alteration and grain margin dissolution

4000

35-70

k m so sf sm

QC2

2000

0-35

0

110

T°C

M.b.p.

MESOGENESIS

TRIASSIC

PERMIAN

473

Middle Jurassic

Fig. 11. Burial history curve of the Solling Formation in the Rheinhardswald Basin. Modeling position is the center of the Reinhardswald Basin with a 120 m thickness of Solling Formation. Modeling program is PetroMod, IES, Aachen. Schematic view of the subsidence history of all strata from the Zechstein to Recent. Development of burial depth, diagenetic phases, and temperature fields (stippled lines) are shown. After subsidence from the Triassic to Middle Jurassic with a maximum burial depth of approximately 2000 m, the Solling Formation was uplifted during the Upper Cretaceous, leading to the inversion of the Reinhardswald Basin and to the present dome-like structure. Quartz cements were derived internally from feldspar dissolution and compaction during subsidence (QC1, QC2), external silica supply from clay–siltstones during maximum subsidence (QC2, continued), and external silica supply from hot Zechstein fluids (i.e., temperature field 105–140 8C) during uplift (QC3). During the Miocene minor quartz cementation occurred near fault zones caused by rising basaltic melts (after Menning, 1995; Lepper and Ro¨hling, 1998). Modeling input data see Weber (2000).

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Triassic to Middle Jurassic times the Solling Formation was influenced by moderate subsidence down to burial depths of about 2000 m. After a phase of low subsidence rates from the Upper Jurassic to the Lower Cretaceous, uplift and inversion started in the Upper Cretaceous. This pattern was initiated by transpressional tectonics and modified by salt migration of the underlying Zechstein evaporites. During the Miocene, the uplifted parts of the Reinhardswald Basin were overprinted by a small-scale volcanic event, which is demonstrated by basaltic rocks in the Nienover Graben, where residual fluids seemed to be associated with reactivated fault zones. The relative timing of quartz cementation may be related to the pattern of subsidence and uplift and thus to the thermal history of the Solling Formation. The allocation of cement phases on the thermal-subsidence curve is only tentative basing on the available data and may contain large error bars (Fig. 12). During early subsidence from Lower Triassic to Middle Jurassic the Solling stacked sandstone and clay–

siltstone cycles were influenced by meteoric water flow. The climate during the Lower Triassic was semiarid (Wycisk, 1984; Aigner and Bachmann, 1992) with perennial water flow in the source area. The possibly non-buffered meteoric waters in the Buntsandstein environment may have been slightly acidic, which then have caused kaolinitization of potassium feldspar and associated release of silica (De Ros, 1998; Kraishan et al., 2000; Worden and Morad, 2000). This silica released from feldspar alteration in Solling subarkoses and subarkosic wackes could have been a source for quartz cementation within the sandstone beds. During deepest burial from Middle Jurassic to mid-Cretaceous, the sandstones of the Solling Formation may have received additionally external supplied silica primarily from the intercalated clay– siltstones which precipitated as quartz cement in the sandstone beds. During the Upper Cretaceous, tectonic movements caused the inversion of the Reinhardswald Basin into a dome-like structure which was associated with the revitalization of

FLUVIAL ARCHITECTURE BASIN DEVELOPMENT:

Upper Solling Formation: subarcosic wackes MEANDERING RIVER System

subsidence and uplift history

ENVIRONMENT fluvial dynamics

PETROGRAPHY: clays, mica and feldspar content

Fluvial Architectural Elements LA, LS-MR, FF, CS

silica balance or exporter predominant compaction

silica importer

Lower Solling Formation: Subarcoses BRAIDED RIVERSystem

predominant cementation

HISTORY

PORE FLUIDS

compaction cementation mineral transformations

meteoric basic saline

Fluvial Architectural Elements CH, DA, LS-BR, CS, FF

DIAGENETIC ARCHITECTURE Fig. 12. Diagenetic architecture of the Solling Formation in the Reinhardswald Basin and its controlling factors, including environmental conditions, burial and diagenetic history, petrography, and pore fluid evolution.

J. Weber, W. Ricken / Sedimentary Geology 175 (2005) 459–477

fractures. This process was possibly accompanied by ascenting silica-rich hot basinal brines. When the brines migrated to the porous sandy units of the Lower Solling Formation, cooling caused quartz cement precipitation. Our assumption of ascenting brines is supported by the occurrence of fluid inclusions in the quartz cement of the Lower Solling subarkoses, which show homogenization temperatures of approximately 115 to 120 8C. Cretaceous pore water temperatures of 105–140 8C were modeled for the underlying Zechstein evaporites at burial depths of 3300 to 4000 m. Thus, the migration of saline and oversaturated hot fluids may have been the source of the last major phase of quartz cementation (QC 3). In the sandstone beds it may have accounted for approximately 9% of the external silica supply. The last, but locally most effective phase of quartz cementation in the region is thought to be associated with ascending basaltic melts and residual fluids along reactivated Variscian fault zones (QC fault). This type of overprint occurred during the Miocene and is locally observed on the adjoining horsts of Tertiary graben structures (e.g., Nienover Graben). This cementation phase which seems to be associated with the fault zones is characterized by quartz cement contents of 19%, IGV volumes of 20%, and a remnant porosities of 0–1%.

6. Conclusions (i) Diagenetic studies of braided and meandering river architectural elements of the Solling Formation indicate characteristic distribution patterns for the degree and type of quartz cement. On a basin-wide scale the depositional architecture is related to the distribution of sediment dispersal patterns, including the depositional structures and their relationship to both grain size and the quartz/clay ratio. The depositional pattern determined the degree, type and distribution of quartz cement, reflect a close relationship between the fluvial lithologic variation and the diagenetic overprint. For this purpose we define the term Qdiagenetic architectureQ in the observed Reinhardswald Basin. (ii) Quartz cementation in subarkoses and subarkosic wackes of the Solling Formation occurred

475

during three distinct phases of silica supply. First, during early mesogenesis (at 35 8C), when silica was supplied internally from feldspar alteration and grain margin dissolution. Second, at approximately 2000 m burial depth from midJurassic to Upper Cretaceous, when the sandstones received external silica from the intercalated clay–siltstones. The third phase may have occurred from Upper Cretaceous to Lower Tertiary, a period of uplift, and associated silica supply from migrating hot fluids (Zechstein). (iii) In braided river sandy fluvial architectural elements (CH, DA), the subarkoses with low clay contents below 10% contain significant volumes of quartz cement. They underwent minor compaction and were silica importers. Internal silica sources of the CH/DA sandstone layers are the result of feldspar alteration and grain margin dissolution, whereas outside sources might be intercalated clay–siltstones and brines from deeper buried units. Porosity loss in the CH/DA units was dominantly by quartz cementation and through minor compaction. Laminated sandstones with clay contents up to 28% (LS) show more balanced silica budgets. (iv) Sandy fluvial architectural elements from meandering systems (LA, LS), which are composed of subarkosic wackes with N15% clay contents, have balanced silica budgets or were silica exporters. Silica sources in these sandstones are from feldspar alteration and grain margin dissolution. Silica supply from outside the sandstone beds is not required to account for the observed volumes of quartz cement. (v) Quartz cementation depends primarily on mineralogical composition in the Reinhardswald Basin. High clay and mica contents are important factors which inhibit homoaxial quartz precipitation, but promote compaction. (vi) 1D modeling of subsidence and temperature in the Reinhardswald Basin indicates a maximum burial depth of approximately 2000 m for the Solling Formation. Modeled temperatures support the observed fluid inclusion homogenization temperatures of b60 8C for the major phase of cementation (QC 2). The third phase of cementation by externally derived silica (QC 3) corresponds to hot basinal brines which may

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have circulated from the underlying Zechstein evaporates, as expressed by fluid inclusion homogenization temperatures of about 120 8C. This assumption is supported by the modeled burial depth of the underlying Zechstein evaporates of 3300–4000 m and a corresponding temperature of 105–140 8C.

Acknowledgements The authors thank the Deutsche Forschungsgemeinschaft (DFG) for financial support of the project bSilica Diagenesis of the Solling FormationQ. The study has benefited from the discussions and suggestions of many colleagues, especially K. Bjbrlykke, R. Gaupp, A. Immenhauser, J. Lepper, C. Macaulay, Ph. Muchez, K. Ramseyer, C. Spo¨tl, K. Stone, R. Swennen and R. Worden. Thoughts of Hans Fu¨chtbauer who passed away inspired this project. We will remember him as an enthusiastic scientist.

References Aase NE, Bjbrkum PA, Nadeau PH. The effect of grain-coating microquartz on preservation of reservoir porosity. AAPG Bull 1996;80:1654 – 73. Aigner T, Bachmann HG. Sequence-stratigraphic framework of the German Triassic. Sediment Geol 1992;80:115 – 35. Barnes DA, Lundgren CE, Longman MW. Sedimentology and diagenesis of the St Peter Sandstone, Central Michigan Basin, United States. AAPG Bull 1992;76:1507 – 32. Bindig M. R7umliche und zeitliche Entwicklung der fluviatilen Environments der Solling-Formation (Buntsandstein, Germanische Trias). PhD thesis, Technische Hochsch. Darmstadt, Germany; 1991. Bjbrkum PA. How important is pressure dissolution of quartz in sandstones. J Sediment Res 1996;66:147 – 54. Bjbrlykke K. Fluid-flow processes and diagenesis in sedimentary Basins. In: Parnell J, editor. Geofluids: origin, migration and evolution of fluids in sedimentary basins. Geol Soc Am, Sp Publ, vol. 78, 1994, p. 127 – 40. Bjbrlykke K, Aagaard P. Clay minerals in North Sea sandstones. In: Houseknecht DW, Pittman ED, editors. Origin, diagenesis and petrophysics of clay minerals in sandstones. SEPM, Sp Publ, vol. 47, 1992, p. 65 – 80. Boles JR, Johnson KS. Influence of mica surfaces on pore water pH. Chem Geol 1983;43:303 – 17. Brady PV, Walther JV. Controls on silicate dissolution rates in neutral and basic pH solutions at 25 8C. Geochim Cosmochim Acta 1989;53:2823 – 30.

Burley SD, McQuaker JHS. Authigenic clays, diagenetic sequences and conceptual diagenetic models in contrasting basin-margin and basin-center North Sea Jurassic sandstones and mudstones. In: Houseknecht DW, Pittman ED, editors. Origin, diagenesis and petrophysics of clay minerals in sandstones. SEPM, Sp Publ, vol. 47, 1992, p. 81 – 110. Canals M, Meunier JD. A model for porosity reduction in quartzite reservoirs by quartz cementation. Geochim Cosmochim Acta 1995;59:699 – 701. Chuhan FA, Bjbrlykke K, Lowrey C. Closed-system burial diagenesis in reservoir sandstones: examples from the Garn Formation at Haltenbanken area, offshore mid-Norway. J Sediment Res 2001;71:15 – 26. Coleman M. Quantified fluxes of water and transported silica from mud rock to sandstones: what are the transport processes. Geofluids Research Group, quartz cement: origin and effects on hydrocarbon reservoirs, School of Geosciences, Queens Univ. Belfast, Abstract, p. 17. Cord M. Diagenese 7olischer Sandsteine des Rotliegenden Norddeutschlands. PhD thesis, Univ. Mainz, Germany; 1995. De Ros LF. Heterogeneous generation and evolution of diagenetic quartzarenites in the Silurian–Devonian Furnas Formation of the Parana Basin, southern Brazil. Sediment Geol 1998;116: 99 – 128. Dewers T, Ortolewa P. Influences of clay minerals on sandstone cementation and pressure solution. Geology 1991;19:1045 – 8. Dove P, Nix CJ. The influence of the alkaline earth cations, magnesium, calcium, and barium on the dissolution kinetics of quartz. Geochim Cosmochim Acta 1997;61:3329 – 40. Dutton SP. Influence of provenance and burial history on diagenesis of Lower Cretaceous Frontier Formation sandstones, Green River Basin, Wyoming. J Sediment Petrol 1993;63:665 – 77. Folk RL. Petrology of sedimentary rocks. Austin (TX)7 Hemphill; 1974. Fu¨chtbauer H. Zur Herkunft des Quarzzements—Absch7tzung der Quarzauflo¨sung in Silt- und Sandsteinen. Geol Rundsch 1978;67:991 – 1008. Gaupp R, Matter A, Platt J, Ramseyer K, Walzebuck J. Diagenesis and fluid evolution of deeply buried Permian (Rotliegend) gas reservoirs, Northwest Germany. AAPG Bull 1993;77:1111 – 28. Goldstein RH, Reynolds TJ, editors. Systematics of fluid inclusions in diagenetic minerals. SEPM Short Course Notes, vol. 31, 1994, p. 1 – 199. Houseknecht D. Influence of grain size and temperature on intergranular pressure solution, quartz cementation and porosity in a quartzose sandstone. J Sediment Petrol 1984;54:348 – 61. Houseknecht D. Assessing the relative importance of compaction processes and cementation to reduction of porosity in sandstones. AAPG Bull 1987;71:633 – 42. Houseknecht D. Intergranular pressure solution in four quartzose sandstones. J Sediment Petrol 1988;58:228 – 46. Houseknecht D. Use of cathodoluminescence petrography for understanding compaction, quartz cementation and porosity in sandstones. In: Barker CE, Kopp OC, editors. Luminescence microscopy: quantitative and qualitative aspects. SEPM Short Course Notes, vol. 25, 1991, p. 59 – 66.

J. Weber, W. Ricken / Sedimentary Geology 175 (2005) 459–477 Huang W. Illitic clay formation during experimental diagenesis of arkoses. In: Houseknecht DW, Pittman ED, editors. Origin, diagenesis and petrophysics of clay minerals in sandstonesSEPM, Sp Publ, vol. 47, 1992, p. 49 – 64. Kraishan GM, Rezaee MR, Worden RH. Significance of trace element composition of quartz cement as a key to reveal the origin of silica in sandstones: an example from the Cretaceous of the Barrow Sub-Basin, Western Australia. In: Worden R, Morad S, editors. Quartz cementation in sandstones. Int Assoc Sed, Sp Publ, vol. 29, 2000, p. 317 – 31. Land LS, Milliken K. Regional loss of SiO2 and CaCO3, and gain of K2O during burial diagenesis of Gulf Coast mudrocks, USA. In: Worden R, Morad S, editors. Quartz cementation in sandstonesInt Assoc Sed, Sp Publ, vol. 29, 2000, p. 183 – 97. Lepper J. Erla¨uterungen zur Geologischen Karte von NordrheinWestfalen, 1:25 000, Blatt 4322 Karlshafen, 1976, p. 1–190. Lepper J, Ro¨hling H-G. Buntsandstein. In: Bachmann GH, Beutler G, Lerche I, editors. Excursions of the international symposium on the epicontinental Triassic. Hallesches Jahrbuch fu¨r Geowissenschaften, Reihe B, vol. 6, 1998, p. 27 – 34. Lynch LF. Mineral/water interaction, fluid flow, and Frio Sandstone diagenesis: evidence from the rocks. AAPG Bull 1996; 80:486 – 504. Macaulay C. Quartz veins record vertical flow at a graben edge. AAPG Bull 1997;81:2024 – 35. Marfil R, Ross C, Lozano RP, Permanyer A, Ramseyer K. Quartz cementation in Cretaceous and Jurassic reservoir sandstones from the Salam Oil Field, Western Desert, Egypt: constraints on temperature and timing of formation from fluid inclusions. In: Worden R, Morad S, editors. Quartz cementation in sandstones. Int Assoc Sed, Sp Publ, vol. 29, p. 163 – 82. Marshall DJ. Cathodoluminescence of Geological Materials. London7 Unwin Hyman; 1988. McBride EF. Quartz cement in sandstones: a review. Earth-Sci Rev 1989;26:69 – 112. Menning M. A numerical time scale for the Permian and Triassic periods: an integrated time analysis. In: Scholle PA, Peryt TM, Ulmer-Scholle DS, editors. The Permian of Northern Pangea 1. Berlin7 Springer-Verlag; 1995. p. 77 – 97. Miall AD. Architectural element analysis: a new method of facies analysis applied to fluvial deposits. Earth-Sci Rev 1985;22:261–308. Miall AD. The geology of fluvial deposits. Berlin7 Springer-Verlag; 1996. Muchez Ph, Viane W, Dusar M. Diagenetic control on secondary porosity in floodplain deposits: an example of the Lower Triassic of northeastern Belgium. Sediment Geol 1992;78:285 – 98. Mullis AM. A numerical model for porosity modification at a sandstone–mudstone boundary by quartz pressure dissolution and diffusive mass transfer. Sedimentology 1992;39:99 – 107. Neuser RD. The present state of optical cathodoluminescence microscopy: developments and facilities at the Ruhr-Univ, Bochum. Gaea Heidelb 1997;3. Oelkers EH, Bjbrkum A, Murphy WM. A petrographic and computational investigation of quartz cementation and porosity reduction in North Sea sandstones. Am J Sci 1996;296:420 – 52. Olsen H. The architecture of a sandy braided–meandering river system: an example from the Lower Triassic Solling Formation

477

(M Buntsandstein) in W-Germany. Geol Rundsch 1988;77: 797 – 814. ´ rla M, McLaughlin R, Haszeldine S, Fallick AE. Quartz diaO genesis in layered fluids in the South Brae Oilfield, North Sea. In: Crossey LJ, Loucks R, Totten MW, editors. Siliciclastic diagenesis and fluid flow: concepts and applications. SEPM, Sp Publ, vol. 55, 1996, p. 103 – 13. Pittman E, Larese RE, Heald MT. Clay coats: occurrence and relevance to preservation of porosity in sandstones. In: Houseknecht DW, Pittman ED, editors. Origin, diagenesis and petrophysics of clay minerals in sandstones. SEPM, Sp Publ, vol. 47, 1992, p. 241 – 56. Ramseyer K, Baumann J, Matter A, Mullis J. Cathodoluminescence colours of a-quartz. Min Mag 1988;52:669 – 77. Stone WN, Siever R. Quantifying compaction, pressure solution and quartz cementation in moderately- and deeply-buried quartzose sandstones from the greater Green River Basin, Wyoming. In: Crossey LJ, Loucks R, Totten MW, editors. Siliciclastic diagenesis and fluid flow: concepts and applications. SEPM, Sp Publ, vol. 55, 1996, p. 129 – 50. Surdam RC, Jiao ZS, Yin P. Fluid flow regimes and sandstone/ shale diagenesis in the Powder River basin, Wyoming. In: Crossey LJ, Loucks R, Totten MW, editors. Siliciclastic diagenesis and fluid flow: concepts and applications. SEPM, Sp Publ, vol. 55, 1996, p. 59 – 72. Weber J. Kiesels7urediagenese und gekoppelte Sedimentarchitektur—eine Beckenanalyse des Reinhardswald-Troges (Norddeutsches Becken, Solling-Folge, Mittlerer Buntsandstein), PhD thesis, Ko¨lner Forum fu¨r Geol. u. Pal. 7; 2000. Weber J, Lepper J. Depositional environment and diagenesis as controlling factors for petro-physical properties and weathering resistance of siliciclastic dimension stones: integrative case study on the bWesersandsteinQ (northern Germany, Middle Buntsandstein). In: Siegesmund S, Weiss T, Vollbrecht A, editors. Natural stone weathering phenomena, conservation strategies and case studies. Geol Soc London, Spec Publ, vol. 205, 2002, p. 103 – 14. Weyl PK. Pressure solution and the force of crystallization—a phenomenological theory. J Geophys Res 1959;64:2001 – 25. Williams LB, Hervig RL, Dutton SP. Constraints on paleofluid compositions in the Travis Peak Formation, East Texas: evidence from microanalyses of oxygen isotopes in diagenetic quartz. In: Montan˜ez IP, Gregg JM, Shelton KL, editors. Basin-wide diagenetic patterns: integrated petrologic, geochemical, and hydrologic considerations. SEPM, Sp Publ, vol. 57, 1997, p. 269 – 80. Worden RH, Morad S. Quartz cementation in oil field sandstones: a review of the key controversies. In: Worden R, Morad S, editors. Quartz cementation in sandstones. Int Assoc Sed, Sp Publ, vol. 29, 2000, p. 1 – 20. Wright VP, Marriot SB. The sequence stratigraphy of fluvial depositional systems: the role of floodplain sediment storage. Sediment Geol 1993;86:203 – 10. Wycisk P. Faziesinterpretation eines kontinentalen Sedimentationstroges (Mittlerer Buntsandstein/Hessische Senke). PhD thesis, Berliner geowiss. Abhandlungen 1984;54. Ziegler PA. Geological atlas of western and central Europe. The Hague7 Elsevier & Shell Int. Petrol. Maatschappij B.V.; 1990.