Evolution of tectonic events and topography in southeastern Gorny Altai in the Late Mesozoic–Cenozoic (data from apatite fission track thermochronology)

Available online at www.sciencedirect.com

ScienceDirect Russian Geology and Geophysics 57 (2016) 95–110 www.elsevier.com/locate/rgg

Evolution of tectonic events and topography in southeastern Gorny Altai in the Late Mesozoic–Cenozoic (data from apatite fission track thermochronology) E.V. Vetrov a,b, M.M. Buslov a,b,*, J. De Grave c a

V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the Russian Academy of Sciences, pr. Akademika Koptyuga 3, Novosibirsk, 630090, Russia b Novosibirsk State University, ul. Pirogova 2, Novosibirsk, 630090, Russia c Geochronology Group, Department of Mineralogy and Petrology, Ghent University, 281/S8, Krijgslaan, B-900, Ghent, Belgium Received 27 April 2015; accepted 28 August 2015

Abstract Results of apatite fission track dating have been summarized and correlated with stratigraphic, geoelectrical, tectonic, and geomorphological data. The average regional rate of rock denudation in southeastern Gorny Altai is reflected in three thermotectonic events: (1) Late Cretaceous–Early Paleogene tectonic activity with a denudation rate of ~200 m/Myr, related to the distant impact of the Mongol–Okhotsk orogeny; (2) Middle Paleogene–Early Neogene stabilization with peneplanation; and (3) Neogene–Quaternary “stepwise” tectonic activity with a denudation rate of ≤270 m/Myr, related to the distant impact of the Indo-Eurasian collision. We present results of study of the evolution of regional tectonic processes and topography over the last 100 Myr by analysis of digital and shaded elevation models and apatite fission track dating. © 2016, V.S. Sobolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved. Keywords: fission track dating; stratigraphy; neotectonics; paleogeography; Indo-Eurasian and Mongol–Okhotsk collisions; Kurai–Chuya basin; Gorny Altai

Introduction Apatite fission tracking (AFT) is a method of low-temperature geochronology. It is applied for reconstruction of the thermal evolution of the rocks in the upper 3–5 km of the continental crust within intervals of few millions to hundreds of millions of years. One of the AFT applications is the determination of the periods of tectonic events and orogeny as well as denudation rates and extents (Farley, 2002; Gleadow et al., 2002; Kohn et al., 2005). The area under consideration is southeastern Gorny Altai, which is well studied by geological and geophysical methods (Buslov et al., 1999, 2003, 2013; Deev et al., 2012; Delvaux et al., 1995; Devyatkin, 1965; Dobretsov et al., 1995; Nevedrova et al., 2014; Novikov et al., 1995; Zykin and Kazanskii, 1995). The region is characterized by high seismicity (Gol’din et al., 2008; Lununa et al., 2008). More than 100 apatite track dates were obtained for the rocks of Gorny Altai, based on

* Corresponding author. E-mail address: [email protected] (M.M. Buslov)

which >60 thermal models were constructed (De Grave et al., 2002, 2007a,b, 2008; Glorie et al., 2012a). These works show the nonuniform neotectonic evolution of the Gorny Altai structures, expressed in the differentiation of the values of track parameters and in the change of the thermal evolution trends of the rocks. For example, the authors stress the role of activity of Late Paleozoic regional fault zones, manifested in the increase in denudation rates and reflected in the change of the thermal trend (Glorie et al., 2012a). Based on analysis of AFT results and their correlation with stratigraphic, tectonic, geomorphological, and geophysical data, we describe a thermotectonic model for southeastern Gorny Altai and present results of study of the regional tectonic evolution and topography in the Late Mesozoic–Cenozoic. Track dating of Gorny Altai and the Tien Shan has been developing actively for the last 25 years under the Russian–Belgian joint projects, the founders and the organizers of which are Academician N.L. Dobretsov and Prof. J. Klerkx (Buslov et al., 2008; De Grave et al., 2002, 2007a,b, 2008, 2009, 2011a,b; De Pelsmaeker et al., 2015; Glorie et al., 2010, 2011, 2012a,b).

1068-7971/$ - see front matter D 201 6, V.S. So bolev IGM, Siberian Branch of the RAS. Published by Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.rgg.201 + 6.01.007

96

E.V. Vetrov et al. / Russian Geology and Geophysics 57 (2016) 95–110

Methods and terms The understanding of kinematics of track annealing is key to the AFT study of thermal processes. Apatite track annealing is a thermally activated process which usually takes place at >100–120 °C on the scale of geologic time. As the annealing levels increase, the tracks shorten progressively; when rock cools down to the temperature range of relative track stability, they retain most of their initial length. During the annealing the tracks shorten to the lengths controlled by the maximum temperatures to which they were brought. Therefore, the track lengths reflect the paleotemperatures accumulated by the samples within different time intervals. The joint consideration of track age and track lengths shows the combination of time over which the tracks have been preserved and the thermal evolution of the rocks over this period. So, the integration of track age and track lengths can place strict constraints on the cooling history through the partial-annealing zone; i.e., it permits determining how fast and for how long the sample under study cooled down. The measured data on tracks and the modeled thermal evolutions can be visualized by thermotectonic modeling, based on the quantitative understanding of the annealing dynamics (Laslett et al., 1987). The modeling consists in the making of a series of images which show the regional distribution of track parameters (track ages and average track lengths), thermal and denudation histories integrated in space, and the evolution of paleotopography. The distribution of track ages and track lengths must demonstrate general trends on the regional scale, reflecting the character of ascent of samples through the partial-annealing zone. The zones with the minimum track ages can be interpreted as the later intersection of the crustal isotherm of 100 °C with repect to the adjacent areas with the maximum values. Track lengths, in turn, determine the time of residence of the sample within the temperature range of the partial-annealing zone (60–90 °C): The longest time yilds a wide distribution of decreased track lengths. Thermotectonic modeling is described in the series of works (Gleadow et al., 2002; Kohn et al., 2005) for southern Canada, South Africa, East Africa, and Australia. Paleotemperatures are shown on the scheme as paleoisotherms. Provided that all the samples were taken from the day surface, a series of such images for similar times demonstrates the dynamics and character of cooling of rock on the regional scale. The regional thermal evolution is converted into denudation chronology with regard to the geothermal gradient, which averages 25–30 °C. A series of denudation images shows the quantities of denuded material over the selected period and, therefore, the rates of denudation events tied to the absolute geochronological scale. Denudation data combined with the data of the digital elevation model are used to model the evolution of paleotopography. The latter is estimated by successive subtraction of the quantity of denuded material on the current surface during some period with the setting of isostatic equilibrium. Such reconstructed paleoaltitude estimates should be interpreted with caution, because they reflect only a passive response to denudation discharge but do

not reflect possible accompanying episodes of tectonic uplifting, the fall of the level with respect to the Earth’s present-day surface, or correction for local deformation and/or thrusting (Kohn et al., 2005). Uplifting is the main factor measured to obtain information on tectonic forces in mountain belts (England and Molnar, 1990). The term “tectonic uplifting” is used when vertical movements have a tectonic driving force. Tectonic uplifting is mostly reached by crustal thickening with horizontal shortening, which is controlled by the velocities of tectonicplate movement (Harrison, 1994). The removal of material from the surface suggests the removal of mass from the crust, which disturbs density equilibrium; the disturbance is then compensated for by isostatic response, but the denudation rates give no information on the rates of surface uplifting (England and Molnar, 1990). Moreover, high altitudes are not the main evidence for high erosion rates. In fact, the altitude difference in a horizontal segment (topography) is the key factor. Topography mainly depends on fluvial or glacial incision and, therefore, is controlled by climate (Sugai and Ohmori, 1999). On the other hand, a change in topography combined with isostatic response can also cause the so-called “isostatic uplifting” of mountain summits or the uplifting of a ridge. For example, this process is responsible for 20–30% of uplifting of peaks in the Himalayan orogen (Montgomery, 1994). The isostatic component is due to the erosion discharge of the rock column and, probably, to fluvial incision, which, in turn, is related to climate changes; the changes are sometimes caused by the growth of the orogen itself (Hartshorn et al., 2002; Peizhen et al., 2001; Willett, 1999). The uplifting of the Tibetan Plateau is a good illustration of this fact; it resulted in the dramatic change of the atmospheric-circulation model in Asia, wet monsoon climate in Southeast Asia, and arid conditions in Central Asia. Thus, track analysis reveals the stages of peneplanation and tectonic activity, whereas the thermal evolution of apatite shows the erosion rate and the thickness of the denuded rocks. The thermal evolution of the rocks is modeled using the software (Ketcham et al., 2005) with plots which show the trend of change of the rock temperature regime over time (t, T). Based on the temperature gradient (25–30 °C/km), the obtained t, T-trend can be used to estimate how thick the denuded layer was and how long the denudation lasted. The gentle slope of the t, T-trend is interpreted as a period of regional tectonic stability with peneplanation. The inclinations of the line indicate the denudation rate and intensity, which can be regarded as the regional degree of tectonic activity, expressed in the growth of mountain ranges and uplifts.

Geologic position and sampling sites Gorny Altai is part of the world’s largest Central Asian intracontinental mountain region (Fig. 1). It stretches from the zone of active deformations of the Indo-Eurasian collision (Himalayas, Pamirs, and Tibet) to the north through the Tien Shan, including the mountain belts of southern Siberia and the

E.V. Vetrov et al. / Russian Geology and Geophysics 57 (2016) 95–110

97

Fig. 1. Position of Gorny Altai on the topographical sketch map of Central Asia. 1, thrusts; 2, shears.

Baikal Rift Zone of Eat Siberia. The northern tip of the deformation front is the Siberian Platform. The basement structure of Central Asia consists of numerous Precambrian microcontinents of different sizes, surrounded by Paleozoic– Mesozoic fold belts. As a result of distant impact of the Indo-Eurasian collision, deformations were passed to long distances by the “domino effect,” through the rigid structures of the Precambrian microcontinents. The compression caused the formation of mountain ranges at the place of folded areas, and the microcontinents served as a basement for Cenozoic basins (Tarim, Tajik, Junggar, etc.) (Buslov, 2012; Buslov et al., 2008; Dobretsov et al., 1996). As a result of distant impact of convergence between Indian and Eurasian continents, recent tectonic processes in Central Asia were expressed in the formation of large lithospheric folds complicated by fault zones; basins of different morphologies, separated by ridges, formed in these zones (Delvaux et al., 2013). During some periods of neotectonic evolution, the basins formed as compression structures (ramps or halframps); during others, as strike-slip extension structures (grabens and pull-apart structures) or shear zones not clearly reflected in topography (Buslov et al., 2007, 2008, 2012, 2013; De Grave et al., 2002, 2007a,b, 2012, 2013; Delvaux et al., 1995, 2013; Dobretsov et al., 1995, 1996; Glorie et al., 2010, 2012a; Molnar and Tapponnier, 1975; Sobel et al., 2006; Thomas et al., 2002; Zabelina et al., 2013). The most contrasting Cenozoic movements and deformations took place in southeastern Gorny Altai, near the Mongolian frontier (Figs. 2, 3); the Chulyshman (Kurai– Chulyshman block) and Ukok (northeastern South Altai block) high-altitude plateaus and separating ridges (North Chuya, South Chuya, Kurai, Shapshal, and others). In the Pleistocene the deformations spread to the more northerly regions of Gorny Altai, where they were expressed in the formation of

fault-line basins (e.g., Lake Teletskoe) or E–W tectonic steps. The contrast of neotectonic movements in Gorny Altai decreases northward. Arched uplifts formed in central and northern Gorny Altai; they were bordered by the E–W fault zone along which the Paleozoic rocks of the Gorny Altai block are thrust over the Oligocene–Quaternary deposits of the Biya–Barnaul basin with an amplitude of ≤700 m (Dobretsov et al., 1995; Zyat’kova, 1977). The reconstructions of Late Mesozoic–Cenozoic evolution of southeastern Gorny Altai are based on the thermotectonic evolution of the South Altai, Kurai–Chulyshman, and West Sayan blocks (Fig. 2), separated by active fault zones. They formed as a result of renewed activity of Late Paleozoic regional fault structures (Charysh–Terekta, Kurai, Teletskoe– Bashkaus, and Shapshal). Samples for apatite track analysis were recovered mainly from Paleozoic igneous rocks (Table 1). Samples from the rocks of the Chulyshman Plateau (Kurai–Chulyshman block) were taken along a profile oriented from west to east, from altitudes of 1300–2500 m. The Kurai Ridge, bordering on the block in the south, was sampled along the axial part at altitudes of 2170–3024 m. The South Chuya Ridge, bordering on the South Altai block in the north, was analyzed based on rock samples recovered at altitudes of 2700–3500 m. Apatite track dating was carried out at Ghent University (Belgium); results of analyses are shown in Table 2 and Fig. 3. On the assumption that orogeny is controlled by the renewed activity of fault zones, the track analyses permitted obtaining data on the time and intensity of neotectonic movements and substantiating the conclusions on the ages of tectonic activity in the study area and denudation rates and extent. Also, the track dating allowed a conclusion on the evolution of intermontane basins and topography in general.

98

E.V. Vetrov et al. / Russian Geology and Geophysics 57 (2016) 95–110

Fig. 2. Neotectonic sketch map of Gorny Altai. 1, Cenozoic basins; 2, Late Paleozoic regional shears; 3, secondary faults.

Evolution of tectonic processes and topography in southeastern Altai in the Late Mesozoic–Cenozoic Based on analysis of stratigraphic, tectonic, geomorphological, and geoelectrical data and their correlation with apatite tracking data, we studied the evolution of tectonic processes and topography on the mountain framing of the Kurai–Chuya basin (southeastern Gorny Altai). The Late Mesozoic–Cenozoic evolution of the Kurai Ridge. To interpret the thermal evolution of the rocks of the Kurai Ridge, we used sample KU-43 (Early Cambrian tonalite; 50°06′18″ N; 088°30′52″ E; h = 2557 m), recovered from the base of the Kurai Ridge, because it was the most illustrative for the definition of the fundamentally different stages of the ridge formation (Figs. 3, 4). The thermal evolution of the sample is divided into three stages. Stage 1 (from 125 to 112 Ma (Early Cretaceous, Aptian)), characterized by the steep slope of the t, T-trend, reflects the fast cooling of rock from 120 to 50 °C. At stage 2 (from 112 to 7 Ma (Cretaceous–Neogene)), the t, T-trend becomes nearhorizontal, which suggests the gradual slow cooling of the sample from 50 to 45 °C. Stage 3 (the last 7 Myr (Late Miocene–Holocene)), characterized by the steep slope of the t, T-trend, testifies to the fast cooling of rock from 45 to 20 °C. The change of the normal temperature gradient (25–30 °C/km) shows that the rocks of the Kurai Ridge cooled down to 70 °C over 13 Myr at stage 1, which corresponds to the denudation of a rock series ~2500 m in thickness. At stage 2 the rocks cooled down to 5 °C and a rock series ~180 m in thickness was denuded over 105 Myr. Over the last 7 Myr, the rocks have cooled down to 25 °C, which corresponds to the denudation of a rock series ~825 m in thickness. The rock cooling (denudation) rate is ~5.4 °C/Myr (190 m/Myr)

for stage 1, ~0.05 °C/Myr (1.75 m/Myr) for stage 2, and ~3.6 °C/Myr (120 m/Myr) for stage 3. The Late Mesozoic–Cenozoic evolution of the South Chuya Ridge. By analogy with sample KU-43, the thermal evolution of sample G-07-06 (Devonian diorite; 49°54′48″ N; 087°57′01″ E; h = 2753 m) was studied for the South Chuya Ridge. Four stages were distinguished. Stage 1 (from 88 to 83 Ma (Late Cretaceous, Coniacian–Santonian)), with the steep slope of the t, T-trend, reflects the fast cooling of rock from 120 to 88 °C. Stage 2 (from 83 to 25 Ma (Late Cretaceous–Oligocene)) is characterized by the medium slope of the t, T-trend, which indicates the gradual cooling of the sample from 88 to 40 °C. Stage 3 (from 25 to 8 Myr (Oligocene–Miocene)): near-horizontal t, T-trend and gradual slow cooling from 40 to 35 °C. Stage 4 (the last 8 Myr (Miocene– Holocene)): steep slope of the t, T-trend and fast cooling of the sample from 35 to 22 °C. At stage 1 the rocks of the South Chuya Ridge cooled by 32 °C over 5 Myr, which corresponds to the denudation of a rock series ~1050 m in thickness. At stage 2 the rocks cooled by 48 °C and a rock series ~2000 m in thickness was denuded over 58 Myr. Stage 3: 5 °C cooling and denudation of a rock series ~165 m in thickness over 17 Myr. Stage 4: 13 °C cooling and denudation of a rock series ~435 m in thickness over 8 Myr. The cooling (denudation) rate is ~6.4 °C/Myr (210 m/Myr) for stage 1, ~0.8 °C/Myr (34 m/Myr) for stage 2, ~0.3 °C/Myr (9.7 m/Myr) for stage 3, and ~1.6 °C/Myr (54 m/Myr) for stage 4. The Late Mesozoic–Cenozoic evolution of the Kurai basin. Three stages are distinguished in the thermal evolution of sample KU-58 (Devonian felsite recovered near Kurai Village; 50°10′11″ N; 087°52′52″ E; h = 1564 m), which is the denuded basement of the basin. Stage 1 (from 71 to 53 Ma

Fig. 3. Neotectonic sketch map of southeastern Gorny Altai, with the position of the dated samples and plots showing the trends of change of rock temperature regimes over time (t, T). The sampling sites and track dating are described in Tables 1 and 2. 1, Cenozoic basins; 2, active faults. APAZ, Apatite partial-annealing zone (120–60 °C); t (AFT), apatite fission track age. Left plots: Track occurrence is shown along the vertical axis; track length (µm), along the horizontal one.

E.V. Vetrov et al. / Russian Geology and Geophysics 57 (2016) 95–110 99

100

E.V. Vetrov et al. / Russian Geology and Geophysics 57 (2016) 95–110

Table 1. Sampling sites and lithology No.

Sample no.

Latitude

Longitude

Altitude, m

Correlation

Lithology

1

Al-235

4944′06″

8805′50″

3490

Dzhankol’ pass

Pegmatite

2

Al-239

5016′31″

8804′25″

2720

Il’dugem pass

Mylonite

3

Al-240

5016′00″

8804′00″

2440

Il’dugem pass

Granodiorite

4

GA-09

5043′00″

8915′17″

2240

Mt. Marikbashi

Gneiss

5

GA-12

5045′50″

8918′10″

2785

Mt. Trekhglavaya

Granodiorite

6

GA-13

5045′11″

8919′28″

2500

Mt. Trekhglavaya

Granodiorite

7

GA-20

5037′54″

8914′18″

2015

Uzun-Uyuk River

Granite

8

CHU-01

5105′30″

8749′50″

1350

Chulyshman Plateau

Granite

9

GA-06

5032′21″

8809′23″

1365

Chulyshman Plateau

Gneiss

10

GA-07

5036′21″

8849′11″

1630

Chulyshman Plateau

Gabbro

11

GA-08

5035′25″

8859′58″

1870

Chulyshman Plateau

Gneiss

12

GA-15

5035′57″

8851′10″

1585

Chulyshman Plateau

Gneiss

13

GA-16

5035′30″

8851′04″

1720

Chulyshman Plateau

Amphibolite

14

GA-18

5035′26″

8847′50″

1635

Chulyshman Plateau

Gneiss

15

GA-19

5036′49″

8845′03″

1300

Chulyshman Plateau

Gneiss

16

GA-21

5033′48″

8833′32″

2325

Chulyshman Plateau

Diabase

17

GA-23

5032′57″

8747′30″

1580

Chulyshman Plateau

Granite

18

G07-02

4954′47″

8756′51″

2810

South Chuya Ridge

Granite

19

G07-06

4954′48″

8757′01″

2753

South Chuya Ridge

Diorite

20

KU-57

5009′00″

8853′25″

3000

Kokorya river valley

Felsic tuff

21

KU-52

5008′50″

8853′30″

2830

Kokorya river valley

Quartz porphyry

22

KU-43

5006′18″

8830′52″

2557

Ortolyk Village

Tonalite

23

KU-84

5012′18″

8820′10″

3024

Chagan-Uzun

Diorite

24

KU-66

5012′28″

8810′25″

2170

Tybtugom river valley

Diorite

25

KU-58

5010′11″

8752′52″

1564

Chuya River

Felsic tuff

26

KU-59

5009′31″

8749′14″

1680

Ak-Tru River

Granite

27

KU-42

5026′13″

8741′23″

2514

Chibitka River

Orthogneiss

28

KU-41

5027′20″

8740′29″

2157

Chibitka River

Orthogneiss

29

KU-71

5030′11″

8739′23″

2033

Ulagan pass

Diorite

30

CHU-02

5032′57″

8747′32″

1585

Ulagan pass

Granite

31

KU-69

5035′07″

8746′03″

1609

Ulagan pass

Orthogneiss

32

KU-70

5034′56″

8746′15″

1614

Ulagan pass

Granodiorite

33

KU-68

5034′11″

8747′16″

1630

Ulagan pass

Orthogneiss

34

KU-82

5035′08″

8802′23″

1711

Malyi Ulagan River

Gabbro

35

KU-83

5035′08″

8802′23″

1711

Malyi Ulagan River

Quartz porphyry

36

KU-79

5032′26″

8810′56″

1425

Saratan Village, Aturkol River

Granite

Note. 1–7, (De Grave et al., 2007a,b); 8–17, (De Grave et al., 2008); 18–36, (Glorie et al., 2012a).

(Late Cretaceous–Eocene)), characterized by the steep slope of the t, T-trend, reflects the fast cooling of rock from 120 to 50 °C. At stage 2 (from 53 to 5 Ma (Eocene–Pliocene), the t, T-trend descends, which suggests the gradual heating of the sample from 50 to 64 °C. Stage 3 (the last 5 Myr (Pliocene– Holocene)), characterized by the near-vertical t, T-trend, testifies to the fast cooling of rock from 64 to 23 °C. At stage 1 the rocks of the Kurai basin cooled by 70 °C over 18 Myr, which corresponds to the denudation of a rock series ~2450 m in thickness. At stage 2 the rocks were heated by 14 °C; this might be due to the loading of the basement with Paleogene

and Neogene sediments >400 m in thickness. Over the last 5 Myr, the rocks have cooled by 41 °C and a rock series ~1350 m in thickness has been denuded. The cooling (denudation) rate is ~3.9 °C/Myr (135 m/Myr) for stage 1 and ~8.2 °C/Myr (270 m/Myr) for stage 3. As a result, the Early Cretaceous stage of tectonic activity was defined for the rocks of the Kurai Ridge; this is evidenced by the fast cooling (temperature decrease) of the samples, followed by a relatively quiet period till the Late Pliocene and then a stage of fast exposure to the surface. After the stage of tectonic activity, the South Chuya Ridge continued to grow

E.V. Vetrov et al. / Russian Geology and Geophysics 57 (2016) 95–110

101

Table 2. Results of apatite fission track analysis No.

Sample no. na1

ρs (±1σ)b

Nsc

ρi (±1σ)b

Nic

ρd (±1σ)b

Ndc

e P(χ2)d t(ζ)

lmf

nf

σf 1.7

1

Al-235

30

2.175 (0.055)

1580

1.263 (0.042)

912

4.133 (0.080)

2633

0.36

99.6 ± 4.7

13.8

100

2

Al-239

50

1.219 (0.032)

1486

0.683 (0.024)

832

3.315 (0.083)

1614

1.00

77.9 ± 4.0

11.2

51

2.2

3

Al-240

30

1.657 (0.026)

3937

0.950 (0.020)

2257

3.934 (0.111)

1259

1.00

87.9 ± 3.5

13.5

100

1.3

4

GA-09

30

2.009 (0.068)

862

0.992 (0.046)

457

4.054 (0.080)

2595

0.99

97.5 ± 6.0

–

–

–

5

GA-12

30

3.433 (0.100)

1188

1.407 (0.063)

503

4.049 (0.079)

2592

0.30

132.6 ± 7.6

–

–

–

6

GA-13

30

2.846 (0.078)

1332

0.872 (0.043)

408

3.851 (0.083)

2169

0.99

157.2 ± 9.6

13.4

100

1.4

7

GA-20

20

1.197 (0.031)

1532

0.588 (0.021)

753

4.024 (0.079)

2576

0.76

105.6 ± 5.2

14.1

100

1.4

8

CHU-01

30

1.841 (0.075)

601

1.216 (0.061)

397

3.293 (0.082)

1603

0.52

82.4 ± 5.8

11.8

32

2.3

9

GA-06

60

0.800 (0.029)

768

0.310 (0.018)

298

4.068 (0.080)

2604

1.00

130.8 ± 9.3

13.9

65

2

10

GA-07

50

1.283 (0.041)

1001

0.550 (0.027)

429

3.854 (0.083)

2171

1.00

114.8 ± 7.2

14.0

100

1.4

11

GA-08

20

3.904 (0.109)

1296

2.084 (0.079)

691

4.058 (0.080)

2597

0.99

97.4 ± 5.1

13.3

65

1.8

12

GA-15

30

0.918 (0.038)

582

0.309 (0.023)

179

4.044 (0.079)

2588

0.99

152.7 ± 13.5

–

–

–

13

GA-16

35

0.873 (0.035)

619

0.352 (0.022)

262

4.039 (0.079)

2585

1.00

123.6 ± 9.5

–

–

–

14

GA-18

30

4.899 (0.085)

3307

2.609 (0.062)

1761

3.844 (0.083)

2165

1.00

91.4 ± 3.5

13.6

100

1.4

15

GA-19

50

2.698 (0.062)

1865

1.463 (0.046)

1011

4.034 (0.079)

2582

0.98

100.4 ± 4.5

14.0

100

1.5

16

GA-21

25

1.338 (0.047)

795

0.706 (0.034)

429

4.019 (0.079)

2572

1.00

97.3 ± 6.2

13.0

30

1.7

17

GA-23

30

0.964 (0.028)

1157

0.463 (0.020)

555

3.833 (0.82)

2159

0.99

104.4 ± 5.9

14.2

100

1.5

18

G07-02

13

6.410 (0.298)

464

2.904 (0.201)

208

3.889 (0.101)

1492

0.91

118.0 ± 10.4

–

–

–

19

G07-06

20

25.470 (0.860)

900

16.930 (0.690)

597

3.882 (0.093)

1738

0.55

82.0 ± 4.9

13.94

52

1.43

20

KU-57

12

5.427 (0.290)

350

4.161 (0.258)

261

4.043 (0.103)

1501

0.27

69.1 ± 6.0

–

–

–

21

KU-52

25

10.718 (0.321)

1115

7.881 (0.274)

828

3.999 (0.079)

2559

0.92

72.2 ± 3.7

13.18

62

1.2

22

KU-43

9

10.803 (0.482)

502

7.668 (0.403)

363

3.853 (0.092)

2462

0.64

73.7 ± 5.5

13.74

37

0.96

23

KU-84

16

15.781 (0.310)

2530

11.590 (0.268)

1852

3.841 (0.083)

2460

0.62

72.2 ± 2.8

12.72

97

1.78

24

KU-66

9

6.678 (0.356)

352

5.112 (0.312)

269

3.947 (0.079)

2526

0.65

61.9 ± 5.2

–

–

–

25

KU-58

16

7.683 (0.321)

572

6.226 (0.291)

457

3.938 (0.078)

2520

0.78

57.1 ± 3.8

12.21

30

1.07

26

KU-59

20

5.679 (0.288)

388

4.569 (0.257)

316

3.942 (0.078)

2523

0.97

63.5 ± 5.0

–

–

–

27

KU-42

35

5.277 (0.154)

1173

3.567 (0.127)

794

3.965 (0.079)

2538

0.92

82.5 ± 4.3

13.53

91

1.18

28

KU-41

14

8.320 (0.358)

541

5.207 (0.278)

330

3.962 (0.079)

2535

0.37

88.9 ± 6.6

–

–

–

29

KU-71

20

6.369 (0.274)

539

4.481 (0.226)

392

3.982 (0.079)

2548

0.86

78.0 ± 5.5

13.03

31

1.28

30

CHU-02

20

7.094 (0.235)

908

4.141 (0.180)

530

3.833 (0.082)

2159

0.97

87.0 ± 5.2

14.03

100

1.55

31

KU-69

25

20.260 (0.370)

3006

12.389 (0.288)

1845

3.973 (0.079)

2543

0.52

83.7 ± 3.2

14.02

100

1.02

32

KU-70

20

20.251 (0.422)

2299

14.770 (0.359)

1696

3.977 (0.079)

2545

0.06

73.2 ± 2.9

13.37

100

1.1

33

KU-68

30

13.179 (0.308)

1828

9.560 (0.261)

1343

3.969 (0.079)

2540

0.06

73.8 ± 3.2

13.10

100

1.29

34

KU-82

6

13.507 (0.694)

379

8.472 (0.554)

234

3.990 (0.079)

2554

0.28

83.2 ± 7.2

–

–

–

35

KU-83

15

11.366 (0.381)

889

7.162 (0.305)

551

3.993 (0.079)

2555

0.96

80.8 ± 4.8

13.53

37

1.27

36

KU-79

30

10.885 (0.245)

1976

5.623 (0.175)

1029

3.875 (0.078)

2480

0.92

98.6 ± 4.5

13.66

49

1.04

a

Number of analyzed grains. ρs, ρi, ρd, Densities of spontaneous and induced tracks and induced tracks at the external detector, 105 tracks/cm2. c N , N , N , Number of spontaneous and induced tracks and induced tracks at the external detector. s i d d Probability of the constant ρ /ρ ratio in the dated grains. s i e Apatite fission track ages (Ma). f Data on track lengths: average track length (l ) and standard deviation (σ), obtained by measurements of the number (n) of limited natural horizontal tracks. m b

but at a considerably lower rate, varying within 1 °C/Myr; the Late Pliocene tectonic pulse began at 6 (sample G-07-06) or 2.5 Ma (sample Al-235). In the sample from the basement of the Kurai basin (KU-58), the Cretaceous–Early Paleogene tectonic stage is observed; afterward the rocks subside because of Eocene–Miocene sedimentation and are exposed to the surface at a rate of ~8 °C/Myr (270 m/Myr) in the Pliocene– Quaternary.

Correlation of geological and geomorphological data with AFT data. It is believed that a peneplain and weathering crusts formed in Gorny Altai in the Late Mesozoic–Early Paleocene (Devyatkin, 1965; Zykin and Kazanskii, 1995). In the track dating of the rocks of the Kurai–Chulyshman block (Fig. 3), this stage is distinguished by the gentle slope of the t, T-trend, which begins at 150 to 80 Ma and ends at 7 to 0 Ma. The South Altai block is characterized by track dating

102

E.V. Vetrov et al. / Russian Geology and Geophysics 57 (2016) 95–110

Fig. 4. Neotectonic sketch map projected on the shaded elevation model and geological sections of the Kurai–Chuya basin and mountain framing. 1, strike-slip fault–thrust and displacement direction; 2, thrusts; 3, lithologic boundaries, from VES and TEM data (Nevedrova et al., 2014); 4, position of sections; 5, position of the studied samples; their numbers correspond to those in Tables 1 and 2.

to a smaller extent. The tentative conclusion can be made that its northern part (Fig. 3, points 18, 19) has not been denuded intensely over the last 80 years, whereas in the southern part (Fig. 3, point 1), near the active fault zone, a rock series ~2 km in thickness has been denuded over the last 7 Myr. Similar activity is typical of the framing of the Kurai–Chulyshman block. The observed regularity can be explained by the fact that relics of the ancient peneplanation surface with remnants of Cenozoic sediments are preserved to a larger extent in the inner parts of the blocks, which are uplifted with respect to intermontane basins filled with Cenozoic sediments (e.g., in the Kurai–Chuya basin). On all the plots (Fig. 3), the t, T-trends in the period before 80 Ma have a steep slope, which testifies to intense denudation (>2 km over 3–5 Myr) and can be explained by the manifestation of a large orogenic stage.

Models for the thermal evolutions of the basement rocks of the Kurai basin and Kurai and South Chuya Ridges are compared with the evolution of Cenozoic sedimentation in the Kurai–Chuya basin in Fig. 5. Four distinct types of sediments are recognized which differ in the character of sedimentation. The first type includes Late Cretaceous–Paleogene weathering crust and the Oligocene Karachum Formation, which consists of its redeposition products; the second, the carbonaceous sediments of the Kosh-Agach Formation; the third, the lacustrine alluvium and clay–carbonate sediments of the Tueryk and Kyzylgir Formations; and the fourth, the molasse of the Beken and Bashkaus Formations. According to track dating, medium-dissected topography with altitudes of 1000 to 1600 m existed in southeastern Gorny Altai (Fig. 6) in the late Mesozoic (95–65 Ma). In the Paleogene (65–25 Ma), the differentiation of topography took place, with the formation of high-altitude topography (from

E.V. Vetrov et al. / Russian Geology and Geophysics 57 (2016) 95–110

103

Fig. 5. Evolution of sedimentation in the Kurai–Chuya basin (correlation scheme for stratigrphic data and results of track analysis). 1, Karachum (kch) Formation, which consists of products of weathering-crust redeposition; 2, carbonaceous sediments of the Kosh-Agach (ksch) Formation; 3, lacustrine sediments of the Tueryk (tr) Formation; 4, lacustrine alluvium of the Kyzylgir (kzg) Formation; 5, molasse of the Beken (bek) Formation; 6, molasse of the Bashkaus (bshk) Formation.

1000 to 2500 m). During that period the South Altai, Kurai–Chulyshman, and West Sayan blocks were separated; they are high-altitude plateaus which are separated by basins located in regional fault zones (Charysh–Terekta, Kurai, and Shapshal). Topography formed by lithospheric folding, including the peneplanation surface, as a result of the initial stage of distant impact of the Indo-Eurasian collision (Delvaux et al., 2013). For example, the formation of an anticline is traced for the Kurai–Chulyshman block starting from 25 Ma. At the same time, a syncline filled with the sediments of the Kurai–Chuya basin formed on the peneplanation surface to the southwest. In the late Oligocene, the basin was filled with redeposited weathering crust (Karachum Formation and its analogs) supplied from high-altitude plateaus (anticlines).

Later (26–12 Ma), topography did not change much and the basins were filled with the carbonaceous sediments of the Kosh-Agach Formation. The deepening of the basin with the clay–carbonate sedimentation of the Late Miocene Tueryk and Kyzylgir Formations (total thickness of 565 m) is reflected in the descent of the T, t- trend of the sample from the basement of the Kurai basin. At that time tectonic scarps began to form and the erosion and accumulation of coarse-clastic sediments in the basin became more intense (Devyatkin, 1965; Zykin and Kazanskii, 1995). When the mountain framing of the Kurai–Chuya basin began to grow, that was marked by the formation of coarse interbeds with poorly rounded fragments at the basin edges. In thermal-evolution models, this event is reflected in the change of the slope of the T, t-trend to a

Fig. 6. Schemes for Late Mesozoic–Cenozoic topography in southeastern Gorny Altai over the last 95 Myr. 1, lines of Late Paleozoic regional faults; 2, Cenozoic basins; 3, axis of the anticline of the peneplain of the Kurai–Chulyshman block.

104 E.V. Vetrov et al. / Russian Geology and Geophysics 57 (2016) 95–110

E.V. Vetrov et al. / Russian Geology and Geophysics 57 (2016) 95–110

steeper one. Afterward (by the example of thermal evolution of the Kurai Ridge), the slope of the T, t-trend became steeper; the tectonic movements became intense; and the blocks were thrust over the sediments of the basins, with the gradual involvement of their edges in the orogeny. In the geologic record, that stage was expressed in the accumulation of the Late Pliocene–Quaternary molasse of the Beken and Bashkaus Formations, ≤250 m in thickness (Devyatkin, 1965; Zykin and Kazanskii, 1995).

Thermotectonic modeling of southeastern Gorny Altai The regional distribution of track parameters (ages and average lengths) for southeastern Gorny Altai is shown in Fig. 7a, b. The distribution of track ages is from 60 to 150 Ma, with younger ages concentrated near the Kurai– Chuya trough and north to the Teletskoe graben. This so-called anomalous zone means the later intersection of the crustal

105

isotherm of 100 °C with respect to the adjacent areas and, therefore, later vertical uplifting. On the map showing the distribution of average track lengths, the anomalous zone (warmer colors, Fig. 7b) with low values (12 µm) means the delay of massifs in the partial-annealing zone, whereas the green hues show the fast exposure of the rocks to the surface. The zone distinguished based on track parameters correlates with the present-day seismically active region, whose presence is proven by the geophysical observations of the last 50 years: The epicenters of the strongest earthquakes and aftershocks are concentrated near the Kurai–Chuya trough (Fig. 7c, d). The results of thermal-evolution modeling reflect the regional history of cooling of the present-day surface rocks during their transport through the upper crust. Figure 8 shows how the rocks of southeastern Gorny Altai have cooled over the last 95 Myr, with intervals of 10 Myr. The dynamics of cooling of the area is inhomogeneous, but some general regularities are observed. The periods from 95 to 75 Ma and

Fig. 7. Regional distribution of track parameters (ages and average lengths) in southeastern Gorny Altai for intervals of 60–150 Ma (a), distribution of average track lengths (b), and present-day seismic activity: position of aftershocks (c) and epicenters of the strongest earthquakes (d). 1, epicenters of earthquakes with M = 3 (a), 5 (b), and 8 (c); 2, epicenters of aftershocks. See Fig. 6 for the rest of the legend.

Fig. 8. History of cooling of rocks in southeastern Gorny Altai over the last 95 Myr, with 10-Myr intervals. See legend in Fig. 6.

106 E.V. Vetrov et al. / Russian Geology and Geophysics 57 (2016) 95–110

Fig. 9. Model for regional denudation events over the last 95 Myr, with 10-Myr intervals. See legend in Fig. 6.

E.V. Vetrov et al. / Russian Geology and Geophysics 57 (2016) 95–110 107

108

E.V. Vetrov et al. / Russian Geology and Geophysics 57 (2016) 95–110

the last 15 Myr are characterized by the fastest cooling. The paleoisotherms are stable from 55 to 25 Ma. A model for regional denudation events over the last 95 Myr with 10-Myr intervals is presented in Fig. 9. The volumes of denuded rock series from 30 to 1300 m in size are shown in a series of images. The change of regions with the maximum denudation indicates the stages of activity of Late Paleozoic regional fault zones. In southeastern Gorny Altai, we recognize four stages with different denudation extents (rates) over the last 95 Myr. At stage 1 (95–55 Myr), the junction of the Charysh–Terekta and Kurai faults experienced the most intense denudation. The denudation in the other areas was weak. At stage 2 (55–25 Ma), the entire area of southeastern Gorny Altai was characterized by tectonic stability with minimum denudation. Stage 3 (25–15 Ma) differs from stage 2 in the slightly larger extent of denudation for the Kurai–Chulyshman block with respect to general tectonic stability. Stage 4 (the last 15 Myr) is characterized by the intense renewed activity of fault zones in southeastern Gorny Altai with the maximum denudation near the Kurai– Chuya trough. Only estimates of vertical movements based on track dating data are taken into account in thermotectonic modeling, but the applied approach has high potential for reconstructing topography evolution over almost 100 Myr (Fig. 6). The series of paleotopographical maps shows that the territory of southeastern Gorny Altai evolved as a peneplanation surface with an uplifted northeastern part (Shapshal Ridge of the West Sayan block) from 95 to 65 Ma. The interval of 55–25 Ma was characterized by homogeneous denudation and the lack of tectonic uplifts. Over the last 15 Myr, the rocks of the South Altai and West Sayan blocks have been denuded intensely, whereas the Kurai–Chulyshman block experienced minimum denudation. Paleogeographical schemes over the last 95 Myr with 10-Myr intervals are given in Fig. 6. The present-day orography of southeastern Gorny Altai has formed over the last 5 Myr. That period was marked by the formation of the highest mountain ranges and intermontane basins in which the molasses of the Beken and Bashkaus Formations accumulated (≤250 m in thickness) (Devyatkin, 1965; Zykin and Kazanskii, 1995). The lacustrine sediments of the Tueryk and Kyzylgir Formations (total thickness of ≤565 m) accumulated from 12 to 5 Ma. Lacustrine sediments were preserved in the Kurai– Chuya basin and might have spread over a much wider territory. Judging by the results of thermotectonic modeling, shown on paleogeographical schemes (Fig. 6), large lakes existed both in the southern and northern prts of the region.

Discussion and conclusions Results of AFT dating have been summarized and correlated with stratigraphic, geoelectrical, tectonic, and geomorphological data. The average regional rate of rock denudation in southeastern Gorny Altai is reflected in three thermotectonic events: (1) Late Cretaceous–Early Paleogene tectonic activity

with a denudation rate of ~200 m/Myr, which might be related to the distant impact of the Mongol–Okhotsk orogeny; (2) Middle Paleogene–Early Neogene stabilization with peneplanation; and (3) Neogene–Quaternary “stepwise” tectonic activity with a denudation rate of ≤270 m/Myr, related to the distant impact of the Indo-Eurasian collision. We present results of study of the evolution of regional tectonic processes and topography over the last 100 Myr by analysis of apatite track dating and geological and geophysical data. A series of paleotopographical maps has been compiled for southeastern Gorny Altai; they show that (1) the territory evolved as a peneplanation surface with an uplifted northeastern part (Shapshal Ridge of the West Sayan block) from 95 to 55 Ma; (2) the interval of 55–25 Ma was characterized by homogeneous denudation and the lack of large tectonic uplifts; (3) at ~25 Ma, the initial stage of compression caused by the Indo-Eurasian collision manifested itself as formation of anticline of the Chulyshman plateau peneplain; (4) over the last 15 Myr, the rocks in the southern (South Altai block) and northwestern (West Sayan block) parts have been denuded intensely, whereas the central part (Kurai–Chulyshman block) experienced minimum denudation; and (5) the highest mountain ranges and intermontane basins have formed over the last 7 Myr. This study carried out under the Research Project of the IGM SB RAS and the grant no. 154-17-20000 of the Russian Scientific Foundation

References Brown, R.W., Summerfield, M.A., Gleadow, A.J.W., 1994. Apatite fission track analysis: Its potential for the estimation of denudation rates and implications of long-term landscape development, in: Kirkby, M.J. (Ed.), Process Models and Theoretical Geomorphology. Wiley, New York, pp. 23–53. Buslov, M.M., 2012. Geodynamic nature of the Baikal Rift Zone and its sedimentary filling in the Cretaceous–Cenozoic: the effect of the far-range impact of the Mongolo-Okhotsk and Indo-Eurasian collisions. Russian Geology and Geophysics (Geologiya i Geofizika) 53 (9), 955–962 (1245–1255). Buslov, M.M., Zykin, V.S., Novikov, I.S. Delvaux, D., 1999. The Cenozoic history of the Chuya basin (Gorny Altai): structure and geodynamics. Geologiya i Geofizika (Russian Geology and Geophysics) 40 (12), 1720–1736 (1702–1713). Buslov, M.M., Watanabe, T., Smirnova, L.V., Fujiwara, I., Iwata, K., De Grave, I., Semakov, N.N., Travin, A.V., Kir’yanova, A.P., Kokh, D.A., 2003. Role of strike-slip faults in Late Paleozoic-Early Mesozoic tectonics and geodynamics of the Altai-Sayan and East Kazakhstan folded zone. Geologiya i Geofizika (Russian Geology and Geophysics) 44 (1–2), 49–75 (47–71). Buslov, M.M., De Grave, J., Bataleva, E.A., Batalev, V.Yu., 2007. Cenozoic tectonics and geodynamics in the Tian Shan: synthesis of geology and geophysical data. J. Asian Earth Sci. 29, 205–214. Buslov, M.M., Kokh, D.A., De Grave, J., 2008. Mesozoic-Cenozoic tectonics and geodynamics of Altai, Tien Shan, and Northern Kazakhstan, from apatite fission-track data. Russian Geology and Geophysics (Geologiya i Geofizika) 49 (9), 648–654 (862–870). Buslov, M.M., Geng, H., Travin, A.V., Otgonbaatar, D., Kulikova, A.V., Chen Ming, Glorie, S., Semakov, N.N., Rubanova, E.S., Abildaeva, M.A., Voitishek, E.E., Trofimova, D.A., 2013. Tectonics and geodynamics of Gorny Altai and adjacent structures of the Altai–Sayan folded area.

E.V. Vetrov et al. / Russian Geology and Geophysics 57 (2016) 95–110 Russian Geology and Geophysics (Geologiya i Geofizika) 54 (10), 1250–1271 (1600–1628). Deev, E.V., Nevedrova, N.N., Zol’nikov, I.D., Rusanov, G.G., Ponomarev, P.V., 2012. Geoelectrical studies of the Chuya basin sedimentary fill (Gorny Altai). Russian Geology and Geophysics (Geologiya i Geofizika) 53 (1), 92–107 (120–139). De Grave, J., Van den Haute, P., 2002. Denudation and cooling of the Lake Teletskoye Region in the Altai Mountains (South Siberia) as revealed by apatite fission-track thermochronology. Tectonophysics 349, 145–159. De Grave, J., Buslov, M.M., Van den Haute, P., Dehandschutter, B., 2007a. Meso-Cenozoic evolution of mountain range—intramontane basin systems in the southern Siberian Altai Mountains by apatite fission track thermochronology. J. Asian Earth Sci. 29, 2–9. De Grave, J., Buslov, M.M., Van den Haute, P., 2007b. Distant effects of India—Eurasia convergence and Mesozoic intracontinental deformation in Central Asia: Constraints from apatite fission-track thermochronology. J. Asian Earth Sci. 29, 188–204. De Grave, J., Van den Haute, P., Buslov, M.M., Dehandschutter, B., Glorie, S., 2008. Apatite fission-track thermo-chronology applied to the Chulyshman Plateau, Siberian Altai Region. Radiat. Meas. 43, 38–42. De Grave, J., Buslov, M.M., Van den Haute, P., Metcalf, J., Dehandschutter, B., McWilliams, M.O., 2009. Multi-method chronometry of the Teletskoye graben and its basement, Siberian Altai Mountains: new insights on its thermo-tectonic evolution, in: Lisker, F., Ventura, B., Glasmacher, U.A. (Eds.), Thermochronological Methods: From Paleotemperature Constraints to Landscape Evolution Models. Geol. Soc. London, Spec. Publ. 324, 237–259. De Grave, J., Glorie, S., Buslov, M.M., Izmer, A., Fournier-Carrie, A., Elburg, M., Batalev, V.Yu., Vanhaeke, F., Van den Haute, P., 2011a. The thermo-tectonic history of the Song-Kul Plateau, Kyrgyz Tien Shan: constraints by apatite and titanite thermo-chronometry and zircon U/Pb dating. Gondwana Res. 20, 745–763. De Grave, J., Glorie, S., Zhimulev, F.I., Buslov, M.M., Elburg, M., Vanhaecke, F., Van den Haute, P., 2011b. Emplacement and exhumation of the Kuznetsk-Alatau basement (Siberia): implications for the tectonic evolution of the Central Asian Orogenic Belt and sediment supply to the Kuznetsk, Minusa and West Siberian Basins. Terra Nova 23, 248–256. De Grave, J., Glorie, S., Ryabinin, A., Zhimulev, F.I., Buslov, M.M., Izmer, A., Elburg, M.A., Vanhaecke, F., 2012. Late Palaeozoic and Meso-Cenozoic tectonic evolution of the southern Kyrgyz Tien Shan: Constraints from multi-method thermochronology in the Trans-Alai, Turkestan-Alai segment and the southeastern Ferghana Basin. J. Asian Earth Sci. 44, Spec. Issue, 149–168. De Grave, J., Glorie, S., Buslov, M.M., Stockli, D.F., McWilliams, M.O., Batalev, V.Y., Van den Haute, P., 2013. Thermo-tectonic history of the Issyk-Kul basement (Kyrgyz Northern Tien Shan, Central Asia). Gondwana Res. 23 (3), 998–1020. Delvaux, D., Theunissen, K., Van-der-Meier, R., Berzin, N., 1995. Dynamics and paleostress of the Cenozoic Kurai–Chuya depression of Gorny Altai (South Siberia): tectonics and climatic control. Geologiya i Geofizika (Russian Geology and Geophysics) 36 (10), 31–51 (26–45). Delvaux, D., Cloetingh, S., Beekman, F., Sokoutis, D., Burov, E., Buslov, M.M., Abdrakhmatov, K.E., 2013. Basin evolution in a folding lithosphere: Altai-Sayan and Tien Shan belts in Central Asia. Tectonophysics 602, 194–222. De Pelsmaeker, E., Glorie, S., Buslov, M.M., Zhimulev, F.I., Poujol, M., Valeriy V. Korobkin, V.V., Vanhaecke, F., Vetrov, E.V., De Grave, J., 2015. Late-Paleozoic emplacement and Meso-Cenozoic reactivation of the southern Kazakhstan granitoid basement. Tectonophysics 622, 416–433, doi: 10.1016/j.tecto.2015.06.14. Devyatkin, E.V., 1965. Cenozoic Sediments and Neotectonics of Southeastern Altai (Trans. Geol. Inst., Issue 126) [in Russian]. Nauka, Moscow. Dobretsov, N.L., Berzin, N.A., Buslov, M.M., Ermikov, V.D., 1995. General aspects of the evolution of the Altai region and the interrelationships between its basement pattern and neotectonic structural development. Geologiya i Geofizika (Russian Geology and Geophysics) 36 (10), 5–19 (3–15). Dobretsov, N.L., Buslov, M.M., Delvaux, D., Berzin, N.A., Ermikov, V.D., 1996. Meso- and Cenozoic tectonics of the Central Asian mountain belt:

109

effects of lithospheric plate interaction and mantle plume. Int. Geol. Rev. 38, 430–466. England, P., Molnar, P., 1990. Surface uplift, uplift of rocks, and exhumation of rocks. Geology 18, 1173–1177. Farley, K.A., 2002. (U–Th)/He dating: Techniques, calibrations, and applications, in: Noble Gases in Geochemistry and Cosmochemistry. Rev. Mineral. Geochem. 47, 819–844. Gleadow, A.J.W., Kohn, B.P., Brown, R.W., O’Sullivan, P.B., Raza, A., 2002. Fission track thermotectonic imaging of the Australian continent. Tectonophysics 349, 5–21. Glorie, S., De Grave, J., Buslov, M.M., Elburg, M.A., Stockli, D.F., Gerdes, A., Van den Haute, P., 2010. Multi-method chronometric constraints on the evolution of the Northern Kyrgyz Tien Shan granitoids (Central Asian Orogenic Belt): from emplacement to exhumation. J. Asian Earth Sci. 38, 131–146. Glorie, S., De Grave, J., Buslov, M.M., Zhimulev, F.I., Stockli, D.F., Batalev, V.Yu., Izmer, A., Van den Haute, P., Vanhaecke, F., Elburg, M.A., 2011. Thermotectonic history of the Kyrgyz South Tien Shan (Atbashi-Inylchek) suture zone: the role of inherited structures during deformation-propagation. Tectonics 30 (6), doi: 10.1029/2011TC002949. Glorie, S., De Grave, J., Buslov, M.M., Zhimulev, F.I., Elburg, M.A., Van den Haute, P., 2012a. Structural control on Meso-Cenozoic tectonic reactivation and denudation in the Siberian Altai: Insights from multimethod thermochronometry. Tectonophysics 544–545, 75–92. Glorie, S., De Grave, J., Delvaux, D., Buslov, M.M., Zhimulev, F.I., Van den Haute, P., 2012b. Tectonic history of the Irtysh shear zone (NE Kazakhstan): new constraints from zircon U/Pb dating, apatite fission track dating and paleostress analysis. J. Asian Earth Sci. 45, 138–149. Gol’din, S.V., Kuchai, O.A., 2008. Seismotectonic deformations in the vicinity of strong earthquakes in Altai. Fizicheskaya Mezomekhanika 11 (1), 5–13. Harrison, C.G.A., 1994. Rates of continental erosion and mountain building. Geol. Rundsch. 83, 431–447. Hartshorn, K., Hovius, N., Dade, W.B., Slingerland, R.L., 2002. Climatedriven bedrock incision in an active mountain belt. Science 297, 2036–2038. Ketcham, R.A., 2005. Forward and inverse modelling of low-temperature thermochronometry data. Rev. Mineral. Geochem. 58, 275–314. Kohn, B.P., Gleadow, A.J.W., Brown, R.W., Gallagher, K., Lorencak, M., Noble, W.P., 2005. Visualizing thermotectonic and denudation histories using apatite fission-track thermochronology. Rev. Mineral. Geochem. 58, 527–565. Laslett, G.M., Green, P.F., Duddy, I.R., Gleadow, A.J.W., 1987. Thermal annealing of fission tracks in apatite. 2. A quantitative analysis. Chem. Geol. (Isot. Geosci. Sect.) 65, 1–13. Lunina, O.V., Gladkov, A.S., Novikov, I.S., Agatova, A.R., Vysotskii, E.M., Emanov, A.A., 2008. Geometry of the fault zone of the 2003 Ms = 7.5 Chuya earthquake and associated stress fields, Gorny Altai. Tectonophysics 453 (1–4), 276–294. Molnar, P., Tapponnier, P., 1975. Cenozoic tectonics of Asia: Effects of a continental collision. Science 189, 419–426. Montgomery, D.R., 1994. Valley incision and the uplift of mountain peaks. J. Geophys. Res. 99, 13913–13921. Nevedrova, N.N., Deev, E.V., Sanchaa, A.M., 2014. Deep structure and margins of the Kurai Basin (Gorny Altai), from controlled-source resistivity data. Russian Geology and Geophysics (Geologiya i Geofizika) 55 (1), 98–107 (119–132). Novikov, I.S., Mistryukov, A.A., Trefua, F., 1995. Geomorphological structure of the Chuya intermontane depression. Geologiya i Geofizika (Russian Geology and Geophysics) 36 (10), 64–74 (57–66). Peizhen, Z., Molnar, P., Downs, W.R., 2001. Increased sedimentation rates and grain sizes 2–4 Myr ago due to the influence of climate change on erosion rates. Nature 410, 891–897. Sobel, E.R., Oskin, M., Burbank, D., Mikolaichuk, A., 2006. Exhumation of basement-cored uplifts: Example of the Kyrgyz range quantified with fission track thermochronology. Tectonics 25 (2), doi: 10.1029/2005TC 001809. Sugai, T., Ohmori, H., 1999. A model of relief forming by tectonic uplift and valley incision in orogenesis. Basin Res. 11, 43–57.

110

E.V. Vetrov et al. / Russian Geology and Geophysics 57 (2016) 95–110

Thomas, J.C., Lanza, R., Kazansky, A., Zykin, V., Semakov, N., Mitrokhin, D., Delvaux, D., 2002. Paleomagnetic study of Cenozoic sediments from the Zaisan basin (SE Kazakhstan) and the Chuya depression (Siberian Altai): tectonic implications for central Asia. Tectonophysics 351, 119– 137. Willet, S.D. Orogeny and orography: the effects of erosion on the structure of mountain belts. J. Geophys. Res. 104 (B12), 28,957–28,981. Zabelina, I.V., Koulakov, I.Yu., Buslov, M.M., 2013. Deep mechanisms in the Kyrgyz Tien Shan orogen (from results of seismic tomography).

Russian Geology and Geophysics (Geologiya i Geofizika) 54 (7), 695–706 (906–920). Zyat’kova, L.K., 1977. Structural Geomorphology of the Altai–Sayan Mountain Region (Trans. Inst. Geol. Geophys., Issue 366) [in Russian]. Nauka, Novosibirsk. Zykin, V.S., Kazanskii, A.Yu., 1995. Stratigraphy and paleomagnetism of Cenozoic (pre-Quaternary) deposits of the Chuya Depression in Gorny Altai. Geologiya i Geofizika (Russian Geology and Geophysics) 36 (10), 75–90 (67–80).