Meso-Cenozoic tectonic evolution of the Talas-Fergana region of the Kyrgyz Tien Shan revealed by low-temperature basement and detrital thermochronology

Abstract

International audienceThis study provides new low-temperature thermochronometric data, mainly apatite fission track data on the basement rocks in and adjacent to the Talas-Fergana Fault, in the Kyrgyz Tien Shan in the first place. In the second place, we also present new detrital apatite fission track data on the Meso-Cenozoic sediments from fault related basins and surrounding intramontane basins. Our results confirm multi-staged Meso-Cenozoic tectonic activity, possibly induced by the accretion of the so-called Cimmerian blocks to the Eurasian margin. New evidence for this multi-staged thermo-tectonic activity is found in the data of both basement and Meso-Cenozoic sediment samples in or close to the Talas-Fergana Fault. Zircon (U–Th)/He and apatite fission track data constrain rapid Late Triassic–Early Jurassic and Late Jurassic–Early Cretaceous basement cooling in the Kyrgyz Tien Shan around 200 Ma and 130–100 Ma respectively. Detrital apatite fission track results indicate a different burial history on both sides of the Talas-Fergana Fault. The apatite fission track system of the Jurassic sediments in the Middle Tien Shan unit east of the Talas-Fergana Fault is not reset, while the Jurassic sediments in the Fergana Basin and Yarkand-Fergana Basin, west of the fault zone, are partially and in some cases even totally reset. The totally reset samples exhibit Oligocene and Miocene ages and evidence the Cenozoic reactivation of the western Kyrgyz Tien Shan as a consequence of the India-Eurasia convergence

Provenance of the uppermost clastic rocks of the Lower Cretaceous Kezilesu Group from the Ulugqat Basin, Xinjiang, NW China and its tectonic implications: Insights from sedimentary records and detrital zircon U–Pb geochronology

“…Palaeocurrent directions during the Early Cretaceous were mainly considered to be south-directed in the basin (Figure 10a; Yang, Guo, Jiang, et al, 2017), similar to the Meso-Cenozoic foreland basins in front of the South Tianshan Orogen (Hendrix, 2000;Li et al, 2004;Li & Peng, 2010), indicating that the source area may be situated in the piedmont region of South Tianshan Orogen. Framework compositions of polymictic conglomerate and gravelly sandstone in this study have revealed that the Late Carboniferous-Permian alkali granite, F I G U R E 1 3 (a) Relative probability plots of these apatite fission-track (AFT) ages and apatite (U-Th)/He (AHe) ages across the western Tianshan Orogen showing multistage Meso-Cenozoic exhumation history (Bullen et al, 2001;Chang, Qiu, & Li, 2012;De Grave et al, 2011Dumitru et al, 2001;Glorie et al, 2010Glorie et al, , 2011Jia et al, 2015;Macaulay et al, 2013;Nachtergaele et al, 2017;Sobel, Chen, & Heermance, 2006;Sobel, Oskin, et al, 2006;Yang et al, 2014;Zhang, Li, et al, 2009;Zhang, Huang, et al, 2009); (b) Summary of AFT ages and apatite (U-Th)/He (AHe) ages of the Late Jurassic-Early Cretaceous across the western Tianshan Orogen (Bullen et al, 2001;Chang et al, 2012;De Grave et al, 2011Dumitru et al, 2001;Glorie et al, 2010Glorie et al, , 2011Jia et al, 2015;Macaulay et al, 2013;Nachtergaele et al, 2017;Sobel, Chen, & Heermance, 2006;Sobel, Oskin, et al, 2006;Yang et al, 2014;Zhang, Li, et al, 2009;Zhang, Zhu, et al, 2009;…”

“…The Late Jurassic–Early Cretaceous reactivation has been widely accepted based on coeval uplifting and exhumation in the western Tianshan (De Grave et al, ; Glorie et al, ) and sedimentary transformation from an extremely low‐energy, humid depositional environment, and wide source areas in the Middle Jurassic to a relatively high‐energy, semi‐arid/arid depositional environment, and local source areas in the Early Cretaceous (Jolivet et al, ; Sobel, ), in the foreland basins (Junggar, Turfan, Kuqa, and Ulugqat) on the north and south piedmonts of the western Tianshan Orogen (Li et al, ; Li & Peng, ; Li & Zeng, ; Yang et al, ). Although systematic detrital zircon U–Pb dating of Meso‐Cenozoic sequences has been conducted in the Ulugqat Basin (Yang et al, ; Yang, Guo, Jiang, et al, ), it is still controversial on the geodynamic mechanism resulting in the rapid exhumation and coarse‐grained clastic rocks sedimentation during the Late Jurassic–Early Cretaceous, as the rapid closure of Mongol–Okhotsk Ocean during the latest Jurassic–earliest Cretaceous (Nachtergaele et al, and references therein) is almost simultaneous with the collision of the Karakoram–Lhasa Block from late Middle Jurassic to Early Cretaceous (Wilhem et al, ;Yang, Guo, et al, ; Yang, Guo, & Luo, ). However, East Asia wholly entered into an escape tectonic setting in the Early Cretaceous due to the continental collision of the Karakoram–Lhasa Block at the southern margin of Asia (Yang, Guo, et al, ; Yang, Guo, & Luo, ), probably suggesting little tectonic influence of Mongol–Okhotsk Orogeny.…”

“…It is therefore coincident with the basin‐range reversal during Late Jurassic–Early Cretaceous period (Rolland et al, ; Yang, Guo, & Luo, ). Previous numerous low‐temperature thermochronological datasets including apatite fission‐track ages (AFT) and apatite (U‐Th)/He (AHe) ages have revealed multistage Meso‐Cenozoic uplifting of the Western Tianshan Orogen (Figure 13a; Bullen, Burbank, Garver, & Abdrakhmatov, ; Chang et al, ; De Grave et al, , ; Dumitru et al, ; Glorie et al, , ; Jia et al, ; Macaulay et al, ; Nachtergaele et al, ; Sobel, Chen, & Heermance, ; Sobel, Oskin, Burbank, & Mikolaichuk, ; Yang et al, ; Zhang, Zhu, et al, ), possibly responding to the accretion of the various Cimmerian blocks to the southern Asian margin (Jia et al, ; Li et al, ; Roger, Jolivet, & Malavieille, ). In particular, an intensive uplifting of late Early Cretaceous with a peak age of 121.2 Ma has been detected by the statistical analysis of AFT/AHe ages in the western Tianshan Orogen (Figure 13a), and it is also indicated by the sedimentary transition in the upper part of the Lower Cretaceous Kezilesu Group in the Ulugqat Basin.…”

“…(a) Relative probability plots of these apatite fission‐track (AFT) ages and apatite (U‐Th)/He (AHe) ages across the western Tianshan Orogen showing multistage Meso‐Cenozoic exhumation history (Bullen et al, 2001; Chang, Qiu, & Li, ; De Grave et al, , ; Dumitru et al, ; Glorie et al, , ; Jia et al, ; Macaulay et al, ; Nachtergaele et al, ; Sobel, Chen, & Heermance, ; Sobel, Oskin, et al, ; Yang et al, ; Zhang, Li, et al, ; Zhang et al, ; Zhang, Huang, et al, ); (b) Summary of AFT ages and apatite (U‐Th)/He (AHe) ages of the Late Jurassic–Early Cretaceous across the western Tianshan Orogen (Bullen et al, 2001; Chang et al, ; De Grave et al, , ; Dumitru et al, ; Glorie et al, , ; Jia et al, ; Macaulay et al, ; Nachtergaele et al, ; Sobel, Chen, & Heermance, ; Sobel, Oskin, et al, ; Yang et al, ; Zhang, Li, et al, ; Zhang, Zhu, et al, ; Zhang, Huang, et al, ) and adjacent Pamir salient (Yang, Guo, & Luo, and references therein). MTS, Middle Tianshan; NTS, North Tianshan; STS, South Tianshan; MPT, Main Pamir Thrust; PFT, Pamir Frontal Thrust [Color figure can be viewed at wileyonlinelibrary.com]…”

“…A major period of tectono‐magmatic quiescence was recognized during the Triassic and Jurassic times (Dumitru et al, ; Han, He, Wang, & Guo, ; Jolivet et al, ), and renewed tectonic uplifting occurred in late Mesozoic, especially in the Late Jurassic–Early Cretaceous period, as demonstrated by sedimentological and structural studies in the Junggar Basin (Jolivet, Bourquin, & Heilbronn, ; Yang et al, ) and Kuqa Sub‐basin of the Tarim Basin (Dumitru et al, ; Li et al, ; Li, Song, Peng, Wang, & Zhang, ), which flank the western Tianshan Orogen on the north and south. However, the Late Jurassic–Early Cretaceous reactivation may have been caused by far‐field geodynamic processes of either the closure of the Mongol–Okhotsk Ocean (Jolivet et al, ) or the collision of the Karakoram–Lhasa Block with the southern Asian margin (Hendrix et al, ; Sobel, ), because the Mongol–Okhotsk Ocean mainly closed on a relative short time scale (10 Ma) around the latest Jurassic–earliest Cretaceous transition (Nachtergaele et al, ; Wilhem, Windley, & Stamp, ; Yang, Guo, Song, Li, & He, ), which almost overlaps with the collision of Karakoram–Lhasa Block from late Middle Jurassic to Early Cretaceous (Li et al, ; Yang, Guo, & Luo, ). Owing to a lack of conclusive, detailed geological evidence during the Early Cretaceous, it remains unclear whether the Late Jurassic–Early Cretaceous reactivation in the western Tianshan was related to the Mongol–Okhotsk Orogeny or not, although the Late Jurassic–Early Cretaceous uplifting in Altai Shan and Sayan ranges was interpreted as an effect of this tectonic event (De Grave et al, ; De Grave, Buslov, & Haute, ; Glorie & De Grave, ; Jolivet et al, ).…”