The Junggar Alatau forms the northern extent of the Tian Shan within the Central Asian Orogenic Belt(CAOB)at the border of SE Kazakhstan and NW *** study presents the Palaeozoic-Mesozoic post-collisional thermo-tecton...
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The Junggar Alatau forms the northern extent of the Tian Shan within the Central Asian Orogenic Belt(CAOB)at the border of SE Kazakhstan and NW *** study presents the Palaeozoic-Mesozoic post-collisional thermo-tectonic history of this frontier locality using an integrated approach based on three apatite geo-/thermochronometers:apatite U-Pb,fission track and(U-Th)/*** apatite U-Pb dates record Carboniferous-Permian post-magmatic cooling ages for the sampled granitoids,reflecting the progressive closure of the Palaeo-Asian *** apatite fission track(AFT)data record(partial)preservation of the late Palaeozoic cooling ages,supplemented by limited evidence for Late Triassic(~230-210 Ma)cooling and a more prominent record of(late)Early Cretaceous(~150-110 Ma)*** apatite(U-Th)/He age results are consistent with the(late)Early Cretaceous AFT data,revealing a period of fast cooling at that time in resulting thermal history *** Cretaceous rapid cooling signal is only observed for samples taken along the major NW-SE orientated shear zone that dissects the study area(the Central Kazakhstan Fault Zone),while Permian and Triassic cooling signals are preserved in low-relief areas,distal to this *** distinct geographical trend with respect to the shear zone,suggests that fault reactivation triggered the Cretaceous rapid cooling,which can be linked to a phase of slab-rollback and associated extension in the distant Tethys *** conclusions were drawn for thermochronology studies along other major NW-SE orientated shear zones in the Central Asian Orogenic Belt,suggesting a regional phase of Cretaceous exhumation in response to fault reactivation at that time.
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