Episodic Late Cretaceous to Neogene crustal thickness variation in southern Tibet
Episodic Late Cretaceous to Neogene crustal thickness variation in southern Tibet
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DOI：
10.1111/ter.12689
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发表时间：
2023-10
期刊：
影响因子：
2.4
通讯作者：
K. Sundell;A. Laskowski;Caden J. Howlett;P. Kapp;Mihai Ducea;James B. Chapman;Lin Ding
中科院分区：
文献类型：
--
作者：
K. Sundell;A. Laskowski;Caden J. Howlett;P. Kapp;Mihai Ducea;James B. Chapman;Lin Ding
近年来在定量估算地质历史中地壳厚度方面取得的进展为检验解释藏南构造演化的假说提供了机会。关于藏南新生代地质演化的争论因对中生代构造认识不足而变得复杂。本文报道了藏南冈底斯山脉现代河流碎屑锆石的U-Pb年代学和微量元素化学特征。结果与最近发表的从中间成分全岩记录中得出的地壳厚度定量估计值相似，并显示从90到70 Ma约30 km的地壳变薄，然后从70到40 Ma增厚到近现代值。这些结果将晚白垩世沿沿着向西的南北向伸展的证据扩大了约200 km，并支持了这样一种构造模式，即在印度与欧亚大陆最终碰撞之前，板片回滚期间沿沿着欧亚大陆南缘形成了一个东西向的弧后盆地。
Recent advancements in quantitatively estimating the thickness of Earth's crust in the geologic past provide an opportunity to test hypotheses explaining the tectonic evolution of southern Tibet. Outstanding debate on southern Tibet's Cenozoic geological evolution is complicated by poorly understood Mesozoic tectonics. We present new U‐Pb geochronology and trace element chemistry of detrital zircon from modern rivers draining the Gangdese Mountains in southern Tibet. Results are similar to recently published quantitative estimates of crustal thickness derived from intermediate‐composition whole rock records and show ~30 km of crustal thinning from 90 to 70 Ma followed by thickening to near‐modern values from 70 to 40 Ma. These results extend evidence of Late Cretaceous north–south extension along strike to the west by ~200 km, and support a tectonic model in which an east–west striking back‐arc basin formed along Eurasia's southern margin during slab rollback, prior to terminal collision of India with Eurasia.