锆石
地质学
地质年代学
地球化学
出处
造山运动
深熔
冈瓦纳大陆
克拉通
片麻岩
超大陆
奥陶纪
混合岩
人口
古生物学
结壳
构造学
变质岩
部分熔融
人口学
社会学
作者
Shashi Ranjan,Himanshu K. Sachan,Christopher J. Spencer,Aditya Kharya,Saurabh Singhal,Arun Kumar Ojha,Pallavi Chattopadhaya,Pitambar Pati
标识
DOI:10.1017/s0016756822000449
摘要
Abstract U–Pb geochronology, Hf isotopes and trace-element chemistry of zircon grains from migmatite of the upper Sutlej valley (Leo Pargil), Northwest Himalaya, reveal a protracted geological evolution and constrain anatexis and tectonothermal processes in response to Himalayan orogenesis. U–Pb geochronology and ϵHf record separate clusters of ages on the concordia plots in the migmatite (1050–950 Ma, 850–790 Ma and 650–500 Ma). The 1050–950 Ma zircon population supports a provenance from magmatic units related to the assembly of Rodinia. A minor amount of Palaeoproterozoic grains were likely derived from the Indian craton. The potential source rock of the 930–800 Ma detrital zircons may be granitoid present in Greater Himalayan rocks themselves and the Aravalli Range, which has 870–800 Ma granitic rocks. The arc-type basement within the Himalayan–Tibet orogen recorded (900–600 Ma) igneous activity, which may depict a northeasterly extension of juvenile terranes in the Arabian–Nubian Shield. The granitoid of 800 Ma may be a potential source for 790 Ma detrital zircons owing to scatter in 206/238 dates. The 650–500 Ma zircon population suggests their derivation from the East African Orogen and Ross–Delamerian Orogen of Gondwana. The Cambrian–Ordovician magmatism during the Bhimphedian Orogeny and observed late Neoproterozoic to Ordovician detrital zircons have been derived to some extent from Greater Himalayan magmatic sources. We found no detrital zircon grains that cannot be explained as coming from local sources. One sample yielded a discordia lower intercept age of 15.6 ± 2.2 Ma, the age of melt crystallization.
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