Provenance of Late Triassic sediments in central Lhasa terrane, Tibet and its implication

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• 作者：Guangwei Li^a ; ^b ; ^{guangwei.li@unimelb.edu.au" class="auth_mail} ; Mike Sandiford^b ; Xiaohan Liu^c ; Zhiqin Xu^a ; Lijie Wei^c ; Huaqi Li^a
• 关键词：Provenance ; Late Triassic ; Lhasa terrane ; Chronology ; Hf isotopes
• 刊名：Gondwana Research
• 出版年：May, 2014
• 年：2014
• 卷：25
• 期：4
• 页码：1680-1689
• 全文大小：1337 K

文摘

In southern Tibet, Late Triassic sequences are especially important to understanding the assembly of the Lhasa terrane prior to Indo-Asian collision. We report new data relevant to the provenance of a Late Triassic clastic sequence from the Mailonggang Formation in the central Lhasa terrane, Tibet. Petrographic studies and detrital heavy mineral assemblages indicate a proximal orogenic provenance, including volcanic, sedimentary and some ultramafic and metamorphic rocks. In situ detrital zircon Hf and U-Pb isotope data are consistent with derivation of these rocks from nearby Triassic magmatic rocks and basement that comprise part of the newly recognized Late Permian-Triassic Sumdo-Cuoqen orogenic belt. The new data suggests correlation with the Upper Triassic Langjiexue Group which lies on the opposing (southern) side of Indus-Yarlung ophiolite. Sediments from both the Mailonggang Formation and Langjiexue Group are interpreted to represent formerly contiguous parts of a sequence deposited on the southern flanks of the Sumdo-Cuoqen belt.