Zircon Hf-O-Li isotopes of granitoids from the Central Asian Orogenic Belt: Implications for supercontinent evolution |
| |
| Institution: | 1. Key Laboratory of Orogenic Belts and Crustal Evolution, Ministry of Education, School of Earth and Space Sciences, Peking University, Beijing 100871, PR China;2. Key Laboratory of Ministry of Education on Safe Mining of Deep Metal Mines, Department of Geology, School of Resources and Civil Engineering, Northeastern University, Shenyang 110819, PR China;1. Key Laboratory of Metallogeny and Mineral Assessment, Ministry of Natural Resources, Institute of Mineral Resources, Chinese Academy of Geological Sciences, Beijing 100037, China;2. No. 4 Geological Team of the Xinjiang Bureau of Geology and Mineral Exploration and Development, Altay 836500, Xinjiang, China |
| |
| Abstract: | Deep lithospheric processes associated with the formation of major orogens, including the removal of lower crust and underlying mantle through delamination associated with orogen building are poorly constrained. With a view to evaluate the potential link between deep geodynamic processes and magmatic events, we performed in situ zircon Hf-O-Li isotopic analyses of granitoids from the Eastern and Western Junggar, Altai and Beishan orogens, within the Central Asian Orogenic Belt (CAOB). The εHf(t) and δ18O values of magmatic zircons crystallized during 443 Ma and 252 Ma indicate diverse and heterogeneous magma sources. The corresponding δ7Li peaks at ~440 Ma and ~250 Ma, suggesting two distinct high-temperature magmatic events. Based on a comparison with global data, we argue that large-scale delamination formed through Gondwana and Pangaea supercontinent assembly, may have occurred at Ordovician to Silurian boundary (OSB) and Permian to Triassic boundary (PTB), which we term as super-delamination. The subsequent widespread magmatism and volcanism might have made significant impact on the Earth surface ecosystems, ultimately leading to the OSB and PTB mass extinction events. We propose super-delamination as a potential mechanism to explain the link between Earth's internal and external processes, thus providing novel insights into the trigger for mass extinction events. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
