| Title | Multi-stage metallogeny in the southwestern part of South China, and paleotectonic and climatic implications: A high precision geochronologic study |
| Authors | Liu, Yanbin Zhang, Lifei Santosh, M. Dong, Guochen Zhou, Hongying Que, Chaoyang Yang, Cheng-Xue |
| Affiliation | China Univ Geosci, State Key Lab Geol Proc & Mineral Resources, Beijing 100083, Peoples R China China Univ Geosci, Sch Earth Sci & Resources, Beijing 100083, Peoples R China Peking Univ, Sch Earth & Space Sci, MOE Key Lab Orogen Belts & Crustal Evolut, Beijing 100871, Peoples R China Univ Adelaide, Dept Earth Sci, Adelaide, SA 5005, Australia China Geol Survey, Tianjin Inst Geol & Mineral Resources, Tianjin 300170, Peoples R China Zijin Min Ind Grp Co Ltd, Xiamen 361009, Fujian, Peoples R China |
| Keywords | SOUTHEASTERN YUNNAN PROVINCE U-PB GEOCHRONOLOGY TECTONIC EVOLUTION ORE DISTRICT INDO-CHINA ZIRCON DEPOSIT CONSTRAINTS MINERALIZATION CASSITERITE |
| Issue Date | May-2023 |
| Publisher | GEOSCIENCE FRONTIERS |
| Abstract | The South China Block (SCB) is among the large-scale W-Sn mineralized regions of the globe. The Laojunshan W-Sn-dominant ore area (LOA) in the western part of the SCB preserves the records of the tectonic history of the Tethys realm extending through North Vietnam, and Yangtze to Cathaysia blocks, with coeval formation of giant metallic deposits. The prolonged tectonic activities and their control on the genesis and spatio-temporal distribution of giant metallic deposits in the LOA provide a window for a holistic understanding of the tectono-metallogenesis of the SCB. In this study, we present results from a multi-chronologic study to determine the timing of formation of the cassiterite-wolframite-schee lite mineralization. The results suggest three distinct tectono-metallogenic periods in the LOA during the geodynamic evolution of the surrounding tectonic units. The opening of the Proto-Tethys Ocean between the Yangtze-Indochina blocks and the westward Paleo-Pacific subduction beneath the Cathaysia block (420-380 Ma) jointly contributed to the Silurian to early Devonian intracontinental orogeny in the mid-dle of the SCB that involved top-to-the-north thrusting along NE-striking shear zones. This event gener-ated the Dulong-Song Chay granitoids, together with the formation of Xinzhai Sn deposit related to sheared mylonitic granites (ca. 419 Ma) and pegmatites (ca. 389 Ma), which include the early-stage Sn-sulfide skarn (ca. 418 Ma) and the late-stage Sn-bearing schist (ca. 389 Ma). During the Late Permian to Late Triassic (260-220 Ma), with the closure of the Proto-Tethys oceans in the west and ongo-ing Paleo-Pacific westward subduction in the east, the SCB and Indochina Block (IB) were amalgamated which also marks the time of formation of the Nanwenhe scheelite skarn deposit. The subducted Paleo-Tethys oceanic crust was likely entrained by the nearby rising Emeishan mantle plume (270-259 Ma), which formed the Maguan diabase (ca. 260 Ma) that shows significantly older Re-Os model age of ca. 268 Ma, suggesting that the Nanwenhe mineralization is potentially derived from ca. 260 Ma source. Furthermore, the intraplate shortening induced thin skinned crustal deformation and low grade meta-morphism (ca. 230 Ma), with the main stage of scheelite-Sn-Mo mineralization (229.9, 229.8 and 219 Ma) and contemporary formation of the pegmatite (230.7 Ma). The Late Cretaceous involved two epi-sodes of alternate extension and shortening, driven by the subduction polarity change from northwest-ward subduction of the Okhotomorsk block to northward subduction of the NeoTethys seafloor. The evolution of the LOA consists of the NW-SE transpression ending ca. 100 Ma, the WNW-ESE extension in the earlier episode lasting from 100 Ma to 86 Ma, the WNW-ESE transpression beginning at ca. 85 Ma and the NAS extension in the later episode during the latest Cretaceous, which produced the extension-related three periods of Laojunshan granitic magmatism and coeval Sn-W mineralization, with ages in the range of 90-89 Ma, 87-85 Ma and 83-79 Ma. We also evaluate the implications of magmatic-metamorphic-metallogenic degassing on the regional paleoclimatic history.(c) 2023 China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/). |
| URI | http://hdl.handle.net/20.500.11897/670299 |
| ISSN | 1674-9871 |
| DOI | 10.1016/j.gsf.2023.101536 |
| Indexed | SCI(E) |
| Appears in Collections: | 地球与空间科学学院 造山带与地壳演化教育部重点实验室 |
