Postcollisional delamination and partial melting of enriched lithospheric mantle: Evidence from Oligocene (ca. 30 Ma) potassium-rich lavas in the Gemuchaka area of the central Qiangtang Block, Tibet
2018; Geological Society of America; Volume: 131; Issue: 7-8 Linguagem: Inglês
10.1130/b31911.1
ISSN1943-2674
AutoresQuan Ou, Qiang Wang, Derek A. Wyman, Chunfu Zhang, Lu‐Lu Hao, Wei Dan, Zi‐Qi Jiang, Fu‐Yuan Wu, Jin‐Hui Yang, Haixiang Zhang, Xiaoping Xia, Lin Ma, Xiaoping Long, Jie Li,
Tópico(s)High-pressure geophysics and materials
ResumoResearch Article| December 05, 2018 Postcollisional delamination and partial melting of enriched lithospheric mantle: Evidence from Oligocene (ca. 30 Ma) potassium-rich lavas in the Gemuchaka area of the central Qiangtang Block, Tibet Quan Ou; Quan Ou 1State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China2Key Laboratory of Metallogenic Prediction of Nonferrous Metals and Geological Environment Monitoring, Ministry of Education, School of Geosciences and Info-Physics, Central South University, Changsha 410083, China Search for other works by this author on: GSW Google Scholar Qiang Wang; Qiang Wang † 1State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China3CAS Center for Excellence in Tibetan Plateau Earth Sciences, Beijing 100101, China4College of Earth and Planetary Sciences, University of Chinese Academy of Sciences, Beijing 100049, China †Corresponding author: wqiang@gig.ac.cn. Search for other works by this author on: GSW Google Scholar Derek A. Wyman; Derek A. Wyman 5School of Geosciences, The University of Sydney, New South Wales 2006, Australia Search for other works by this author on: GSW Google Scholar Chunfu Zhang; Chunfu Zhang 6Department of Geosciences, Fort Hays State University, Hays, Kansas 67601-4099, USA Search for other works by this author on: GSW Google Scholar Lu-Lu Hao; Lu-Lu Hao 1State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Search for other works by this author on: GSW Google Scholar Wei Dan; Wei Dan 1State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Search for other works by this author on: GSW Google Scholar Zi-Qi Jiang; Zi-Qi Jiang 1State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China7School of Earth Science, Guilin University of Technology, Guilin 541004, China Search for other works by this author on: GSW Google Scholar Fu-Yuan Wu; Fu-Yuan Wu 8Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China Search for other works by this author on: GSW Google Scholar Jin-Hui Yang; Jin-Hui Yang 8Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing 100029, China Search for other works by this author on: GSW Google Scholar Hai-Xiang Zhang; Hai-Xiang Zhang 1State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Search for other works by this author on: GSW Google Scholar Xiao-Ping Xia; Xiao-Ping Xia 1State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Search for other works by this author on: GSW Google Scholar Lin Ma; Lin Ma 1State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Search for other works by this author on: GSW Google Scholar Xiao-Ping Long; Xiao-Ping Long 1State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Search for other works by this author on: GSW Google Scholar Jie Li Jie Li 1State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China Search for other works by this author on: GSW Google Scholar GSA Bulletin (2019) 131 (7-8): 1385–1408. https://doi.org/10.1130/B31911.1 Article history received: 12 Aug 2017 rev-recd: 29 Mar 2018 accepted: 03 Oct 2018 first online: 05 Dec 2018 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Quan Ou, Qiang Wang, Derek A. Wyman, Chunfu Zhang, Lu-Lu Hao, Wei Dan, Zi-Qi Jiang, Fu-Yuan Wu, Jin-Hui Yang, Hai-Xiang Zhang, Xiao-Ping Xia, Lin Ma, Xiao-Ping Long, Jie Li; Postcollisional delamination and partial melting of enriched lithospheric mantle: Evidence from Oligocene (ca. 30 Ma) potassium-rich lavas in the Gemuchaka area of the central Qiangtang Block, Tibet. GSA Bulletin 2018;; 131 (7-8): 1385–1408. doi: https://doi.org/10.1130/B31911.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract Postcollisional potassium (K)-rich magmatic rocks have important implications for unveiling the deep geodynamic processes active during the evolution of orogenic belts and the surface uplift of plateaus. However, their petrogenesis remains highly controversial. Here we report on zircon U-Pb and mineral 40Ar-39Ar age, zircon Hf-O isotope, mineral composition, whole-rock major and trace element composition, and Nd-Sr isotope data for the postcollisional K-rich lavas in the Gemuchaka area of the central Qiangtang Block (central Tibet). Age dating suggests that these lavas were generated in the late Early Oligocene (ca. 30 Ma). Two series of rocks were recognized: silica-undersaturated and -saturated lavas. Both series are geochemically characterized by continuous variation trends. All rocks are enriched in light rare earth elements (LREEs) relative to heavy REEs (HREEs) and depleted in Ta-Nb-Ti, with negligible Sr and Eu and obviously positive Pb anomalies. The rocks have higher Th/La (0.2–0.8) and Nb/Ta (18.6–19.8) values than asthenospheric mantle-derived rocks but slightly variable values of εNd(t) (–6.0 to –4.6), (87Sr/86Sr)i (0.7076–0.7083), and zircon εHf(t) (–7.2 to +0.8) and δ18O (7.1–8.5‰). We suggest that the parental magmas of these K-rich lavas were likely derived by variable partial melting of lithospheric mantle metasomatized by subducting continental sediment-derived melts with the addition of minor asthenospheric components. Element modeling results suggest that the basic end members were likely generated by fractionation processes dominated by olivine and minor clinopyroxene from parental magmas, and some other evolved rocks were generated by crystal (olivine, clinopyroxene, Fe-Ti oxides) fractionation from basic magmas. Combining geological and Cenozoic magmatic rock data in the Qiangtang Block, we propose that the Gemuchaka magmatism was most likely triggered by the delamination of lithospheric mantle thickened by early (Paleocene–Eocene) intracontinental subduction and subsequent asthenospheric upwelling. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
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