Coexistence of MORB- and OIB-like dolerite intrusions in the Purang ultramafic massif, SW Tibet: A paradigm of plume-influenced MOR-type magmatism prior to subduction initiation in the Neo-Tethyan lithospheric mantle

Research Article| January 25, 2019 Coexistence of MORB- and OIB-like dolerite intrusions in the Purang ultramafic massif, SW Tibet: A paradigm of plume-influenced MOR-type magmatism prior to subduction initiation in the Neo-Tethyan lithospheric mantle Hao Zheng; Hao Zheng 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China Search for other works by this author on: GSW Google Scholar Qiangtai Huang; Qiangtai Huang † 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China †Corresponding authors. Search for other works by this author on: GSW Google Scholar Argyrios Kapsiotis; Argyrios Kapsiotis 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China Search for other works by this author on: GSW Google Scholar Davide Lenaz; Davide Lenaz 2Department of Mathematics and Geosciences, University of Trieste, Via Weiss 8, Trieste 34128, Italy Search for other works by this author on: GSW Google Scholar Matteo Velicogna; Matteo Velicogna 2Department of Mathematics and Geosciences, University of Trieste, Via Weiss 8, Trieste 34128, Italy Search for other works by this author on: GSW Google Scholar Chi Xu; Chi Xu 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China Search for other works by this author on: GSW Google Scholar Chen Cheng; Chen Cheng 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China Search for other works by this author on: GSW Google Scholar Bin Xia; Bin Xia † 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China †Corresponding authors. Search for other works by this author on: GSW Google Scholar Weiliang Liu; Weiliang Liu 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China Search for other works by this author on: GSW Google Scholar Yang Xiao; Yang Xiao 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China Search for other works by this author on: GSW Google Scholar Peng Yang Peng Yang 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China3School of Earth and Environmental Sciences, The University of Queensland, Brisbane QLD 4072, Australia Search for other works by this author on: GSW Google Scholar Author and Article Information Hao Zheng 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China Qiangtai Huang † 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China Argyrios Kapsiotis 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China Davide Lenaz 2Department of Mathematics and Geosciences, University of Trieste, Via Weiss 8, Trieste 34128, Italy Matteo Velicogna 2Department of Mathematics and Geosciences, University of Trieste, Via Weiss 8, Trieste 34128, Italy Chi Xu 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China Chen Cheng 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China Bin Xia † 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China Weiliang Liu 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China Yang Xiao 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China Peng Yang 1Key Laboratory of Offshore Oil Exploration and Development of Guangdong Higher Education Institutes, Guangdong Provincial Key Laboratory of Marine Resources and Coastal Engineering, School of Marine Science, Sun Yat-sen University, Guangzhou 510275, China3School of Earth and Environmental Sciences, The University of Queensland, Brisbane QLD 4072, Australia †Corresponding authors. Publisher: Geological Society of America Received: 10 Apr 2018 Revision Received: 07 Aug 2018 Accepted: 28 Oct 2018 First Online: 25 Jan 2019 Online Issn: 1943-2674 Print Issn: 0016-7606 © 2019 Geological Society of America GSA Bulletin (2019) 131 (7-8): 1276–1294. https://doi.org/10.1130/B35005.1 Article history Received: 10 Apr 2018 Revision Received: 07 Aug 2018 Accepted: 28 Oct 2018 First Online: 25 Jan 2019 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Hao Zheng, Qiangtai Huang, Argyrios Kapsiotis, Davide Lenaz, Matteo Velicogna, Chi Xu, Chen Cheng, Bin Xia, Weiliang Liu, Yang Xiao, Peng Yang; Coexistence of MORB- and OIB-like dolerite intrusions in the Purang ultramafic massif, SW Tibet: A paradigm of plume-influenced MOR-type magmatism prior to subduction initiation in the Neo-Tethyan lithospheric mantle. GSA Bulletin 2019;; 131 (7-8): 1276–1294. doi: https://doi.org/10.1130/B35005.1 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 The Yarlung Zangbo Suture Zone (YZSZ) of South Tibet is divided by the Zhongba-Zhada terrane into two subparallel ophiolitic belts in its western end. The peridotite massifs of the southern belt tectonically overlie the Tethyan Himalaya sequence. The Purang peridotite body in this belt is intruded by two groups of dolerite dikes, providing significant compositional, geochronological, and isotopic information about the melting history of the Neo-Tethyan mantle. U-Pb ages of zircons separated from dolerites show that peridotites of West Purang were intruded by an early generation of dikes at 138.5 ± 2.0 Ma (Valanginian). These dolerites show ocean island basalt (OIB)-type normalized multi-elemental profiles and Sr-Nd isotopic signatures [(La/Yb)N = 13–16], high initial 87Sr/86Sr ratios (0.70598–0.70765), and low εNd(t) values (–2.6 to –2.3). Zircons separated from this group of dolerites have slightly radiogenic εHf(t) values (+2.6 to +4.6). The next generation of dolerite dikes intruded the East Purang peridotites between 124.5 ± 2.5 Ma and 124.4 ± 3.2 Ma (Aptian). These East Purang dolerites show normal mid-ocean ridge basalt (N-MORB)-type normalized multi-element patterns [(La/Yb)N = 0.6–0.9] with noticeable negative Nb and Th (±Ti) anomalies, and have high 87Sr/86Sr(i) (0.70295–0.70618) and high εNd(t) values (+7.7 to +9.2). Zircons separated from the East Purang dolerites show strongly radiogenic εHf(t) values (+3.5 to +17.0).Semiquantitative geochemical modeling demonstrates that the parental magmas of West Purang dolerites were generated from 5%–10% polybaric partial melting of a deep-seated juvenile asthenospheric source enriched by plume-type components. In contrast, the parental melts of East Purang dolerites were derived from more than 20% melting of a juvenile spinel-bearing MORB-type mantle source that was modified by subduction-related melts/fluids to a minor extent. A possible tectono-magmatic model for the petrogenesis of the Purang ophiolitic massif could be linked to incipient continental rifting and subsequent oceanic seafloor spreading associated with decompression upwelling of an asthenospheric source contaminated by plume-type components. This plume-proximal seafloor spreading-system was succeeded by the initiation of Neo-Tethyan intra-oceanic subduction close to the active continental margin of Eurasia during the Early Cretaceous. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.