Full-Text Search:
Home|About CNKI|User Service|中文
Add to Favorite Get Latest Update

Multiple phases of cretaceous mafic magmatism in the Gyangze-Kangma area,Tethyan Himalaya,southern Tibet

WANG YaYing;GAO LiE;ZENG LingSen;CHEN FuKun;HOU KeJun;WANG Qian;ZHAO LingHao;GAO JiaHao;Innovative Research Center of Continental Tectonics and Dynamics,CGS;,Institute of Geology,Chinese Academy of Geological Sciences;School of Earth and Space Sciences,University of Science and Technology of China;Institute of Mineral Resources,Chinese Academy of Geological Sciences;National Research Center for Geoanalysis,Chinese Academy of Geological Sciences;  
A large number of E-W trending subparallel diabases occurred in the Gyangze-Kangma area,eastern Tethyan Himalaya,southern Tibet.Results from field observation,zircon U-Pb dating,whole-rock geochemical and Sr-Nd isotopic data indicate that they represent at least three episodes of Cretaceous mafic magmatism within the Tethyan Himalaya at~140 Ma,~120 Ma,and~90 Ma,respectively.(1) The T0907 suite,occurred at 142.0 ± 1.4Ma,is characterized by OIB-like trace element patterns and Sr-Nd isotopic compositions,similar to those in the~132 Ma Comei-Bunbury Large Igneous Province to the east.However,the contemporaneous T0902 suite shows elevated Mg,Cr and Ni contents,but Nb-Ta negative anomalies,Pb positive anomalies and negative εNd(t) values,which could be derived from an enriched lithospheric source;(2) The T0904 suite,formed at 121.1 ± 0.7Ma,displays N-MORB-like geochemical characteristics;(3) The T0901 suite,formed at~90 Ma,displays E-MORB-like geochemical characteristics.Combined with the evolutional history of the breakup of the East Gondwana continent and the hotspot track of the Kerguelen mantle plume,we suggest that the mafic magmatism at~140 Ma in Gyangze-Kangma area represents the products from interaction between the Kerguelen mantle plume and the overlying East Gondwana continental lithospheric mantle,possibly due to relatively long-time incubation of the Kerguelen mantle plume beneath the East Gondwana supercontinent.However,with the breakup of the East Gondwana continent and the initiation and spreading of the Indian oceanic ridge,the Indian continent started to drift away from the Kerguelen hotspot.Mafic magmatism at~120 Ma and~90 Ma in this studied area represent the products formed by partial melting of asthenosphere mantle under Indian ridges,rather than the products of Kerguelen mantle plume.Data presented above indicates that mafic rocks within the Himalayan terrane were produced by multiple episodes of magmatism associated with the breakup of the East Gondwana continent and the intitiation and spreading of the Indian Ocean since~140 Ma.These mafic rocks formed at different times provide important time frames for paleomagentic studies and further constrains on the tectonic history of the Himalayan orogenic belt.
Download(CAJ format) Download(PDF format)
CAJViewer7.0 supports all the CNKI file formats; AdobeReader only supports the PDF format.
©CNKI All Rights Reserved