Origin of the Volcanic Rocks Erupted in the Eastern Manus Basin：Basaltic Andesite-Andesite-Dacite Associations  

作　　者：MA Yao ZENG Zhigang CHEN Shuai YIN Xuebo WANG Xiaoyuan 

机构地区：[1]Seafloor Hydrothermal Activity Laboratory of the Key Laboratory of Marine Geology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, P. R. China [2]University of Chinese Academy of Sciences, Beijing 100049, P. R. China [3]Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, P. R. China

出　　处：《Journal of Ocean University of China》2017年第3期389-402,共14页中国海洋大学学报（英文版）

基　　金：supported by the National Key Basic Research Program of China (No. 2013CB429700);the National Natural Science Foundation of China (Nos. 4132 5021, 41306053, 40476044);the Strategic Priority Research Program of the Chinese Academy of Sciences (No XDA11030302);the Special Fund for the Taishan Scholar Program of Shandong Province (No. ts201511061);the AoShan Talents Program Supported by Qingdao Nationa Laboratory for Marine Science and Technology (No. 2015 ASTP-0S17);the Innovative Talent Promotion Program (No. 2012RA2191);the Science and Technology Devel opment Program of Shandong Province (No. 2013GRC 31502);the Scientific and Technological Innovation Project Financially Supported by Qingdao National Labora tory for Marine Science and Technology (No. 2015ASKJ 03);the National High Level Talent Special Support Program;the CAS/SAFEA International Partnership Program for Creative Research Teams;the Qingdao Collaborative Innovation Center of Marine Science and Technology

摘　　要：There has been much recent interest in the origin of intermediate lava and several hypotheses are: 1) direct melting of the mantle under water-saturated conditions, 2) partial melting of altered crust, 3) fractional crystallization of parent magma, and 4) magma mixing of mafic magmas with dacitic/rhyolitic magmas. Volcanic rocks series ranging from basaltic andesite to dacite(SiO_2 ranges from 53.8 to 63.0 wt.%) from the eastern Manus Basin were detected for major and trace element compositions to understand their origin. Low H_2O contents, positive correlations of La-SiO_2 and Yb-SiO_2, oxygen isotope data and the indistinct change of trace element concentrations in oscillatory zoning of plagioclase phenocrysts rule out the models in which silicic lava results from direct melting of hydrous mantle, partial melting of altered oceanic crust or gabbros, and magma mixing, respectively. Besides, the geochemical data of whole rock and melt inclusions indicate that fractional crystallization plays a dominant role in generating the intermediate lava with subduction features.There has been much recent interest in the origin of intermediate lava and several hypotheses are： 1） direct melting of the mantle under water-saturated conditions, 2） partial melting of altered crust, 3） fractional crystallization of parent magma, and 4） magma mixing of mafic magmas with dacitic/rhyolitic magmas. Volcanic rocks series ranging from basaltic andesite to dacite（SiO2 ranges from 53.8 to 63.0 wt.%） from the eastern Manus Basin were detected for major and trace element compositions to understand their origin. Low H2O contents, positive correlations of La-SiO2 and Yb-SiO2, oxygen isotope data and the indistinct change of trace element concentrations in oscillatory zoning of plagioclase phenocrysts rule out the models in which silicic lava results from direct melting of hydrous mantle, partial melting of altered oceanic crust or gabbros, and magma mixing, respectively. Besides, the geochemical data of whole rock and melt inclusions indicate that fractional crystallization plays a dominant role in generating the intermediate lava with subduction features.

关 键 词：Eastern Manus Basin fractional crystallization volcanic rocks 

分 类 号：P588.1[天文地球—岩石学]