Geochemical records of hydrothermal activities in the sediment fillings within pumice's vesicles in the vicinity of a seafloor hydrothermal field in the Okinawa Trough
ZHANG Yuxiang;ZENG Zhigang;YIN Xuebo;LI He;QI Haiyan;WANG Xiaoyuan;CHEN Shuai;Key Laboratory of Marine Geology and Environment,Institute of Oceanology,Chinese Academy of Sciences;University of Chinese Academy of Sciences;Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology;Institute of Geology and Geophysics,Chinese Academy of Sciences;
The pumices samples from HOBAB2-T3 and HOBAB2-T6 near the Iheya North hydrothermal field,Okinawa Trough(OT)are divided into two groups.One group(T3-C and T6-C)was carefully cleaned to remove any sediment filled in vesicles,while the second group(T3-D and T6-D)remained unchanged.To qualitatively understand the mineral and chemical compositions of the sediment fillings in pumice's vesicles,each group of pumices was examined by scanning electron microscope(SEM)and their mineralogy and trace elemental compositions were analyzed and compared.Results show that the sediments in pumices are mainly from OT clastic deposits.Vesicles in T3 pumice are smaller and they are mainly filled by illite and quartz in terms of mineral compositions.However,sediments in larger vesicles of T6 pumice are dominated by quartz and feldspar,same as the minerals in OT in general.The sediments in T3 pumice,adjacent to the hydrothermal field,however,contain extremely high concentrations of Pb(101μg/g),Zn(196μg/g),and Cu(47μg/g),indicatingstrong hydrothermal activities.For T6 pumice that is slightly farther away from the hydrothermal field,the sediment fillings also exhibit anomalies in Pb and Cu,which might stand for relatively weaker hydrothermal signal.The above indicates that sediments in pumice's vesicle near the hydrothermal field may record information of hydrothermal activity,which has great significance in exploring new hydrothermal filed in the region with pumiceous volcanic rocks.
【Fund】： 国家重点基础研究发展计划“典型弧后盆地热液活动及其成矿机理”(2013CB429700);; 国家自然科学基金项目“海底热液活动研究”(41325021) “台湾东北部龟山岛安山岩的成因研究”(41306053) “龟山岛热液流体扩散及其对元素分布的影响”(41476044) “俯冲作用对岩浆活动的影响机制研究:以东马努斯海盆为例”(41706052);; 中国科学院战略性先导科技专项“热液系统的物质能量输运及其动力学解析”(XDA11030302);; 全球变化与海气相互作用专项“西太平洋俯冲带及弧后盆地体系”(GASI-GEOGE-02);; 泰山学者工程专项(ts201511061);; 青岛海洋科学与技术国家实验室“鳌山人才”计划项目(2015ASTP-0S17)
【CateGory Index】： P744.4
【CateGory Index】： P744.4