摘要
海底热液活动一直是当代海洋科学研究的重要前沿领域之一,了解地质构造对海底热液活动的控制作用对于认识热液系统的形成机理及寻找海底硫化物资源具有重要的指示意义。总结了冲绳海槽中部和南部地形与断裂构造、地壳结构、重磁场、热流及岩浆活动等方面的地质构造特征以及海槽热液区分布和热液产物的基本特征。通过比较冲绳海槽与马努斯海盆、马里亚纳海槽、北斐济海盆、劳海盆等基底和扩张阶段不同的弧后盆地构造特征的差异,归纳了冲绳海槽地质构造的特殊性,包括过渡性地壳性质、低扩张程度、高热流值、巨厚沉积层及双峰式火山作用等。冲绳海槽热液活动受到断裂构造、岩浆活动、扩张速率等构造因素的控制,同时受到基岩类型和沉积物盖层等地质条件的影响。海槽中部和南部平行和垂直盆地走向的两组断裂带为流体循环提供了通道,大规模的岩浆活动则为热液系统提供了充足的热量。此外,海槽内广泛分布的酸性火山岩和较厚的沉积盖层与流体相互作用,使得热液产物富含有机质、二氧化碳以及Ag和Au等金属元素。根据冲绳海槽的扩张速率和地质构造特征,推测冲绳海槽仍具有发现新热液区的潜力,其中部和南部两组断裂交汇的部位、轴部火山、受海脊俯冲影响的区域以及靠近岛弧一侧的新火山带是最有潜力的海底热液活动探索远景区。
Revealing the controlling effect of geological structure on seafloor hydrothermal activities is of great significance in understanding the formation mechanism of hydrothermal system and searching for seafloor sulfide resources. This article summarized the topography and faults,crustal structure,gravity and magnetic field, heat flow and magmatism in the middle and southern Okinawa Trough, as well as the general characteristics of hydrothermal field distributions and hydrothermal products. By comparing the Okinawa Trough with the Manus Basin,Mariana Trough,North Fiji Basin and Lau Basin with different rock basements and extension stages,we generalized some specific geological characteristics of the Okinawa Trough,including the transitional crustal nature,low extension degree,high heat flow value,extremely thick sediments,and bimodal volcanism. The hydrothermal activities in the Okinawa Trough are controlled by fault structures,magmatism,and spreading rate,and at the same time,are affected by basement rock types and sediment covers. In the middle and southern parts of the trough,two group of faults that are parallel and perpendicular to the strike of the backarc basin promote the fluid circulation,and large-scale magmatic activity provides sufficient heat for the hydrothermal system. In addition,the interaction of fluids with the widespread silicic volcanic rocks and thick sediments leads to the enrichment of organic matter,CO2,and metals such as Ag and Au in the hydrothermal products. According to the extension rate and geological features of the Okinawa Trough,we believe that the Okinawa Trough has potential to have new hydrothermal fields discovered and we speculate that new hydrothermal fields most possibly exist in the regions influenced by ridge subduction as well as the neo-volcanic zones closed to the island arc.
作者
张玉祥
曾志刚
王晓媛
陈帅
殷学博
陈祖兴
Zhang Yuxiang;Zeng Zhigang;Wang Xiaoyuan;Chen Shuai;Yin Xuebo;Chen Zuxing(Key Laboratory of Marine Geology and Environment,Institute of Oceanology,Chinese Academy of Sciences,Qingdao 266071,China;Laboratory for Marine Mineral Resources,Qingdao National Laboratory for Marine Science and Technology,Qingdao 266071,China;Center for Ocean Mega-Science,Chinese Academy of Sciences,Qingdao 266071,China)
出处
《地球科学进展》
CAS
CSCD
北大核心
2020年第7期678-690,共13页
Advances in Earth Science
基金
国家自然科学基金项目“西太平洋俯冲体系中岩浆活动及其对热液物质供给的制约”(编号:91958213)
中国科学院国际合作局对外合作重点项目“冲绳海槽热液活动成矿机理及其沉积效应”(编号:133137KYSB20170003)资助
关键词
冲绳海槽
热液活动
地质构造
弧后盆地
Okinawa Trough
Hydrothermal activity
Geological structure
Back arc basin
