西南印度洋中脊51°E(#26洋脊段)地质特征及其对海底热液活动的指示  

Geological characteristics at 51°E(Segment 26) of the Southwest Indian Ridge:implication to submarine hydrothermal activity

作　　者：董振 梁锦 曹志敏[3] 贺惠忠 陈亮 吕修亚 孙金烨 DONG Zhen;LIANG Jin;CAO Zhimin;HE Huizhong;CHEN Liang;LV Xiuya;SUN Jinye(South China Sea Marine Survey Center,Key Laboratory of Marine Environmental Survey Technology and Application,Ministry of Natural Resources,Guangzhou 510275,China;Second Institute of Oceanography,Key Laboratory of Submarine Geosciences,Ministry of Natural Resources,Hangzhou 310012,China;College of Marine Geosciences,Ocean University of China,Qingdao 266100,China;College of Earth Sciences and Resources,China University of Geosciences,Beijing 100083,China)

机构地区：[1]自然资源部南海调查中心,海洋环境探测技术与应用重点实验室,广州510275 [2]自然资源部第二海洋研究所,海底科学重点实验室,杭州310012 [3]中国海洋大学海洋地球科学学院,青岛266100 [4]中国地质大学(北京)地球科学与资源学院,北京100083

出　　处：《海洋地质前沿》2023年第4期14-22,共9页Marine Geology Frontiers

基　　金：中央级公益性科研院所基本科研业务费专项资金项目“‘龙旂’热液区成为首个公海世界自然遗产的可行性研究”(SZ2201)。

摘　　要：在海底多金属硫化物调查过程中,对于已知热液区需要精细地质填图工作,而这种填图往往存在覆盖面积较小、所包含的地质要素较少以及与区域构造作用和岩浆活动联系不足等问题。基于历年大洋航次在西南印度洋中脊#26洋脊段(51°E区域)所获得的深海光学拖曳系统的资料,结合高精度多波束水深数据,提出一种系统的底质热液异常划分原则,识别出热液蚀变岩石或角砾、疑似热液沉积物、热液生物及其遗骸富集和胶结碳酸盐4种底质热液异常类型。高分辨率海底地质填图结果表明,本区存在4处热液活动的异常区。#26洋脊段热液活动频率值为2~10,至少是全球海底热液活动频率经验公式的1.8倍以上。我们认为在超慢速扩张脊局部熔融异常或者发育非转换不连续带的洋脊段,可能存在更多的海底热液活动,也具有形成大型多金属硫化物矿床的潜力。In the survey of oceanic polymetallic sulphides, detailed geological mapping is needed for a known hydrothermal area, which often covers a small area, contains less geological elements, and is not connected with regional tectonism and magmatism. Based on the data of deep-towed optical system obtained from ocean voyages over the years in the Segment 26(51°E) of the Southwest Indian Ridge(SWIR), and combined with high-precision multi-beam bathymetric data, we proposed a systematic division principle of substrate hydrothermal anomaly,and identified four types of substrate hydrothermal anomaly: hydrothermal altered rocks or breccia, suspected hydrothermal sediments, hydrothermal organisms and their remains enrichment, and cemented carbonate rocks. The results of high-resolution submarine geological mapping show that there are 4 abnormal areas of hydrothermal activity in Segment 26. The hydrothermal activity occurrence rate of Segment 26 ranged 2~10, which is at least 1.8 times higher of the global one using empirical formula. Therefore, there may be more submarine hydrothermal activities in Segment 26 with melting anomalies or non-transform discontinuities of ultra-slow spreading ridge,and it also has the potential to form large polymetallic sulfide deposits.

关 键 词：底质类型 热液异常 #26洋脊段 西南印度洋中脊 

分 类 号：P736[天文地球—海洋地质]