从西南印度洋中脊轴部形态及其两侧沉降速率变化探讨热点与洋中脊相互作用  

Discussion on the interaction between hot spots and mid-ocean ridge from the axial morphology and the variation of subsidence rate on both sides of the Southwest Indian Ridge

作　　者：王昊 谭平川 阮爱国 Wang Hao;Tan Pingchuan;Ruan Aiguo(Key Laboratory of submarine Geosciences,Second Institute of Oceanography,Ministry of Natural Resources,Hangzhou 310012,China;School of Oceanography,Shanghai Jiaotong University,Shanghai 200240,China;School of Earth Sciences,Zhejiang University,Hangzhou 310027,China)

机构地区：[1]自然资源部第二海洋研究所海底科学重点实验室,杭州310012 [2]上海交通大学海洋学院,上海200240 [3]浙江大学地球科学学院,杭州310027

出　　处：《地震学报》2023年第3期455-470,共16页Acta Seismologica Sinica

基　　金：国家自然科学基金(42076047,42006072);自然资源部第二海洋研究所所基金(HYGG2001);浙江省钱江人才D基金(QJD2002033)共同资助.

摘　　要：基于高精度地形数据,将西南印度洋中脊(11.88°E—66.75°E)分为6个区域,按不同区域分析洋脊轴部形态及其两侧基底沉降曲线的变化,由此探讨西南印度洋中脊的岩浆活动及其受热点影响的机制。结果显示:①对于整个西南印度洋中脊,轴部隆起占13.38%,轴部裂谷占82.8%,平坦过渡形占3.82%,其中19°E,36°E,41.2°E,43.7°E,50.4°E和64.5°E等处为较集中的洋脊轴部隆起;②埃里克辛普森—英多姆转换断层之间的区域(39.4°E—45.77°E)显示出异常浅的轴部裂谷和异常小且南北不对称的基底沉降速率,这表明埃里克辛普森—英多姆转换断层之间的区域是热点对洋中脊影响较为明显的区域,南侧较北侧异常小的基底沉降速率表明热点与洋中脊的相互作用主要表现为热点岩浆从洋中脊南部向上流动到岩石圈底部,然后与岩石圈发生相互作用。Based on high resolution seafloor bathymetry map,we divided the Southwest Indian Ridg(SWIR)(11.88°E—66.75°E)into six regions.In each region,we estimate the variation of the axial morphology,and the basement subsidence curve over the flanks of the spreading ridge,which can be used to indicate the spreading process of the SWIR and how it was affected by the hot spot.The result shows that:①For the entire SWIR,axial uplift accounts for 13.38%,axial rift accounts for 82.8%,and flat transitional shape accounts for 3.82%,the areas at 19°E,36°E,41.2°E,43.7°E,50.4°E,64.5°E have focus magmatic ridge representing axial ridge uplift;②The area between the Eric Simpson-Indomed transition faults(39.4°E—45.77°E)shows axial valley with anomalous shallow bathymetry and asymmetrical anomalous low basement subsidence rates between north and south.Therefore,we believe that the area between the Eric Simpson-Indomed transition faults has been significantly affected by the hot spots.Compared with the subsidence rate north of the spreading ridge,the anomalous low subsidence rate in the south indicates that the interaction between the hot spots and the ridge is characterized by the hot spots flowing upward from the south of the SWIR to the bottom of the lithosphere,and then interact with the lithosphere.

关 键 词：西南印度洋中脊 洋中脊轴部形态 基底沉降曲线 热点与洋中脊相互作用 

分 类 号：P736[天文地球—海洋地质]