摘要
This study investigates the relationship between the hotspot-ridge interaction and the formation of oceanic plateaus and seamounts in the Southwest Indian Ocean.We first calculated the relative distance between the Southwest Indian Ridge (SWIR) and relevant hotspots on the basis of models of plate reconstruction,and then calculated the corresponding excess magmatic anomalies of the hotspots on the basis of residual bathymetry and Airy isostasy.The results reveal that the activities of the Marion hotspot can be divided into three main phases:interaction with the paleo-Rodrigues triple junction (73.6-68.5 Ma),interaction with the SWIR (68.5-42.7 Ma),and intra-plate volcanism (42.7-0 Ma).These three phases correspond to the formation of the eastern,central,and western parts of the Del Cano Rise,respectively.The magnitude and apparent periodicity of the magmatic volume flux of the Marion hotspot appear to be dominated by the hotspot-ridge distance.The periodicity of the Marion hotspot is about 25 Ma,which is much longer than that of the Hawaii and Iceland hotspots (about 15 Ma).
This study investigates the relationship between the hotspot-ridge interaction and the formation of oceanic plateaus and seamounts in the Southwest Indian Ocean.We first calculated the relative distance between the Southwest Indian Ridge (SWIR) and relevant hotspots on the basis of models of plate reconstruction,and then calculated the corresponding excess magmatic anomalies of the hotspots on the basis of residual bathymetry and Airy isostasy.The results reveal that the activities of the Marion hotspot can be divided into three main phases:interaction with the paleo-Rodrigues triple junction (73.6-68.5 Ma),interaction with the SWIR (68.5-42.7 Ma),and intra-plate volcanism (42.7-0 Ma).These three phases correspond to the formation of the eastern,central,and western parts of the Del Cano Rise,respectively.The magnitude and apparent periodicity of the magmatic volume flux of the Marion hotspot appear to be dominated by the hotspot-ridge distance.The periodicity of the Marion hotspot is about 25 Ma,which is much longer than that of the Hawaii and Iceland hotspots (about 15 Ma).
作者
ZHANG Tao 1,2,3,4,LIN Jian 5 & GAO JinYao 3,4 1 Institute of Geodesy and Geophysics,Chinese Academy of Sciences,Wuhan 430077,China
2 Graduate University of Chinese Academy of Sciences,Beijing 100049,China
3 The Second Institute of Oceanography,State Oceanic Administrator,Hangzhou 310012,China
4 Key Laboratory of Submarine Geosciences,State Oceanic Administrator,Hangzhou 310012,China
5 Department of Geology and Geophysics,Woods Hole Oceanographic Institution,Woods Hole,MA 02543,USA
基金
supported by SOA Funds for Young Scientists(Grant Nos.1084-10)
Special Funding for the Basic Scientific Research(Grant Nos.JG0706and JG0716)
关键词
南印度洋
相互作用
板内
洋脊
西南
海山
高原
海洋
Southwest Indian Ocean
hotspot-ridge interaction
magmatic volume flux
oceanic plateaus
seamounts