Mantle plume trail beneath the ca. 1.1 Ga North American Midcontinent Rift revealed by magnetotelluric data  

作　　者：Wule Lin Adam Schultz Bo Yang Lyal B.Harris Xiangyun Hu 

机构地区：[1]Hubei Subsurface Multi-scale Imaging Key Laboratory,School of Geophysics and Geomatics,China University of Geosciences,Wuhan 430074,China [2]Department of Ocean Scienceand Engineering,Southern Universityof Science and Technology,Shenzhen 518005,China [3]Advanced Institute for Ocean Research,Southern University of Science and Technology,Shenzhen 518005,China [4]College of Earth,Ocean,and Atmospheric Sciences,Oregon State University,Corvallis,OR 97331,USA [5]Key Laboratory of Ocean and Marginal Sea Geology,South China Sea Institute of Oceanology,Chinese Academy of Sciences,Guangzhou 511458,China [6]China-Pakistan Joint Research Center on Earth Sciences,CAS-HEC,Islamabad 45320,Pakistan [7]Eau Terre Environnement Research Centre,Institut Nationaldela Recherche Scientifique,Quebec,QC G1K9A9,Canada

出　　处：《National Science Review》2024年第8期140-150,共11页国家科学评论（英文版）

基　　金：supported by the National Natural Science Foundation of China (42220104002 and 42327803);the National Key Research and Development Program of China (2022YFF0802800);the China Scholarship Council (201906410007);supported by the United States National Science Foundation (EAR-0323311);IRIS Subaward 478 and 489 under the United States National Science Foundation Cooperative Agreement (EAR-0350030 and EAR-0323309);IRIS Subaward 75-MT under the United States National Science Foundation Cooperative Agreement (EAR-0733069);IRIS Subaward 05-OSU-SAGE under the United States National Science Foundation Cooperative Agreement (EAR-1261681);Research by L.B.H.on deep structures of the Superior Province was supported by a TGI-S grant by Natural Resources Canada.

摘　　要：Whilst the 1.1 Ga North American Midcontinent Rift(MCR)system is formed in association with the Keweenaw mantle plume,the absence of a northern third rift arm or aulacogen(a general characteristic of mantle plumes)has previously not been well understood.To help clarify this unusual plume-rift relationship and to better establish the region affected by the Keweenaw mantle plume,we present the first electrical resistivity model of the MCR derived from 3D inversion of EarthScope USArray and Lithoprobe magnetotelluric(MT)data,extending northwards into the Archean Superior Province.Our model shows a prominent highly conductive anomaly trending NW-SE at the base of Western Superior's cratonic lithospheric mantle,cross-cutting and extending for over 300 km on both sides of the western rift branch.We propose that this anomaly reflects the ancient signature of a plume trail,resulting from metasomatism and/or partial melting of the sulfide-rich basal lithospheric mantle during impingement of the Keweenaw mantle plume.

关 键 词：MAGNETOTELLURIC Midcontinent Rift Keweenaw mantle plume Superior Province North America 

分 类 号：P54[天文地球—构造地质学]