The drift history of the Dharwar Craton and India from 2.37 Ga to 1.01 Ga with refinements for an initial Rodinia configuration  

作　　者：Scott R.Miller Joseph G.Meert Anthony F.Pivarunas Anup K.Sinha Manoj K.Pandit Paul A.Mueller George D.Kamenov 

机构地区：[1]Department of Geological Sciences,University of Florida,Gainesville,FL 32601,USA [2]U.S.Geological Survey,Geology,Minerals,Energy,and Geophysics Science Center,United States Geological Survey,Moffett Field,CA 94035,USA [3]Dr.K.S.Krishnan Geomagnetic Research Laboratory,Chamanganj Bazaar,Allahabad 221505,India [4]Department of Geology,University of Rajasthan,Jaipur 302004,Rajasthan,India

出　　处：《Geoscience Frontiers》2023年第4期245-269,共25页地学前缘（英文版）

基　　金：This work was supported by the United States of America National Science Foundation grants EAR13-47942 and 602 EAR18-50693 to JGM。

摘　　要：Coupled paleomagnetic and geochronologic data derived from mafic dykes provide valuable records of continental movement.To reconstruct the Proterozoic paleogeographic history of Peninsular India,we report paleomagnetic directions and U-Pb zircon ages from twenty-nine mafic dykes in the Eastern Dharwar Craton near Hyderabad.Paleomagnetic analysis yielded clusters of directional data that correspond to dyke swarms at 2.37 Ga,2.22 Ga,2.08 Ga,1.89-1.86 Ga,1.79 Ga,and a previously undated dual polarity magnetization.We report new positive baked contact tests for the 2.08 Ga swarm and the 1.89-1.86 Ga swarm(s),and a new inverse baked contact test for the 2.08 Ga swarm.Our results promote the 2.08 Ga Dharwar Craton paleomagnetic pole(43.1°N,184.5°E;A95=4.3°)to a reliability score of R=7 and suggest a position for the Dharwar Craton at 1.79 Ga based on a virtual geomagnetic pole(VGP)at 33.0°N,347.5°E(a95=16.9°,k=221,N=2).The new VGP for the Dharwar Craton provides support for the union of the Dharwar,Singhbhum,and Bastar Cratons in the Southern India Block by at least 1.79 Ga.Combined new and published northeast-southwest moderate-steep dual polarity directions from Dharwar Craton dykes define a new paleomagnetic pole at 20.6°N,233.1°E(A95=9.2°,N=18;R=5).Two dykes from this group yielded 1.05-1.01 Ga 207Pb/206Pb zircon ages and this range is taken as the age of the new paleomagnetic pole.A comparison of the previously published poles with our new 1.05-1.01 Ga pole shows India shifting from equatorial to higher(southerly)latitudes from 1.08 Ga to 1.01 Ga as a component of Rodinia.

关 键 词：Dharwar INDIA RODINIA U-Pb PALEOGEOGRAPHY GRENVILLE 

分 类 号：P534[天文地球—古生物学与地层学] P581[天文地球—地质学] P597.3