A. Sarkar , A.K. Datta , B.C. Poddar , B.K. Bhattacharyya , V.K. Kollapuri , R. Sanwal
{"title":"Geochronological studies of Mesozoic igneous rocks from eastern India","authors":"A. Sarkar , A.K. Datta , B.C. Poddar , B.K. Bhattacharyya , V.K. Kollapuri , R. Sanwal","doi":"10.1016/0743-9547(96)00009-8","DOIUrl":null,"url":null,"abstract":"<div><p>A wide variety of Mesozoic basaltic and alkaline igneous rocks crop out on the eastern margin of the Indian shield. We present new KAr isotopic age data on whole rock samples and mineral separates from several igneous rock suites from the Meghalaya-Nagaland region of northeast India. The KAr isotopic ages of these samples lie between 149-107 Ma, i.e., Late Jurassic to Early Cretaceous. Published data on the tectonic setting and petrology of the basaltic and alkaline rocks suggest that their emplacement was controlled by major fault systems. Active mantle upwelling in an extensional tectonic régime related to the fragmentation of the indian plate from Australia-Antarctica in the Early Cretaceous, appears to have been the main trigger for the magmatic activity.</p></div>","PeriodicalId":85022,"journal":{"name":"Journal of Southeast Asian earth sciences","volume":"13 2","pages":"Pages 77-81"},"PeriodicalIF":0.0000,"publicationDate":"1996-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1016/0743-9547(96)00009-8","citationCount":"82","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Southeast Asian earth sciences","FirstCategoryId":"1085","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/0743954796000098","RegionNum":0,"RegionCategory":null,"ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"","JCRName":"","Score":null,"Total":0}
引用次数: 82
Abstract
A wide variety of Mesozoic basaltic and alkaline igneous rocks crop out on the eastern margin of the Indian shield. We present new KAr isotopic age data on whole rock samples and mineral separates from several igneous rock suites from the Meghalaya-Nagaland region of northeast India. The KAr isotopic ages of these samples lie between 149-107 Ma, i.e., Late Jurassic to Early Cretaceous. Published data on the tectonic setting and petrology of the basaltic and alkaline rocks suggest that their emplacement was controlled by major fault systems. Active mantle upwelling in an extensional tectonic régime related to the fragmentation of the indian plate from Australia-Antarctica in the Early Cretaceous, appears to have been the main trigger for the magmatic activity.