Feeder and post Deccan Trap dyke activities in the northern slope of the Satpura Mountain： Evidence from new 40Ar-39Ar ages  

作　　者：J.P.Shrivastava R.Kumar N.Rani 

机构地区：[1]Department of Geology,University of Delhi

出　　处：《Geoscience Frontiers》2017年第3期483-492,共10页地学前缘（英文版）

基　　金：Department of Science and Technology,Government of India for financial support to this work(Project Grant No.ESS/16/286/2006);Post-Doctoral,D.S. Kothari Fellowship for financial support

摘　　要：We present new 40Ar-39Ar plagioclase crystallization ages from the dykes exposed at the northern slope of the Satpura Mountain range near Betul-Jabalpur-Pachmarhi area, - 800 km NE of the Western Ghats escarpment. Among the two plateau ages, the first age of 66.56 ± 0.42 Ma from a dyke near Mohpani village represents its crystallization age which is either slightly older or contemporaneous with the nearby Mandla lava flows （63-65 Ma）. We suggest that the Mohpani dyke might be one of the feeders for the surrounding lava flows as these lavas are significantly younger than the majority of the main Deccan lavas of the Western Ghats （66.38-65.54 Ma）. The second age of 56.95 -- 1.08 Ma comes from a younger dyke near Olini village which cuts across the lava flows of the area. The age correlates well with the Mandla lavas which are chemically similar to the uppermost Poladpur, Ambenali and Mahabaleshwar Formation lavas of SW Deccan. Our study shows that the dyke activities occurred in two phases, with the second one representing the terminal stage.We present new 40Ar-39Ar plagioclase crystallization ages from the dykes exposed at the northern slope of the Satpura Mountain range near Betul-Jabalpur-Pachmarhi area, - 800 km NE of the Western Ghats escarpment. Among the two plateau ages, the first age of 66.56 ± 0.42 Ma from a dyke near Mohpani village represents its crystallization age which is either slightly older or contemporaneous with the nearby Mandla lava flows （63-65 Ma）. We suggest that the Mohpani dyke might be one of the feeders for the surrounding lava flows as these lavas are significantly younger than the majority of the main Deccan lavas of the Western Ghats （66.38-65.54 Ma）. The second age of 56.95 -- 1.08 Ma comes from a younger dyke near Olini village which cuts across the lava flows of the area. The age correlates well with the Mandla lavas which are chemically similar to the uppermost Poladpur, Ambenali and Mahabaleshwar Formation lavas of SW Deccan. Our study shows that the dyke activities occurred in two phases, with the second one representing the terminal stage.

关 键 词：40Aro39Ar ages Deccan dykes Betul-Jabalpur-Pachmarhi area Narmada-Tapi dyke system 

分 类 号：P542[天文地球—构造地质学] P597.3[天文地球—地质学]