Age of the Marwar Supergroup,NW India:A note on the U–Pb geochronology of Jodhpur Group felsic volcanics  

作　　者：Huiru Xu Joseph G.Meert Manoj K.Pandit 

机构地区：[1]Hubei Subsurface Multi-scale Imaging Key Laboratory,Institute of Geophysics and Geomatics,China University of Geosciences,Wuhan 430074,China [2]Department of Earth and Planetary Sciences,University of Florida,Gainesville,FL 32611,United States [3]Department of Geology,University of Rajasthan,Jaipur 302004,India

出　　处：《Geoscience Frontiers》2022年第1期244-254,共11页地学前缘（英文版）

基　　金：JGM by the US National Science Foundation Grant EAR09-10888;HRX by the National Natural Science Foundation of China Grant 41974078。

摘　　要：The Marwar Supergroup(NW Peninsular India)is thought to be of Ediacaran-Cambrian age,based on previous paleontological and geochronological studies.However,direct constraints on the onset of sedimentation within the Marwar basin are still scarce.In this study,we report U–Pb zircon,LA-ICP-MS,and SIMS ages from the Chhoti Khatu felsic volcanic rocks,interlayered with the Jodhpur Group sandstones(Lower Marwar Supergroup).The cathodoluminescence images of the zircons indicate complex morphologies,and core-rim textures coupled with the wide range of ages indicate that they are likely inherited or in the case of thin poorly indurated ash-beds,detrital in origin.The age spectra of 68 zircon analyses from our sampling display a dominant 800–900 Ma age peak corresponding to the age of basement"Erinpura granite"rocks in the region.The youngest inherited zircon from a felsic ash layer yielded a U–Pb age of651 Ma±18 Ma that,together with previous studies and paleontological evidence,indicates a postCryogenian age for the initiation of Marwar sedimentation following a~125 Ma hiatus between the end of Malani magmatism and Marwar deposition.

关 键 词：Marwar Supergroup Sedimentation age Zircon U-Pb dating Chhoti Khatu felsic volcanics 

分 类 号：P588.14[天文地球—岩石学] P597.3[天文地球—地质学]