【摘 要】
：
The Marwar Supergroup (NW Peninsular India) is thought to be of Ediacaran-Cambrian age,based on pre-vious paleontological and geochronological studies.However,direct constraints on the onset of sedimen-tation within the Marwar basin are still scarce.In th
【机 构】
：
Hubei Subsurface Multi-scale Imaging Key Laboratory,Institute of Geophysics and Geomatics,China Univ
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The Marwar Supergroup (NW Peninsular India) is thought to be of Ediacaran-Cambrian age,based on pre-vious paleontological and geochronological studies.However,direct constraints on the onset of sedimen-tation 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 of 651 Ma ± 18 Ma that,together with previous studies and paleontological evidence,indicates a post-Cryogenian age for the initiation of Marwar sedimentation following a ～125 Ma hiatus between the end of Malani magmatism and Marwar deposition.
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