Detrital zircon and monazite track the source of Mesozoic sediments in Kutch to rocks of Late Neoproterozoic and Early Palaeozoic orogenies in northern India |
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| Institution: | 1. State Key Laboratory of Geological Processes and Mineral Resources, School of Earth Sciences, China University of Geosciences, Wuhan 430074, China;2. Department of Geology, University of Rajasthan, Jaipur 302004, India;3. State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550081, China;1. Department of Geological Sciences, Jadavpur University, Kolkata 700032, India;2. Geological Stduies Unit, Indian Statistical Institute, Kolkata 700108, India;3. Department of Geology, University of Delhi, Delhi 110007, India;1. Department of Geology, Delhi University, India;2. Department of Earth and Planetary Systems Science, Hiroshima University, Japan;1. Department of Geology, University of Delhi, Delhi 110007, India;2. Department of Earth and Planetary Systems Science, Hiroshima University, Hiroshima, Japan;1. Department of Geology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata, 700019, India;2. Department of Geology, Durgapur Government College, Durgapur, 713214, India;3. Department of Earth and Planetary Systems Science, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan;4. Hiroshima Institute of Plate Convergence Region Research, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan;5. Geological Survey of Japan, AIST, Tsukuba, Ibaraki, 305-8567, Japan;6. Submarine Resources Research Center, Japan Agency for Marine-Earth Science and Technology (JAMSTEC), Yokosuka, Kanagawa, 237-0061, Japan |
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| Abstract: | Detrital zircon and monazite dating of clastic rocks in the Mesozoic Kutch Basin at the western continental margin of India reveals predominant sediment derivation from rocks of Neoproterozoic Pan-African orogeny, followed by those of Cambro-Ordovician Bhimphedian (or Kurgiakh) orogeny and 850–1000 Ma rocks, with subordinate input from rocks of 700–800 Ma, 1500–1600 Ma, 2400–2500 Ma and 2800–3300 Ma. This finding refutes the existing idea regarding the predominant Mesoproterozoic source inferred for this basin. The dominance of southwesterly palaeocurrent data of Mesozoic rocks in Kutch Basin rules out sediment supply from south or west. Th/U ratios of detrital zircon grains indicate predominantly magmatic and subordinately metamorphic source rock. Petrographic data, particularly the QFR plot supports this interpretation of source rock. Rocks belonging to the Pan-African orogeny are poorly exposed in northwestern India while isolated outcrops of peralkaline granites in the Himalayan region bear testimony of the Bhimphedian orogeny. While the paucity of records of the Pan-African orogeny in western India possibly relates to either burial under the Deccan Flood Basalts or extensive erosion during Mesozoic greenhouse climate, the dearth of rocks of Bhimphedian orogeny results from its occurrence along the present-day Himalayan thrust belt. The absence of detrital zircon grains younger than 458 Ma indicates that post-Ordovician tectono-thermal events skipped the source area. The large gap between youngest detrital zircon and the depositional age of the Mesozoic sediments, suggests long-distance sediment transport as well as sediment recycling. This study, therefore, indicates the existence of widespread younger magmatic rocks to the north during the deposition of Mesozoic of Kutch. |
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