Micropalaeontological and Geochemical Evidence of the Late Jurassic Radiolarians Cherts of Naga Ophiolite Hill, Nagaland, Northeast-India  

作　　者：Ramamoorthy Ayyamperumal Ramasamy Sooriamuthu Gnanachandrasamy Gopalakrishnan Ganga Biswa Rajkumar Perumal Prerna Gahlaut Nusrat Nazir Justine Kandathil Antony Ramamoorthy Ayyamperumal;Ramasamy Sooriamuthu;Gnanachandrasamy Gopalakrishnan;Ganga Biswa;Rajkumar Perumal;Prerna Gahlaut;Nusrat Nazir;Justine Kandathil Antony(MOE Key Laboratory of Western China’s Environmental System, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, China;Department of Geology, University of Madras, Chennai, India;School of Geography and Planning, Sun Yat-sen University, Guangzhou, China;Department of Geology, Mohanlal Sukhadia University, Udaipur, India;Centre for Earth Sciences, Indian Institute of Science, Bangalore, India;Department of Geology, Hemwati Nandan Bahuguna Garhwal University, Srinagar, India;School of Earth Sciences, Lanzhou University, Lanzhou, China;Department of Earth Sciences, Annamalai University, Chidambaram, India)

机构地区：[1]MOE Key Laboratory of Western China’s Environmental System, College of Earth and Environmental Sciences, Lanzhou University, Lanzhou, China [2]Department of Geology, University of Madras, Chennai, India [3]School of Geography and Planning, Sun Yat-sen University, Guangzhou, China [4]Department of Geology, Mohanlal Sukhadia University, Udaipur, India [5]Centre for Earth Sciences, Indian Institute of Science, Bangalore, India [6]Department of Geology, Hemwati Nandan Bahuguna Garhwal University, Srinagar, India [7]School of Earth Sciences, Lanzhou University, Lanzhou, China [8]Department of Earth Sciences, Annamalai University, Chidambaram, India

出　　处：《Open Journal of Geology》2021年第8期356-372,共17页地质学期刊（英文）

摘　　要：We analyzed the radiolarian assemblages (pelagic sediments) and geochemical studies of 15 samples collected from Meluri district Nagaland, Naga Hills Ophiolite belt (NHO) and it consists of the Flysch Naga-Arakan-Yoma trough beyond the Indo-Myanmar border. It reflects one of the many components of the Himalayan Orogenic systems of Tethyan oceanic crust discovered in Nagaland at Meluri district of India and they have very well-preserved studies and can be identified to Upper Jurassic (Kimmeridgian-mid-Tithonian). As well as a continuous sequence of Kimmeridgian-mid-Tithonian, five radiolarian assemblages have been identified in this study. This is so far the first recovery of pelagic sediment assemblages (Radiolarians) from the Naga Hills Ophiolite complex. Samples of Naga Hills Ophiolite belts fell in the Sublitharenite, Litharenite, and Fe-shale Fe-sand area, and the A-CN-K diagram indicates that these sediments in the source region were exposed deep to moderate weathering conditions. In the discriminant plot, the Naga Hill-Ophiolite-Chert samples occupy the field of origin of the sediment quartzose, and the log (K₂O/Na₂O) versus SiO₂samples fall into the active continental marginal field, and only one sample falls into an island arch, suggesting that the tectonic framework of the Naga Hills-Chert samples was deposited in the active continental margin and the diagrams K₂O/Al₂O₃ and MgO/Al₂O₃ illustrated the tectonic setting of the marine environment from Naga Hill Ophiolite Chert. Such findings have been consistent with the current geology of Naga Hills in the province of Nagaland.We analyzed the radiolarian assemblages (pelagic sediments) and geochemical studies of 15 samples collected from Meluri district Nagaland, Naga Hills Ophiolite belt (NHO) and it consists of the Flysch Naga-Arakan-Yoma trough beyond the Indo-Myanmar border. It reflects one of the many components of the Himalayan Orogenic systems of Tethyan oceanic crust discovered in Nagaland at Meluri district of India and they have very well-preserved studies and can be identified to Upper Jurassic (Kimmeridgian-mid-Tithonian). As well as a continuous sequence of Kimmeridgian-mid-Tithonian, five radiolarian assemblages have been identified in this study. This is so far the first recovery of pelagic sediment assemblages (Radiolarians) from the Naga Hills Ophiolite complex. Samples of Naga Hills Ophiolite belts fell in the Sublitharenite, Litharenite, and Fe-shale Fe-sand area, and the A-CN-K diagram indicates that these sediments in the source region were exposed deep to moderate weathering conditions. In the discriminant plot, the Naga Hill-Ophiolite-Chert samples occupy the field of origin of the sediment quartzose, and the log (K₂O/Na₂O) versus SiO₂samples fall into the active continental marginal field, and only one sample falls into an island arch, suggesting that the tectonic framework of the Naga Hills-Chert samples was deposited in the active continental margin and the diagrams K₂O/Al₂O₃ and MgO/Al₂O₃ illustrated the tectonic setting of the marine environment from Naga Hill Ophiolite Chert. Such findings have been consistent with the current geology of Naga Hills in the province of Nagaland.

关 键 词：Geochemistry Late Jurassic RADIOLARIANS Naga Hill Ophiloite Northeast Nagaland India 

分 类 号：P58[天文地球—岩石学]