Early Paleozoic basement diorite of arc-magmatism from Kutch basin, Western India  

作　　者：Piyush Gupta Sandeep Singh Shakti Singh Rathore Argha Narayan Sarkar 

机构地区：[1]Geochronology Laboratory,KDMIPE,Oil and Natural Gas Corporation Ltd.,9,Kaulagarh Road,Dehradun 248195,India [2]Department of Earth Sciences,Indian Institute of Technology,Roorkee 247667,India

出　　处：《Acta Geochimica》2024年第2期296-307,共12页地球化学学报（英文）

摘　　要：In this study,we report for thefirst time an Early Palaeozoic basement diorite from the drilled well Nirona-A in the Banni Half-Graben of the Kutch basin,western India.The 40Ar–39Ar dates provided a plateau age of 441.84±2.66 Ma and another pseudo plateau of 441.28±5.82 to 388.08±16.65 Ma for the basement diorite.These ages constrain the basement formation age to the Late Ordovician-Early Silurian period.The obtained basement ages are correlatable with the later part of Cambro-Ordovician alkaline magmatism that has been reported from the Huqf area in Central Oman,whereas their lithological and petrographic correlativity with base-ment diorites occurring in the Dinsi Body of Nagar Parkar igneous complex in Pakistan can also be envisaged.The geochemical studies characterized the diorite with enrich-ment of LILE(Rb,Ba,and K)and LREE(La,Ce,Nd),strong depletion of HFSE(Nb,Sr,P,and Ti),along with weakly negative Eu anomalies.The geochemical signatures indicate their petrogenetic affiliation with mantle-derived magmas,as well as their tectonic setting to be arc-related,having post-collisional continental-arc type affinity.The*440 Ma basement of Kutch,therefore,appears to rep-resent the later thermal event associated with the reworked Neoproterozoic subduction-related suite from Greater India’s northwest edge,which has implications for Gond-wana assembly in the northwest Indian subcontinent.

关 键 词：Kutch basin 40Ar–39Ar ages Early palaeozoic basement Continental-arc magmatism Calc-alkaline magmatism 

分 类 号：P588.11[天文地球—岩石学] P534.4[天文地球—地质学]