First observation of microspherule from the infratrappean Gondwana sediments below Killari region of Deccan LIP,Maharashtra(India) and possible implications  

作　　者：G.Parthasarathy O.P.PANDey B.Sreedhar Mukund Sharma Priyanka Tripathi Nimisha Vedanti 

机构地区：[1]CSIR-National Geophysical Research Institute,Hyderabad,500007,India [2]National Institute of Advance Studies,School of Natural Sciences and Engineering,Indian Institute of Science Campus,Bengaluru,560012,India [3]CSIR-Indian Institute of Chemical Technology,Hyderabad,500007,India [4]Birbal Sahni Institute of Palaeosciences,53 University Road,Lucknow,226007,India [5]Presently at Banaras Hindu University,Varanasi,India [6]Geological Survey of India,Bandalaguda,Hyderabad,50068,India

出　　处：《Geoscience Frontiers》2019年第6期2281-2285,共5页地学前缘（英文版）

基　　金：PLANEX,Physical Research Laboratory;ISRO-Space Application center,Ahmedabad for financial supporting;supported by the CSIR-Emeritus Scientist project sanctioned to O.P.Pandey

摘　　要：A rare occurrence of a microspherule has been found in the infratrappean sediments,encountered below338 m thick Deccan volcanic cover in KLR-1 scientific borehole,drilled in the epicentral zone of the 1993 Killari earthquake(Maharashtra,India).Palynological studies of the sediments indicate their age as Early Permian(Asselian,298-295 Ma) for deposition.Transmission electron microscope studies reveal that the spherule from the infratrappeans,is having a similar composition to that of the Neoarchean amphibolite to granulite facies mid crustal basement.The spherule is non-spherical in nature,containing mostly FeO(10.70±0.20 wt.%),CaO(13.8±0.5 wt.%),Al203(7.78±0.30 wt.%),MgO(6.47±0.3 wt.%),Si02(47,46±0.50 wt.%),Ti02(2.47±0.3 wt.%).K20(1.89±0.20 wt.%).and Cl(0.33±0.05 wt.%).Since the Fe composition of the spherule is almost same as the basement rock(10.5 wt.%),and the chlorine content is also in the same range as the basement(0.04-0.24 wt.%),it would suggest possibility of an extraterrestrial impact over the Indian terrain during the erstwhile Gondwana sedimentation period that may be associated with the Permian-Triassic mass extinction,the most severe one in the Earth's history.A rare occurrence of a microspherule has been found in the infratrappean sediments,encountered below338 m thick Deccan volcanic cover in KLR-1 scientific borehole,drilled in the epicentral zone of the 1993 Killari earthquake（Maharashtra,India）.Palynological studies of the sediments indicate their age as Early Permian（Asselian,298-295 Ma） for deposition.Transmission electron microscope studies reveal that the spherule from the infratrappeans,is having a similar composition to that of the Neoarchean amphibolite to granulite facies mid crustal basement.The spherule is non-spherical in nature,containing mostly FeO（10.70±0.20 wt.%）,CaO（13.8±0.5 wt.%）,Al2O3（7.78±0.30 wt.%）,MgO（6.47±0.3 wt.%）,SiO2（47,46±0.50 wt.%）,TiO2（2.47±0.3 wt.%）.K20（1.89±0.20 wt.%）.and Cl（0.33±0.05 wt.%）.Since the Fe composition of the spherule is almost same as the basement rock（10.5 wt.%）,and the chlorine content is also in the same range as the basement（0.04-0.24 wt.%）,it would suggest possibility of an extraterrestrial impact over the Indian terrain during the erstwhile Gondwana sedimentation period that may be associated with the Permian-Triassic mass extinction,the most severe one in the Earth’s history.

关 键 词：DECCAN trap Killari borehole Microspherules Condwana SEDIMENTS TECTONICS P-T impact 

分 类 号：P59[天文地球—地球化学]