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

Parthasarathy, G and Pandey, OP and Sreedhar, B and Sharma, Mukund and Tripathi, Priyanka and Vedanti, Nimisha (2019) First observation of microspherule from the infratrappean Gondwana sediments below Killari region of Deccan LIP, Maharashtra (India) and possible implications. In: GEOSCIENCE FRONTIERS, 10 (6). pp. 2281-2285.

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Abstract

A rare occurrence of a microspherule has been found in the infratrappean sediments, encountered below 338 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.%), K2O (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.

Item Type:	Journal Article
Publication:	GEOSCIENCE FRONTIERS
Publisher:	CHINA UNIV GEOSCIENCES, BEIJING
Additional Information:	Copyright of this article belongs to CHINA UNIV GEOSCIENCES
Keywords:	Deccan trap; Killari borehole; Microspherules; Gondwana sediments; Tectonics; P-T impact
Department/Centre:	Others
Date Deposited:	12 Feb 2020 08:03
Last Modified:	12 Feb 2020 08:03
URI:	http://eprints.iisc.ac.in/id/eprint/63949

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