Changes in abundance and nature of microimpact craters on the surfaces of Australasian microtektites with distance from the proposed source crater location

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dc.contributor.author ShyamPrasad, M.
dc.contributor.author Roy, S.K.
dc.contributor.author Gupta, A.
dc.date.accessioned 2010-10-07T08:58:10Z
dc.date.available 2010-10-07T08:58:10Z
dc.date.issued 2010
dc.identifier.citation Meteoritics & Planetary Science, vol.45(6); 990-1006
dc.identifier.other no
dc.identifier.uri http://drs.nio.org/drs/handle/2264/3722
dc.description.abstract Over 4600 Australasian microtektites from 11 sediment cores along an N-S transect in the Central Indian Ocean have been investigated optically for microimpact features on their surfaces. Detailed scanning electron microscope examination of 68 microtektites along this transect shows 4091 such features. These samples are located between approximate distances of 3900-5000 km from the suggested impact site in Indochina and therefore constitute distal ejecta. The morphology of the microimpacts seems to show distinct variations with distance from the source crater. The total number of microcraters on each microtektite decreases drastically from North to South indicating systematic decrease in the spatial density of the ejecta, and decrease in collisional activity between microtektites with distance from the proposed source crater location. Closer to the proposed source crater location, the microcraters are predominantly small (few lm), pit bearing with radial and concentric cracks, suggestive of violent interparticle collisions. The scenario is reverse farther from the source crater with smaller numbers of impacted microtektites due to increased dispersion of the ejecta and the microcraters are large and shallow, implying gentle collisions with larger particles. These observations provide systematic ground truth for the processes that take place as the ejecta of a large oblique impact which generated the Australasian tektite strewn field is emplaced. The microimpacts appear to take place during the descent of the ejecta and their intensity and number density decrease as a function of the spatial density of the ejecta at any given place and with distance from the source region. These features could help understand processes that take place during ejecta emplacement on planets with substantial atmosphere such as Mars and Venus
dc.language.iso en
dc.publisher Wiley-Blackwell
dc.relation.requires Meteor_Planet_Sci_45_990.jpg
dc.rights An edited version of this paper was published by Blackwell. Copyright [2009] Blackwell. Copyright [2010] The Meteoritical Society. All efforts have been made to respect the copyright to the best of our knowledge. Inadvertent omissions, if brought to our notice, stand for correction and withdrawal of document from this repository.
dc.subject meteorite impacts
dc.subject microtektites
dc.subject extraterrestrial material
dc.subject sediment cores
dc.title Changes in abundance and nature of microimpact craters on the surfaces of Australasian microtektites with distance from the proposed source crater location
dc.type Journal Article


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