Extraterrestrial components from deep sea sediments of Indian Ocean
DRS at CSIR-National Institute of Oceanography
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Title |
Extraterrestrial components from deep sea sediments of Indian Ocean
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Creator |
Rudraswami, N.G.
ShyamPrasad, M. |
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Subject |
Geology and geophysics
Geology and geophysics Chemistry and biogeochemistry |
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Description |
Two different types of extraterrestrial particulate matter collections were undertaken during the last few years-by using magnets encased in dredges that were dragged along the seafloor and by sieving massive quantities of deep sea sediments from which cosmic spherules were subsequently isolated. Detailed investigations on close to 1000 sectioned cosmic spherules revealed the presence of Pt-group nuggets in all the three basic types of cosmic spherules - all of whom had carbonaceous chondritic meteorites as precursors, thus in a way unifying them. Further, Fe-Ni beads in all types of the investigated cosmic spherules further confirmed this finding. Oxygen isotopes of relict-grains in silicate cosmic spherules suggested chondrules from carbonaceous chondrites to be major contributors. In addition, relict chromite grains and dusty olivines observed in several cosmic spherules suggested that at least 3% of the cosmic material that rains on the earth is sourced from ordinary chondrites. The Australasian microtektites found in the Indian Ocean retained unique microimpact features generated while they were in flight due to inter-particle collisions in the ejecta. This unique phenomenon outlined the importance of the impact process during estimation of cosmic dust fluxes estimated from lunar materials
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Date |
2016-10-13T12:22:10Z
2016-10-13T12:22:10Z 2016 |
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Type |
Journal Article
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Identifier |
Proceedings of the Indian National Science Academy, vol.82(3); 2016; 653-661
http://drs.nio.org/drs/handle/2264/5017 |
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Language |
en
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Rights |
This is an open access article © (2016) Indian National Science Academy.
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Publisher |
Indian National Science Academy
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