Shukla, P. N. ; Shukla, A. D. ; Rai, V. K. ; Murty, S. V. S. ; Bhandari, N. ; Goswami, J. N. ; Mazumdar, A. C. ; Phukon, P. ; Duorah, K. ; Greenwood, R. E. ; Franchi, I. A. (2005) The Dergaon, H5 chondrite: fall, classification, petrological and chemical characteristics, cosmogenic effects and noble gas records Meteoritics & Planetary Science, 40 (4). pp. 627-637. ISSN 1086-9379
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Official URL: http://www3.interscience.wiley.com/journal/1232554...
Related URL: http://dx.doi.org/10.1111/j.1945-5100.2005.tb00967.x
Abstract
A multiple fall of a stony meteorite occurred near the town of Dergaon in Assam, India, on March 2, 2001. Several fragments weighing <2kg and a single large fragment weighing ∼10 kg were recovered from the strewn field, which extended over several tens of square kilometers. Chemical, petrographic, and oxygen isotopic studies indicate it to be, in most aspects, a typical H5 chondrite, except the unusually low K content of ∼ 340 ppm. A cosmic ray exposure of 9.7 Ma is inferred from the cosmogenic noble gas records. Activities of eleven cosmogenic radionuclides were measured. 26Al and 22Na activities as well as the 22Na/26Al activity ratio are close to the values expected on the basis of solar modulation of galactic cosmic rays. The low 60Co activity (<1 dpm/kg) is indicative of a small preatmospheric size of the meteorite. Cosmic ray heavy nuclei track densities in olivine grains range from ∼ 106cm-2 in samples from the largest fragment to approximately (4-9)×105 cm-2 in one of the smaller fragments. The combined track, radionuclide, and noble gas data suggest a preatmospheric radius of ∼20 cm for the Dergaon meteorite.
Item Type: | Article |
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Source: | Copyright of this article belongs to University of Arizona. |
ID Code: | 18593 |
Deposited On: | 17 Nov 2010 12:44 |
Last Modified: | 17 May 2016 03:18 |
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