Cosmogenic nuclides in the Brenham pallasite

Details Cosmogenic nuclides in the Brenham pallasite Cosmogenic nuclides in the Brenham pallasite

Dec 2002

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002m%26ps...37.1711h&link_type=abstract

Meteoritics & Planetary Science, vol. 37, no. 12, pp. 1711-1728 (2002)

Physics

11

Scientific paper

Cosmic-ray-produced (cosmogenic) nuclides were studied in fragments of the Brenham pallasite, a large stony iron meteorite. The contents of light noble gases (He, Ne, and Ar) and long-lived radionuclides (10Be, 26Al, 36Cl, and 53Mn), produced by nuclear reactions with cosmic rays, were measured in the separated metal and olivine phases from numerous samples representing a wide range of shielding conditions in the meteoroid. The distribution of cosmogenic nuclide concentrations in the metal follows patterns similar to that observed in large iron meteorites. Shielding effects were estimated from the relative proportions of low- and high-energy reaction products. The production rates varied, from surface to interior, by a factor of more than several hundred. The 36Cl-36Ar cosmic-ray exposure age of Brenham is 156 +/- 8 Myr. This determination is based on a multiple nuclide approach that utilizes cosmogenic nuclide pairs. This approach not only yields a "shielding independent" exposure age but also demonstrates that the production of cosmogenic nuclides occurred in a single stage. The depth profiles of 10Be in the stone phase and 53Mn in the metal phase are shown superimposed on corresponding profiles from the Apollo 15 long drill core. Surprisingly low abundances of lithophile elements, such as K, U, and Th, provided a unique opportunity to examine the production systematics of those nuclides whose inventories typically have significant contributions from non-cosmogenic sources, particularly radiogenic contributions. The U and Th contents of the olivine samples are extremely low, allowing detection of cosmogenic 4He production from oxygen, magnesium, silicon, and iron.

Affiliated with

Also associated with

No associations

Rating

Cosmogenic nuclides in the Brenham pallasite does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Cosmogenic nuclides in the Brenham pallasite, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Cosmogenic nuclides in the Brenham pallasite will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-967982