Meteoritic event recorded in Antarctic ice
- Case Western Reserve Univ., Cleveland, OH (United States). Dept. of Geological Sciences
- New Mexico Inst. of Mining and Technology, Socorro, NM (United States). Dept. of Earth and Environmental Science
- Univ. of California, Berkeley, CA (United States). Space Sciences Lab.
- Cold Regions Research and Engineering Lab., Hanover, NH (United States)
- Lawrence Livermore National Lab., CA (United States)
During systematic sampling of volcanic ash (tephra) layers at a well-known Antarctic meteorite collection site (the Allan Hills main ice field), a band of unusually dark and rounded (many spheroidal) particles was discovered. This debris layer (BIT-58) extends parallel to the stratigraphy of the ice established from the tephra bands, apparently marking a single depositional event. The shapes, internal texture, major element composition, and levels of cosmogenic nuclides of particles from within BIT-58 all strongly suggest that this material represents ablation debris from the passage of a large H-group ordinary chondrite. Preliminary cosmogenic isotope dating suggests an age of 2.8 Ma, implying that the East Antarctic ice sheet has been stable since that time. The relationship of the Bit-58 layer to known impact events is not clear.
- Sponsoring Organization:
- National Science Foundation, Washington, DC (United States); National Aeronautics and Space Administration, Washington, DC (United States)
- OSTI ID:
- 653368
- Journal Information:
- Geology, Vol. 26, Issue 7; Other Information: PBD: Jul 1998
- Country of Publication:
- United States
- Language:
- English
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