Mineralogical aspects of terrestrial weathering effects in chondrites from Allan Hills, Antarctica

The work reported here represents a first attempt at comparing the mineralogical aspects of weathering effects in selected Antarctic chondrites with those present in a petrologically similar chondrite which was weathered in the Arizona desert. The methods of analysis employed include X-ray diffracto...

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Bibliographic Details
Main Author: Gooding, J. L.
Format: Other/Unknown Material
Language:unknown
Published: 1982
Subjects:
91
Online Access:http://ntrs.nasa.gov/search.jsp?R=19820048214
Description
Summary:The work reported here represents a first attempt at comparing the mineralogical aspects of weathering effects in selected Antarctic chondrites with those present in a petrologically similar chondrite which was weathered in the Arizona desert. The methods of analysis employed include X-ray diffractometry, differential thermal analysis, and reflectance spectrophotometry. It is found that the dominant weathering products in the rocks are complex, multiple-phase, hydrous ferric oxides which formed by alteration of Ni-Fe metal and sulfide particles under the influence of liquid water. The Fe-oxide weathering products may comprise approximately 15-20 wt % of the most intensely weathered samples although the same samples contain not more than 5% goethite as the only well-crystallized hydrous ferric oxide.