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THE LOOP CHONDRITE: PETROLOGY, MINERAL CHEMISTRY, AND OPAQUE MINERALOGY
Author(s) -
Boctor Nabil Z.,
Kullerud Gunnar
Publication year - 1981
Publication title -
meteoritics
Language(s) - English
Resource type - Journals
eISSN - 1945-5100
pISSN - 0026-1114
DOI - 10.1111/j.1945-5100.1981.tb00185.x
Subject(s) - troilite , chondrite , meteorite , chondrule , geology , kamacite , ordinary chondrite , geochemistry , olivine , chromite , mineral , plagioclase , mineralogy , chemistry , astrobiology , physics , paleontology , quartz , organic chemistry
The Loop meteorite was found in 1962 in Gaines County, Texas, at a location very close to that where the Ashmore chondrite was found in 1969. The two specimens were assumed to be fragments of the same meteorite. The Loop meteorite is a type L6 chondrite composed of olivine (Fo 75.4 Fa 24.6 ), orthopyroxene (En 77.6 Wo 1.5 Fs 20.9 ), clinopyroxene (En 47.5 Wo 45.1 Fs 7.4 ), plagioclase (Ab 84.3 Or 5.5 An 10.2 ), Fe‐Ni metal, troilite, and chromite. Fe‐Ni metal is represented by kamacite (5.8‐6.4 wt % Ni, 0.88‐1.00 wt % Co), taenite (30.0–52.9 wt % Ni, 0.16‐0.34 wt % Co), and plessite (16.8–28.5 wt % Ni, 0.38‐0.54 wt % Co). Native copper occurs as rare inclusions in Fe‐Ni metal. Both chondrules and matrix have similar mineral compositions. The mineral chemistry of the Loop meteorite is quite different from that of the Ashmore, which was classified as an H5 chondrite by Bryan and Kullerud (1975). Therefore, the Ashmore and Loop meteorites are two different chondrites, even though they were recovered from the same geographic location.