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COMPOSITIONAL STUDY OF THE LONE TREE, IOWA, CHONDRITE
Author(s) -
McCormick G. R.,
Carman J. H.
Publication year - 1975
Publication title -
meteoritics
Language(s) - English
Resource type - Journals
eISSN - 1945-5100
pISSN - 0026-1114
DOI - 10.1111/j.1945-5100.1975.tb00009.x
Subject(s) - troilite , chondrule , kamacite , olivine , chondrite , meteorite , geology , pyroxene , petrography , geochemistry , augite , lithic fragment , electron microprobe , mineralogy , enstatite , mineral , plagioclase , astrobiology , materials science , physics , metallurgy , paleontology , quartz , clastic rock , sedimentary rock
A meteorite, named for the location of its discovery near Lone Tree, Iowa, was found by Loren Westfall in May 1971. Electron microprobe and petrographic studies reveal its mineral composition to be olivine, low‐calcium clinopyroxene, high‐calcium clinopyroxene, troilite, kamacite, taenite and iron oxides. On the basis of texture, olivine composition (19% Fa), low‐calcium clinopyroxene composition (17% Fs, 2% Wo) and metal (determined by modal analysis), this meteorite is classified as an H group bronzite chondrite. While it has characteristics of classes 3 and 4 (Van Schmus and Wood, 1967, Table 2) it fits class 4 better since low‐calcium pyroxene has a MD of 5.6%, olivine has a MD of 3.2%, turbid glass is present in chondrules, feldspar is absent, and the matrix is opaque. The opacity of the matrix may be due to iron oxides in microfractures in a microcrystalline matrix.