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|Title: ||Inclusions in the Allende Meteorite|
|Authors: ||Mason, Brian|
Taylor, S. R.
|Issue Date: ||5-Oct-1982|
|Citation: ||Smithsonian Contributions to the Earth Sciences; 25|
|Abstract: ||Six discrete groups of inclusions have been distinguished in the Allende meteorite. Groups I, V, and VI are mostly melilite-rich chondrules, although some have been extensively altered to fine-grained aggregates; Groups II and III are mostly fine-grained aggregates made up largely of spinel and fassaite; Group IV are olivine-rich aggregates and chondrules. Each group has a distinctive trace-element pattern, most clearly shown by the rare-earth (RE) distribution pattern. Group I has an unfractionated pattern (except for a small positive Eu anomaly) at about 10-15 times chondrites; Group II has a highly fractionated pattern with depletion of the heavier lanthanides (Gd-Er) and negative Eu and positive Tm and Yb anomalies; Group III has an unfractionated pattern at about 20 times chondrites, except for negative Eu and Yb anomalies; Group IV has a relatively unfractionated pattern at 2-4 times chondrites; Group V has an unfractionated pattern at 10-20 times chondrites; Group VI has an unfractionated pattern at 10-20 times chondrites, except for positive Eu and Yb anomalies (i.e., complementary to Group III). The complex patterns of trace element distribution in these Allende inclusions indicate a complex history of formation of this meteorite from the solar nebula.|
|Appears in Collections:||Smithsonian Contributions to the Earth Sciences|
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