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Petrology and thermal history of type IA chondrules in the Semarkona (LL3.0) chondriteDetailed petrologic studies have been made of 15 type IA, Fe-poor, porphyritic olivine chondrules in Semarkona (LL3.0). Major and minor element concentrations in olivines, pyroxenes, and mesostases, and bulk composition so the chondrules are measured along with zoning profiles in the olivine and pyroxene crystals. The mineral compositions and textures are best interpreted in terms of closed system crystallization in which the olivines and pyroxenes crystallized in situ from a melt corresponding to the bulk composition of the chondrule. Relict olivine grains are not found in the chondrules. Crystallization probably occurred at a cooling rate of the order of 1000 C/hr. Precursor materials of the chondrules were composed of two components, one refractory Ca-, Al-, and Ti-rich, and one less refractory Si-, Fe-, Cr-, and Mn-rich. The evidence is consistent with Semarkona being one of the least metamorphosed ordinary chondrites.
Document ID
19890049161
Acquisition Source
Legacy CDMS
Document Type
Conference Paper
Authors
Jones, R. H.
(New Mexico Univ. Albuquerque, NM, United States)
Scott, E. R. D.
(New Mexico, University Albuquerque, United States)
Date Acquired
August 14, 2013
Publication Date
January 1, 1989
Subject Category
Lunar And Planetary Exploration
Meeting Information
Meeting: Lunar and Planetary Science Conference
Location: Houston, TX
Country: United States
Start Date: March 14, 1988
End Date: March 18, 1988
Accession Number
89A36532
Funding Number(s)
CONTRACT_GRANT: NAG9-30
Distribution Limits
Public
Copyright
Other

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