Modeling the evolution of the parent body of acapulcoites and lodranites: A case study for partially differentiated asteroids
| Autor: | Wladimir Neumann, Doris Breuer, Hans-Peter Gail, Jens Hopp, Stephan Henke, Mario Trieloff, Tilman Spohn, Winfried H. Schwarz |
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| Rok vydání: | 2018 |
| Předmět: |
Planetesimal
Accretion Metamorphic rock 010502 geochemistry & geophysics 01 natural sciences Mantle (geology) Parent body chemistry.chemical_compound 0103 physical sciences Planetesimals Petrology 010303 astronomy & astrophysics Achondrite 0105 earth and related environmental sciences Interiors Partial melting Astronomy and Astrophysics Silicate Asteroids Meteorite chemistry Space and Planetary Science Geology Thermal histories Composition Meteorites |
| Popis: | The acapulcoites and lodranites are rare groups of primitive achondrites that originate from a common parent body and are of particular interest since they experienced only partial melting. We calculated thermal evolution and differentiation models of the parent body of the Acapulco-Lodran meteorite clan. The models were compared to the maximum metamorphic temperatures, differentiation degree, and thermo-chronological data available. An optimized set of parameters which fits to the data was determined: A radius of ≈ 260 km, a formation time of ≈ 1.7 Ma after CAIs and an initial temperature of ≈ 250 K. The burial depths derived are 7–13 km. The respective layers experienced minor melting and small-scale melt migration, matching the differentiation degree of the meteorites. The resulting structure has an iron core, a silicate mantle, a partially differentiated layer, and an undifferentiated outer shell. Our results indicate a larger size, an earlier formation time, and a formation closer to the sun of the parent body of acapulcoites and lodranites than typical estimates for ordinary chondritic parent bodies, consistent with a stronger thermal metamorphism. The burial depths support excavation by a single impact. The presence of core and mantle indicates that these meteorites could share a common parent body with differentiated stony and iron meteorites. |
| Databáze: | OpenAIRE |
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