ORCID Profile
0000-0003-2144-5917
Current Organisation
University of Maryland at College Park
Does something not look right? The information on this page has been harvested from data sources that may not be up to date. We continue to work with information providers to improve coverage and quality. To report an issue, use the Feedback Form.
Publisher: Springer Science and Business Media LLC
Date: 2009
DOI: 10.1038/NATURE07651
Abstract: Mechanisms for the formation of crust on planetary bodies remain poorly understood. It is generally accepted that Earth's andesitic continental crust is the product of plate tectonics, whereas the Moon acquired its feldspar-rich crust by way of plagioclase flotation in a magma ocean. Basaltic meteorites provide evidence that, like the terrestrial planets, some asteroids generated crust and underwent large-scale differentiation processes. Until now, however, no evolved felsic asteroidal crust has been s led or observed. Here we report age and compositional data for the newly discovered, paired and differentiated meteorites Graves Nunatak (GRA) 06128 and GRA 06129. These meteorites are feldspar-rich, with andesite bulk compositions. Their age of 4.52 +/- 0.06 Gyr demonstrates formation early in Solar System history. The isotopic and elemental compositions, degree of metamorphic re-equilibration and sulphide-rich nature of the meteorites are most consistent with an origin as partial melts from a volatile-rich, oxidized asteroid. GRA 06128 and 06129 are the result of a newly recognized style of evolved crust formation, bearing witness to incomplete differentiation of their parent asteroid and to previously unrecognized ersity of early-formed materials in the Solar System.
Publisher: Elsevier BV
Date: 07-2013
Publisher: Elsevier BV
Date: 04-2008
Publisher: Elsevier BV
Date: 08-2017
Publisher: Wiley
Date: 22-08-2023
DOI: 10.1111/MAPS.14031
Abstract: Mesosiderites are an amalgamation of crustal silicates and molten metal, and their formational history is not well understood. It is widely believed that redox reactions occurred in the mesosiderites during metal–silicate mixing. Previous studies evaluated redox reactions by studying the silicates within mesosiderites, but little attention has been given to the metal for complementary evidence of such processes. Here, the evidence for redox within the metal portion of five mesosiderites is documented, most notably lower P content in the matrix metal relative to clast metal (nodule). These observations, together with the noted FeO reduction in silicates, provide further support for redox reactions occurring during metal–silicate mixing. S les with differing Ir concentrations, such as Chaunskij and RKP A70015, have been previously classified as anomalous. However, the marked variation in highly siderophile element concentrations in all of these mesosiderites is consistent with fractional crystallization. These compositional trends could be explained by isolated metallic masses that underwent fractional crystallization before mixing or by hit‐and‐run collisions that produced metallic masses that ranged in size.
Publisher: Elsevier BV
Date: 2017
Publisher: Elsevier BV
Date: 05-2017
Publisher: Elsevier BV
Date: 2010
Publisher: Elsevier BV
Date: 03-2012
Publisher: Elsevier BV
Date: 08-2019
Publisher: Elsevier BV
Date: 07-2006
Publisher: Springer Science and Business Media LLC
Date: 10-07-2014
Publisher: Elsevier BV
Date: 05-2009
Publisher: Elsevier BV
Date: 11-2011
Publisher: Elsevier BV
Date: 04-2017
Publisher: Elsevier BV
Date: 02-2009
Publisher: Elsevier BV
Date: 2014
Publisher: Elsevier BV
Date: 06-2020
Publisher: Elsevier BV
Date: 2005
Publisher: Springer Science and Business Media LLC
Date: 05-2009
DOI: 10.1038/NATURE08078
Publisher: Elsevier BV
Date: 11-2011
Publisher: Elsevier BV
Date: 09-2005
Publisher: Wiley
Date: 04-04-2017
DOI: 10.1111/MAPS.12864
Publisher: Elsevier BV
Date: 05-2011
Publisher: Wiley
Date: 17-04-2016
DOI: 10.1111/MAPS.12643
Location: United States of America
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
Location: United States of America
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Richard Ash.