Sign on

SAO/NASA ADS Astronomy Abstract Service

· Find Similar Abstracts (with default settings below)
· Electronic Refereed Journal Article (HTML)
· References in the article
· Citations to the Article (2) (Citation History)
· Refereed Citations to the Article
· Reads History
·
· Translate This Page
Title:
H/L chondrite LaPaz Icefield 031047 - A feather of Icarus?
Authors:
Wittmann, Axel; Friedrich, Jon M.; Troiano, Julianne; Macke, Robert J.; Britt, Daniel T.; Swindle, Timothy D.; Weirich, John R.; Rumble, Douglas; Lasue, Jeremie; Kring, David A.
Affiliation:
AA(Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States), AB(Department of Chemistry, Fordham University, Bronx, NY 10458, United States; Department of Earth & Planetary Sciences, American Museum of Natural History, New York, NY 10024, United States), AC(Department of Chemistry, Fordham University, Bronx, NY 10458, United States), AD(University of Central Florida, Orlando, FL 32816, United States), AE(University of Central Florida, Orlando, FL 32816, United States), AF(Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, United States), AG(Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721, United States), AH(Geophysical Laboratory, Carnegie Institution of Washington, Washington, DC 20015, United States), AI(Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States; Los Alamos National Laboratory, Los Alamos, NM 87545, United States), AJ(Lunar and Planetary Institute, 3600 Bay Area Boulevard, Houston, TX 77058, United States)
Publication:
Geochimica et Cosmochimica Acta, Volume 75, Issue 20, p. 6140-6159. (GeCoA Homepage)
Publication Date:
10/2011
Origin:
ELSEVIER
Abstract Copyright:
Elsevier Ltd
DOI:
10.1016/j.gca.2011.07.037
Bibliographic Code:
2011GeCoA..75.6140W

Abstract

Antarctic meteorite LAP 031047 is an ordinary chondrite composed of loosely consolidated chondritic fragments. Its petrography, oxygen isotopic composition and geochemical inventory are ambiguous and indicate an intermediate character between H and L chondrites. Petrographic indicators suggest LAP 031047 suffered a shock metamorphic overprint below ˜10 GPa, which did not destroy its unusually high porosity of ˜27 vol%. Metallographic textures in LAP 031047 indicate heating above ˜700 °C and subsequent cooling, which caused massive transformation of taenite to kamacite. The depletion of thermally labile trace elements, the crystallization of chondritic glass to microcrystalline plagioclase of unusual composition, and the occurrence of coarsely crystallized chondrule fragments is further evidence for post-metamorphic heating to ˜700-750 °C. However, this heating event had a transient character because olivine and low-Ca pyroxene did not equilibrate. Nearly complete degassing up to very high temperatures is indicated by the thorough resetting of LAP 031047's Ar-Ar reservoir ˜100 ± 55 Ma ago. A noble gas cosmic-ray exposure age indicates it was reduced to a meter-size fragment at <0.5 Ma. In light of the fact that shock heating cannot account for the thermal history of LAP 031047 in its entirety, we test the hypothesis that this meteorite belonged to the near-surface of an Aten or Apollo asteroid that underwent heating during orbital passages close to the Sun.
Bibtex entry for this abstract   Preferred format for this abstract (see Preferences)
  New!

Find Similar Abstracts:

Use: Authors
Title
Abstract Text
Return: Query Results Return    items starting with number
Query Form
Database: Astronomy
Physics
arXiv e-prints