Xrd Analyses of Stardust Tracks 176, 177, 178: Terminal Grains From Magnetite-Rich, Chondrite-Like Matrix

Authors: Leon Hicks (University of Leicester) , John Bridges (University of Leicester) , Graeme Hansford (University of Leicester) , Steve Gurman (University of Leicester)
Co-authored by industrial partner: No

Type: Conference Paper
Conference: 45th Lunar and Planetary Science Conference
Peer Reviewed: Yes

State: Published (Approved)
Published: March 2014
Diamond Proposal Number(s): 9418

Abstract: The terminal grains of the Stardust keystones have preserved the least thermally altered Comet Wild2 samples and some of the most pristine cometary material currently available for analysis. The micron-scale of the terminal grains requires synchro-tron analyses to perform X-ray diffraction (XRD) and X-ray Absorption, Fluorescence (XAS, XRF). In par-ticular, we have studied Fe oxides in order to be able to make increasingly detailed comparisons to carbo-naecous chondrites and understand the variation in Fe oxidation state within Wild2 [1,2]. Fe oxides, includ-ing magnetite or magnetite-hematite mixtures have been identified along track walls [1,3] and leave a characteristic oxidized iron signature on keystone Fe-K XANES and XRF maps. However, the potential ef-fects of capture heating, and terrestrial oxidation, has meant that the origin of the scattered Fe oxides has required further study through comparison to a terminal grain.

Subject Areas: Physics, Chemistry

Instruments: I18-Microfocus Spectroscopy

Other Facilities: No