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Diversity in C-Xanes Spectra Obtained from Carbonaceous Solid Inclusions from Monahans HaliteMonahans meteorite (H5) contains fluid inclusion- bearing halite (NaCl) crystals [1]. Microthermometry and Raman spectroscopy showed that the fluid in the inclusions is an aqueous brine and they were trapped near 25degC [1]. Their continued presence in the halite grains requires that their incorporation into the H chondrite asteroid was post metamorphism [2]. Abundant solid inclusions are also present in the halites. The solid inclusions include abundant and widely variable organics [2]. Analyses by Raman microprobe, SEM/EDX, synchrotron X-ray diffraction and TEM reveal that these grains include macromolecular carbon similar in structure to CV3 chondrite matrix carbon, aliphatic carbon compounds, olivine (Fo99−59), high- and low-Ca pyroxene, feldspars, magnetite, sulfides, lepidocrocite, carbonates, diamond, apatite and possibly the zeolite phillipsite [3]. Here we report organic analyses of these carbonaceous residues in Monahans halite using C-, N-, and O- X-ray absorption near edge structure (XANES). Samples and Methods: Approximately 100 nm-thick sections were extracted with a focused ion beam (FIB) at JSC from solid inclusions from Monahans halite. The sections were analyzed using the scanning transmission X-ray microscope (STXM) on beamline 5.3.2.2 at the Advanced Light Source, Lawrence Berkeley National Laboratory for XANES spectroscopy. Results and Discussion: C-XANES spectra of the solid inclusions show micrometer-scale heterogeneity, indicating that the macromolecular carbon in the inclusions have complex chemical variations. C-XANES features include 284.7 eV assigned to aromatic C=C, 288.4-288.8 eV assigned to carboxyl, and 290.6 eV assigned to carbonate. The carbonyl features obtained by CXANES might have been caused by the FIB used in sample preparation. No specific N-XANES features are observed. The CXANES spectra obtained from several areas in the FIB sections include type 1&2 chondritic IOM like, type 3 chondritic IOM like, and none of the above. The natures of the macromolecular carbon in the solid inclusions observed by C-XANES are consistent with the previous studies showing that the carbonaceous solid inclusions have not originated from Monahans parent body [1-3], and have various origins, including various chondritic meteorite parent bodies as well as other unknown source(s).
Document ID
20140010586
Acquisition Source
Johnson Space Center
Document Type
Abstract
Authors
Kebukawa, Y. (Yokohama National Univ. Japan)
Zolensky, M. E. (NASA Johnson Space Center Houston, TX, United States)
Fries, M. (NASA Johnson Space Center Houston, TX, United States)
Kilcoyne, A. L. D. (California Univ., Lawrence Berkeley National Lab. Berkeley, CA, United States)
Rahman, Z. (Jacobs Sverdrup Technology, Inc. Houston, TX, United States)
Cody, G. D. (Carnegie Institution of Washington Washington, DC, United States)
Date Acquired
August 13, 2014
Publication Date
September 7, 2014
Subject Category
Geophysics
Report/Patent Number
JSC-CN-31632
Meeting Information
Meeting: Annual Meeting of the Meteoritical Society
Location: Casablanca
Country: Morocco
Start Date: September 7, 2014
End Date: September 12, 2014
Sponsors: Meteoritical Society
Distribution Limits
Public
Copyright
Public Use Permitted.

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