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Proceedings Paper

Combined SEM (secondary electrons, backscatter, cathodoluminescence) and atomic force microscope investigation of fracture surfaces in Martian meteorite ALH84001: preliminary results
Author(s): Frances Westall; Pier Giorgio Gobbi; Giovanni Mazzoti; Dane Gerneke; Robert W. Stark; Tanya Dobrek; Wolfgang M. Heckl; Everett J. Gibson Jr.; David S. McKay; Carlton Allen; Andrew Steele; Kathy L. Thomas-Keprta
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Paper Abstract

A variety of microscope techniques have been used to study surficial phenomena on the fracture surfaces of the Martian meteorite ALH84001. The aim of the investigation was to determine the most useful microscopy methods in the search for morphological signs of biogenic activity. Emphasis was placed on scanning electron microscopy (SEM) using secondary, backscatter and cathodoluminescence modes combined with observation of samples at a variety of accelerating voltages. High resolution SEM imaging was compared with atomic force microscopy. These techniques revealed a number of structures of possible abiotic and biotic origin: (1) a large, fibrous-looking carbonaceous structure, (2) fine, flaky films coating pyroxene surfaces, (3) finely granular calcium carbonate deposit is associated with the fine film, and (4) lacy-structured, mineralized polymers on the pyroxene surface. Another sample contains further evidence of water-lain deposits in a cracked, iron oxide coat on a fracture surface.

Paper Details

Date Published: 6 July 1998
PDF: 9 pages
Proc. SPIE 3441, Instruments, Methods, and Missions for Astrobiology, (6 July 1998); doi: 10.1117/12.319841
Show Author Affiliations
Frances Westall, Univ. of Bologna (Italy) and NASA Johnson Space Ctr. (United States)
Pier Giorgio Gobbi, Univ. of Bologna (Italy)
Giovanni Mazzoti, Univ. of Bologna (Italy)
Dane Gerneke, Univ. of Cape Town (Italy)
Robert W. Stark, Univ. of Munich (Germany)
Tanya Dobrek, Univ. of Munich (Germany)
Wolfgang M. Heckl, Univ. of Munich (Germany)
Everett J. Gibson Jr., NASA Johnson Space Ctr. (United States)
David S. McKay, NASA Johnson Space Ctr. (United States)
Carlton Allen, NASA Johnson Space Ctr./Lockheed Martin (United States)
Andrew Steele, NASA Johnson Space Ctr (United States)
Kathy L. Thomas-Keprta, NASA Johnson Space Ctr./Lockheed Martin (United States)

Published in SPIE Proceedings Vol. 3441:
Instruments, Methods, and Missions for Astrobiology
Richard B. Hoover, Editor(s)

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