Importance of a Martian Hematite Site for Astrobiology

被引:39
作者
Allen, Carlton C. [1 ]
Westall, Frances [2 ]
Schelble, Rachel T. [3 ]
机构
[1] NASA, Lyndon B Johnson Space Ctr, Houston, TX 77058 USA
[2] Lunar & Planetary Inst, Houston, TX 77058 USA
[3] Univ New Mexico, Dept Earth & Planetary Sci, Albuquerque, NM 87131 USA
关键词
Mars; Hematite; Microfossils; Banded iron formation; Astrobiology;
D O I
10.1089/153110701750137495
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Defining locations where conditions may have been favorable for life is a key objective for the exploration of Mars. Of prime importance are sites where conditions may have been favorable for the preservation of evidence of prebiotic or biotic processes. Areas displaying significant concentrations of the mineral hematite (alpha-Fe2O3), recently identified by thermal emission spectrometry, may have significance in the search for evidence of extraterrestrial life. Since iron oxides can form as aqueous mineral precipitates, the potential exists to preserve microscopic evidence of life in iron oxide-depositing ecosystems. Terrestrial hematite deposits proposed as possible analogs for hematite deposits on Mars include massive (banded) iron formations, iron oxide hydrothermal deposits, iron-rich laterites and ferricrete soils, and rock varnish. We report the potential for long-term preservation of microfossils by iron oxide mineralization in specimens of the similar to 2,100-Ma banded iron deposit of the Gunflint Formation, Canada. Scanning and analytical electron microscopy reveals micrometer-scale rods, spheres, and filaments consisting predominantly of iron and oxygen with minor carbon. We interpret these objects as microbial cells permineralized by an iron oxide, presumably hematite. The confirmation of ancient martian microbial life in hematite deposits will require the return of samples to terrestrial laboratories. A hematite-rich deposit composed of aqueous iron oxide precipitates may thus prove to be a prime site for future sample return.
引用
收藏
页码:111 / 123
页数:13
相关论文
共 77 条
[1]  
Allen C. C., 2001, 32 LUN PLAN SCI C
[2]   A Case for Ancient Springs in Arabia Terra, Mars [J].
Allen, Carlton C. ;
Oehler, Dorothy Z. .
ASTROBIOLOGY, 2008, 8 (06) :1093-1112
[3]   HYDROTHERMALLY ALTERED IMPACT MELT ROCK AND BRECCIA - CONTRIBUTIONS TO THE SOIL OF MARS [J].
ALLEN, CC ;
GOODING, JL ;
KEIL, K .
JOURNAL OF GEOPHYSICAL RESEARCH, 1982, 87 (NB12) :83-101
[4]   Microscopic physical biomarkers in carbonate hot springs: Implications in the search for life on Mars [J].
Allen, CC ;
Albert, FG ;
Chafetz, HS ;
Combie, J ;
Graham, CR ;
Kieft, TL ;
Kivett, SJ ;
McKay, DS ;
Steele, A ;
Taunton, AE ;
Taylor, MR ;
Thomas-Keprta, KL ;
Westall, F .
ICARUS, 2000, 147 (01) :49-67
[5]   ALTERED BASALTIC GLASS - A TERRESTRIAL ANALOG TO THE SOIL OF MARS [J].
ALLEN, CC ;
GOODING, JL ;
JERCINOVIC, M ;
KEIL, K .
ICARUS, 1981, 45 (02) :347-369
[6]   Meridiani Planum hematite deposit and the search for evidence of life on Mars - iron mineralization of microorganisms in rock varnish [J].
Allen, CC ;
Probst, LW ;
Flood, BE ;
Longazo, TG ;
Schelble, RT ;
Westall, F .
ICARUS, 2004, 171 (01) :20-30
[7]   DESERT VARNISH OF SONORAN DESERT - OPTICAL AND ELECTRON-PROBE MICROANALYSIS [J].
ALLEN, CC .
JOURNAL OF GEOLOGY, 1978, 86 (06) :743-752
[8]  
[Anonymous], GEOMICROBIOLOGY
[9]  
[Anonymous], 2001, ASTROBIOLOGY, V1, P529
[10]   GUNFLINT MICROBIOTA [J].
AWRAMIK, SM ;
BARGHOORN, ES .
PRECAMBRIAN RESEARCH, 1977, 5 (02) :121-142