scholarly journals Viscous relaxation on early Mars: A study of ancient impact basins

2007 ◽  
Vol 34 (21) ◽  
Author(s):  
P. Surdas Mohit ◽  
Roger J. Phillips
Keyword(s):  
Early Mars ◽  
Impact Basins ◽  
Viscous Relaxation

The evolution of impact basins: Viscous relaxation of topographic relief

1982 ◽  
Vol 87 (B5) ◽  
pp. 3975 ◽  
Author(s):  
Sean C. Solomon ◽  
Robert P. Comer ◽  
James W. Head
Keyword(s):  
Impact Basins ◽  
Viscous Relaxation ◽  
Topographic Relief

On Venus impact basins: Viscous relaxation of topographic relief

1982 ◽  
Vol 87 (B9) ◽  
pp. 7763 ◽  
Author(s):  
Sean C. Solomon ◽  
Stuart K. Stephens ◽  
James W. Head
Keyword(s):  
Impact Basins ◽  
Viscous Relaxation ◽  
Topographic Relief

Mars: was There an Ancient Eden?

1997 ◽  
Vol 161 ◽  
pp. 203-218 ◽  
Author(s):  
Tobias C. Owen
Keyword(s):  
Positive Answer ◽  
Biogenic Elements ◽  
Habitable Zones ◽  
The Face ◽  
The Origin Of Life ◽  
Early Mars ◽  
Favorable Conditions ◽  
Open Question ◽  
Rocky Planets ◽  
Impact Erosion

AbstractThe clear evidence of water erosion on the surface of Mars suggests an early climate much more clement than the present one. Using a model for the origin of inner planet atmospheres by icy planetesimal impact, it is possible to reconstruct the original volatile inventory on Mars, starting from the thin atmosphere we observe today. Evidence for cometary impact can be found in the present abundances and isotope ratios of gases in the atmosphere and in SNC meteorites. If we invoke impact erosion to account for the present excess of129Xe, we predict an early inventory equivalent to at least 7.5 bars of CO2. This reservoir of volatiles is adequate to produce a substantial greenhouse effect, provided there is some small addition of SO2(volcanoes) or reduced gases (cometary impact). Thus it seems likely that conditions on early Mars were suitable for the origin of life – biogenic elements and liquid water were present at favorable conditions of pressure and temperature. Whether life began on Mars remains an open question, receiving hints of a positive answer from recent work on one of the Martian meteorites. The implications for habitable zones around other stars include the need to have rocky planets with sufficient mass to preserve atmospheres in the face of intensive early bombardment.

scholarly journals Evidence for Past Life on Early Mars: How the Evidence Stands

2004 ◽  
Vol 213 ◽  
pp. 203-208 ◽  
Author(s):  
Everett K. Gibson ◽  
Kathie L. Thomas-Keprta ◽  
Simon J. Clemett ◽  
David S. Mckay ◽  
Christopher Romanek ◽  
...  
Keyword(s):  
Scientific Community ◽  
Current Status ◽  
Martian Meteorite ◽  
Martian Meteorites ◽  
Past Life ◽  
Early Mars ◽  
World’S Scientific Community

Martian Meteorite ALH84001 contains four unusual features which have been interpreted as possible signatures of relic biogenic activity. After six years of intense study by the world's scientific community, the current status of the biogenic hypothesis is reviewed and shown to still be valid. Furthermore additional features have been observed in two younger Martian meteorites. The strongest argument for possible evidence of biogenic activity within the ALH84001 meteorite is the presence of truncated hexa-octahedral magnetite crystals which are only known on Earth to be the products of biology.

scholarly journals Origin of Life on Mars: Suitability and Opportunities

Life ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 539
Author(s):  
Benton C. Clark ◽  
Vera M. Kolb ◽  
Andrew Steele ◽  
Christopher H. House ◽  
Nina L. Lanza ◽  
...  
Keyword(s):  
Origin Of Life ◽  
Energy Sources ◽  
Early Earth ◽  
Sediment Samples ◽  
Life On Mars ◽  
Eventual Return ◽  
History Of ◽  
Early Mars ◽  
Chemical Conditions ◽  
Physical And Chemical

Although the habitability of early Mars is now well established, its suitability for conditions favorable to an independent origin of life (OoL) has been less certain. With continued exploration, evidence has mounted for a widespread diversity of physical and chemical conditions on Mars that mimic those variously hypothesized as settings in which life first arose on Earth. Mars has also provided water, energy sources, CHNOPS elements, critical catalytic transition metal elements, as well as B, Mg, Ca, Na and K, all of which are elements associated with life as we know it. With its highly favorable sulfur abundance and land/ocean ratio, early wet Mars remains a prime candidate for its own OoL, in many respects superior to Earth. The relatively well-preserved ancient surface of planet Mars helps inform the range of possible analogous conditions during the now-obliterated history of early Earth. Continued exploration of Mars also contributes to the understanding of the opportunities for settings enabling an OoL on exoplanets. Favoring geochemical sediment samples for eventual return to Earth will enhance assessments of the likelihood of a Martian OoL.

scholarly journals A sedimentary origin for intercrater plains north of the Hellas basin: Implications for climate conditions and erosion rates on early Mars

2016 ◽  
Vol 121 (11) ◽  
pp. 2239-2267 ◽  
Author(s):  
Francesco Salese ◽  
Veronique Ansan ◽  
Nicolas Mangold ◽  
John Carter ◽  
Anouck Ody ◽  
...  
Keyword(s):  
Climate Conditions ◽  
Erosion Rates ◽  
Early Mars

Stochastic Late Accretion to Earth, the Moon, and Mars

Science ◽  
2010 ◽  
Vol 330 (6010) ◽  
pp. 1527-1530 ◽  
Author(s):  
William F. Bottke ◽  
Richard J. Walker ◽  
James M. D. Day ◽  
David Nesvorny ◽  
Linda Elkins-Tanton
Keyword(s):  
Size Distribution ◽  
Asteroid Belt ◽  
The Moon ◽  
Core Formation ◽  
Highly Siderophile Elements ◽  
Earth’S Mantle ◽  
Distribution Matching ◽  
Siderophile Elements ◽  
Impact Basins

Core formation should have stripped the terrestrial, lunar, and martian mantles of highly siderophile elements (HSEs). Instead, each world has disparate, yet elevated HSE abundances. Late accretion may offer a solution, provided that ≥0.5% Earth masses of broadly chondritic planetesimals reach Earth’s mantle and that ~10 and ~1200 times less mass goes to Mars and the Moon, respectively. We show that leftover planetesimal populations dominated by massive projectiles can explain these additions, with our inferred size distribution matching those derived from the inner asteroid belt, ancient martian impact basins, and planetary accretion models. The largest late terrestrial impactors, at 2500 to 3000 kilometers in diameter, potentially modified Earth’s obliquity by ~10°, whereas those for the Moon, at ~250 to 300 kilometers, may have delivered water to its mantle.

Importance of post-seismic viscous relaxation in southern Iceland

2008 ◽  
Vol 1 (2) ◽  
pp. 136-139 ◽  
Author(s):  
Sigurjón Jónsson
Keyword(s):  
Viscous Relaxation
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