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Abstract
Until the acquisition of in-situ measurements, the study of the present-day heat flow of Mars must rely on indirect methods, mainly based on the relation between the thermal state of the lithosphere and its mechanical strength, or on theoretical models of internal evolution. Here, we present a first-order global model for the present-day surface heat flow for Mars, based on the radiogenic heat production of the crust and mantle, on scaling of heat flow variations arising from crustal thickness and topography variations, and on the heat flow derived from the effective elastic thickness of the lithosphere beneath the North Polar Region. Our preferred model finds heat flows varying between 14 and 25 mW m-2, with an average value of 19 mW m-2. Similar results (although about ten percent higher) are obtained if we use heat flow based on the lithospheric strength of the South Polar Region. Moreover, expressing our results in terms of the Urey ratio (the ratio between total internal heat production and total heat loss through the surface), we estimate values close to 0.7-0.75, which indicates a moderate contribution of secular cooling to the heat flow of Mars (consistent with the low heat flow values deduced from lithosphere strength), unless heat-producing elements abundances for Mars are subchondritic.
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Hu R, Bloom AA, Gao P, Miller CE, Yung YL. Hypotheses for Near-Surface Exchange of Methane on Mars. ASTROBIOLOGY 2016; 16:539-550. [PMID: 27315136 DOI: 10.1089/ast.2015.1410] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
UNLABELLED The Curiosity rover recently detected a background of 0.7 ppb and spikes of 7 ppb of methane on Mars. This in situ measurement reorients our understanding of the martian environment and its potential for life, as the current theories do not entail any geological source or sink of methane that varies sub-annually. In particular, the 10-fold elevation during the southern winter indicates episodic sources of methane that are yet to be discovered. Here we suggest a near-surface reservoir could explain this variability. Using the temperature and humidity measurements from the rover, we find that perchlorate salts in the regolith deliquesce to form liquid solutions, and deliquescence progresses to deeper subsurface in the season of the methane spikes. We therefore formulate the following three testable hypotheses. The first scenario is that the regolith in Gale Crater adsorbs methane when dry and releases this methane to the atmosphere upon deliquescence. The adsorption energy needs to be 36 kJ mol(-1) to explain the magnitude of the methane spikes, higher than existing laboratory measurements. The second scenario is that microorganisms convert organic matter in the soil to methane when they are in liquid solutions. This scenario does not require regolith adsorption but entails extant life on Mars. The third scenario is that deep subsurface aquifers produce the bursts of methane. Continued in situ measurements of methane and water, as well as laboratory studies of adsorption and deliquescence, will test these hypotheses and inform the existence of the near-surface reservoir and its exchange with the atmosphere. KEY WORDS Mars-Methane-Astrobiology-Regolith. Astrobiology 16, 539-550.
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Affiliation(s)
- Renyu Hu
- 1 Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California
- 2 Division of Geological and Planetary Sciences, California Institute of Technology , Pasadena, California
| | - A Anthony Bloom
- 1 Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California
| | - Peter Gao
- 2 Division of Geological and Planetary Sciences, California Institute of Technology , Pasadena, California
| | - Charles E Miller
- 1 Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California
| | - Yuk L Yung
- 1 Jet Propulsion Laboratory, California Institute of Technology , Pasadena, California
- 2 Division of Geological and Planetary Sciences, California Institute of Technology , Pasadena, California
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Cockell CS. Trajectories of martian habitability. ASTROBIOLOGY 2014; 14:182-203. [PMID: 24506485 PMCID: PMC3929387 DOI: 10.1089/ast.2013.1106] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Accepted: 12/29/2013] [Indexed: 05/21/2023]
Abstract
Beginning from two plausible starting points-an uninhabited or inhabited Mars-this paper discusses the possible trajectories of martian habitability over time. On an uninhabited Mars, the trajectories follow paths determined by the abundance of uninhabitable environments and uninhabited habitats. On an inhabited Mars, the addition of a third environment type, inhabited habitats, results in other trajectories, including ones where the planet remains inhabited today or others where planetary-scale life extinction occurs. By identifying different trajectories of habitability, corresponding hypotheses can be described that allow for the various trajectories to be disentangled and ultimately a determination of which trajectory Mars has taken and the changing relative abundance of its constituent environments.
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Affiliation(s)
- Charles S Cockell
- UK Centre for Astrobiology, School of Physics and Astronomy, University of Edinburgh , Edinburgh, UK
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Head JW, Coffin MF. Large Igneous Provinces: A Planetary Perspective. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/gm100p0411] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
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Tanaka KL, Golombek MP, Banerdt WB. Reconciliation of stress and structural histories of the Tharsis region of Mars. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/91je01194] [Citation(s) in RCA: 159] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Beuthe M, Le Maistre S, Rosenblatt P, Pätzold M, Dehant V. Density and lithospheric thickness of the Tharsis Province from MEX MaRS and MRO gravity data. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/2011je003976] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Jones EG, Lineweaver CH, Clarke JD. An extensive phase space for the potential martian biosphere. ASTROBIOLOGY 2011; 11:1017-1033. [PMID: 22149914 DOI: 10.1089/ast.2011.0660] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
We present a comprehensive model of martian pressure-temperature (P-T) phase space and compare it with that of Earth. Martian P-T conditions compatible with liquid water extend to a depth of ∼310 km. We use our phase space model of Mars and of terrestrial life to estimate the depths and extent of the water on Mars that is habitable for terrestrial life. We find an extensive overlap between inhabited terrestrial phase space and martian phase space. The lower martian surface temperatures and shallower martian geotherm suggest that, if there is a hot deep biosphere on Mars, it could extend 7 times deeper than the ∼5 km depth of the hot deep terrestrial biosphere in the crust inhabited by hyperthermophilic chemolithotrophs. This corresponds to ∼3.2% of the volume of present-day Mars being potentially habitable for terrestrial-like life.
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Affiliation(s)
- Eriita G Jones
- Planetary Sciences Institute, Research School of Astronomy and Astrophysics and the Research School of Earth Sciences, Australian National University, Canberra, Australia.
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Clifford SM, Lasue J, Heggy E, Boisson J, McGovern P, Max MD. Depth of the Martian cryosphere: Revised estimates and implications for the existence and detection of subpermafrost groundwater. ACTA ACUST UNITED AC 2010. [DOI: 10.1029/2009je003462] [Citation(s) in RCA: 167] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Ulrich R, Kral T, Chevrier V, Pilgrim R, Roe L. Dynamic temperature fields under Mars landing sites and implications for supporting microbial life. ASTROBIOLOGY 2010; 10:643-650. [PMID: 20735254 DOI: 10.1089/ast.2010.0472] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
While average temperatures on Mars may be too low to support terrestrial life-forms or aqueous liquids, diurnal peak temperatures over most of the planet can be high enough to provide for both, down to a few centimeters beneath the surface for some fraction of the time. A thermal model was applied to the Viking 1, Viking 2, Pathfinder, Spirit, and Opportunity landing sites to demonstrate the dynamic temperature fields under the surface at these well-characterized locations. A benchmark temperature of 253 K was used as a lower limit for possible metabolic activity, which corresponds to the minimum found for specific terrestrial microorganisms. Aqueous solutions of salts known to exist on Mars can provide liquid solutions well below this temperature. Thermal modeling has shown that 253 K is reached beneath the surface at diurnal peak heating for at least some parts of the year at each of these landing sites. Within 40 degrees of the equator, 253 K beneath the surface should occur for at least some fraction of the year; and, within 20 degrees , it will be seen for most of the year. However, any life-form that requires this temperature to thrive must also endure daily excursions to far colder temperatures as well as periods of the year where 253 K is never reached at all.
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Affiliation(s)
- Richard Ulrich
- Department of Chemical Engineering, University of Arkansas, Fayetteville, Arkansas 72701, USA.
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10
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Parmentier EM, Zuber MT. Early evolution of Mars with mantle compositional stratification or hydrothermal crustal cooling. ACTA ACUST UNITED AC 2007. [DOI: 10.1029/2005je002626] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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11
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Belleguic V, Lognonné P, Wieczorek M. Constraints on the Martian lithosphere from gravity and topography data. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2005je002437] [Citation(s) in RCA: 103] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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McGovern PJ. Correction to “Localized gravity/topography admittance and correlation spectra on Mars: Implications for regional and global evolution”. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2004je002286] [Citation(s) in RCA: 141] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ruiz J. Amplitude of heat flow variations on Mars from possible shoreline topography. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2003je002084] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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McGovern PJ, Solomon SC, Smith DE, Zuber MT, Simons M, Wieczorek MA, Phillips RJ, Neumann GA, Aharonson O, Head JW. Localized gravity/topography admittance and correlation spectra on Mars: Implications for regional and global evolution. ACTA ACUST UNITED AC 2002. [DOI: 10.1029/2002je001854] [Citation(s) in RCA: 214] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Sean C. Solomon
- Department of Terrestrial Magnetism; Carnegie Institution of Washington; Washington D.C. USA
| | | | - Maria T. Zuber
- Department of Earth, Atmospheric, and Planetary Sciences; Massachusetts Institute of Technology; Cambridge Massachusetts USA
| | - Mark Simons
- Division of Geological and Planetary Sciences; California Institute of Technology; Pasadena California USA
| | - Mark A. Wieczorek
- Department of Earth, Atmospheric, and Planetary Sciences; Massachusetts Institute of Technology; Cambridge Massachusetts USA
| | - Roger J. Phillips
- Department of Earth and Planetary Sciences; Washington University; St. Louis Missouri USA
| | - Gregory A. Neumann
- Department of Earth, Atmospheric, and Planetary Sciences; Massachusetts Institute of Technology; Cambridge Massachusetts USA
| | - Oded Aharonson
- Department of Earth, Atmospheric, and Planetary Sciences; Massachusetts Institute of Technology; Cambridge Massachusetts USA
| | - James W. Head
- Department of Geological Sciences; Brown University; Providence Rhode Island USA
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Arkani-Hamed J, Riendler L. Stress differences in the Martian lithosphere: Constraints on the thermal state of Mars. ACTA ACUST UNITED AC 2002. [DOI: 10.1029/2002je001851] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
| | - Lucas Riendler
- Earth and Planetary Sciences; McGill University; Montreal Quebec Canada
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Zhong S. Effects of lithosphere on the long-wavelength gravity anomalies and their implications for the formation of the Tharsis rise on Mars. ACTA ACUST UNITED AC 2002. [DOI: 10.1029/2001je001589] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Smith DE, Zuber MT, Frey HV, Garvin JB, Head JW, Muhleman DO, Pettengill GH, Phillips RJ, Solomon SC, Zwally HJ, Banerdt WB, Duxbury TC, Golombek MP, Lemoine FG, Neumann GA, Rowlands DD, Aharonson O, Ford PG, Ivanov AB, Johnson CL, McGovern PJ, Abshire JB, Afzal RS, Sun X. Mars Orbiter Laser Altimeter: Experiment summary after the first year of global mapping of Mars. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2000je001364] [Citation(s) in RCA: 1152] [Impact Index Per Article: 50.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Anguita F, Farelo AF, López V, Mas C, Muñoz-Espadas MJ, Márquez Á, Ruiz J. Tharsis dome, Mars: New evidence for Noachian-Hesperian thick-skin and Amazonian thin-skin tectonics. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2000je001246] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Zuber MT, Solomon SC, Phillips RJ, Smith DE, Tyler GL, Aharonson O, Balmino G, Banerdt WB, Head JW, Johnson CL, Lemoine FG, McGovern PJ, Neumann GA, Rowlands DD, Zhong S. Internal structure and early thermal evolution of Mars from Mars Global Surveyor topography and gravity. Science 2000; 287:1788-93. [PMID: 10710301 DOI: 10.1126/science.287.5459.1788] [Citation(s) in RCA: 457] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Topography and gravity measured by the Mars Global Surveyor have enabled determination of the global crust and upper mantle structure of Mars. The planet displays two distinct crustal zones that do not correlate globally with the geologic dichotomy: a region of crust that thins progressively from south to north and encompasses much of the southern highlands and Tharsis province and a region of approximately uniform crustal thickness that includes the northern lowlands and Arabia Terra. The strength of the lithosphere beneath the ancient southern highlands suggests that the northern hemisphere was a locus of high heat flow early in martian history. The thickness of the elastic lithosphere increases with time of loading in the northern plains and Tharsis. The northern lowlands contain structures interpreted as large buried channels that are consistent with northward transport of water and sediment to the lowlands before the end of northern hemisphere resurfacing.
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Affiliation(s)
- M T Zuber
- Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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Fisk MR, Giovannoni SJ. Sources of nutrients and energy for a deep biosphere on Mars. ACTA ACUST UNITED AC 1999. [DOI: 10.1029/1999je900010] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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23
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Bills BG, James TS. Moments of inertia and rotational stability of Mars: Lithospheric support of subhydrostatic rotational flattening. ACTA ACUST UNITED AC 1999. [DOI: 10.1029/1998je900003] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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McKenzie D, Nimmo F. The generation of martian floods by the melting of ground ice above dykes. Nature 1999; 397:231-3. [PMID: 9930697 DOI: 10.1038/16649] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The surface of Mars is cut by long linear faults with displacements of metres to kilometres, most of which are thought to have been formed by extension. The surface has also been modified by enormous floods, probably of water, which often flowed out of valleys formed by the largest of these faults. By analogy with structures on Earth, we propose here that the faults are in fact the surface expression of dykes, and not of large-scale tectonic movements. We use a numerical model to show that the intrusion of large dykes can generate structures like Valles Marineris. Such dykes can provide a heat source to melt ground ice, and so provide a source of water for the floods that have been inferred to originate in some of the large valleys.
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Affiliation(s)
- D McKenzie
- Institute of Theoretical Geophysics, Department of Earth Sciences, University of Cambridge, UK
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25
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Anderson S, Grimm RE. Rift processes at the Valles Marineris, Mars: Constraints from gravity on necking and rate-dependent strength evolution. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/98je00740] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Possible planetary objects have now been discovered orbiting nine different main-sequence stars. These companion objects (some of which might actually be brown dwarfs) all have a mass at least half that of Jupiter, and are therefore unlikely to be hospitable to Earth-like life: jovian planets and brown dwarfs support neither a solid nor a liquid surface near which organisms might dwell. Here we argue that rocky moons orbiting these companions could be habitable if the planet-moon system orbits the parent star within the so-called 'habitable zone', where life-supporting liquid water could be present. The companions to the stars 16 Cygni B and 47 Ursae Majoris might satisfy this criterion. Such a moon would, however, need to be large enough (>0.12 Earth masses) to retain a substantial and long-lived atmosphere, and would also need to possess a strong magnetic field in order to prevent its atmosphere from being sputtered away by the constant bombardment of energetic ions from the planet's magnetosphere.
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Affiliation(s)
- D M Williams
- Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park 16802, USA.
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Schultz RA, Zuber MT. Observations, models, and mechanisms of failure of surface rocks surrounding planetary surface loads. ACTA ACUST UNITED AC 1994. [DOI: 10.1029/94je01140] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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McGovern PJ, Solomon SC. State of stress, faulting, and eruption characteristics of large volcanoes on Mars. ACTA ACUST UNITED AC 1993. [DOI: 10.1029/93je03093] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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30
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Clifford SM. A model for the hydrologic and climatic behavior of water on Mars. ACTA ACUST UNITED AC 1993. [DOI: 10.1029/93je00225] [Citation(s) in RCA: 555] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Mouginis-Mark PJ, McCoy TJ, Taylor GJ, Keil K. Martian parent craters for the SNC meteorites. ACTA ACUST UNITED AC 1992. [DOI: 10.1029/92je00612] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Zuber MT, Smith DE, Solomon SC, Muhleman DO, Head JW, Garvin JB, Abshire JB, Bufton JL. The Mars Observer laser altimeter investigation. ACTA ACUST UNITED AC 1992. [DOI: 10.1029/92je00341] [Citation(s) in RCA: 399] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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