The Argyre Region as a Prime Target for in situ Astrobiological Exploration of Mars

At the time before ∼3.5 Ga that life originated and began to spread on Earth, Mars was a wetter and more geologically dynamic planet than it is today. The Argyre basin, in the southern cratered highlands of Mars, formed from a giant impact at ∼3.93 Ga, which generated an enormous basin approximately 1800 km in diameter. The early post-impact environment of the Argyre basin possibly contained many of the ingredients that are thought to be necessary for life: abundant and long-lived liquid water, biogenic elements, and energy sources, all of which would have supported a regional environment favorable for the origin and the persistence of life. We discuss the astrobiological significance of some landscape features and terrain types in the Argyre region that are promising and accessible sites for astrobiological exploration. These include (i) deposits related to the hydrothermal activity associated with the Argyre impact event, subsequent impacts, and those associated with the migration of heated water along Argyre-induced basement structures; (ii) constructs along the floor of the basin that could mark venting of volatiles, possibly related to the development of mud volcanoes; (iii) features interpreted as ice-cored mounds (open-system pingos), whose origin and development could be the result of deeply seated groundwater upwelling to the surface; (iv) sedimentary deposits related to the formation of glaciers along the basin's margins, such as evidenced by the ridges interpreted to be eskers on the basin floor; (v) sedimentary deposits related to the formation of lakes in both the primary Argyre basin and other smaller impact-derived basins along the margin, including those in the highly degraded rim materials; and (vi) crater-wall gullies, whose morphology points to a structural origin and discharge of (wet) flows

Formation and degradation of chaotic terrain in the Galaxias regions of Mars: implications for near-surface storage of ice

Galaxias Chaos is a region of low plateaus separated by narrow fractures – a chaotic terrain. Galaxias Mensae and Galaxias Colles are characterised by mesa and knobby terrains of individual landforms, or small assemblages, separated by plains. Galaxias Chaos has been attributed to ground disturbance due to sublimation in shallow subsurface ice-rich deposits, Galaxias Mensae and Galaxias Colles to sublimation and degradation of icy surface materials, without production of chaotic terrain. Liquid water has not been regarded as a product of the degradation of these icy terrains. This paper asks two research questions: (1) what was the total extent of the different modes of landscape degradation, especially chaotic terrain, involved in producing the present landscapes of Galaxias Chaos and Galaxias Mensae–Colles; (2) can the generation of liquid water as a product of landscape degradation be ruled-out? Using a morphological-statistical approach, including power spectrum analysis of relief, our observations and analyses show that present mesa-knobby terrains of Galaxias Mensae–Colles evolved from a landscape that had the same directional pattern and relief as presently found in Galaxias Chaos. This terrain extended across ∼440,000 km2 but ∼22,000 km3 (average thickness, 77 m) have been lost across ∼285,000 km2. This represents a significant loss of ice-bearing deposits. Moreover, this surface degradation was spatially partitioned by landforms associated with elevated ground heating and the transmission of a fluid in the shallow subsurface towards a distal channel. In answer to research question 2, it cannot be determined definitively if the fluid involved was groundwater, generated by the thermal destabilisation of the icy deposits, or low viscosity lava. However, it is likely that the degradation of Galaxias Mensae–Colles was not a consequence of sublimation alone. These findings underscore the significance of cryo-volcanic interactions in the cycling of water between the Martian surface and the atmosphere

Sub-kilometre (intra-crater) mounds in Utopia Planitia, Mars: character, occurrence and possible formation hypotheses

At the middle latitudes of Utopia Planitia (∼35–45°N; ∼65–101°E) hundreds of small-sized mounds located in sub-kilometre impact craters dot the landscape. Their shape varies from circular to crescentic and their height ranges from ∼10 to 50 m. Often, metre to decametre pitting is observed, as is metres-thick banding or stratification. Mound albedo is relatively high, i.e. ∼0.16. The plain’s terrain in the region, previously linked to the latitude-dependent mantle (LDM) of ice–dust, displays pitting and albedo similar to the small intra-crater mounds. Some workers have suggested that the mounds and the plain’s terrain share a common ice–dust origin. If so, then scrutinising the mounds could provide analogical insight on the key geological characteristics and spatial distribution of the LDM itself. Other workers have hypothesised that the mounds are eroded sedimentary landforms or periglacial mounds underlain by a perennial ice-core (closed-system pingos). In this article we develop and then discuss each of the three mound-hypotheses in a much more substantial manner than has been done hitherto. Towards this end we use high-resolution images, present a detailed regional-map of mound distribution and establish a regional platform of topographical analysis using MOLA data superposed on a large-scale CTX mosaic. Although the ice–dust hypothesis is consistent with some observations and measurements, we find that a (loess-based) sedimentary hypothesis shows greater plausibility. Of the three hypotheses evaluated, the pingo or periglacial one is the weakest

Relationship between thermal-contraction polygons and substrate properties on Mars

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Relationship between the density/type of thermal-contraction polygons and the geology of the substrate at the Martian midlatitudes.

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Dynamic Mars : recent and current landscape evolution of the red planet /

Dynamic Mars: Recent Landscape Evolution of the Red Planet presents the latest developments in understanding the geological history of Mars. Presenting observational data and tightly-linked scientific hypotheses across a broad swath of landscapes, latitudes and geological contexts, as well as an examination of the impact of climate change mitigated by multiple geomorphological agents, the book covers a diverse array of themes and subjects. This highly illustrated book includes data from recent missions, and will be of interest to all levels of research in the geological history of Mars, as well as other terrestrial planets. For years after the first detailed orbital and ground images of Mars were taken, it was thought that the red planet could have been wetter and warmer in its deep past than today. However, as the book demonstrates, the possible involvement of water in recent, if not contemporary, gully-like flows and slope streaks (i.e. recurring slope lineae), as well as the identification of a suite of geomorphological agents (i.e. glacial, periglacial, aeolian, meteorological, volcanic and meteoric) associated with surface and near-surface changes on a local to regional scale, suggest the history of the red planet may be much more dynamic than previously thought.Includes bibliographical references and index.Dynamic Mars: Recent Landscape Evolution of the Red Planet presents the latest developments in understanding the geological history of Mars. Presenting observational data and tightly-linked scientific hypotheses across a broad swath of landscapes, latitudes and geological contexts, as well as an examination of the impact of climate change mitigated by multiple geomorphological agents, the book covers a diverse array of themes and subjects. This highly illustrated book includes data from recent missions, and will be of interest to all levels of research in the geological history of Mars, as well as other terrestrial planets. For years after the first detailed orbital and ground images of Mars were taken, it was thought that the red planet could have been wetter and warmer in its deep past than today. However, as the book demonstrates, the possible involvement of water in recent, if not contemporary, gully-like flows and slope streaks (i.e. recurring slope lineae), as well as the identification of a suite of geomorphological agents (i.e. glacial, periglacial, aeolian, meteorological, volcanic and meteoric) associated with surface and near-surface changes on a local to regional scale, suggest the history of the red planet may be much more dynamic than previously thought.Online resource; title from digital title page (viewed on August 20, 2018).Front Cover; Dynamic Mars; Dynamic Mars; Copyright; Contents; List of Contributors; MARINERS' WAY: BEYOND THE FUTURE TO THE PAST; 1. THE FUTURE; 2. THE PAST; 3. NOTES; 1 -- LATE AMAZONIAN EPOCH CLIMATE; 1 -- ORBITAL (CLIMATIC) FORCING AND ITS IMPRINT ON THE GLOBAL LANDSCAPE; 1.1 INTRODUCTION; 1.1.1 A BRIEF HISTORY OF MARS CLIMATE OBSERVATIONS; 1.1.2 THE PRESENT ATMOSPHERE OF MARS; 1.2 CLIMATE FORCING; 1.2.1 OBLIQUITY; 1.2.2 ECCENTRICITY; 1.2.3 ARGUMENT OF PERIHELION; 1.2.4 TOTAL INSOLATION; 1.2.5 ORBITAL-DRIVEN CIRCULATION; 1.2.6 SURFACE PROPERTIES; 1.2.7 PUTTING IT TOGETHER1.3 VOLATILE EMPLACEMENT1.3.1 SURFACE LAYERING; 1.3.2 ATMOSPHERIC DUST; 1.3.3 SUBSURFACE ICE AND VAPOR DIFFUSION; 1.3.4 LIQUID WATER; 1.4 MORPHOLOGICAL EVIDENCE FOR RECENT CLIMATE CHANGE; 1.4.1 POLAR ICE; 1.4.2 HIGH-LATITUDE ICE; 1.4.2.1 Observations by Mars Odyssey Gamma Ray Spectrometer; 1.4.2.2 Measurements by the Mars Phoenix Lander; 1.4.3 MID-LATITUDE ICE; 1.4.3.1 Latitude-Dependent Mantle; 1.4.3.2 Pedestal Craters; 1.4.3.3 Other Impact Craters; 1.4.3.4 Expanded Impact Craters; 1.4.3.5 Scalloped Depressions; 1.4.3.6 Putative Periglacial Landforms; 1.4.3.7 Terraced Craters1.4.4 OTHER MID- AND LOW-LATITUDE ICE DEPOSITS1.4.4.1 Pasted-on Terrain and Gullies; 1.4.4.2 Lobate Debris Aprons, Lineated Valley Fill, and Ice-Rich Flows; 1.4.4.3 Radar Observations; 1.4.4.4 Tropical Mountain Glaciers; 1.5 CONCLUSIONS; ACKNOWLEDGMENTS; REFERENCES; 2 -- RECENT SURFACE WATER AT/NEARTHE MID-LATITUDES?; 2 -- UNRAVELING THE MYSTERIES OF RECURRING SLOPE LINEAE; 2.1 INTRODUCTION; 2.2 METHODS; 2.3 OBSERVATIONS; 2.3.1 GLOBAL; 2.3.2 SOUTHERN MIDLATITUDE; 2.3.3 VALLES MARINERIS; 2.3.4 CHRYSE AND ACIDALIA PLANITIAE; 2.3.5 KASEI VALLES; 2.3.6 CERBERUS FOSSAE2.3.7 MARGARITIFER AND ARABIA TERRAE2.3.8 LOW-ALBEDO TROPICAL HIGHLANDS; 2.4 DISCUSSION; 2.4.1 RECURRING SLOPE LINEAE VERSUS SLOPE STREAKS; 2.4.2 RECURRING SLOPE LINEAE SEASONALITY; 2.5 MECHANISMS; 2.5.1 DRY GRANULAR FLOW MECHANISMS; 2.5.2 WET-TRIGGERED DEBRIS FLOW MECHANISMS; 2.5.3 WET-DOMINATED FLOW MECHANISMS; 2.5.4 MECHANISM DISCUSSION; 2.6 SUMMARY AND IMPLICATIONS; ACKNOWLEDGMENTS; REFERENCES; 3 -- MARTIAN GULLIES AND THEIR CONNECTION WITH THE MARTIAN CLIMATE; 3.1 INTRODUCTION; 3.2 CLIMATIC ORIGINS FOR MARTIAN GULLIES; 3.2.1 MELTING OF WATER ICE; 3.2.1.1 Aquifer; 3.2.1.2 Ground Ice3.2.1.3 Atmospheric Ice Deposits3.2.1.4 Melting the Ice; 3.2.2 CO2 SUBLIMATION; 3.3 APPROACH; 3.4 RESULTS AND DISCUSSION; 3.4.1 ZERO-CELSIUS CYCLES; 3.4.2 CO2 DEPOSITION; 3.4.3 SUMMARY; 3.5 CONCLUSIONS; ACKNOWLEDGMENTS; REFERENCES; 4 -- LATE AMAZONIAN-AGED CHANNEL AND ISLAND SYSTEMS LOCATED EAST OF OLYMPUS MONS, MARS; 4.1 INTRODUCTION; 4.2 METHODS AND TERMINOLOGY; 4.3 THE NORTHWESTERN THARSIS CHANNELS AND ISLANDS; 4.3.1 REGIONAL PHYSIOGRAPHIC PROVINCES; 4.3.1.1 The Olympica Region; 4.3.1.2 The Cyane-Pavonis Flows and Channels; 4.3.1.3 The Gordii Region; 4.4 STREAMLINED FORMS AND ISLANDSElsevie

POSSIBLE PINGO & ICE WEDGE/THERMOKARST COMPLEXES IN UTOPIA PLANITIA, MARS

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