Geography Of Mars

Mars Global Surveyor Mars Orbiter Camera: Interplanetary Cruise through Primary Mission

by Ken Edgett

(2001)
M. C. Malin and K. S. Edgett
Journal of Geophysical Research, 106(E10), 23,429–23,570. doi:10.1029/2000JE001455

More than 3 years of high-resolution (1.5–20 m/pixel) photographic observations of the surface of Mars have... more More than 3 years of high-resolution (1.5–20 m/pixel) photographic observations of the surface of Mars have dramatically changed our view of that planet. Among the most important observations and interpretations derived therefrom are that much of Mars, at least to depths of several kilometers, is layered; that substantial portions of the planet have experienced burial and subsequent exhumation; that layered and massive units, many kilometers thick, appear to reflect an ancient period of large-scale erosion and deposition within what are now the ancient heavily cratered regions of Mars; and that processes previously unsuspected, including gully-forming fluid action and burial and exhumation of large tracts of land, have operated within near-contemporary times. These and many other attributes of the planet argue for a complex geology and complicated history.

Mars landscape evolution: Influence of stratigraphy on geomorphology in the north polar region

by Ken Edgett

(2003) **SELF ARCHIVED PDF AVAILABLE HERE**
K. S. Edgett, R. M. E. Williams, M. C. Malin, B. A. Cantor, and P. C. Thomas
Geomorphology, 52(3–4), 289–297. doi:10.1016/S0169-555X(02)00262-3

Lithology and physical properties of strata exposed at the Earth's surface have direct influence on the erosion and... more Lithology and physical properties of strata exposed at the Earth's surface have direct influence on the erosion and geomorphic expression of landforms. While this is well known on our planet, examples on Mars are just coming to light among the tens of thousands of airphoto-quality images (resolutions 1.5–12 m/pixel) acquired since 1997 by the Mars Global Surveyor (MGS) Mars Orbiter Camera (MOC). Specific examples occur among martian north polar layered materials, which MOC images reveal are divided into two distinct stratigraphic units: a lower, dark-toned layered unit and a younger, upper, lighter-toned layered unit. The lower unit is less resistant to wind erosion than the upper unit. The upper unit most likely consists of stratified dust and ice, while the lower unit contains abundant, poorly cemented sand. Sand is more easily mobilized by wind than dust; the lower resistance to erosion of the lower unit results from the presence of sand. Where wind erosion in polar troughs has penetrated to the lower unit, geomorphic change has proceeded more rapidly: sand has been liberated from the lower unit, and arcuate scarps have formed as the upper unit has been undermined. Wind erosion of the lower unit thus influences the geomorphology of the north polar region; this result likely explains the genesis of the large polar trough, Chasma Boreale, and the relations between dunes and arcuate scarps that have puzzled investigators for nearly three decades. The properties of the stratigraphic units suggest that the upper limit for the amount of water contained in the north polar layered materials may be 30–50% less than previously estimated.

Oceans or seas in the martian northern lowlands: High resolution imaging tests of proposed coastlines

by Ken Edgett

(1999) **SELF ARCHIVED PDF AVAILABLE HERE**
M. C. Malin and K. S. Edgett
Geophysical Research Letters, 26(19), 3049–3052. doi:10.1029/1999GL002342

Mars Global Surveyor Mars Orbiter Camera images that were targeted specifically to observe locations where published... more Mars Global Surveyor Mars Orbiter Camera images that were targeted specifically to observe locations where published accounts argue for the presence of landforms created by the interaction of a large body of water with Martian topography fail to reveal any evidence to support the hypothesis that the northern lowlands were once the site of oceans or seas. Given the difficulty of identifying ancient coastlines on Earth from orbital and aerial photography in the absence of field work, this result does not preclude the possibility that Mars once had large standing bodies of water on its surface, but calls into question shorelines previously proposed.

An overview of the 1985–2006 Mars Orbiter Camera science investigation

by Ken Edgett

(2010) **OPEN ACCESS**
M. C. Malin, K. S. Edgett, B. A. Cantor, M. A. Caplinger, G. E. Danielson, E. H. Jensen, M. A. Ravine, J. L. Sandoval, K. D. Supulver
Mars, 5, 1–60. doi:10.1555/mars.2010.0001

The Mars Observer Camera (MOC) investigation was proposed in 1985 and selected in 1986 for the Mars Observer mission,... more The Mars Observer Camera (MOC) investigation was proposed in 1985 and selected in 1986 for the Mars Observer mission, a spacecraft that was lost enroute to Mars in 1993. Re-named the Mars Orbiter Camera, MOC was re-flown on Mars Global Surveyor and successfully provided more than 4 Mars years (between September 1997 and October 2006) of daily global meteorological observations and observed ancient, water-lain sedimentary rock, present-day impact cratering, and youthful gullies (some of which may be showing evidence for present-day liquid water), among many other results from its more than 243,000 images.

Utah's geologic and geomorphic analogs to Mars--An overview for planetary exploration

by Kathleen Nicoll

--> Citation Chan, M.A., Nicoll, K., Ormö, J., Okubo, C.H., and Komatsu, G. 2011. Utah's geologic and geomorphic analogs to Mars--An overview for planetary exploration. In Garry, WB and Bleacher, JE (eds.), Analogs for Planetary Exploration: Geological Society of America Special Paper 483. Chapter 21. p. 349–375. doi:10.1130/2011.2483(22).

ABSTRACT Utah offers spectacular geologic features and valuable analog environments and processes for Mars studies.... more ABSTRACT Utah offers spectacular geologic features and valuable analog environments and processes for Mars studies. Horizontal strata of the Colorado Plateau are analogous to Mars because the overprint of plate tectonics is minimal, yet the effects of strong ground motion from earthquakes or impacts are preserved in the sedimentary record. The close proximity of analog environments and lack of vegetative cover are advan-
tages for fi eld and remote-sensing studies. Dry, desert climate and modern wind processes of Utah are comparable to Mars and its current surface. Analogs in Utah include eolian, sabkha, and saline bodies, glacial, lacustrine, spring, alluvial, fl uvial,
delta, and outfl ow channel depositional environments, as well as volcanic landforms and impact craters. Analogous secondary processes producing modification features include: diagenetic concretions, weathering and soils, sinkholes, sapping, knobs and pinnacles, crusts and varnish, and patterned grounds. Utah’s physical and chemical environments are analogous to conditions on Mars where water existed and could support microorganisms. The development of Mars includes: ancient and modern depositional records, burial and diagenesis, uplift and tectonic alteration, and modern sculpting or weathering of the surface exposures. Recent satellite images are providing unprecedented details that rival the outcrop scale. Analogs in Utah are prime field localities that can be utilized in planning future robotic and human missions to Mars, and for teaching the next generation of planetary explorers.

A multi-goal Mars analogue expedition (Expedition Two) to the Arkaroola region, Australia

by Kathryn Fitzsimmons

Clarke, J.D.A., Persaud, R., Rupert, S., Bishop, M., Brown, A., Clarke, A., Clarke, J.P., Clarke, R., Cutler, N., Dawson, S., Fitzsimmons, K.E., et al. (2006) A multi-goal Mars analogue expedition (Expedition Two) to the Arkaroola region, Australia. In Clarke, J.D.A. (ed) Mars Analog Research, American Astronautical Society Science & Technology Series 111, 3-15