Featured image for January 2008: Raised Curvilinear Features on Mars

Image and caption contributed by Dr. Devon Burr

[Click for high resolution version]

Medusae Fossae Formation on Mars

Raised curvlinear features (RCFs) detected on the surface of Mars, as in the image shown here, have a sinuous and branching character. This is evocative of river networks, and suggests their formation by flowing water. On Earth, flowing water commonly forms curvilinear troughs or river channels, which are negative-relief features. How could flowing water form raised or positive-relief features? There are two mechanisms by which this happens on Earth and possibly on Mars.

1) River channels may form in negative relief and then become inverted to positive relief. This process occurs when the channel floor becomes more resistant to erosion than the surrounding terrain. This increased resistance could be a result of inundation by lava, geochemical cementation, or deposition by the river of a coarse-grained lag. After the channel floor develops this increased resistance, regional erosion then removes the surrounding terrain, leaving the channel floor in positive relief.

2) Glaciofluvial channels may form in positive relief from flow on, within, or most commonly beneath glaciers. The flow of the glacial meltwater melts a tunnel in the ice, in which it deposits sediment. This deposited sediment is supported by the confining ice walls of the tunnel, so it sits above the surrounding land surface. Removal of the overlying glacier by climate change reveals these sedimentary deposits in positive relief. These resultant ridges are called eskers, derived from the Irish word for 'ridge.' Examples of eskers are found in Canada and the northern United States, Scandanavia, and of course Ireland.

This image shows half a dozen different examples within a limited area, and more regional coverage shows upwards of 150 individual RCFs. Determining the origin of these features will be difficult because of their partial erosion (and probable partial preservation.) However, inverted fluvial channels and glaciofluvial eskers each carry important implications for climate and astrobiological potential. On-going mapping and quantitative characterization aim to determine their origin(s) and infer their various implications for the geologic history of Mars.

Image caption: This THEMIS visible wavelength image (number V05875001) from the western Medusae Fossae Formation of Mars shows a variety of raised curvlinear features (RCFs), annotated with labels A through F. Work on these intriguing features by Devon Burr at the Carl Sagan Center and Rebecca Williams at the Planetary Science Institute is seeking to characterize these RCFs and determine their mode(s) of formation. Image credit: THEMIS Public Data Releases. Mars Space Flight Facility, Arizona State University.

Further Reading:

Brennand, T.A. (2000) Deglacial meltwater drainage and glaciodynamics: inferences from Laurentide eskers, Canada. Geomorphology doi:10.1016/S0169-555X(99)00100-2 32, 263-293. [abstract]

Burr, D.M., R.M.E. Williams, J. Nussbaumer and J.R. Zimbelman (2006) Multiple, distinct, (glacio?)fluvial paleochannels throughout the western Medusae Fossae Formation, Mars. Lunar Planet. Sci. XXXVII. [abstract 1367]

Maizels. J.K.(1987). Plio-Pleistocene raised channel systems of the western Sharqiya (Wahiba), Oman. In: L. Frostick and I. Reid (Editors), Desert Sediments: Ancient and Modem. Geol. Sot. Spec. Publ.35: 31-50.

Pain, C. P., Clarke, J. D. A., and Thomas, M. (2007). Inversion of relief on Mars. Icarus 190, 478-491. [abstract]

Pain, C.F. and C.D. Ollier (1995) Inversion of relief - a component of landscape evolution. Geomorphology doi:10.1016/0169-555X(94)00084-5 12, 151-165. [abstract]

Shreve, R.L. (1972) Movement of water in glaciers. J. Glaciol. 11, 205-214.

Shreve, R.L., (1985). Esker characteristics in terms of glacial physics, Katahdin esker system, Maine. Geol. Soc. Am. Bull. 96, 639-646. [abstract]

Watters, T. R., Campbell, B., Carter, L., Leuschen, C. J., Plaut, J. J., Picardi, G., Orosei, R., Safaeinili, A., Clifford, S. M., Farrell, W. M., Ivanov, A. B., Phillips, R. J., and Stofan, E. R. (2007). Radar Sounding of the Medusae Fossae Formation Mars: Equatorial Ice or Dry, Low-Density Deposits? Science 318, 1125-1128. [abstract]

Williams, R.M.E., and K.S. Edgett (2005) Valleys in the Martian rock record. Lunar Planet Sci. XXXVI. [abstract 1099]

Williams, R.M.E., M.C. Malin, and K.S. Edgett (2005) Remnants of the courses of fine-scale, precipitation-fed runoff streams preserved in the Martian rock record. Lunar Planet Sci. XXXVI. [abstract 1173]

Williams, R.M.E. (2007) Global spatial distribution of raised curvilinear features on Mars. Lunar Planet Sci. XXXVIII. [abstract 1821]

Williams, R.M.E., Chidsey, T.C., Jr., and Eby, D.E., (2007), Exhumed paleochannels in central Utah - analogs for raised curvilinear features on Mars, in Willis, G.C., Hylland, M.D., Clark, D.L., and Chidsey, T.C., Jr., editors, Central Utah - diverse geology of a dynamic landscape: Utah Geological Association Publication 36, Salt Lake City, Utah.