Weizmann Institute of Science Department of Earth and Planetary Sciences Center for Planetary Science Rehovot 76100, Israel Tel: 972-8-934 6961 Email: Oded.Aharonson[at]weizmann.ac.il Fax: 972-8-934 4124

Exoplanets	Mars Surface Simulations & Experiments	Mars Sedimentology & Stratigraphy
Mars Exploration Rover	Mars Bedrock Mineralogy	Planetary Geomorphology
	The Man in the Moon	Titan's Lakes

Mars: Sedimentology and Stratigraphy

The Holden NE distributary system is a unique sedimentary structure on Mars. The well-preserved nature of channels and layered outcrops exposed in this landform is unparalleled among known geologic features on Mars. This fact allows for a more rigorous and quantitative approach to geomorphologic interpretation than is often possible on Mars. This process is aided by high resolution imagery from the Mars Orbiter Camera (MOC), in orbit around Mars since 1997. We have used pairs of MOC images, in stereo, to derive high-resolution topographic information about the layered deposits in Holden NE crater. Using this data, we have found evidence that the distributary network was once a delta emptying into a lake on the floor of Holden NE crater. Below is a 3D view of the layered outcrops along the edge of this ancient delta, which shows a MOC image draped over the stereo-derived topographic data.

Flythrough movie (QuickTime or AVI format)

A key aspect of geomorphologic interpretation of a layered geologic sequence lies in understanding the orientation of the layers exposed in an outcrop. This measurement aids in distinction between various methods of formation, and in detection of post-depositional deformation and tilting. We have used a stereo-derived Digital Elevation Model (DEM) to assess the orientation of many of the layers exposed in the Holden NE deposit. The image on the left below shows the strike and dip measurements (blue marks and corresponding figures) for the layers used in our analysis. Red lines show the trace of the layers. These measurements have revealed a complex internal structure, not obvious in imagery alone. However, trends can be seen among several layers. One such area where strike measurements are correlated among several layers is denoted by '*'. The image on the right is a MOC mosaic of the entire Holden NE distributary network, created by Malin Space Science Systems.

References

Lewis K.W., Aharonson O., Occurrence and origin of rhythmic sedimentary rocks on Mars, J. Geophys. Res. Planets, 119 (6), 1432-1457, 2014. [DOI: 10.1002/2013JE004404]

Lewis K.W., Aharonson O., Grotzinger J.P., Kirk R.L., McEwen A.S., Suer T.-A., Quasi-periodic bedding in the sedimentary rock record of Mars, Science, 322 (5907), 1532-1535, 2008. [DOI: 10.1126/science.1161870]

Lewis K.W., Aharonson O., Grotzinger J.P., Squyres S.W., Bell III J F., Crumpler L.S., Schmidt M.E., Structure and stratigraphy of Home Plate from the Spirit Mars Exploration Rover, J. Geophys. Res. Planets, 113, E12S36, 2008. [DOI: 10.1029/2007JE003025]

Lewis K.W., Aharonson O., Stratigraphic analysis of the distributary fan in Eberswalde crater using stereo imagery, J. Geophys. Res. Planets, 111, E06001, 2006. [DOI: 10.1029/2005JE002558]

More information about this and other research is available in the form of published manuscripts here.