Dr. Ross Irwin Geologist Center for Earth and Planetary Studies National Air and Space Museum irwinr@si.edu

My research focuses on Martian landforms that are related to surface water, including valley networks and possible former lakes and ocean basins. Ongoing projects include: 1) why are drainage networks on Mars better developed in some regions than in others; 2) what were the discharges of ancient Martian rivers (volume of water per second) and how much precipitation was needed to generate that amount of runoff; 3) where did lakes occur on Mars and how can we tell from river topography and old shorelines, given that the basins are presently dry; 4) what was the climatic history and suite of processes that allowed so much erosion of craters while leaving only immature valley networks; and 5) what was the history of tectonics, erosion and deposition that created the unique rugged landscape along the highland-lowland dichotomy boundary.

Our findings so far suggest that early Mars was ephemerally warm and wet, like a terrestrial desert and with Earthlike runoff following precipitation at times. Episodes of flow in valley networks were sometimes separated by long drier spells. Impact cratering and other processes worked to disrupt and fill the river valleys as they were forming, leaving a poorly developed landscape by terrestrial standards. Runoff may have become more intense and ephemeral with time before it declined completely. Basins near the equator may have been dry much of the time, but some intriguing observations suggest ancient lakes in the mid-latitudes that overflowed to carve valleys. Fretted terrains along the dichotomy boundary appear to have formed in a sedimentary deposit and were eroded largely by wind and possible subsurface processes.

Dr. Irwin's CV (PDF)

Some of Dr. Irwin's research projects:
Identification of Former Lake on Mars
Development of the highland/lowland dichotomy boundary on Mars
Channels in Martian Valley Networks
Interior Channels in Martian Valleys (press release)