Mathematics – Logic
Scientific paper
Nov 2004
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004dps....36.4505m&link_type=abstract
American Astronomical Society, DPS meeting #36, #45.05; Bulletin of the American Astronomical Society, Vol. 36, p.1178
Mathematics
Logic
Scientific paper
We discuss the changing styles of erosion in the highlands during the Noachian and early Hesperian. Taken together the features we report in this study fit into a hypothesis in which a climate optimum occurred around the Noachian-Hesperian (N-H) boundary imposing the last great act of large-scale Martian fluvial activity. We review the some of the morphologic evidence for a possible N-H climate optimum.
The contrast in erosional style between the widespread Noachian erosion and more limited 'pristine' channels (and other features) indicates different climatic regimes. Several scenarios for this change of erosional style, including headward migration of channel knickpoints by sapping, low intensity but continuous precipitation, and basal melting beneath a thick ice cover have been proposed. One possibility is that the limited headward extent of channel incision is best explained by runoff from snowmelt, with development of duricrusts as a contributing factor. Alluvial fans formed during this time period but appear to lack the secondary drainage that occurs on most terrestrial alluvial fans that results from post-depositional runoff erosion. This suggests that the source of water for these fans was restricted to the contributing basins on the crater headwalls. Such headwall alcoves might be natural traps for snowfall. A cold climate with relatively abundant snowfall is also consistent with the possible occurrence of large, possibly ice-covered lakes on the highlands and in Hellas at this time. Runoff might have occurred during favorable obliquity conditions. In addition, the early Hesperian was noted for widespread large-scale volcanic activity, possibly contributing to greenhouse warming and water inventories. Although impact-induced climate optima might aid either enhanced precipitation or snowmelt, the presence of long-lived deltas suggests volcanism or orbital mechanics controlling the N-H climate.
Howard Alan D.
Moore Jeffery M.
No associations
LandOfFree
Changing Styles of Erosion During the Noachian-Hesperian Transition: Evidence for a Possible Climatic Optimum? does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Changing Styles of Erosion During the Noachian-Hesperian Transition: Evidence for a Possible Climatic Optimum?, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Changing Styles of Erosion During the Noachian-Hesperian Transition: Evidence for a Possible Climatic Optimum? will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1015454