On Thu, 21 Aug 2003 12:30:11 -0700 (PDT) Robert Verish >This most recent influx of moisture >into the deserts has caused severe >flash-flooding. Up until now, the >"dry" lakes have been overly wet with >standing water, but flash-flooding >has the energy to bring large volumes >of mud and rock with that water, out >into the middle of these playas and >bury any promising surface with a new >layer of sediment.
First, the flooding is not going carry any rock of any size into the playa. Any rock, except for pumice, of any size is going to drop out along the edges of the playa lake. Just the finer- grained sediments, i.e. mostly silt and clay will get carried out into the playa. Along the edges of any playa, there might be a substantial accumulation of sediments. However, the actual thickness of accumulation will drastically decrease towards the interior of any lake bed to the point where it can be quite thin. Finally, the deposition of sediment is not altogether a bad thing. Any of the clutter and garbage that has accumulated on the playa lake surfaces because of human activity should be buried, in a some cases just awhile, giving the meteorite hunter a clean surface on which a person can more easily find any meteorite falls after the lake dries out. I qualify my statements with "awhile" because, in some lake beds, the pedoturbation of the lake sediments after the lake bed dries out might cause larger pieces of rock, older meteorites, and human debris to resurface in the next decade or so if they are not too deeply buried. Also, after a lake dries out, wind action can significantly erode and move any silt, clay,or fine sand that might accumulated during these floods and also expose, in time, objects buried outside of the lake margins. Again, in time, some of stuff that was buried by these floods within the lake beds away from its margins will start to resurface in the next few years as wind erodes the new lake sediments and deflates the lake surface. Yours, Paul Baton Rouge, LA __________________________________ Do you Yahoo!? Yahoo! SiteBuilder - Free, easy-to-use web site design software http://sitebuilder.yahoo.com ______________________________________________ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
