Welcome Professor "brine splat" Burt, "a chance to ask questions... or raise objections" |
Welcome Professor "brine splat" Burt, "a chance to ask questions... or raise objections" |
Jun 15 2007, 03:04 AM
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Member Group: Members Posts: 384 Joined: 4-January 07 Member No.: 1555 |
Relevant to Emily's boulder observation, the "Gullies and layers" HiRISE image was not the first to show layers with abundant boulders, indicating poor sediment sorting in layered slopes. Previous images included, e.g., PSP_001691_1320 "Gullied trough in Noachis Terra, released on 28 Feb., and PSP_001942_2310 "Signs of fluids and ice in Acidalia Planitia" released on 9 May. That these bouldery layers might represent ancient ballistic impact ejecta seems a reasonable suggestion, because much of the present martian surface is littered with boulders presumed to be ballistic impact ejecta. Other possibilities for boulder deposits might include, e.g., ancient talus or landslide deposits at the foot of slopes, stream boulders in channels, volcanic ejecta near vents, glacial moraines, or iceberg dropstones.
As an aside, the related suggestion that at least some of the fine-grained layers above or below any boulder deposits (or elsewhere on Mars) could likewise represent ancient impact deposits (non-ballistic fine-grained sand and dust distributed over vast areas by fast-moving, turbulent, erosive gaseous density currents - a.k.a. impact surge clouds - or by the winds as later fallout) already seems to have aroused considerable controversy on this forum, but again that's peripheral to Emily's boulder comment. --Don [MOD EDIT: "Brine Splat Burt" discussion moved here -> http://www.unmannedspaceflight.com/index.p...ic=4308&hl= -EGD] |
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Jun 15 2007, 08:37 PM
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Senior Member Group: Members Posts: 2173 Joined: 28-December 04 From: Florida, USA Member No.: 132 |
As an aside, the related suggestion that at least some of the fine-grained layers above or below any boulder deposits (or elsewhere on Mars) could likewise represent ancient impact deposits (non-ballistic fine-grained sand and dust distributed over vast areas by fast-moving, turbulent, erosive gaseous density currents - a.k.a. impact surge clouds - or by the winds as later fallout) already seems to have aroused considerable controversy on this forum, but again that's peripheral to Emily's boulder comment. So you're the dburt of Basal Surge fame? "ASU geologists L. Paul Knauth and Donald Burt, who along with Kenneth Wohletz of Los Alamos National Laboratory, say that base surges resulting from massive explosions caused by meteorite strikes offer a simpler and more consistent explanation for the rock formations and sediment layers found at the Opportunity site." http://www.asu.edu/news/stories/200512/200..._meteorites.htm I haven't followed the situation closely enough to ask any good questions, but I wonder if anyone else here would like to ask about your current views. for reference, the basal surge thread is here: http://www.unmannedspaceflight.com/index.p...surge&st=30 |
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Jun 19 2007, 02:40 AM
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Senior Member Group: Members Posts: 3419 Joined: 9-February 04 From: Minneapolis, MN, USA Member No.: 15 |
There is much more data to collect before any theory is proven. I really do appreciate your efforts, Professor. And I surely understand the difficulty in direct observation of large impact events. Even if you eventually are proven wrong, we will always need people to challenge the conventional wisdom, or else misinterpretations will never get addressed!
Thanks again for joining this forum. -the other Doug -------------------- “The trouble ain't that there is too many fools, but that the lightning ain't distributed right.” -Mark Twain
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