[meteorite-list] Part2: Professor Rejects Meteor Theory of Carolina Bays' Origin
From: Paul <bristolia_at_meteoritecentral.com>
Date: Wed Mar 29 22:29:46 2006 Message-ID: <20060329195322.20899.qmail_at_web36215.mail.mud.yahoo.com> Susan Web wrote: ?Their key mysterious features are their number (half a million of them), their regularity of form, their common orientation, their extreme shallowness, their low rim heights.? Their ?common orientation? is not as consistent as the proponents of an impact origin falsely claim them to be. In the southern and northern ends of their distribution, the long axis of Carolina Bays actually show a wide range of orientations, which fails to support either an air-burst or impact origin. Within the middle range of their distribution, the orientation of the Carolina Bays are consistent with Pleistocene paleowind directions as determined from ancient dune fields, loess distribution patterns, and paleoclimate models. I would find it quite remarkable that either a meteorite or comet would take the time and trouble to plan its impact as to perfectly coincide with the prevailing winds at the time it hit like an airplane landing at an airport. The wide spread of orientations at the northern and southern ends of their distributions is also consistent with what is known about the variability of Pleistocene paleowind patterns over time. Another and major problem, which the proponents of either an impact or air-burst origin is that the shape, orientation, and depth of the Carolina Bays have been altered by over a 100,000 years of modification by eolian and lacustrine processes. For example, Ivester et al. (2003) found that the multiple sand rims found within Big Bay in South Carolina become progressively younger towards the center of this Carolina Bay. In this case, Optically Stimulated Luminescence (OSL) dates from sand rims starting from the outer rim to the inner rim produced a perfectly chronologically consistent set dates of 35,660?2600; 25,210?1900; 11,160?900; and 2,150?300 years BP. In this case, the Big Bay has shrunk by 1.6 km over the last 36,000 years, with rims being produced about 36,000 BP, 25,000 BP, 11,000 BP, and 2,000 BP as it shrunk. If a person wants to argue that these sand rims are of impact or air-burst origin, they need to explain how either impacts or air-bursts managed to precisely excavate tens of thousand of years apart sucessive craters in precise center of Big Bay and similar Carolina Bays and with ever decreasing energy as to produce sand rims of smaller and smaller diameter, which are nicely nested within each other. Their nothing mysterious about these rims as (Ivester et al. 2004a) studied the sedimentology and stratigraphy of these rims and found them to be ?composed of both shoreface and eolian deposits". Eolian and lacustrine processes are perfectly capable of producing the low rims processes by Carolina Bays. The low rims can be easily explained by a combination of eolian and lacustrine processes. As a result of the OSL dating of the rims of numerous Carolina Bays, Ivester et al (2004b) concluded: "The optical dating results indicate that present-day bay morphology is not the result of a single event, catastrophic formation, but rather they have evolved through multiple phases of activity and inactivity over tens of thousands of years. This is evidenced both by multiple rims of differing ages along the same bay, and by multiple ages within single rims." Because the Carolina Bays have been modified for over a 100,000 years by both eolian and lacustine processes, their form, orientation, shallowness, and sand rims are useless as evidence of how they were originally created. References Cited: Ivester, A.H., Godfrey-Smith, D. I., Brooks, M. J., and Taylor, B. E., 2003, Concentric sand rims document the evolution of a Carolina bay in the Middle Coastal Plain of South Carolina. Geological Society of America Abstracts with Programs. vol. 35, no. 6, pp. 169. Ivester, A. H., Godfrey-Smith, D. I., Brooks, M. J., and Taylor B. E., 2004a, The timing of Carolina Bay and inland activity on the Atlantic coastal plain of Georgia and South Carolina. Geological Society of America Abstracts with Programs. vol. 36, no. 5, p. 69 Ivester, A. H., Godfrey-Smith, D. I., Brooks, M. J., and Taylor B. E., 2004b, Chronology of Carolina bay sand rims and inland dunes on the Atlantic Coastal Plain, USA. The 3rd New World Luminescence Dating Workshop. July 4 - 7, 2004, Department of Earth Science, Dalhousie University, Halifax, Nova Scotia. Mrs. Webb also wrote: ?It is also worth noting that all the geological theories of their origins are based on the erroneous notion that the Carolina Bays are all to be found in only one type of geological terrain, the coastal plains. But they have since been found in other terrain types, which effectively rules out most of the prior geological theories (except for those fish fins, of course).? Unfortunately, the only ?erroneous notion? here is the pervasive Internet folklore about Carolina Bays having been found on a variety of geologic terrains. The fact of the matter is that Carolina Bays are **not** found in a diverse assortment geologic terrains. The Internet fiction about Carolina Bays being found in a wide range of geologic terrains was soundly refuted by the detailed analysis, which May and Warme (1999) did of Carolina Bays, including those found within the coastal plains of Mississippi and Alabama. They found that these bays are restricted to deeply weathered, very low relief, and very poorly drained, geomorphic surfaces. Reference Cited: May, James H., and Warne, Andrews G., 1999, Hydrogeologic and Chemical Factors Required for the Development of Carolina Bays Along the Atlantic and Gulf of Mexico Coastal Plain, USA. Environmental Engineering and Geoscience. vol. 5, no. 3, pp. 261-270. The abstract for May and Warme (1999) can be found at: http://eeg.geoscienceworld.org/cgi/content/abstract/5/3/261 Best, Paul __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com Received on Wed 29 Mar 2006 02:53:22 PM PST |
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