[meteorite-list] Bad Science on ancient meteorite impactor?, Part 2
From: Paul <bristolia_at_meteoritecentral.com>
Date: Mon, 31 Mar 2008 18:26:24 -0700 (PDT) Message-ID: <900230.1831.qm_at_web36203.mail.mud.yahoo.com> meteorite-list at meteoritecentral.com Sterling K. Webb wrote: ?See, I started out sceptical, and now I'm not so sure... This collector considers "k?felsite" as an impactite: http://www.somerikko.net/collection/index.html "Age between 8000 and 16000 years is from glass.. Theory has been recently presented that k?fels has been formed during a giant landslide about 9000 years ago. That landslide was so huge that rock melted because friction. So there is still a possibility that K?fels is not an impact structure. However, there is lots of big landslides in Alps but no other similar cases is found yet. Also PDF's in quartz has been reported in samples from K?fels, and PDF's are produced only by impacts." http://www.somerikko.net/old/geo/imp/refer.htm There has been iridium analysis, but it's inconclusive.? The origin of the pumice, called either ?hyalomylonites? or ?frictionites? associated with the K?fels has been studied in great detail by: Erismann, T. H., 1977, Der bimsstein von K?fels impaktit oder friktionit?. Material und Technik. vol. 5, pp.. 190?196. and Erismann, T. H., H. Heuberger, and E. Preuss, 1977, Der Bimsstein von K?fels (Tirol), ein Bergsturz-?Friktionit. Mineralogy and Petrology. vol. 24, no. 1-2, pp. 67-119. The abstract to Erismann et al. (1977) stated: ?For more than a century the genesis of the fused rocks found in the landslide masses of K?fels (?tztal, Tyrol) has remained enigmatic. The initially promoted hypothesis of a volcanic origin could not be backed by sufficient evidence. So in the last decade the possibility of a meteorite impact has been accepted by a large number of scientists. It is, however, by no means in accordance with all facts observed. In 1971, Preuss presented the idea of the melting heat being generated by the friction between sliding and stationary rock surfaces. As this working hypothesis proved to be in good accordance with petrographic and geomorphological evidence it was studied in detail by the authors in cooperation with the Swiss Federal Laboratory for Testing Materials (EMPA). The corresponding research project (ldquoBig Sliderdquo) was based on a careful analysis of the effects of the energy generated by the landslide. By setting up plausible models for movement, heat generation, and heat transfer and by solving the resulting differential equations it became evident that ? as far as the landslide masses did not glide on a very thick layer of stone powder (dynamically a rather unprobable supposition)-large amounts of fused rock (ldquofrictioniterdquo, for definition see chapter 2.2) must have been produced. The enormous size of the particular landslide was recognized as a determining factor in this connection. The theoretical results thus obtained could be backed experimentally by producting artificial pumice under conditions approaching those of the K?fels landslide.? Erismann et al. (1977) fairly well demonstrates that the estimated kinetic energy of the rock mass displaced by the landslide would have generated the heat necessary to melt the rock and form the ?pumice?, which they called ?frictionite?. The frictionite occurs in dikes several decimeters to meter thick at the top of the landslide deposit. The K?fels landslide, about 2 to 3 cubic kilometers in mass, is the **largest** landslide in Europe. It is not surprising that it has some unique aspects to it being the only one of its size. Another study, which examined glass found in the K?fels landslide is: Masch, L., H. R. Wenk, and E. Preuss, 1985. Electron microscopy study of hyalomylonites-evidence for frictional melting in landslides. Tectonophysics. vol. 115, pp. 131?160. They studied glass, which they called ?hyalomylonite?, which occurs in the K?fels landslide deposits. It differs from frictionite in that it occurs as veins 1 mm to 3 cm thick and lacks porosity. from their analysis, they concluded that the hyalomylonite was created by kinetic heating of the rock during the landslide. Similar hyalomylonite / frictionite deposits has also been found in megalandslides in the Himalayas of Nepal and Peru as discussed by: Heuberger, H., L. Masch, E. Preuss, and A. Schrocker, 1984, Quaternary Landslides and Rock Fusion in Central Nepal and in the Tyrolean Alps. Mountain Research and Developments. vol. 4, no. 4, pp. 345-362. Weidinger, J. T., J.-M. Schramm, and R. Surenian, 1996, On preparatory causal factors, initiating the prehistoric Tsergo Ri landslide (Langthang Himal, Nepal). Tectonophysics. vol. 260, no. 1-3, pp. 95-107. and Legros, F., J.-M. Cantagrel, and B. Devouard, 2000, Pseudotachylyte (Frictionite) at the Base of the Arequipa Volcanic Landslide Deposit (Peru): Implications for Emplacement Mechanisms. The Journal of Geology. vol. 108, no. 5, pp. 601?611. Hermanns et al. (2006) presents significant problem for the impact hypothesis in that he found that there is evidence of multiple landslides. It was the largest and youngest of these landslides that created the frictionite when it slid over the older deposits. To explain multiple periods of landsliding, a person would have to argue that two different impacts occurred at virtually same spot at different times separated by a significant period of time. Hermanns et al. (2006) also noted of the younger deposits, which contain the frictionite: ?Pieces of wood recovered from a reconnaissance gallery in the Tauferberg gave a conventional 14C age of 8710+/-150 years BP (Heuberger, 1966), and an AMS 14C age of 8705+/- 55 years BP (Ivy-Ochs et al., 1998),? References Cited: Hermanns, R.., L. Blikra, M. Naumann, B. Nilsen, K. Panthi, D. Stromeyer, O. Longva, 2006, Examples of multiple rock-slope collapses from K?fels (?tz valley, Austria) and western Norway. Engineering Geology. vol. 83, no. 1-3, pp. 94-108. -- Alledged PDFs -- Impacts and meteorites http://www.somerikko.net/old/geo/imp/refer.htm The above web page, states ?Also PDF's in quartz has been reported in samples from K?fels, and PDF's are produced only by impacts.? The alleged PDFs found in the deposits of the K?fels landslide were examined by Dr. Christian Koeberl according to: Deutsch, A., C. Koeberl, J.D. Blum, B.M. French, B.P. Glass, R. Grieve, P. Horn, E.K. Jessberger, G. Kurat, W.U. Reimold, J. Smit, D. stoffler, and S.R. Taylor, 1994, The impact-flood connection: Does it exist? Terra Nova. vol. 6, pp. 644-650. This paper reports that Dr. Koeberl found them **not** to be PDFs. Rather, he identified them to be nonPDF llamellar deformation features typical of tectonic, not impact, processes. How these llamellar features would have formed is discussed by: Leroux, H., and J.-C. Doukhan, 1993, Dynamic deformation of quartz in the landslide of Koefels, Austria. European Journal of Mineralogy. vol. 5, no. 5, pp. 893-902. -- Additional Note -- Sorenson et al. (2003) concluded: ?Analysis of the K?fels sturzstrom seems to indicate that most aspects can be explained without recourse to exotic emplacement scenarios. The bulk of the material resembles the debris from an energetic but conventional landslide.? Reference Cited Sorensen, S.-A., and Berthold Bauer, 2003, On the dynamics of the K?fels sturzstrom. Geomorphology, vol. 54, no. 1-2, pp. 11-19. Yours, Paul H. ____________________________________________________________________________________ OMG, Sweet deal for Yahoo! users/friends:Get A Month of Blockbuster Total Access, No Cost. W00t http://tc.deals.yahoo.com/tc/blockbuster/text2.com Received on Mon 31 Mar 2008 09:26:24 PM PDT |
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