detailed careful fair critique of most cases of purported impact
causes of extinctions, Grzegorz Racki, Silesian U., Poland, 64 p: Rich Murray 2012.03.13 http://rmforall.blogspot.com/2012/03/detailed-careful-fair-critique-of-most.html http://tech.groups.yahoo.com/group/astrodeep/message/97 [ I'm grateful to find this posted on http://cosmictusk.com/tree-falls-in-forest-and-one-hand-claps-science-press-picks-the-new-mexican-black-mat-study/comment-page-1/#comments as a link given in a comment by Thomas Lee Elifritz March 8, 2012 at 4:33 pm I was impressed by how difficult it is to gather and mobilize evidence in this very complex research. Really courteous, patient, open-minded, detail oriented collaboration is essential. Grzegorz Racki, like many experts, in this review accepted the recent refutation of the YD impact hypothesis -- I wonder how he will respond to the new wave of confirming evidence. ] http://www.app.pan.pl/archive/published/app57/app20110058_acc.pdf 64 pages This manuscript is a part of a special issue titled “Thirty odd years after Alvarez’s discovery: Faunal evolution and principal bio-events of the Cretaceous Period – recent progress and future directions” (guest editors: Elena A. Jagt-Yazykowa and John W.M. Jagt). The Alvarez impact theory of mass extinction; limits to its applicability and the ‘great expectations syndrome’ GRZEGORZ RACKI Racki, G. 201X. The Alvarez impact theory of mass extinction; limits to its applicability and the ‘great expectations syndrome’. Acta Palaeontologica Polonica 5X (X): xxx–xxx. http://dx.doi.org/10.4202/app.2011.0058 [ abstract ] For the past three decades, the Alvarez impact theory of mass extinction, causally related to catastrophic meteorite impacts, has been recurrently applied to multiple extinction boundaries. However, these multidisciplinary research efforts across the globe have been largely unsuccessful to date, with one outstanding exception: the Cretaceous-Paleogene boundary. The unicausal impact scenario as a leading explanation, when applied to the complex fossil record, has resulted in force fitting of data and interpretations (‘great expectations syndrome’ of Tsujita). The misunderstandings can be grouped at three successive levels of the testing process, and involve the unreflective application of the impact paradigm: (i) factual misidentification, i.e., an erroneous or indefinite recognition of the extraterrestrial record in sedimentological, physical and geochemical contexts, (ii) correlative misinterpretation of the adequately documented impact signals due to their incorrect dating, and (iii) causal overestimation when the proved impact characteristics are doubtful as a sufficient trigger of a contemporaneous global cosmic catastrophe. Examples of uncritical belief in the simple cause-effect scenario for the Frasnian–Famennian, Permian–Triassic and Triassic–Jurassic (and the Eifelian–Givetian and Paleocene–Eocene as well) global events include mostly item-1 pitfalls (factual misidentification), with Ir enrichments and shocked minerals frequently misidentified. Therefore, these mass extinctions are still at the first test level, and only the F–F extinction is potentially seen in the context of item-2, the interpretative step, because of the possible causative link with the Siljan Ring crater (53 km in diameter). The erratically recognized cratering signature is often marked by large timing and size uncertainties, and item-3, the advanced causal inference, is in fact limited to clustered impacts that clearly predate major mass extinctions. The multi-impact lag-time pattern is particularly clear in the Late Triassic, when the largest (100-km diameter) Manicouagan crater was possibly concurrent with the end-Carnian extinction (or with the late Norian tetrapod turnover on an alternative time scale). The relatively small crater sizes and cratonic (crystalline rock basement) setting of these two craters further suggest the strongly insufficient extraterrestrial trigger of worldwide environmental traumas. However, to discuss the kill potential of impact events in a more robust fashion, their location and timing, vulnerability factors, especially target geology and palaeogeography in the context of associated climate-active volatile fluxes, should to be rigorously assessed. The current lack of conclusive impact evidence synchronous with most mass extinctions may still be somewhat misleading due to the predicted large set of undiscovered craters, particularly in light of the obscured record of oceanic impact events. K e y w o r d s: Bolide impacts, extraterrestrial markers, impact craters, mass extinctions, Cretaceous–Paleogene boundary, Triassic–Jurassic boundary, Frasnian–Famennian boundary. Grzegorz Racki [ [hidden email] ], Department of Earth Sciences, Silesian University, Będzińska Str. 60, PL-41-200 Sosnowiec, Poland. Received 9 July 2011, accepted 18 December 2011, available online 24 February 2012. 10 m broken rock hill with black glazes, W of Rancho Alegre Road, S of Coyote Trail, W of Hwy 14, S of Santa Fe, New Mexico, tour of 50 photos 1 MB size each via DropBox: Rich Murray 2011.07.28 2011.08.03 http://rmforall.blogspot.com/2011/08/10-m-broken-rock-hill-with-black-glazes.html http://rmforall.blogspot.com/2011/08/35479730-106085926-1865-km-el-top-10-m.html photos 3-5 of 50 http://tech.groups.yahoo.com/group/astrodeep/message/92 ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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God this is cool stuff:
- Impact phenomena: direct hits, glancing interactions, comet vs meteor
- Geology: Detective stories of the earth's surface, including new and improved core sampling and "nano-diamonds"
- Anthropology: Sampling our own history and folk/religious tales for impact events stories, including cave paintings and other human artifacts.
- Paleoclimatology: Investigating unusual shifts in weather, not just globally but within much smaller areas. .. and so on.
I think the most interesting part for me was the study of varying types of impacts, especially glancing fragmented comets.
It is fun to see the main proponents try to be polite but they're as raucous as we are. I presume that's with 1 sigma of par.
-- Owen On Wed, Mar 14, 2012 at 12:54 AM, Rich Murray <[hidden email]> wrote: detailed careful fair critique of most cases of purported impact ============================================================ FRIAM Applied Complexity Group listserv Meets Fridays 9a-11:30 at cafe at St. John's College lectures, archives, unsubscribe, maps at http://www.friam.org |
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