[meteorite-list] 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

From: Rich Murray <rmforall_at_meteoritecentral.com>
Date: Tue, 13 Mar 2012 23:54:41 -0700
Message-ID: <CAHqJ8paNeD+r5_p5456DdPekUoODJEin_4wREeMpubgBOo1PVw_at_mail.gmail.com>

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 [ racki at us.edu.pl ],
Department of Earth Sciences,
Silesian University,
B?dzi?ska 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
Received on Wed 14 Mar 2012 02:54:41 AM PDT