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Thursday, 18 March 2010

K/T Boundary Clay at Stevns Klint Wednesday, March 17, 2010

K/T Boundary Clay at Stevns Klint

Wednesday, March 17, 2010 12:25 AM

(“K/T Boundary Clay”), Ed Majden wrote:

“There is some dispute with this material, as some
think it may be of volcanic origin, rather than
a meteorite impact, K/T boundary layer material”

The volcanic origin is an old hypothesis that has been
largely abandoned. The Fish Clay at Klint now is largely
regarded to consist of terrigenous sediments that
accumulated in the absence of biogenic carbonate during
the aftermath of the terminal Cretaceous impact. There
is an extraterrestrial component that has been mixed with
detrital terrestrial sediments by bioturbation and
reworking and redeposition of pre-existing sediments.

For example, Premovi (2009) concluded:

1. “IIIA smectite is probably mainly detrital and
redeposited from adjacent coastal and/or marine

2. “The goethite-/FeS2-rich microspherules of layer
IIIA were initially enriched in Fe-oxides which were
replaced by goethite or FeS2 during early diagenesis

and 3. “Most of the microspherules and glasses of
layer IIIA are also probably detrital and simultaneously
redeposited with the smectite.”

The Fish Clay contains goethite-rich microspherules.
Currently, are argued as being authigenic in origin and
unrelated to any Cretaceous-Paleogene ejecta. Premovi
(2009) regards these microspherules to have been
created by pseudomorphic replacement of FeS2 rich
biogenic spherules.

Locality: Stevns Klint, Description of a Danish GeoSite

Some papers about this are:

Bauluz, B., D. R. Peacor, and W. C. Elliott, Coexisting
Altered Glass and Fe-Ni Oxides at the Cretaceous-
Tertiary Boundary, Stevns Klint (Denmark): Direct
Evidence of Meteorite Impact,” Earth Planet. Science
Letters. vol. 182, pp. 127–136.

Christensen, L., S. Fregerslev, A. Simonsen, and
J. Thiede, 1973, Sedimentology and depositional
environment of Lower Danian fish clay from Stevns
Klint, Denmark. Bulletin of the geological Society
of Denmark. vol. 22, pp. 193-212.

Drits, V. A., H. Lindgreen, B. A. Sahaov, H. J.
Jakonson, and B. B. Zviagina, 2004, The detailed
structure and origin of clay minerals at the
Cretaceous/Tertiary boundary, Stevns Klint (Denmark).
Clay Minerals. vol. 39, no. 4, pp. 367-390;
DOI: 10.1180/0009855043940141

Ekdale, A. A., and R. G. Bromley, 1984, Sedimentology
and ichnology of the Cretaceous-Tertiary boundary in
Denmark; implications for the causes of the terminal
Cretaceous extinction. Journal of Sedimentary Research.
vol. 54, no. 3, p. 681-703

Note: The above paper is a strong supporter of volcanic origin.

Hart, M. B., S. E. Feist, G. D. Price and M. J. Leng,
2004, Reappraisal of the K/T boundary succession at
Stevns Klint, Denmark. Journal of the Geological
Society. vol. 161, no. 5, pp. 885-892;

Kastner, M., F. Asaro, H. V. Michel, W. Alvarez,
and L. W. Alvarez, 1984, The Precursor of the
Cretaceous-Tertiary Boundary Clays at Stevns Klint,
Denmark, and DSDP Hole 465A. Science. vol. 226.
no. 4671, pp. 137-143 DOI: 10.1126/science.226.4671.137

“Formation from impact rather than from volcanic
glass is supported by its major element chemistry.”

Ortega-Huertas, M., F. Martinez-Ruiz, I. Palomo-Delgado,
and H. Camley, 2002, Review of the mineralogy of the
Cretaceous-Tertiary boundary clay: evidence supporting
a major extraterrestrial catastrophic event. Clay
Minerals. vol. 37, no. 3, pp. 395-411;
DOI: 10.1180/0009855023730054

Premovi, P. I., 2004, Cretaceous-Tertiary boundary
deposits in Denmark: A diachroneity. Journal Serbian
Chemical Society. vol. 71, no.7, pp. 793-806.

Premovic, P. I., 2009, The conspicuous red “impact”
layer of the Fish Clay at Højerup (Stevns Klint,
Denmark). Geochemistry International. vol. 47, no. 5,
pp. 513-521.

“Smectite of the red layer of the KPB section at
Højerup is probably detrital and redeposited from
adjacent coastal or marine areas. This clay mineral
is likely mixed with a small amount of smectite
derived from impact glasses. Most of the
microspherules and nano-size glasses of the red
layer at Hojerup are probably detrital and
simultaneously redeposited with smectite.”

Premovi, P. I., B. Z. Todorovi, and M. S. Pavlovi,
2007, Cretaceous Paleogene boundary Fish Clay at
Hojerup (Stevns Klint, Denmark): trace metals in
kerogen. Bulletin de la Societe Geologique de France.
vol. 178, no. 5, p. 411-421; DOI: 10.2113/gssgfbull.178.5.411

Premovic, P. I., B. Z. Todorovic, and M. S.
Pavlovic, 2008, Cretaceous-Paleogene boundary (KPB)
Fish Clay at Hojerup (Stevns Klint, Denmark): Ni, Co,
and Zn of the black marl Geologica Acta, vol. 6,
no. 4, pp. 369-382. DOI: 10.1344/105.000000264

Premovi, P. I., M. M. Krsmanovic, B. Z. Todorovi,
M. S. Palovi, N. D. Nikolic, and D. M. Djordjevi,
2006, Geochemistry of the Cretaceous-Tertiary
boundary (Fish Clay) at Stevns Klint (Denmark): Ir,
Ni and Zn in kerogen. Journal Serbian Chemical
Society. vol. 71, no.7, pp. 793-806.

Surlyk, F., T. Damholt, and M. Bjerager, 2006, Stevns Klint,
Denmark: Uppermost Maastrichtian Chalk, Cretaceous–
Tertiary Boundary, and Lower Danian Bryozoan Mound
Complex. Bulletin of the Geological Society of Denmark.
vol. 4, pp. 1–48.

Paul H.

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