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The Usselo Soil and the Younger Dryas Extraterrestrial Impact Hypothesis

A new paper, which is in press in âBoreasâ, about the 
Usselo Soil and the Younger Dryas extraterrestrial impact 
hypothesis, has recently appeared. It is:

Kaiser, K. H., A., N. Schlaak, M. Jankowski, M, P. Kuhn, 
S. Bussemer, and K. Przegietka, in press, Palaeopedological 
marker horizons in northern central Europe: characteristics 
of Lateglacial Usselo and Finow soils. Boreas.
Doi: 10.1111/j.1502-3885.2008.00076.x. ISSN 0300-9483

One important point that this paper makes is that what 
has been called either the âUsselo Horizonâ or âUsselo 
Layerâ is not a "layer" in terms of being a tabular 
depositional body of either rock or unconsolidated sediment 
created separately from the sediments above and below it. 
Rather, it is a relict, buried Albic Arenosol and Brunic 
Arenosol (paleosol) that developed in preexisting sediment 
as the result of a period of surface weathering during a 
period of nondeposition. As a paleosol, it is pedolostratigraphic
marker horizon, not a depositional horizon as some 
proponents of the Younger Dryas extraterrestrial impact 
hypothesis imply by the use of the term âhorizonâ.

Another important points this paper makes is that like 
any paleosol, the Usselo Soil and its correlative Finow 
Soil are time-transgressive in terms of when their burial 
ended the period of weathering and soil formation that
created these paleosols. Radiocarbon dates from the 
Usselo Soil represent all of the Allerod and Younger 
Dryas age with a few outlier dates of Preboreal age. Thus, 
both paleosols represent a variable period of nondeposition 
encompassing either only the Allerod age or the Allerod 
and Younger Dryas ages depending on specific location 
at which it is examined. Thus, the Osselo Soil cannot be 
a single event bed created during a single instantaneous 
event. Instead, it is a paleosol that reflects nondeposition 
over a variable period of time that varies between 1,000 
and 1,500 years in length.

This paper a
of eolian sand overlying the 
Usselo Soil. These OSL dates demonstrate that within 
some parts of the area, in which the Usselo Soil occurs, it 
was initially buried by eolian sands of late Allerod age. 
Thus, at several locations, the Usselo Soil predates the 
Allerod-Younger Dryas boundary and it is impossible for 
the Usselo Soil at several locations be to connected with 
any Allerod-Younger Dryas boundary event of any type.

Some other papers about the Usselo Soil (Usselo Layer /
Horizon), are:

Bertran, P., G. Ge. Allenet, T., F. Naughton, P. Poirier, M. F.
and Goni, 2009. Coversand and Pleistocene palaeosols 
in the Landes region, southwestern France. Journal of
Quaternary Science. no. 3, vol. 24 pp. 259â269.

Derese, C. D. Vandenberghe, E. Paulissen, P. V. den Haute, in
press, Revisiting a type locality for Late Glacial aeolian sand 
deposition in NW Europe: Optical dating of the dune complex 
at Opgrimbie (NE Belgium). Geomorphology.

Hoek, W. Z., 1997, Paleogeography of Lateglacial vegetations:
Aspects of Lateglacial and Early Holocene vegetation, abiotic 
landscape, and climate in The Netherland. Ook verschenen als 
handelsed.: Utrecht: Koninklijk Nederlands Aardrijkskundig
Genootschap (Nederlandse Geografische Studies, 
ISSN 0169-4839 ; 230) Proefschrift Vrije Universiteit 

Hoek, W. Z., and S. J. P. Bohncke, 2002, Climatic and 
environmental events over the Last Termination, as recorded 
in The Netherlands: a review. Netherlands Journal of 
Geosciences (Geologie en Mijnbouw) vol. 81, no. 1, pp. 123-137

Kasse, C., 1997, Cold-Climate Aeolian Sand-Sheet Formation 
in North-Western Europe (c. 14Â12.4 ka); a Res
radation and Increased Aridity. Permafrost and 
Periglacial Processes. vol. 8, pp. 295-311.

Kasse, C., 2002, Sandy aeolian deposits and environments 
and their relation to climate during the Last Glacial Maximum 
and Lateglacial in northwest and central Europe. Progress in 
Physical Geography. vol. 26, no. 4, pp. 507-532.

Kasse, C., D. Vandenberghe, F. De Corte, and P. Van den 
Haute, 2007, Late Weichselian fluvio-aeolian sands and 
coversands of the type locality Grubbenvorst (southern 
Netherlands): sedimentary environments, climate record and 
age. Journal of Quaternary Science. vol. 22, pp. 695â708. 

van der Hammen, T., and B. van Geel, 2008, Charcoal in 
soils of the AllerÃd-Younger Dryas transition were the 
result of natural fires and not necessarily the effect of
an extra-terrestrial impact. Netherlands Journal of 
Geosciences. vol. 8. no. 4, pp. 359-361


Paul V. Heinrich
Baton Rouge, Louisiana