Chiemgau impact: contributions to the 76th Annual Meteoritical Society Meeting (2013)

The following contributions to the MetSoc Meeting, July 29 – August 2, Edmonton, Canada, may be downloaded here:

Michael A. Rappenglück, Frank Bauer, Michael Hiltl, Andreas Neumair, Kord Ernstson:

CALCIUM-ALUMINUM-RICH INCLUSIONS (CAIs) IN IRON SILICIDE (XIFENGITE, GUPEIITE, HAPKEITE) MATTER: EVIDENCE OF A COSMIC ORIGIN

Poster CAIs mini Click poster!

Click Abstract CAIs!

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Frank Bauer, Michael Hiltl, Michael A. Rappenglück, Andreas Neumair, Kord Ernstson:

Fe2Si (HAPKEITE) FROM THE SUBSOIL IN THE ALPINE FORLAND (SOUTHEAST GERMANY): IS IT ASSOCIATED WITH AN IMPACT?

Poster hapkeite mini  Click Poster!

Click Abstract hapkeite !

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Andreas Neumair, Kord Ernstson:

PECULIAR HOLOCENE SOIL LAYERS: EVIDENCE OF POSSIBLE DISTAL EJECTA DEPOSITS IN THE CHIEMGAU REGION, SOUTHEAST GERMANY

Poster distal ejecta png Click Poster!

Click Abstract distal ejecta !

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Kord Ernstson, Werner Müller, Andreas Neumair:

THE PROPOSED NALBACH (SAARLAND, GERMANY) IMPACT SITE: IS IT A COMPANION TO THE CHIEMGAU (SOUTHEAST BAVARIA, GERMANY) IMPACT STREWN FIELD?

Poster Nalbach Chiemgau mini Click Poster!

Click Abstract Nalbach Chiemgau impact

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Chiemgau impact: two contributions to the AGU 2011 Fall Meeting, San Francisco

At the AGU (American Geophysical Union) Fall Meeting, December 5-9, two contributions focusing on special features of the Chiemgau meteorite impact strewn field have been presented:

Neumair, A. & Ernstson, K. (2011), Geomagnetic and morphological signature of small crateriform structures in the Alpine Foreland, Southeast Germany, Abstract GP11A-1023 presented at 2011 Fall Meeting, AGU, San Francisco, Calif., 5-9 Dec.

The poster may be clicked here: Poster Neumair & Ernstson

Ernstson, K. & Neumair, A. (2011), Geoelectric Complex Resistivity Measurements of Soil Liquefaction Features in Quaternary Sediments of the Alpine Foreland, Germany, Abstract NS23A-1555 presented at 2011 Fall Meeting, AGU, San Francisco, Calif., 5-9 Dec.

The poster may be clicked here:  Poster Ernstson & Neumair

Chiemgau impact: an article on the impact-induced soil liquefaction (rock liquefaction)

Article on the Thunderhole phenomenon in the Chiemgau impact area: 

The sinkhole enigma in the alpine foreland, Southeast Germany: Evidence of impact-induced rock liquefaction processes

Kord Ernstson, Werner Mayer, Andreas Neumair and Dirk Sudhaus

CENTRAL EUROPEAN JOURNAL OF GEOSCIENCES 

The article describes the very first geologic and geophysical investigations of the so-called Thunderhole (“Donnerloch“) phenomenon in the region of the small town of Kienberg north of Lake Chiemsee in Southeast Bavaria. The authors conclude that the innumerable enigmatic sudden sinkhole cave-ins having happened in living memory originate from late and even today acting processes of an earlier shock-induced underground rock liquefaction known from strong earthquake shocks. The geologically prominent underground structures that have now been uncovered are considered the result of impact shocks in the course of the formation of the Chiemgau meteorite crater strewn field (Chiemgau impact).

Some characteristic images of this highlighting rock liquefaction (or soil liquefaction) process can be seen on continuing

Continue reading

Shock spallation – a typical impact process in the Chiemgau meteorite crater strewn field

The term spallation is used in various meanings, e.g. in nuclear physics and fracture mechanics. For impact processes, spallation plays an important role (however seldom appreciated appropriately) and is closely related with the propagation of shock waves. To put it simply, the process runs as follows: On impinging on a free surface, the shock compressive wave is reflected as a tensile wave of practically identical energy. And while a compressive pulse is squeezing a rock, a tensile pulse is stretching the material thus enabling the development of tensile fractures and in an extreme case leading to the detachment of a spall or series of spalls. This is favored by the fact that the tensile strength of all materials and, hence, also of rocks is considerably less than the compressive strength. This is why it is often disregarded that the enormous destructions upon meteorite impact are not so much the result of the shock wave pressure as of the pull of the rarefaction waves. Spallation may take place also when a compressive shock pulse impinges on a boundary of material with reduced impedance (= the product of density and sound velocity) where part of its energy is reflected as a rarefaction pulse that may likewise enable tensile fracturing. It is worth remarking, however compatible with shock physics, that the process of spallation can be observed on arbitrary scales, from microscopically small deformations right up to the movement of huge rock complexes.

limestone cobble shock spallation fracture chiemgau impact

Fig. 1. A limestone cobble (14 cm long) exhibiting the typical open spallation tensile fractures. The process is nicely documented by the observation that the running fractures have come to standstill midway through the cobble. In case they had continued running, the cobble would have been fractionized to pieces, and nothing of note would have remained. Continue reading

The Chiemgau impact hypothesis and Wikipedia

We are watching with interest discussions on relevant Wikipedia articles, and we would like to put the reader of this website in a position to receive a first-hand impression of the varied quality of the contributions to the discussion and to form her/his own opinion about the various versions of the Wikipedia articles:

http://en.wikipedia.org/wiki/Talk:Chiemgau_impact_hypothesis