Chiemgau impact: conducting hypervelocity impact experiments

Experimental hypervelocity impact crater generation and the formation of the Lake Tüttensee crater

Fig. 1. Snapshot of a hypervelocity impact into flour taken from a high-speed camera video. The full video may be played back by clicking on the image.

Meteorite impact is a fascinating geologic process that for many geologists, however, has remained enigmatic. Therefore we are glad to present here on our website some results of experimental impacts that have been recorded by high speed cameras. This has been possible by a cooperation between the CIRT and Werner Mehl who is a world-wide known specialist for ballistics and high speed photography http://www.kurzzeit.com/eng/startseite.htm).

Fig. 2. Experimental hypervelocity impact crater produced by a projectile (as lying in the hand) in a target of flour. The angle of the impact trajectory was 30°. On clicking on the image in Fig. 1 the full video can be played back that shows the impact process recorded with a high speed camera. The outer ring-like fold of the foil is a side effect of the experimental set-up.

Details of the experiment are as follows: Continue reading “Chiemgau impact: conducting hypervelocity impact experiments”

Chiemgau impact: Pumice as an impact rock (impactite)

Pumice is a porous volcanic rock that is formed in gas-rich explosive eruptions on mixing of lava and water. When pressure releases, the melt froths by expansion of carbon dioxide and water vapor, and on rapid cooling the peculiar strongly vesicular texture forms. Pumice is nearly exclusively composed of glass with few mineral inclusions and has up to 90 % porosity which is why in general it floats in water. Depending on the source material and the texture pumice occurs in a broad color spectrum, from nearly white to yellow, gray and practically black. Well known is the Italian pumice from Lipari and Stromboli, and in Germany pumice from the Eifel volcanism is exploited.

Pumice from Lake Chiemsee

Since a few years the intensified geological investigations of the crater strewn field of the Chiemgau meteorite impact has revealed abundant finds of pumice cobbles in the shore region of Lake Chiemsee.

Fig. 1. Pumice varieties from Lake Chiemsee. White pumice – gray, marginally whitish pumice – gray pumice – grayish-black pumice (from top left to lower right). Samples by courtesy of Ernst Neugebauer.

The pumice occurs in various color varieties (Fig. 1) the white pumice rather being rare. Under the microscope the texture of the white form differs from the gray and grayish-black varieties (Figs. 2, 3). Continue reading “Chiemgau impact: Pumice as an impact rock (impactite)”

Chiemgau impact: A new carbon impactite

Presentation: 43. Lunar and Planetary Science Conference (LPSC), March 19–23, 2012, The Woodlands, Texas, USA: http://www.lpi.usra.edu/meetings/lpsc2012/programAbstracts/view/

Shumilova T. G.¹ Isaenko S. I.¹ Makeev B. A.¹ Ernstson K.² Neumair A.³Rappenglück M. A.³: Enigmatic Poorly Structured Carbon Substances from the Alpine Foreland, Southeast Germany: Evidence of a Cosmic Relation [Abstract #1430]

¹Institute of Geology, Komi SC, Russian Academy of Sciences, Pervomayskaya st. 54, Syktyvkar, 167982 Russia, ²Faculty of Philosophy I, University of Würzburg, D-97074 Würzburg, Germany, ³Institute for Interdisciplinary Studies, D-82205 Gilching, Germany.

Abstract download:

http://www.lpi.usra.edu/meetings/lpsc2012/pdf/1430.pdf

Poster download:

Poster LPSC

The study deals with a so far unknown impactite from the Chiemgau meteorite crater strewn field incorporating a high pressure/high temperature carbon allotrop.

Shatter cones from the Lake Tüttensee crater (Chiemgau impact)

Shatter cones are conical fractures in rocks exhibiting typical fracture markings that are produced by shock waves and that belong to the well-known and reliable macroscopic shock features in rocks from meteorite craters (impact structures).

So far, shatter cones have never been found in the crater strewn field of the Chiemgau impact as a positive impact evidence, which we explained by the predominant uncemented loose sediments of the impact target. In this regard, a change of thinking is necessary since only recently clear shatter cone structures were detected in a rock sample from the Lake Tüttensee ring wall (Fig. 1).

Fig. 1. Shatter cones with counter orientation from the Lake Tüttensee crater. Continue reading “Shatter cones from the Lake Tüttensee crater (Chiemgau impact)”

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:

http://www.springerlink.com/content/1166143hjp83647w/ (Reference and abstract)

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

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

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

New article in Mediterranean Archaeology & Archaeometry – International Scientific Journal

THE CHIEMGAU METEORITE IMPACT AND TSUNAMI EVENT (SOUTHEAST GERMANY): FIRST OSL DATING

I. Liritzis, N. Zacharias, G.S. Polymeris, G. Kitis, K. Ernstson, D. Sudhaus, A. Neumair, W. Mayer, M.A. Rappenglück, B. Rappenglück

Mediterranean Archaeology and Archaeometry, Vol. 10, No. 4, pp. 17‐33

The full article may be clicked here:

PDF

The Chiemgau meteorite impact event – also in the Saarland (West Germany) region?

by CIRT – Chiemgau Impact Research Team
The abstracts for the 74th Annual Meeting of the Meteoritical Society, August 8-12, in Greenwich, England, UK, have now been published in the Internet. With regard to the Holocene Chiemgau large meteorite strewn field three contributions are especially interesting because of their immediate relation to this impact event. The abstract pdfs can be downloaded:

[1] A POSSIBLE NEW IMPACT SITE NEAR NALBACH (SAARLAND, GERMANY)
E. Buchner, W. Müller and M. Schmieder
www.lpi.usra.edu/meetings/metsoc2011/pdf/5048.pdf
[2] NALBACH (SAARLAND, GERMANY) AND WABAR (SAUDI ARABIA) GLASS – TWO OF A KIND?
M. Schmieder, W. Müller and E. Buchner
www.lpi.usra.edu/meetings/metsoc2011/pdf/5059.pdf
[3] IMPACTITES AND RELATED LITHOLOGIES IN GERMANY – CURRENT STATE OF KNOWLEDGE
M. Schmieder, W. Müller, L. Förster and E. Buchner
www.lpi.usra.edu/meetings/metsoc2011/pdf/5060.pdf

Among the authors W(erner) Müller is particularly singled out who has only recently performed meticulous field work near the town of Nalbach in the Saarland region near the French border. He sampled a large amount of peculiar rocks and natural glasses as well as suspected iron meteorites. From these finds he concludes the possible existence of a meteorite impact only in younger times, and as the discoverer of the phenomenon he has published an article in the Scribd scientific internet forum:

Prims: a possible Holocene meteorite impact in the Saarland region, West Germany
which may be clicked HERE

This postulated meteorite impact is shortly attended by the other authors in the above-mentioned abstracts where the original Scribd article is referred to only in abstract [2], but strangely not in abstract [1] obviously standing more to reason thematically.

Amazingly similar: Finds from the Saarland suspected impact and the Chiemgau impact.

The close relation to the Chiemgau impact arises from Werner Müller’s Scribd article and, hence, comprises the abstract articles of Buchner et al. and Schmieder et al. As can be read in the article of Müller and especially pointed out by him, many striking parallels to finds in the Chiemgau meteorite crater strewn field are obvious:

— pebbles and cobbles showing mechanical load and high-temperature signature in the form of glass coating and interspersing the in most cases sandstone samples
— polymictic breccias
— slag-like melt rocks
— glass as matrix of melt rocks with various rock fragments
— glass-like carbon
— spherules
— probably shock-induced spallation effects in melt rocks

The reader is encouraged to take a look at the images in Werner Müller’s Scribd article and to compare them with the Chiemgau samples. Images are to be found on the website https://www.chiemgau-impact.com/petrographie.html and in the Ernstson et al., 2010 article or, as originals, in the Grabenstätt impact museum

Although there is so far no definite age for the postulated Saarland impact, W. Müller, because of first-sight field impressions and considering the in most cases very fresh glasses, clearly favors a Holocene age. Hence, with regard to the Chiemgau impact Holocene age the obvious question arises whether the Chiemgau and Saarland impacts may belong to the very same cosmic event. This can be imagined given the cosmic projectile was already in disintegration when approaching Earth (like, e.g. in the 1994 Shoemaker-Levi-9 comet crash with Jupiter) and in the end leaving impact scars in an even much larger strewn field than hitherto assumed for the Chiemgau impact.

From this viewpoint of a relation of both phenomena it is rather remarkable if the CIRT research project on the Chiemgau meteorite impact achieves considerable support by two of the abstract authors (E. Buchner, M. Schmieder) as is well known confirmed opponents of the CIRT research and of the Chiemgau impact at all. Notably the hint of Buchner et al. [1] to a possible meteoritic airburst to have produced the Saarland impact signature raises attention because such a possibility has already been discussed for the Chiemgau impact event in the context of the formation of some peculiar craters there (e.g. Ernstson et al., 2010, S. 92-93).

A comment on the abstract article of Schmieder et al. [3] is being added. The authors refer to several structures in Germany for which a meteoritic origin has been postulated, “[cit.] however, all of these geologic features currently lack evidence for shock metamorphism and/or meteoritic matter as proof for impact”. Among these structures, the Chiemgau impact has been classified, thereby referring to the 30 pages article ‘Ernstson K. et al. 2010. J. Siberian Fed. Univ. Engin. Technol. 1:72–103 (HERE to be downloaded)‘ Either have Schmieder and Buchner never read this basic and comprehensive article about the Chiemgau impact or they calculatedly conceal that on p. 82-83 under the heading 8. Shock metamorphism generally accepted impact shock effects in rocks from the Chiemgau craters together with several photomicrographs are reported. The shock effects include multiple sets of planar deformation features (PDFs) with up to five sets in one quartz grain, and diaplectic glass requiring even higher shock pressures of formation than do PDFs.

This keeping silence about proofs for the Chiemgau impact and at the same time claiming the Chiemgau impact is not confirmed [3], is rather odd with regard to the fact that comparably unambiguous impact proofs for the Saarland phenomenon could so far not be presented [1].

Owing to the promising similarities between Chiemgau impact material and material from the Saarland area we can but encourage the colleagues to perform continuing research. We are glad to see that the research of Buchner and Schmieder on the Saarland impact contributes to a better understanding of the Chiemgau impact, even though their work features some deficits and oddness.