A Baverian meteorite crater strewn field
Chiemgau impact (hypothesis) is a term that denotes a meanwhile manifoldly proved meteorite impact that happened as an extraordinary event in prehistoric times (Bronze Age, Celtic era) in southeast Bavaria (Germany). A large cosmic body (a comet or an asteroid) hit the ground and left a big crater strewn field with all relevant impact evidence. This website focuses on all aspects of the related scientific research including reports and publications on geosciences, astronomy, archeology and science of history, but also on discussions of this spectacular research area. In the Wikipedia four-line article "Chiemgau impact hypothesis" this event is characterized as "an obsolete scientific theory" that has been raised "by a team of hobby-archaeologists". This is grossly deceptive and typifies the standpoint of a few obstinate opponents of the Chiemgau impact, hence taking their side and thwarting Wikipedia requirements.
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:
The poster may be clicked here: Poster Neumair & Ernstson
The poster may be clicked here: Poster Ernstson & Neumair
Article on the Thunderhole phenomenon in the Chiemgau impact area:
http://www.springerlink.com/content/1166143hjp83647w/ (Reference and abstract)
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
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.
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”
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
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:
The air photo (1)* originates from the northern part of the impact strewn field near Perach and shows (arrow) a crater leveled on an acre.
Image 1: Chiemgau impact; leveled crater near Perach
Source BLfD
Image 2
By image processing, the in the original photo only adumbrated structure gains amazingly sharp contours (2) clearly exhibiting four different concentric zones (3):
Image 3
The following attribution of the individual zones is suggested:
The interpretation of the central spot orients by the GPR (ground penetrating radar) measurements (Dr. Patzelt, Terrana Geophysik; inhttp://www.rssd.esa.int/SYS/docs/ll_transfers/295499_Roesler_pres.pdf and http://www.rssd.esa.int/SYS/docs/ll_transfers/295499_roesler.pdf) that have been conducted over another crater (our crater no. 004 – also see http://www.chiemgau-impakt.de/mineral.html) located in the northern part of the strewn field. The GPR soundings show prominent reflections from the crater floor possibly related with strong compaction of the underground material. Assumed this compaction also exists within the Perach crater serving as impermeable rock, a corresponding moisture penetration could optically be traceable to the surface.
The adjoining 12 m-diameter zone could represent the material from the leveling of the crater. The annular zone is suggested to reflect remnants of the original rim wall. Taken the middle of this zone to have been the location of the rim crest, a 20 m diameter of the original crater results.
Finally, the exterior zone is suggested to reflect the zone of the crater ejecta radiating up to 50 m from the crater center.
This documentation of a ring structure illustrates that alternate explanations (geologic glacial formations, anthropogenic (archeological) structures, primitive industrial sites) readily and frequently given by opponents of the Chiemgau impact and skeptics of the meteorite origin for the innumerable craters, continue to have a hard time.
In any case, it is planned to investigate the Perach leveled crater by various geophysical measuring systems trying to characterize the optical zoning in more detail physically.
* In earlier texts, the air photo was erroneously labeled an infrared image.
Critics of the impact origin for the Lake Tüttensee crater (e.g., Doppler & Geiß 2005) argue that the strong deformations exhibited by the cobbles and boulders from the rim wall are the result of tectonic processes in the Alps and that the tectonically deformed clasts were transported and deposited in the region of the strewnfield. The impact advocates counter that such deformed cobbles and boulders would not have survived any transport over a distance of more than 50 m. Instead, they point to the typical features of a high-pressure/short-term process of deformation and to the fact that gravel pits outside the Lake Tüttensee area are void of these characteristically deformed rocks.
We have received a comment on this controversy by F. Claudin, geologist from Barcelona (Spain):
“We can compare the deformations observed in the Lake Tüttensee rim wall with the supposed deformations that must be present in other glacial moraines. In the Pyrenees, near Les Bordes de Llestui at the Clot and Malmarrui torrents, we can observe a glaciolacustrine-glacial complex. Neither in the clasts of the subglacial till nor in those of the supraglacial till, deformations as described for Lake Tüttensee can be seen. Only striae on the clasts are observed. The same observations can be made in the moraine deposits near Vilaller (Verge de Riupedrós, Sant Mamés, Sant Antoni), near the hospital of Vielha, or in the “Barranco de la runada” (near Senet). Glaciers may produce enough pressure to ensure striae deformations or fragmentation of clasts, but they are unable to produce short-term deformations under high confining pressure as seen in the photos of the Lake Tüttensee clasts. Typical aspects of the Pyrenees glacial deposits are shown down below the text.
The above-mentioned deposits have in more detail been described by
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von Till Ernstson, 2007
