• EP53B-1700: Meteorite Impact “Earthquake” Features (Rock Liquefaction, Surface Wave Deformations, Seismites) from Ground Penetrating Radar (GPR) and Geoelectric Complex Resistivity/Induced Polarization (IP) Measurements, Chiemgau (Alpine Foreland, Southeast Germany)

Authors

• Kord Ernstson 
  • Faculty of Philosophy I, University of Würzburg
• Jens Poßekel
  • Geophysik Poßekel Hornhof 14, 45479 Mülheim

Friday, 15 December 2017  13:40 – 18:00 New Orleans Ernest N. Morial Convention Center – Poster Hall D-F – Session EP53B Earth and Planetary Surface Processes General Contributions Posters

Abstract. – Densely spaced GPR and complex resistivity measurements on a 30,000 square meters site in a region of enigmatic sinkhole occurrences in unconsolidated Quaternary sediments have featured unexpected and highlighting results from both a meteorite impact research and an engineering geology point of view. The GPR measurements and a complex resistivity/IP electrical imaging revealed extended subrosion depressions related with a uniformly but in various degrees of intensity deformed loamy and gravelly ground down to at least 10 m depth. Two principle observations could be made from both the GPR high-resolution measurements and the more integrating resistivity and IP soundings with both petrophysical evidences in good complement. Subrosion can be shown to be the result of prominent sandy-gravelly intrusions and extrusions typical of rock liquefaction processes well known to occur during strong earthquakes. Funnel-shaped structures with diameters up to 25 m near the surface and reaching down to the floating ground water level at 10 m depth were measured. GPR radargrams could trace prominent gravelly-material transport bottom-up within the funnels. Seen in both GPR tomography and resistivity/IP sections more or less the whole investigated area is overprinted by wavy deformations of the unconsolidated sediments with wavelengths of the order of 5 – 10 m and amplitudes up to half a meter, likewise down to 10 m depth. Substantial earthquakes are not known in this region. Hence, the observed heavy underground disorder is considered the result of the prominent earthquake shattering that must have occurred during the Holocene (Bronze Age/Celtic era) Chiemgau meteorite impact event that produced a 60 km x 30 km sized crater strewn field directly hosting the investigated site. Depending on depth and size of floating aquifers local concentrations of rock liquefaction and seismic surface waves (probably LOVE waves) to produce the wavy deformations could develop, when the big disintegrated meteoroid (a loosely bound asteroid or a comet of roughly estimated 1 km size) hit the ground. The observations in the Chiemgau area emphasize that studied paleoliquefaction features and wavy deformations (e.g. seismites) need not necessarily have originated solely from paleoseismicity but can provide a recognizable regional impact signature.

Already in the early days of the exploration of the Chiemgau impact crater strewn field at the beginning of the new millennium, a perfectly semicircular structure was discovered during a flight, which seemed to be punctured into the bank of the Inn river near Marktl. Geological research on the ground and sampling quickly proved the impact nature of this well 50 m measuring crater, which was introduced as No. 24 into the crater list of the Chiemgau impact, which had been meticulously conducted by local history researchers. The semicircular structure was easily explained by the erosion of floods in the valley of the Inn river

Not recorded in the topographical maps and soon blocked with a large stable it fell into oblivion and was only recently opened to the eye in full splendor by the Digital Terrain Model DGM 1 (Fig. 1).

Fig. 1. Aiching semi crater in the Inn river bank vis-à-vis the town of Marktl (UTM coordinates 338863, 5346952). Digital Terrain Model. Continue reading →

At the this year’s prestigious meeting of  the Lunar and Planetary Institute in The Woodlands, Texas, the following abstract articles that relate to the Chiemgau meteorite impact have been published:

Molnár M. Ventura K. Švanda P. Štaffen Z. Rappenglück M. A., Ernstson, K.:

Chrudim – Pardubice: Evidence for a Young Meteorite Impact Strewn Field in the Czech Republic –  Widespread finds of rocks and glasses with shock metamorphism and typical of meteorite impact suggest a Holocene impact event in the Czech Republic.

The article reports on a newfound very young meteorite impact event in the Czech Republic amazingly similar to the Chiemgau and Saarland (Nalbach) impact events in Germany. A possibly simultaneous impact having affected Central Europe over a distance of more than 650 km is discussed. Click the abstract article!

Procházka V. Trojek T.
XRF- and EMP- Investigation of Glass Coatings and Melted Domains of Pebbles from Craters in Chiemgau, Germany
Shock-induced melting mainly of biotite (?) produced typically porous veinlets. External glass coatings are rich in K and Cu (from plant biomass?), rarely in Ni.

The Czech authors report on investigations of shocked cobbles excavated from the Kaltenbach and #004 impact craters belonging to the Chiemgau meteorite impact strewn field. Click the abstract article!

The Digital Terrain Model (DTM) and the evaluation of known and the search for new craters in the Chiemgau meteorite impact strewn field [PDF DOWNLOAD]

Kord Ernstson* (2017)

Abstract. – For several known and a few newly proposed meteorite craters in the Chiemgau meteorite impact strewn field the LiDAR data of the Digital Terrain Model DTM have been processed to reveal various maps and cross sections based on a high-resolution mesh down to 1 m and contour interval down to 0.2 m. The data processing highlights particular crater features that remain hidden in fieldwork and on conventional topographic maps and even may debunk mistaken structures.

********************************************************************************************************* *Faculty of Philosophy I, University of Würzburg, Germany, kernstson@ernstson.de

Content 1 Introduction – 2 The Chiemgau meteorite impact event 3 Data processing 3.1 Terrain imagery 3.2 Horizontal gradient 3.3 Data filtering 3.4 Cross sections 4 Examples 4.1 Small craters in the DTM 4.2 Peripheral depressions around small craters 4.3 Medium-sized craters in the DTM 4.4 Mistaken structures 5 A possible large-sized crater in the DTM 6 Discussion and conclusions 7 References Appendix

At the this year’s internationally prestigious Lunar and Planetary Science Conference in the Woodlands, Texas, two contributions on the Chiemgau meteorite impact crater strewn field in Germany have been presented (after preceding LPSC contributions in the years 2011, 2012 and 2014).

Our Czech colleagues presented their results on rock magnetic properties of shocked rocks from smaller craters in the strewn field (click to download the full abstract article):

Evidence for superparamagnetic nanoparticles in limestones from Chiemgau crater field, SE Germany. V. Procházka1 , G. Kletetschka1 , 1 Institute of Hydrogeology, Engineering Geology and Applied Geophysics, Charles Univ., Albertov 6, CZ-12843 Praha 2, Czech Republic (vprochaska@seznam.cz)

and the Chiemgau Impact Research Team (CIRT) reported on the meteorite impact-induced Lake Chiemsee tsunami (click to download the full abstract article):

EVIDENCE OF A METEORITE IMPACT-INDUCED TSUNAMI IN LAKE CHIEMSEE (SOUTHEAST GERMANY) STRENGTHENED. K. Ernstson, Faculty of Philosophy I, University of Würzburg, D-97074 Würzburg, Germany, kernstson@ernstson.de

Only recently an article has been published in the reputable journal Carbon with our colleague Dr. Tatyana Shumilova, Russian Academy of Sciences, as first author and Dr. M.A, Rappenglück from our CIRT research group as one of the co-authors:

T. Shumilova, S.N. Tkachev, S. Isaenko, S. Shevchuk, M.A. Rappenglück & V.A. Kazakov (2016): A “diamond-like star” in the lab. Diamond-like glass. – Carbon 100(100):703-709. Continue reading →

At the this year’s Lunar and Planetary Science Conference in the Woodlands, Texas, the abstract article entitled “Strong shock metamorphism and a crater: evidence of a Holocene meteorite impact event near Nalbach (Saarland, Germany)” by Nico Berger, Werner Müller and Kord Ernstson was presented. Here, we in particular point out that the peculiar findings in the Nalbach area are revealing remarkable similarities to impact features in the Holocene large Chiemgau impact strewn field in southeast Germany, and meanwhile the possibility that the Nalbach impact is a companion to the Chiemgau impact is seriously being discussed. Click on the image to open the full text!

   Under the scanning electron microscope (SEM): The odd world of the iron silicides from the Chiemgau impact meteorite crater strewn field (click to enlarge). Contribution to the mineralogy meeting of the Russian Academy of Sciences in Syktyvkar:

Meteorite impact on a micrometer scale: iron silicide, carbide and CAI minerals from the Chiemgau impact event (Germany)

 Michael A. Rappenglück1, Frank Bauer2, Kord Ernstson3, Michael Hiltl4

1 Institute for Interdisciplinary Studies, Gilching, Germany; mr@infis.org – 2 Oxford Instruments GmbH NanoScience, Wiesbaden, Germany; Frank.bauer@oxinst.com – 3Faculty of Philosophy I, University of Würzburg, Germany; kernstson@ernstson.de – 4 Carl Zeiss Microscopy GmbH, Oberkochen, Germany; mhiltl@online.de 

Shortly after the meeting between the 19th and 22nd May in Syktyvkar the Proceedings volume has been published:

Problems and perspectives of modern mineralogy (Yushkin Memorial Seminar–2014) Proceedings of mineralogical seminar with international participation Syktyvkar, Komi Republic, Russia 19–22 May 2014

The Rappenglück et al. contribution condenses the mineralogical evidence of the iron silicides from the Chiemgau impact crater strewn field that has been compiled with invaluable support by Carl Zeiss Microscopy und Oxford Instruments NanoScience.

We remind of the fact that in the beginning of the research on the Chiemgau impact the group of quite experienced local historians and amateur archeologists had detected the metallic iron silicides and, after having been aware of their relation to crateriform structures, had published the possible meteoritic origin of the matter. Investigations and attempts, respectively, to dismiss all iron silicides as industrial waste product, or at least as terrestrial, followed, and they are still spread rumors as for instance by the Bavarian Geological Survey (Landesamt für Umwelt, LfU) which is commented (in German) elsewhere and may be clicked HERE.

Ultimately it is evident that these local historians who later got together with scientists from geosciences, astronomy, archeology and historical scholarship to establish the Chiemgau Impact Research Team (CIRT), are proved right!

The abstract article from the Proceedings volume may be clicked HERE. The corresponding, much more informative POSTER may be clicked also for download. PLEASE NOTE: Depending on the selected browser the screen quality may appear quite different. As the case may be we suggest to save the file on the computer and to activate it with a pdf reading program. WARNING: The poster pdf has a size of more than 50 megabyte.

In addition to the report on the microtektites from the foothills of the Alps we present here the LPSC abstract paper (click to open the full article):