Impact polymictic breccia dike

Polymictic impact breccia dike sharply cutting through well-bedded Muschelkalk limestone. – Rubielos de la Cérida impact basin (Spain) near Olalla.

polymictic breccia dike Rubielos de la Cérida impact structure
Very nice example of the many breccia dikes in the Spanish Azuara impact structure and the Rubielos de la Cérida impact basin (crater chain). – More about impressive breccia dikes (dike breccias) in the Rubielos de la Cérida basin and the Azuara structure.

Ground Penetrating Radar (GPR) – Chiemgau impact – Emmerting crater

Ground Penetrating Radar (GPR): Emmerting #004 crater, Chiemgau meteorite impact strewn field (Bavaria, Southeast Germany)

Ground Penetrating Radar (GPR) – meteorite crater Chiemgau impact

Diametral radargram across one of the most spectacular craters in the Chiemgau meteorite impact strewn field. Loamy-gravelly target material. Impact melt rocks, strong shock metamorphism. Strong reflectivities down to several meters depth are explained by extreme high-temperature sintering of the underground material. Note the complex excavation with the ring wall wandering outwards (as indicated with “real reflections”). 25 MHz center frequency with modulated 200 MHz.

More about GPR measurements over young meteorite craters: Click HERE

Chiemite – carbon impactite

Chiemite – carbon impact rock (impactite) – the Chiemgau impact event as namesake

chiemite impact rock impactite Chiemgau impact even

REM image. – Formation in spontaneous shock carbonization of the vegetation in the impact area. Investigations at the Diamond Laboratory, Geological Institute, Russian Academy of Science Syktyvkar, with optical and atomic force microscopy (AFM), X-ray fluorescence spectroscopy (RFA), scanning electron (SEM) and transmission electron (TEM) microscopy, high-resolution Raman spectroscopy, X-ray diffraction (XRD) and differential thermal analysis (DTA) as well as δ13C and 14C radiocarbon isotope data analysis.

Approx. 95% carbon; detection of diamond and carbyne; formation conditions for the latter 2500 – 4000°C and some GPa pressure.

Very “smart” people are still of the opinion that it is coke. Take a look at that too: file: EGU 2019 chiemite poster.pdf – Wikipedia

SEM detail view of the chiemite.
An extensive article on the chiemite has recently been published in print:
Enigmatic Glass‐Like Carbon from the Alpine Foreland, Southeast Germany: A Natural Carbonization Process.

Picture of the month – thermal shock in quartz

Impact feature: thermal shock in quartz

Using shock effects in quartz as an impact indicator has a long tradition. They are created in the first phase of impact cratering (contact and compression phase) and produce well known PDFs, PFs and diaplectic glasses in various minerals. The fact that thermal shock has so far been virtually ignored in impact research is due to the fact that the effects mentioned above precede thermal shock during pressure release. However, if extreme shock pressures lead to melting and vaporization of the rocks (> roughly 50 GPa), violent thermal shock can occur when slightly or not at all shocked material is immersed in melt and/or vapor. In anticipation of a publication, some photomicrographs of isolated quartz grains from meteorite impact sites are shown here, which have obviously experienced such a short thermal shock and reveal quite unusual micro-fracturing patterns.

Meteorite impact thermal shock micro-fracturing in quartz
Meteorite impact thermal shock micro-fracturing in quartz
Meteorite impact thermal shock micro-fracturing in quartz

Photomicrographs (crossed polarizers): Isolated quartz grains (size about 1 mm) “floating” in a fine grained matrix. In many of the grains this micro-fracturing is more or less sharply limited to a concentric rim zone encasing a largely untouched core with a few sub-planar fractures in some cases. Chrudim impact, Czech Republic.

Meteorite impact thermal shock micro-fracturing and cleavage (PFs) in quartz

Quartz grains from the same impact site showing irregular micro-fracturing that merges into sets of planar fractures (PF) after the rhombohedron.

Meteorite impact thermal shock micro-fracturing in quartz

Saarland impact: Quartz grains in impact melt nearly pulverized by extreme micro-fracturing.

Picture of the month – ballen structures

Impact shock feature: ballen structures from four new impact sites in Central Europe (Germany, Czech Republic)

Ballen structures in silica form a characteristic texture in quartz that in general is considered a result from various stages of phase transformation and recrystallization of amorphous silica like e.g., diaplectic glass and hence are regarded as shock indicator. A different model has recently been suggested that proposes a formation of ballen in quartz in an extreme thermal shock event.

Ballen structures (photomicrographs, plane light and crossed polarizers; field width 560 µm). – Saarland (Nalbach, Saarlouis) impact.

Ballen structures impact merging into tridymite and cristobalite.(photomicrographs, crossed polarizers and plane light; field width 1.4 mm). – Saarland (Nalbach, Saarlouis) impact.

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Ballen structures (plane light and crossed polarizers), Chiemgau impact meteorite crater strewn field; Stöttham archeological excavation, catastrophe layer.       Click the LPSC poster!

Ballen structures; Chrudim – Pardubice impact site (Czech Republic); asphaltic polymict impact breccia.

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Ballen structures (photomicrograph, plane light); granitic impact melt rock sheet, Bach/Regensburg (Germany) impact site.

“Earth’s Impact Events Through Geologic Times”: Comment on Schmieder & Kring article in Astrobiology

Comment on: ” Schmieder, M. and Kring, D. A. (2020) Earth’s Impact Events Through Geologic Time: A List of Recommended Ages for Terrestrial Impact Structures and Deposits. – Astrobiology, 20, 91-141.”

by Kord Ernstson1 & Ferran Claudin2 (Jan. 2021)

Abstract: We use Schmieder and Kring’s article to show how science still works within the so-called “impact community” and how scientific data are manipulated and “rubber-stamped” by reviewers (here, e.g., C. Koeberl and G. Osinski). We accuse the authors of continuing to list the Azuara and Rubielos de la Cérida impact structures and one of the world’s most prominent ejecta occurrences of the Pelarda Fm. in Spain as non-existent in the compilation. The same applies to the spectacular Chiemgau impact in Germany, which has been proven by all impact criteria for several years. For the authors’ dating list, we propose that the multiple impact of Azuara is included together with the crater chain of the Rubielos de la Cérida impact basin as a dated candidate for the third, so far undated impact markers in the Massignano outcrop in Italy.

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1 University of Würzburg, 97074 Würzburg (Germany); kernstson@ernstson.de. 2 Associate Geological Museum Barcelona (Spain); fclaudin@xtec.cat

A PDF of the complete article may be downloaded here.

Continue reading ““Earth’s Impact Events Through Geologic Times”: Comment on Schmieder & Kring article in Astrobiology”

To play with Google Earth …

Taklamakan Desert (China): a mega-impact structure?

Kord Ernstson

University of Würzburg, 97074 Würzburg (Germany), kernstson@ernstson.de        

October 2020

Abstract.- A Google Earth-based morphological analysis of the Taklamakan Desert in the north of the Himalayas shows characteristics of a 1000 km mega-sized impact structure with an elliptical basin and a pronounced elliptical morphological rim. The elliptical structure may possibly have originated from the thrust of the Indian plate and the Himalayas. A gravity anomaly corresponds with the structure. More impact evidence is not known so far.

Key words: Taklamakan Desert, China, impact structure, gravity anomaly, Indian plate

A pdf full article may be downloaded here.

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Continue reading “To play with Google Earth …”

New article: Jiloca graben and Rubielos de la Cérida impact basin (NE Spain)

When modeling ignores observations: The Jiloca graben (NE Spain) and the Rubielos de la Cérida impact basin

by Kord Ernstson1 and Ferran Claudin2

June 2020

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Abstract. – The Iberian System in NE Spain is characterized by a distinctive graben/basin system (Calatayud, Jiloca, Alfambra/Teruel), among others, which has received much attention and discussion in earlier and very recent geological literature. A completely different approach to the formation of this graben/basin system is provided by the impact crater chain of the Rubielos de la Cérida impact basin as part of the important Middle Tertiary Azuara impact event, which has been published for about 20 years. Although the Rubielos de la Cérida impact basin is characterized by all the geological, mineralogical and petrographical impact findings recognized in international impact research, it has completely been hushed up in the Spanish geological literature to this day. The article presented here uses the example of the Jiloca graben to show the absolute incompatibility of the previous geological concepts with the impact structures that can be observed in the Jiloca graben without much effort. Digital terrain modeling and aerial photography together with structural and stratigraphic alien geology define a new lateral Singra-Jiloca complex impact structure with central uplift and an inner ring, which is positioned exactly in the middle of the Jiloca graben. Unusual topographic structures at the rim and in the area of the inner ring are interpreted as strike-slip transpression and transtension. Geological literature that still sticks to the old ideas and develops new models and concepts for the graben/basin structures, but ignores the huge meteorite impact and does not even enter into a discussion, must at best cause incomprehension.

Key words: Meteorite impact, Azuara impact event, Alfambra-Teruel graben, Calatayud basin, strike-slip transgression, transtension, Singra-Jiloca impact

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1 University of Würzburg, 97074 Würzburg (Germany), ernstson@ernstson.de                                                 

2 Associate Geological Museum Barcelona (Spain); fclaudin@xtec.cat

The full article can be clicked HERE.

An article pdf for download can be clicked HERE.