“The convincing identification of terrestrial meteorite impact structures: What works, what doesn’t, and why”

by Kord Ernstson & Ferran Claudin (Dec. 2013)

Abstract. – We use and variegate the title of this article published in Earth-Science Reviews to show how science may (mal)function, how scientific results are manipulated, and how a few exposed impact researchers (the authors of the Earth-Science Reviews article included) are counteracting exactly the ideas presented in that article.

1 Introduction 

“The convincing identification of terrestrial meteorite impact structures: What works, what doesn’t, and why” is the title of a comprehensive and in principle not too bad article written by Bevan M. French and Christian Koeberl and published in Earth-Science Reviews (French & Koeberl 2010). We however would like to take up this title to once more point to the large Azuara and Rubielos de la Cérida impact structures in Spain and the related controversy shedding light on how science is manipulated, in this case with regard to some impact researchers from the so-called “impact community” (whatever that may be).

2 What doesn’t work

With a slight modification we begin with “what doesn’t work”. As for the identification of meteorite impact structures it obviously doesn’t work to publish clear and generally accepted impact shock features (like they are addressed in that article) to get an impact structure being established. This holds true for both the Azuara and Rubielos de la Cérida impact sites that are still opposed vehemently by a few leading impact researchers. Apart from the manifold geologic and geophysical evidence like ubiquitous monomictic and polymictic breccias, large systems of monomictic and polymictic breccia dikes, enormous and extended megabreccias, shatter cones, extended impact ejecta, gravity and geomagnetic anomalies, the unambiguously established shock metamorphism like shock melt, planar deformation features (PDFs) and diaplectic glass in various minerals appears not to convince (title!) Christian Koeberl, Falko Langenhorst, John Spray and others. Therefore, we once more present a collection of impact shock features from the Azuara and Rubielos de la Cérida impact structures in Spain that have all been published earlier in various journals:

Azuara impact structure: Planar deformation features (PDFs)

Fig. 1 A-D: PDFs in quartz from the Azuara impact structure. A, B: in quartzite rocks from the impact ejecta deposit (Pelarda Fm.). C: from a polymictic strongly shocked breccia. D: Frequency diagram of Azuara PDFs based on data elaborated by Dr. A. Therriault. All figures have been published earlier.

An independent investigation of PDFs in samples from the Azuara impact structure (a polymictic dike breccia and Pelarda Fm. ejecta) was made at the Geological Survey of Canada by Dr. Ann Therriault (Therriault 2000). She analyzed the crystallographical orientation of PDFs in quartz (Fig. 1 D) and other parameters such as density, sharpness, spacing, and spreading over the grain (Fig. 1 C). And we cite from her report: Up to five sets of PDFs per grain were observed. The spacing is 1 µm or less, the PDF density high. Practically all sets are decorated. All shocked grains have reduced birefringence of 0.004 – 0.008.  Continue reading →

In the Chiemgau meteorite crater strewn field (Ernstson et al. 2010, and references therein) impact glasses are found widespread in various formations, and tektite-like bodies of a dense black glass with vesicles have attracted considerable attention (Fig. 1).

Fig. 1.Dense black glass particles from the Chiemgau impact strewn field frequently exhibiting tektite-like shape and twisted form similar to irghizites from the Zhamanshin impact crater. – Click to enlarge!

Only recently, outside the crater strewn field in the foothills of the Alps at some 1500 m altitude a systematic search for impact fallout has revealed not only abundant tiny iron silicide particles (e.g., minerals xifengite and gupeiite) but also microtektites widely distributed in the soils (Fig. 2, 3).

A more detailed report can be read HERE.

Added link:  Abstract presented at the LPSC 45th Lunar and Planetary Science Conference 2014

Fig. 3. Microtektites from the soil in the foothills of the Alps near the Chiemgau impact crater strewn field. Optical microscope images, 100 µm scale bar in each case. – Click to enlarge!

Fig. 4. SEM micrographs of microtektite-like glass particles show
very strange surface features and bizarre forms exhibiting micrometer-sized glass filaments and twisted bodies. – Click to enlarge!

Continue reading →

Chiemgau impact: is there a parallel with the Saarland region?

The earlier stated assumption that the Chiemgau impact may have a counterpart in the Saarland region

http://de.scribd.com/doc/51477759/A-possible-Holocene-meteorite-impact-in-the-Saarland-region-West-Germany

has been strengthened by new finds and new geologic and petrographic features. A respective update article may be clicked here:

http://de.scribd.com/doc/111786823/Saarland-impact-suspected-meteorite-impact-near-Nalbach-Prims-update

by Ferran Claudin & Kord Ernstson (2012)

Abstract 

A nappe-like thrust of Cambrian over Tertiary, the Daroca thrust, in northeast Spain has puzzled geologists since longtime. Because of a lacking root zone and a lacking relief it didn’t match a reasonable geologic pattern. In the younger regional geologic literature the thrust is nevertheless incorporated in Alpine regional tectonics. An obviously first closer investigation of the involved Cambrian and Tertiary units, their facies and structural setting leads to a model that relates the Daroca thrust to the nearby roughly 40 km-diameter Azuara impact structure. The thrust is part of the excavation stage of impact cratering which may have affected both the Cambrian plate and the diamictic Tertiary below. The model is strongly substantiated by comparison with the Ries impact structure where similar thrusts and related features occur. The Daroca thrust is one more example reflecting the work of the regional geologists who pretend the giant Azuara impact event with the formation of the Azuara impact structure and the adjacent about 70 km Rubielos de la Cérida  elongated impact basin never happened. Hence, all their regional geologic models still developed which completely ignore the impact and its radical influence on the Tertiary regional geology are without any scientific relevance. 

1 Introduction

Fig. 1. Daroca, Province of Zaragoza, Spain.

The very nice town of Daroca in the Spanish Province of Zaragoza (Fig. 1) hides a peculiar geologic scenario – an enigma for geologists from time out of mind. Being enthroned above the town the geologic stratigraphy shows with a very sharp cut Cambrian dolomite (Ribota dolomite) over Tertiary young sediments (Fig. 2). Older layers over younger ones are not uncommon in geology, and overthrust and thrust faulting are related processes. Continue reading →