Dirty science: The possible Almería (Spain) impact structure


on the EPSC 2022 Meeting abstract paper of Juan Antonio Sánchez Garrido, Jens Olof Ormö, Carl Alwmark, Sanna Alwmark, Gabriel Zachen, Robert Lilljequist, and Sebastián Tomás Sánchez Gómez : A probable impact structure in Betic Cordillera, Almeria, SE Spain.

and its relation to the Azuara impact event comprising the Azuara impact structure and the Rubielos de la Cérida impact basin (Spain)

by Kord Ernstson1 and Ferran M. Claudin2

Abstract.- In an abstract paper presented at the EPSC 2022 Granada (Europlanet Sociey) the authors above from Spain, Sweden and Denmark report about research on what they called the first impact structure in Spain. Numerous media reports about this “first impact structure in Spain” immediately after the meeting suggest that this formulation was directly put into the world by the authors in a press release and that they thereby commit a bad falsification by not mentioning the worldwide prominent gigantic Azuara impact event with the 40 km-diameter Azuara impact structure and the Rubielos de la Cérida impact basin measuring approx. 80 km x 40 km, which has been established for more than 20 years, and, hence, declaring it as non-existent. We report here on key stages of the study of these really first Spanish impact structures since 1985, comment this massive expression of scientific dishonesty, and bring for all less informed and the media-believing people a compilation of the innumerable extremely easily in the Internet accessible contributions in English, Spanish and German, which leads the statement of the alleged first impact structure in Spain ad absurdum.


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

Keywords: Azuara impact event, Azuara impact structure, Rubielos de la Cérida impact basin, Spain, Almería impact, manipulation of science

1 Introduction

At the recently concluded EPSC 2022 meeting in Granada, authors Juan Antonio Sánchez Garrido, Jens Olof Ormö, Carl Alwmark, Sanna Alwmark, Gabriel Zachen, and Sebastián Tomás Sánchez Gómez (University of Almería, Centro Astrobiología, Madrid, Lund University (Sweden), and University of Copenhagen) and Eurogeologist Robert Lilljequist had an abstract contribution entitled “A probable impact structure in Betic Cordillera, Almeria, SE Spain.”

The “probable impact” of the paper is based on a polymict breccia clast and three quartz grains with weak PDF but without any confirmation of cristallographic orientation, and with no further shock metamorphism. After 15-20 years of their research, no word on regional geology, no geophysics, no shatter cones, no impact melt, no impact glasses, no ejecta deposits, no drilling on the presumed impact basement.

We do not want to question the possible evidence of an impact in Almería. What we characterize as dirty science is the fact that immediately after the meeting a large number of media are writing in unison about the FIRST impact structure in Spain:

— First probable impact crater discovered in Spain (phys.org).
— Researchers believe they have discovered the first impact crater in Spain in Almería (time.news).
–First Probable Impact Crater Discovered in Spain (europlanet society.
–First probable impact crater discovered in Spain (Alphagalileo).
— Researchers believe they have discovered the first impact crater in Spain in Almería (Chicago Today).
— First Probable Impact Crater Discovered in Spain (Toptek News).
— Discovered the first possible impact crater by meteorite in Spain (spainsnews) — Discovered the first probable impact crater in Spain (daily-how)

… and many others.

This mass of reports about the FIRST Spanish impact structure has probably been initiated by the media by a press release of the authors of the abstract, and this is exactly what we call dirty science that these authors talk against better knowledge and rather infamously about the FIRST impact structure in Spain. We stand by the word “infamously”, which we will justify in detail below.

2 The current state of research of the established Azuara multiple impact event with the Azuara impact structure and the Rubielos de la Cérida impact basin in the provinces of Zaragoza and Teruel (Spain)

Since the first publication about the impact origin of the Azuara impact in 1985 in Earth and Planetary Science Letters followed by a dozen of diploma and doctoral theses, and the publications in 2001 and 2002 on the meanwhile established Azuara and Rubielos de la Cérida twin impacts, a host of impact-typical proofs have been published having made this Spanish impact to one of the most prominent impact events worldwide. The importance is underlined by the very easy access (frequently simply by car) to a hundred of outcrops or more, where the impact can be experienced up close, and spectacular samples can be obtained effortlessly – in contrast, for example, to the Chicxulub impact, where comparably significant samples are only tangible via kilometer-deep drillings. We list the scientifically most important findings:

— a roughly 40 km-diameter Azuara impact structure with roundish morphological signature

— a roughly 80 km x 40 km-size Rubielos de la Cérida multiple impact basin with impressive elongated basin morphology and a significant central uplift chain

— geophysical, gravity and geomagnetic, signature

In both structures:

— in part brilliantly exposed impact “tectonics” of impressive folds and faults, also documenting the everywhere occurring indication of tensile impact shock rarefaction signature

— a host of impact monomictic and polymictic impact breccias everywhere frequently showing multiple breccia generations typical of impact

— extended suevite breccias

— well-known and unusal impact melt rocks and glasses

— a host of monomictic and polymictic breccia dikes forming dike generations and extended breccia dike systems not known in this impressive concentration from other impacts worldwide

— a host of impact megabreccias (the large Pelarda Fm. ejecta deposit – Azuara; the large Puerto Mínguez ejecta deposit – Rubielos de Cerida; the prominent megabreccias of Barrachina, Belchite/Almonacid de la Cuba and Herrera)

— abundantly exposed accretionary lapillistones

— shatter cones

— strong shock metamorphism: shock melt, diaplectic glass from quartz and feldspar; planar deformation features PDFs in quartz and feldspar, multiple sets of planar fractures PFs in quartz, multiple sets in strongly kinked quartz and mica, multiple sets of microtwinning in calcite

Proofs for all these impact-realated features are published and are easily accessed on clicking the vast of Internet contributions listed below.

3 Lists of early and recent publications on the Spanish impact structures







… and several dozens, maybe more than 100, of WIKIPEDIA URLs for Google “azuara impact” and Rubielos de la Cérida impact” and “Spain impact structures”.

3.2 WEBSITES. pertinent

Azuara impact structure

Rubielos de la Cérida impact structure

Impact structures in Spain and related topics

Estructura de impacto de Azuara

La cuenca de impacto de Rubielos de la Cérida

Las estructuras de impacto en España y temas relacionados

Die Azuara-Impaktstruktur

Das Rubielos de la Cérida-Impaktbecken – ein Teil der Azuara/Rubielos de la Cérida Kraterkette

3.3 Researchgate

Researchgate Ernstson


33 publications about the Spanish impact structures Azuara and Rubielos de la Cerida addressed in Researchgate

2 Research Projects on the Spanish Azuara and Rubielos de la Cérida impacts

Researchgate Claudin


22 publications about the Spanish impact structures Azuara and Rubielos de la Cerida addressed in Researchgate

2 Research Projects on the Spanish Azuara and Rubielos de la Cérida impacts

3.4 Recent publications (2012-2022) of Ernstson and Claudin on the Spanish impact event, the Azuara impact structure and the Rubielos de la Cérida impact basin.

Transpression and Transtension Impact Cratering Features: the Steinheim, Saarlouis (both Germany) and Singra-Jiloca (Spain) Cases.

Shock metamorphism in the Rubielos de la Cérida impact basin (Eocene-Oligocene Azuara multiple impact event, Spain) – reappraisal and photomicrograph image gallery

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

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

Daroca thrust (Iberian Chain, Spain) and the Azuara impact structure -the controversy continues.

New approach to an old debate: The Pelarda Formation meteorite impact ejecta (Azuara structure, Iberian Chain, NE Spain)

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

The Weaubleau impact structure “round rocks” (“Missouri rock balls”, “Weaubleau eggs”): possible analogues in the Spanish Azuara/Rubielos de la Cérida impact structures

Impact deposit at the Moneva reservoir, Azuara impact structure (Spain)

Azuara and Ries impact structures: The Daroca thrust geologic enigma – solved?

3.5 A few early publications

Ernstson, K., Schüssler, U., Claudin, F., Ernstson, T., 2003: An Impact Crater Chain in Northern Spain. – Meteorite, 9, 35-39.

Claudin, F. and Ernstson, K. (2003): Geologia planetaria y Geologia regional: el debate sobre un impacto múltiple en aragón. Enseñanza de las ciencias de la Tierra, vol 11, nº 3, pp 202-212.

Schüssler, U., Hradil, K., Ernstson, K.2002: Impact-related melting of sedimentary target rocks of the Rubielos de la Cérida structure in Spain. Berichte der Deutschen Mineralogischen Gesellschaft, Beiheft 1 zum European Journal of Mineralogy, Vol. 14, S. 149.

Ernstson, K., Claudin, F., Schüssler, U., Hradil, K., 2002: The mid-Tertiary Azuara and Rubielos de la Cérida paired imapct structures (Spain). Treb. Mus. Geol. Barcelona, 11, 5-65.

Ernstson, K., Rampino, M.R. & Hiltl, M.: Cratered of cobbles in Triassic Buntsandstein conglomerates in NE Spain: Shock deformation of in-situ deposits in the vicinity of large impacts. Geology, v. 29, no.1, 11-14, 2001

Hradil, K., Schüssler, U., and Ernstson, K.: Silicate, phosphate and carbonate melts as indicators for an impact-related high-temperature influence on sedimentary rocks of the Rubielos de la Cérida structure, Spain. Abstracts, 6th ESF IMPACT workshop, Impact Markers in the Stratigraphic record, pp. 49-50, 2001.

Ernstson, K., Rampino, M.R., and Hiltl, M.: Shock-induced spallation in Triassic Buntsandstein conglomerates (Spain): an impact marker in the vicinity of large impacts. Abstracts, 6th ESF IMPACT workshop, Impact Markers in the Stratigraphic record, pp. 25-26, 2001.

Ernstson, K., Claudin, F., Schüssler, U., Anguita, F, and Ernstson, T.: Impact melt rocks, shock metamorphism, and structural features in the Rubielos de la Cérida structure, Spain: evidence of a companion to the Azuara impact structure. Abstracts, 6th ESF IMPACT workshop, Impact Markers in the Stratigraphic record, pp. 23-24, 2001.

Ernstson, K., Rampino, M.R., Anguita, F., Hiltl, M., and Siegert, I.: Shock deformation of autochthonous conglomerates near the Azuara impact structure, Spain: Geological Society of America Abstracts with Program, v. 31, p. A-122., 1999.

Ernstson, K. & Claudin, F.: Pelarda Formation (Eastern Iberian Cains, NE Spain): Ejecta of the Azuara impact structure. – N.Jb.Geol.Paläont.Mh., 1990, 581-599, 1990.

Müller, H. & Ernstson, K.: Curved joint sets: Indication of impact-induced fracturing. – In: Mechanics of Jointed and Faulted Rock, H.P.Rossmanith, ed., 257-263, Balkema, Rotterdam 1990.

Ernstson, K.: Looking for Geological Catastrophes: The Azuara Impact Case. – In: Extinción y registro fósil (Extinction and the fossil record, E. Molina, ed.), Cuadernos Interdisciplinares No. 5, 31-57, SIUZ, 1994.

Ernstson, K. & Fiebag, J.: The Azuara impact structure (Spain): new insights from geophysical and geological investigations. – Int. J. Earth Sci., 81/2, 403-427, 1992.

Ernstson, K., Feld, H. & Fiebag, J.: Impact hypothesis for the Azuara structure (Spain) strengthened. – Meteoritical Society Meeting, Newcastle upon Tyne, 1987. – Meteoritics, 22, 373, 1987.

Ernstson, K., Hamman, W., Fiebag, J. & Graup, G.: Evidence of an impact origin for the Azuara structure (Spain). – Earth Planet. Sci. Let., 74, 361-370, 1985.

4 Discussion

The discovery and scientific treatment of the Spanish impact structures has a long history of about 40 years. In 1981, the first field work began in the province of Zaragoza near the village of Azuara, which, together with initial mineralogical studies at the University of Würzburg, resulted in the first publication in Earth and Planetary Science Letters in 1985. As evidence for the impact was considered already at that time the unmistakable finding of PDFs in quartz, for which the spectrum with the typical crystallographic directions of the shock metamorphism from breccias (Fig. 1) of the also already morphologically addressed Azuara structure. Two years later in 1987, Azuara was already listed as a proven impact structure in the book of Richard A.F. Grieve TERRESTRIAl IMPACT STRUCTURES “Annual Review of Earth and Planetary Sciences” and subsequently included in the Canadian Impact Database under the direction of R.A.F. Grieve as a proven impact. R.A.F. Grieve will be mentioned also later. Further articles on the Azuara impact followed in international journals. This remained generally accepted knowledge in the impact community. Until 1996.

In an abstract article of the LPSC Langenhorst & Deutsch (1996) claim [The Azuara and Rubielos structures, Spain: Twin impact craters or Alpine thrust systems? TEM investigations on deformed quartz disprove shock origin (abstract). Lunar and Planetary Science, v. XXVII: 725-726] that there is no evidence of shock in the Azuara impact structure. They base this claim solely on the TEM analysis of a sample given to them by one of the present authors (K.E.). However, this sample did not come from the Azuara structure at all, but was taken far outside the structure. Furthermore, Langenhorst & Deutsch had not taken note at all of the exact description (given to them by K.E.) of the sample, which shows basal deformation lamellae, but not at all planar deformation features (PDF). Although K.E. had insistently pointed out the elementary mistake to the authors, Langenhorst & Deutsch did not withdraw the contribution, which would have been possible. The two authors were then accused of scientific dishonesty.

Fig. 1. PDF diagram from the first publication 1985 on the Azuara impact proving impact shock deformation.

The consequences continue to this day. This abstract was promptly the trigger of the manifold unpleasant campaigns especially by geologists of the University of Zaragoza and the Spanish Geological Survey, who vehemently denied an existence of the impact structures. This was understandable especially against the background that practically all these geologists had made and published their thick doctoral theses exactly in the impact areas, without recognizing such significant eye-catching geological impact findings. Such controversies are known from the whole impact research.

A new phase of the fight against the huge Spanish impact event started around the year 2000. An article by Ernstson, K., Claudin, F., Schüssler, U., Hradil, K.: “The mid-Tertiary Azuara and Rubielos de la Cérida paired impact structures (Spain)”, submitted to the journal Earth and Planetary Science Letters, was rejected by the peer reviewers C. Koeberl and R.A.F. Grieve, by Koeberl with partly absurd falsifications of the text statements. In an adapted 60 pages version, this article was then published in 2002 in the series of the Geological Museum of Barcelona (see above), without this work ever being cited by the Spanish opposing authors.

At the 2001 meeting of the 6th ESF IMPACT workshop in Granada, Impact Markers in the Stratigraphic Record, four poster papers by different authors (cited above) on the Azuara and Rubielos de la Cérida impacts were presented. At a subsequent associated discussion, Dr. Therriault of the Canadian Geological Service had presented her written analysis, initiated by Prof. Anguita (Madrid) and Dr. Rampino (New York), on 31 pages, of a large number of shocked quartz grains from Azuara impact breccias with all the strictly known features of PDFs: Therriault, A. (2000): Report on Azuara, Spain, PDFs, 31 p. In the session she oddly enough presented the PDFs as uncertain, apparently on instruction “from above”. Her fantastically good work can still be consulted today.

At that time there was the next cut. The Canadian Impact Database from the Survey moved to the University of New Brunswick under the new leadership of John Spray. And suddenly the Azuara structure had disappeared from the database and has not been reinstalled in it to this day, not to mention the magnificent multiple Rubielos de la Cérida impact basin, which has also never before been included in the Earth Impact database despite overwhelming published impact evidence. We estimate that in this database over 90% of the impact structures considered proven there do not have this extent of impact evidence of geology, geochemistry, mineralogy-petrography, geophysics and schock metamorphism as is the case for the great Spanish impact event. Characteristic of John Spray’s odd understanding of science: In a written inquiry Ferran Claudin asked him why the Azuara structure formerly established as a proven impact had been eliminated and disqualified from the data base and why also Rubielos de la Cérida despite overwhelming impact evidence has not been recorded. Moreover, Ferran offered to send him reprints of all published articles on the impacts. John Spray wrote back that Ferran were free to do it but that he, John Spray, would not read the articles.

According to the Database Website, major contributions to the development of earlier versions of this database have been made by Richard Grieve and James Whitehead. This is a circumstance that leaves us perplexed that Richard Grieve, who was the first important impact researcher to qualify the Azuara impact as confirmed and proven and absolutely worthy for the Canadian database until 2001 (rightly so), tolerates to this day, despite his closeness to the database, that both Azuara and Rubielos de Cérida are swept under the table by a small clique from the so-called impact community as impact-wise very questionable and not confirmed, still after 40 years of research.

And this is exactly the point with which we want to close the discussion and return to Almería. Because on this concealment of the Spanish Azuara and Rubielos de la Cérída impacts in the Earth impact database until today, in the entire newer Spanisch geological literature including newest text books, the Azuara impact event is nowhere quoted, also not with any counterarguments. And again and again reviewers of impact journal articles demand from the authors that references to the Spanish impacts are taken out with the reason that the Earth Impact Datenbase does not recognize them. Against this background, the Almería authors have of course a carte blanche to publish their assumed crater as the first one in Spain.

5 Conclusions

The first conclusion is not directly about science, but about the media and their reporters who trumpet questionable “messages” without the slightest researche. Apart from the Internet articles listed at the beginning, the inglorious article by Lydia Lawson in techupdate should be mentioned in particular. Although on the one hand she meritoriously deals critically to skeptically with the message about the Almería structure, on the other hand she refers in a single sentence to the discussion about the Azuara impact in 1997 (i.e. 25 (!) years ago) and to the fact that an impact formation is excluded today. This is clearly pretty bad science journalism. We probably hope in vain that the authors of the Web papers mentioned here will present things correctly and apologize to their readers for the dubious “snap judgments”.

Second: Around the early 2000’s, when Azuara and Rubielos de la Cérida had long been treated as print and extensively on the Internet, a strong desire to do their geological fieldwork for their master’s and doctoral exam papers arose among many students of geology at Spanish universities who were, of course, already well informed via the Internet about the exciting and forward-looking research being done there. We have been told by the University of Madrid that students who expressed this wish were told in no uncertain terms: If you ever want to make a career in geology, just don’t do your exam papers in these structures.

We fear that this has not changed to this day; we have not become aware of any such work, although there are still a vast number of geologically-mineralogically highly attractive topics awaiting further work. We wonder if this deplorable behavior within the “impact community” (we will refrain from naming well-known persons and names) makes those responsibles aware that they are not only causing and have caused immeasurable damage to impact research in general, but also are preventing young people eager to produce new significant research results in an exciting field from doing so. Irresponsible that is.