The Azuara structure is a structural feature of about diameter,
[Mikheeva, 2017] located in northeastern Spain, roughly south of
Zaragoza
Zaragoza (), traditionally known in English as Saragossa ( ), is the capital city of the province of Zaragoza and of the autonomous communities of Spain, autonomous community of Aragon, Spain. It lies by the Ebro river and its tributaries, the ...
.
[Azuara]
/ref> The name is attributed to the small town of Azuara located near the center of the structure. It has been subject to controversial, generally rejected claims that it represents an impact feature. It was formerly listed in the Earth Impact Database
The Earth Impact Database is a database of confirmed impact structures or impact crater, craters on Earth. It was initiated in 1955 by the Dominion Observatory, Ottawa, under the direction of Carlyle Smith Beals, Carlyle S. Beals. Since 2001, it h ...
, but was subsequently removed.
History
The first claims of an impact
Impact may refer to:
* Impact (mechanics), a large force or mechanical shock over a short period of time
* Impact, Texas, a town in Taylor County, Texas, US
Science and technology
* Impact crater, a meteor crater caused by an impact event
* Imp ...
origin was given by Wolfgang Hammann as early as 1980, and the first field work was done by Johannes Fiebag in the early eighties. In 1985, Ernstson et al.
Reception
Mainstream scientific opinion rejects the Azuara structure as being of impact origin, with the shock effects being tectonic
Tectonics ( via Latin ) are the processes that result in the structure and properties of the Earth's crust and its evolution through time. The field of ''planetary tectonics'' extends the concept to other planets and moons.
These processes ...
features, the supposed impact ejecta (Pelarda Formation) actually being Quaternary
The Quaternary ( ) is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS), as well as the current and most recent of the twelve periods of the ...
alluvial fans
An alluvial fan is an accumulation of sediments that fans outwards from a concentrated source of sediments, such as a narrow canyon emerging from an escarpment. They are characteristic of mountainous terrain in arid to Semi-arid climate, semiar ...
and supposed impact breccias and dike breccias are generally interpreted as karst
Karst () is a topography formed from the dissolution of soluble carbonate rocks such as limestone and Dolomite (rock), dolomite. It is characterized by features like poljes above and drainage systems with sinkholes and caves underground. Ther ...
features and soil formations.
See also
*
Rubielos de la Cérida impact structure
The c. 80 km x 40 km sized Rubielos de la Cérida structure is a claimed impact feature located in Aragon, northeast Spain, north of Teruel purported to have formed during the Upper Eocene or Oligocene (roughly 30 - 40 Mill. years ago). ...
References
Bibliography
*
External links
EDEIS Expert Database on Earth Impact Structures
{{DEFAULTSORT:Azuara Impact Structure
Geology of Spain
Impact craters of Spain
Possible impact craters on Earth
Paleogene impact craters
Paleogene Spain
Province of Zaragoza