Discovered the first possible impact crater by meteorite in Spain

Location of the center of the crater and a radius of 20 kilometers from the area affected by the impact in the Alhabia-Tabernas basin. / Sánchez-Garrido et al 2022

Science | Geography

It is in Almería, it measures about 4 km in diameter and could have been created eight million years ago

Elena Martin Lopez

After the success of the impact of the
probe DART against an asteroid this Tuesday, whose objective is to demonstrate the human capacity to divert the trajectory of these celestial rocks in the event that one is discovered in the direction of our planet, this week a study has been made public that includes the possible discovery of the first crater of impact due to a meteorite (part of an asteroid or comet that crosses the Earth's atmosphere and reaches the ground) in Spain.

It has been identified in the Alhabia-Tabernas basin (Almería), it is buried 1,000 meters deep, it measures about 4 km in diameter (although the edge of the structure reaches 20 km) and it could have been created by a meteorite that crashed against Earth 8 million years ago. The finding was presented last week at the Europlanet Science Congress (EPSC) 2022, held in Granada, and is the result of 15 years of research by an international team of scientists from the University of Almería, the Madrid Astrobiology Center, the Lund University and the University of Copenhagen.

Up to 200 such structures have been found around the world to date. The largest, 160 kilometers in diameter, is in South Africa; followed by another found in the Yucatan peninsula (150 km in diameter). The one from Almería, however, takes on special relevance in our country as it is the first to be identified on the Iberian Peninsula.

Thin sections showing deformations (lines) in three quartz grains, produced by shock effects, in an impact breccia at Tabernas. /

Sánchez-Garrido et al 2022

About the research, Juan Antonio Sánchez Garrido, lead author of the study and professor at the University of Almería, said in a statement: “We have investigated numerous aspects of the region's geology, mineralogy, geochemistry and geomorphology. The Alhabia and Tabernas basins in the area are filled with sediments dating between 5 and 23 million years old, overlying older metamorphic rocks. Much of the impact structure is buried by younger sediments, but erosion has exposed it and opened up the opportunity for studies."

Evidence from the impact crater includes several examples of 'shocked' quartz grains, a type of sedimentary rock that has a different microscopic structure than normal quartz because it has been subjected to intense pressure. In this case, the meteor impact pressure ranged from 10 to 30 gigapascals. "If the discovery of the crater is confirmed, it would not only be exciting from a scientific perspective, but it would also be a wonderful addition to the scientific and tourist attractions of the province of Almería," added Sánchez Garrido.