After the successful impact of the DART probe against an asteroid this Tuesday, the objective of which is to demonstrate the human ability 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 that includes the possible discovery of the first impact crater caused by a meteorite (part of an asteroid or comet that passes through the Earth’s atmosphere and reaches the ground) in Spain.
It has been identified in the Alhabia-Tabernas basin (Almería), is buried 1,000 meters deep, measures about 4 km in diameter (although the edge of the structure is 20 km) and could have been created by a meteorite that crashed against the Earth 8 million years ago. The discovery 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.
To date, up to 200 structures of this type have been found around the world. The largest, 160 kilometers in diameter, is located in South Africa; followed by another found in the Yucatan Peninsula (150 km in diameter). The one in Almería, however, takes on special relevance in our country as it is the first to be identified in 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
Regarding 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 geology, mineralogy, geochemistry and geomorphology of the region. 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 more modern sediments, but erosion has exposed it and opened 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 meteorite 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.