Experts believe they have found the first crater caused by a meteorite in Spain, located in the Albabia-Tabernas basin in Almeria. It was buried 1,000 metres deep and is about four kilometres in diameter (although the rim is around 20 kilometres) and may have been caused by a meteorite crashing to Earth eight million years ago.
A meteorite is part of an asteroid or comet which passes through the Earth’s atmosphere and reaches the ground.
The discovery was announced at the Europlanet Science Congress in Granada this week. It is the result of 15 years of research by an international team of scientists from the University of Almeria, the Madrid Astrobiology Centre, he Universiy of Lund and the University of Copenhagen.
Around 200 structures of this type have been found in the world so far. The biggest, with a diameter of 160 kilometres, is in South Africa while the second largest (150 kms) is in the Yucatán peninsula. The one in Almeria is much smaller, but is relevant for being the first to be discovered on the Iberian peninsula.
In a statement about their research Juan Antonio Sánchez Garrido, the main author of the study and a lecturer at Almeria university, said they had investigated numerous aspects of the geology, geochemistry and geomorphology of the region.
"The basins of Alhabia and Tabernas in the area are full of sediments dating back between five and 23 million years, overlain by older metamorphic rocks. Much of the impact structure is buried under more modern sediments but erosion has exposed it and that opened up the opportunity for the studies to be carried out," the statement said.
The studies showed several examples of 'blasted' grains of quartz - this type of sedimentary rock has a microscopically different structure to normal quartz because it has been subjected to intense pressure. In this case the pressure of the impact of the meteorite ranged between 10 and 30 gigapascals, the experts found.
“If it is confirmed that this is a crater from a meteorite, it will not only be exciting from a scientific perspective but also a marvellous addition to the scientific and tourist attractions of Almeria province,” Sánchez Garrido said.