Scientists, having studied the stalagmites of the Iranian cave, were able to restore the climatic record of 130 000 past years, and based on the results obtained, it was predicted that the current drought in the Middle East will continue for another 10,000 years.
Stalagmites – mineral formations in the form of outgrowths – are formed during the process of water deposition. They arise due to the fact that dripping from the ceiling of the cave water is saturated with carbon dioxide and calcium bicarbonate. When falling, it loses some of the carbon dioxide, as a result of which bicarbonate passes into calcium carbonate and is deposited either on walls, ceiling or on the floor. When the water drains very slowly, a stalactite appears, having a beginning on the ceiling. If the water drips a little faster, without stopping at the top and falling on the floor of the cave, a stalagmite is formed. Sometimes it happens that the growths combine into columns, which are called stagnantas. In one cave there can not be different stalactites and stalagmites – they all have one composition (most often the main one is calcium carbonate). The growth of formations stretches for millennia, one centimeter can be formed by decades.
Scientists at the University of Miami and the National Institute of Oceanography and the Atmospheric Sciences of Iran investigated two stalagmites in the Cala Kord cave in northern Iran. Thanks to the uranium-thorium method, they obtained data for the last ice age (73 000 – 127 000 years ago) and the early Holocene (6500 – 7500 years ago), according to the website of the American University. The information extracted from the Iranian outgrowths was well coordinated with other paleoclimatic data taken from the ice cores in Greenland, from the deposits of the Sorek caves in Israel and Sanbao in China: cyclical climate variations of several hundred years were confirmed – for about 1470 years. In this case, a large cycle contained several small ones.
It turned out that the Middle Eastern climate changes every few thousand years from relatively humid and cold, to hot and dry, and then vice versa. Today, the region has entered another “warm” phase, which will drag on for another 10,000 years. Therefore, experts warn that in the long term there should be no illusions about the improvement of the water problem – access to water in the Middle East will deteriorate year by year. The amount of precipitation will decrease, because their main suppliers – Mediterranean cyclones – will increasingly change the trajectory of the traffic, bypassing the region.