The age of the Aral Sea is established

Aral Sea

Completion of a 10-year international project

Located in Central Asia, the body of water known as the Aral Sea is not actually a sea, but a vast, undrained lake. Since the 1970s, the Aral Sea has begun to shrink in size and the process has become truly catastrophic. Studies of the causes of what is happening are many years, but an exact and unambiguous answer is still not available.

Investigation by National Geographic: How to Dry the Sea in 50 Years
Since 2008, a group of Russian and American scientists have been searching for new data on the geological history of the Aral Sea. During the work, geologists drilled a number of wells, which revealed the entire thickness of lake sediments. The study area in 2009 – to the south of the former island of Barsa Kelmes; water left there only in 2007, and the area was a plain, covered with poorly dried clay. Borehole B-05-2009 was the most complete with a depth of 15 meters; 10 meters of sediments refer to the time of the existence of the lake. It was used by accelerated mass spectrometry to obtain 23 radiocarbon dates – a record for all the works conducted on the Aral Sea since the 1950s. The lithology (sediment composition) and microfauna (small and microscopic aquatic organisms with calcium carbonate shells – ostracods and foraminifera) were also studied.

Conclusion 1

The Aral Sea – in pre-1970s size – appeared about 17,600 years ago. This conclusion is based on a series of radiocarbon dates from mollusk shells and ostracod shells that have not been redeposited.

However, the very process of the Aral Sea emergence began earlier, about 18-23 thousand years ago, when the glaciers of the Pamirs and Tien Shan began to melt. Water flowed down the Amu-Darya and Syr-Darya rivers and began to gradually fill the basin, in which as a result the Aral Sea appeared.

Conclusion 2

The parameters of the water mass in the interval of 17.6-13 thousand years ago did not remain constant. The earliest phase of the Aral Sea development (17.6-15.3 thousand years ago) was characterized by constant and abundant river water inflow to the lake basin. Around 15.3-14 thousand years ago, the salinity of the water mass significantly increased due to the reduction of river water; salinization peaked 14.5-14 thousand years ago. This was reflected in an increase in the number of shells of the ostracod Cyprideis torosa, capable of withstanding almost any salinity; it is the only survivor of 13 species of ostracods that once inhabited the Aral Sea in the remains of the Large Aral Sea. About 14-13 thousand years ago, the waters of the lake became slightly saline again.Studies were conducted under the auspices of the Sobolev Institute of Geology and Mineralogy. Sobolev Institute of Geology and Mineralogy and the University of Arizona since 2008. Interim results were published in 2014 in Gondwana Research, and the most recent publication was in Quaternary Science Reviews.

In 20 years it is possible to see the Aral Sea – as a “sea” only in photos. Especially for you we provide such an opportunity – Tour to the Aral Sea “Frozen melody”.

Journey to the vanishing legend will take much time, but it’s worth it. To see the Aral Sea and think what we people can do with our planet, its beauty and resources – to preserve or to destroy?

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