The desert covers roughly seventy percent of
Turkmenistan, a long east–west swath. It sits east of the
Caspian Sea which has a steep east bank. It adjoins, to the north, the long delta feeding the
South Aral Sea further north, another
endorheic lake, about higher than the Caspian Sea. The delta is that of the
Amu Darya river to the northeast, demarcating the long border with the
Kyzylkum Desert of
Uzbekistan. The desert is divided into three regions, the elevated northern Trans-Unguz Karakum, the low-lying Central Karakum, and the southeastern Karakum, home to a chain of
salt marshes. Since the early 1980s, the relatively small desert extension, the
Aralkum, has come to occupy most of the former
seabed of the
Aral Sea, about . The sea has fluctuated over millennia, but its majority loss during the
Soviet Union's existence coincided with great irrigation projects. The
North Aral Sea was partly restored, but the South Aral Sea ebbed to a small-size stasis at its river mouth, which itself dried up by 2014, leaving only fragments of the former sea behind, such as
Barsakelmes Lake.. The Karakum Desert is highlighted at the bottom. Within the north-west edge of the desert used to be a river. In the late
Pleistocene, the Amu Darya used to flow beyond the Aral Basin to
Sarykamysh Lake then to the Caspian Sea. Sedimentation and floods during a pluvial period led to overflow to the
Zeravshan River valley to the east. The two flows merged and formed or expanded Horezm Lake, which had been formed by the earlier Khvalinian period, and as it overflowed northwards it carved its link with the Aral Sea along the Akcha Dar'ya population corridor of that low, gentle valley (a remote community of Western Uzbekistan and north-east Turkmenistan). ==Environment==