Lake Aschersleben is a former lake

Lake

A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...

 in Germany

Germany

Germany , officially the Federal Republic of Germany , is a federal parliamentary republic in Europe. The country consists of 16 states while the capital and largest city is Berlin. Germany covers an area of 357,021 km2 and has a largely temperate seasonal climate...

, northeast of the Harz

Harz

The Harz is the highest mountain range in northern Germany and its rugged terrain extends across parts of Lower Saxony, Saxony-Anhalt and Thuringia. The name Harz derives from the Middle High German word Hardt or Hart , latinized as Hercynia. The legendary Brocken is the highest summit in the Harz...

 Mountains, south of the town of Aschersleben

Aschersleben

Aschersleben is a town in the Salzlandkreis district, in Saxony-Anhalt, Germany. It is situated approx. 22 km east of Quedlinburg, and 45 km northwest of Halle .-Pre-20th century:...

. The lake was connected to the rivers of Eine

Eine (river)

The Eine is a river, just under long in the German state of Saxony-Anhalt, which rises southeast of Harzgerode in the Harz mountains at 420 m above sea level. The Eine flows north of the B 242 federal road to Friedrichsrode in an easterly direction and then swings northeast into the Harz Foreland...

 and Elke and was about 12 km long.
When the lake began to shrink in the course of the 15th century, a dam

Dam

A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...

 was built at the source of the Elke. The lake was completely drained at the beginning of the 18th century by an order of Frederick I.
The lake contains 20-25m thick Pleistocene

Pleistocene

The Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....

 and Holocene

Holocene

The Holocene is a geological epoch which began at the end of the Pleistocene and continues to the present. The Holocene is part of the Quaternary period. Its name comes from the Greek words and , meaning "entirely recent"...

 sediments, from the Eemian Stage (previous interglacial

Interglacial

An Interglacial period is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age...

period) to the present. Fluviatile, limnic and periglacial sediments interchange. All in all, 11 sedimentation cycles are present.