the lake occupied an area of , which makes it the twelfth largest lake in Germany. Subsequently, the open-cast mine Kayna-Süd was shut down and rehabilitated as early as 1972, resulting in the Südfeldsee with of water surface. The excavation work in Großkayna had already been completed in 1965 and the remaining hole was used until 1995 as a rinsing dump for waste from the Leuna and Buna plants and then flooded to a lake (Runstedter lake). Both of today's lakes are separated from the Geiseltalsee by a tipping dam up to Open-cast mining activities ended in the late 1990s, and subsequently, nature has reclaimed part of the region. Favored by the position of the host valley in the wind shadow of the Harz creates a special microclimate characterized by a mild average annual average temperature and a relatively low annual precipitation of about . Because of its location, it belongs to the Middle-German dry area. Due to the sandy soil, special flora and fauna community has re-emerged, especially on the northern edge of the valley. In addition, the Geiseltalsee also provides prerequisites for viticulture; In 2002 the first grapes were harvested (Spätburgunder, Cabernet, and Müller-Thurgau). On the north bank is an elevation, the south slope on 25% slope was removed. The north side will be protected by a forest. Fossil record The valley is notable for its fossil record. It has yielded many important specimens of the Eocene including Propalaeotherium, Godinotia, Lophiodon, Oxyaenoides, Asiatosuchus, Geoemyda, Trogulidae and Psiloptera. It is also the site of a notable Bronze Age deposit, known as the Frankleben hoard. Paleontologists found fossils 251–243 million years old. Researchers discovered fossil remains of Straight-tusked elephant. Seven Years' War The valley near Rossbach, between Reichertswerben and Braunsbedra, was the site of the 5 November 1757 Battle of Rossbach between Prussia and the Allied Armies of France and contingents of the Holy Roman Empire, fighting on behalf of Duchy of Austria during the Seven Years' War. The battle had lasted less than 90 minutes but was instrumental in knocking France out of the Silesian theater of the Seven Years' War. Less than five percent of Frederick the Great's entire force had been engaged, and it decisively defeated an army of 42,000. Frederick's use of operational maneuvers and with a fraction of his entire force—3,500 horsemen, 18 artillery pieces, and 3 battalions of infantry—had defeated an entire army of