Geiseltal (fossil deposit)

Other vertebrates include even-toed ungulates, small mammals such as insectivores and bats as well as birds, crocodiles, turtles, snakes, amphibians and fish.

However, the intensive activity of open-cast lignite minings has seriously altered the landscape, especially in the last 150 years, and in addition to the destruction of several villages, has also led to the shaping of an area of around 90 km² with the course of the Geisel river being shifted several times to the south.

The Südfeldsee and Runstedter See were created in the eastern and south-eastern Geiseltal as early as the second half of the 20th century, while in the western part the Geiseltalsee, one of the largest artificial lakes in Central Europe, was only completed in 2011.

Today, the western and eastern Geiseltal valleys are separated by a tipping dam up to 140 m high, which, in addition to the current course of the Geisel River, also carries important transportation routes such as roads and railways.

It is possible that in the Palaeogene the leaching of the Zechstein salt combined with the chemical weathering of the shell limestone (subrosion) led to mass loss in the subsoil, which resulted in the subsidence of the overlying layers and the formation of the basin.

[10][11][12] The retreat of the inland glacier of the Saale glacial period led to the formation of drainless and mostly water-filled depressions, particularly in the north-eastern part of the Geiseltal, in the former open-cast mining field Neumark-Nord, through mollisol diapirism, in which predominantly limnic sediments were deposited.

The upper coal contained only one relevant site and was otherwise largely fossil-free, which is partly due to the diagenetic changes during the Pleistocene under the influence of periglacial conditions.

Mainly responsible are calcareous waters from the neighboring Triassic rocks, here predominantly shell limestone, which penetrated from the south or southwest from the area of the Querfurt-Freyburg Mulde during the formation of the lignite as circulating groundwater.

Several up to 44 cm long bark remains with the so-called "monkey hair", fossilized milky sap tubes, attached to them are also assigned to this plant family.

[65] The iguanas include Geiseltaliellus, a slightly built lizard with an extremely long tail and fine skin scales, which was probably an arboreal dweller.

A special find includes an almost complete skeleton with bone armor and five eggs in close proximity; it is one of the world's rare examples of brood care in fossil crocodiles.

The largest predator in the Geiseltal was Asiatosuchus with a body length of around 3 m. It was ecologically similar to today's Nile crocodile and preferred open waters.

There are over three dozen finds of this large ground-running bird, including several leg bones, but also skull remains and parts of the wings, which represent the largest collection of all sites in Europe.

[94] The rarely occurring Buxolestes, on the other hand, was a stocky, semi-aquatic animal from the Pantolestidae group, whose appearance and way of life corresponded roughly to today's otters.

This early primate, which was closely related to the Darwinius known from the Messel Pit, had a distinctly short facial skull and large eye sockets, indicating a nocturnal lifestyle.

They represent fossilized milky sap tubes of rubber-producing woody plants from the dog poison family, of which leaves of the genus Apocynophyllum are present from the Geiseltal.

[131][36][132] Other finds are mainly the food remains of numerous animals, which were also discovered early on, for example in 1935 in the tapir relative Lophiodon as a greenish plant mass.

The first vertebrate finds discovered at the beginning of the 20th century, tooth remains of the tapir relative Lophiodon, led to the classification of the lignite in the geological epoch of the Middle Eocene.

For example, data determined using potassium-argon dating originate from the important Messel Pit in Hesse, which from a biostratigraphic point of view corresponds to the lower coal section of the Geiseltal, and yielded an age of 47.8 million years.

According to this, the Geiseltal in the Middle Eocene was a water-rich moorland landscape that extended in a north-south direction over a length of four to five kilometers and was located near the coast at a bay that penetrated far inland.

The onset of coalification of the dead plant material led to the formation of thick lignite seams over a period of six to possibly eight million years.

[141] The bog area was interspersed with numerous small pools and ponds, around eight to ten meters in diameter, which are indicated by collapse funnels and served as drinking places for the fossil fauna.

Due to the significant differences in temperature during the summer and winter months, the landscape was subject to an annual periodicity of rainy and dry seasons, which can also be demonstrated by tree rings and a fine warve of the lignite.

However, the Walbeck Fossil Deposit in the northwest of Saxony-Anhalt is one of the most extensive mammal communities in the world from the Middle Palaeocene period almost 60 million years ago.

The earliest fossil find dates back to 1908 and includes remains of the tapir relative Lophiodon, which were picked up rather by chance by a miner in the open-cast mine Cecilie.

The aim was not only to record qualitatively complete specimens, but also to gain a quantitative overview of the fossil content of the lignite, so that even smaller or poorly preserved finds could be documented.

[27] Between the years 2000 and 2003, the last field activities were again carried out together with the Senckenberg Research Institute in the western Geiseltal, which mainly concerned a coal seam over 20 m thick, which contained countless plant material up to 25 m long tree trunks.

[47] In June 2003, the planned flooding of the western Geiseltal to form the Geiseltalsee began, which reached its final water level in spring 2011, creating one of the largest artificial lakes in Central Europe.

In the following years, technical and financial bottlenecks meant that it was not possible to invest in a more modern exhibition or in repairing the buildings of the Neue Residenz, which made it necessary to protect individual objects from damage due to rain or thaw.

[153][154] In spring 2015, a special exhibition entitled "From the dawn: horse-hunting crocodiles and giant birds" at the Tschernyschewski-Haus of the Leopoldina in Halle provided information on the latest findings from research into the Geiseltal fossil deposit.