Geiseltal (fossil deposit)
The Geiseltal is a former brown coal mining area located in Saxony-Anhalt, Germany, renowned for its exceptionally rich and well-preserved Middle Eocene fossil deposits. The area lies near the town of Halle (Saale).
The geological period represented in the Geiseltal strata dates back approximately 47 million years. The former open-cast lignite mine, active from the late 19th century until the 1990s, exposed a series of lake sediments, providing paleontologists with a unique window into the flora and fauna of a subtropical forest environment of the Eocene epoch.
Fossils discovered at Geiseltal include a remarkably diverse range of vertebrates, invertebrates, and plants. Among the most significant finds are early mammals, including complete or nearly complete skeletons, preserving details of their soft tissues such as fur, stomach contents, and even internal organs. Examples include early primates, bats, horses, tapirs, and various other mammals representing evolutionary lineages that eventually led to modern forms. Avian fossils are also abundant and well-preserved, providing insights into the evolution of birds. Crocodilians, turtles, snakes, and fish represent the reptilian and aquatic life of the ancient lake.
Invertebrate fossils are also abundant, including insects, mollusks, and crustaceans, which provide information about the food web and ecological interactions of the Geiseltal ecosystem. Plant fossils include leaves, seeds, fruits, and pollen, providing information about the plant life that supported the animal life of the area.
The exceptional preservation of the Geiseltal fossils is attributed to the anoxic (oxygen-depleted) conditions at the bottom of the ancient lake, which inhibited decomposition and allowed for the fine details of the organisms to be preserved.
Research on the Geiseltal fossils continues to provide valuable information about the evolution of life, the paleoclimate of the Eocene epoch, and the ecological dynamics of ancient ecosystems. Many of the fossils are housed and displayed in the Geiseltalmuseum at the Martin Luther University of Halle-Wittenberg.