Hanau-Seligenstadt Basin
Hanau-Seligenstadt Basin is a subbasin of the Upper Rhine Graben, southeast of Frankfurt in the eastern part of the Lower Main lowlands. The Main River runs through it between Aschaffenburg and Offenbach am Main. The main towns are Hanau, Seligenstadt and Dieburg.
It is a Cenozoic graben and part of the European Cenozoic Rift System. The Spessart mountains lie to the east and the Odenwald mountains to the south. A horst block separates it from the western Upper Rhine Graben, and the graben margins converge toward the north.
The basin sits on older Variscan basement rocks. Sediments from the Oligocene to the Quaternary are up to about 280 meters thick. They include marine, lagoonal and later terrestrial clays, marls, limestones and sands, with some basalt layers. In the Pliocene and Quaternary there are river deposits of sand, gravel and silt, and lignite in the Pliocene. The present landscape shows river terraces.
From Triassic to early Paleogene there was little deposition. Subsidence began in the Oligocene (about 30 million years ago) during the formation of the Upper Rhine Graben. The area was covered by a sea and later a lake. Miocene debris from the highlands filled the basin and formed a river plain. About 15 million years ago, during the Langhian, basalt lava flowed in parts of the area, while rivers started eroding the old sediments. In the Pliocene about 5 million years ago, the Lower Main and its tributaries deposited sand, gravel and silt, and lakes left clay and lignite. The Main reached the area in the early Quaternary and brought a lot of sand and gravel into the basin. In the Middle Pleistocene, rivers cut into the old layers again, creating river terraces.
Today, sand, gravel and clay are mined in many pits. Lignite was mined until the 1930s, and Miocene basalts until the 1980s. The sand and gravel beds provide groundwater for water supply.
This page was last edited on 3 February 2026, at 12:32 (CET).