Wellheim Formation

Wellheim Formation
Stratigraphic range: upper Cenomanian to lower Turonian[1] 98–91 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Siliceous earth quarrying of the Wellheim Formation near Neuburg
Type	Geological formation
Unit of	Danubian Cretaceous Group
Sub-units	basal marine sandstone, Neuburg Kieselerde Member, Homsand facies[2]
Underlies	Upper Freshwater Molasse Formation or Pleistocene loams
Overlies	Schutzfels Formation or Upper Jurassic limestone
Area	southern Franconian Jura, Upper Bavaria[1]
Thickness	up to 130 metres (430 ft)
Lithology
Primary	spiculitic silt, fine and medium sands, fine-grained silica (Kieselerde)[1]
Other	silicified conglomerate
Location
Country	Germany
Extent	200 km2 (77 sq mi)
Type section
Named for	Wellheim
Named by	B. Niebuhr, T. Pürner, and M. Wilmsen
Location	open pit mines near Wellheim, Germany
Year defined	2009
Country	Germany

The Wellheim Formation is a geological formation in southern Germany deposited during the Cenomanian to earliest Turonian stages of the Upper Cretaceous.

The Formation is subdivided into three member units: unnamed basal marine sandstone, the Neuburg Kieselerde Member, and an upper silicified conglomerate (Homsand facies).^[2]
Geographically, this formation is located in the central southernmost part of the Franconian Jura, on the left bank of the Danube, roughly between the towns of Wellheim and Neuburg in Bavaria.
The formation is commercially quarried for siliceous earth, which has a variety of applications.