The Dongen Formation (Dutch : Formatie van Dongen; abbreviation: DO) is a geologic formation in the subsurface of the Netherlands. The formation consists of early Eocene marine clay and sand. It is named after the town of Dongen in North Brabant.
The Dongen Formation consists predominantly of marine clay, alternated with layers of fine sand or glauconiferous marl. The clay can also contain glauconite and locally thin layers of tuffite or loam can occur.
The formation is subdivided into four members:
The base of the formation is often formed by a tuffite layer.
The Dutch Dongen Formation correlates with the Belgian Ieper Group and Zenne Group. All of these units are marine sands and clay cats from the Ypresian (55.8 - 48.6 million years ago) and Lutetian (48.6 - 40.4 million years ago) ages, when the eustatic sea level was relatively high after the Paleocene–Eocene Thermal Maximum. The sea level was so high that the North Sea was connected with the Paris Basin to the south and all of the Netherlands and most of Belgium and northern France was covered by shallow seas.
Dutch stratigraphers put the Dongen Formation together with the older Landen Formation in the Lower North Sea Group. The top of the Dongen Formation is formed by a nonconformity, over which younger formations, such as the Oligocene Rupel Formation or the Miocene Breda Formation, are found.
The Landen Formation is a lithostratigraphic unit in the subsurface of the Netherlands. This formation shares its name with the Belgian Landen Group, but the Belgian unit is thinner and has different definitions. The Landen Formation consists of shallow marine and lagoonal sediments from the late Paleocene to early Eocene. Dutch stratigraphers see the Landen Formation as part of the Lower North Sea Group.
The Hannut Formation is a geologic formation in the subsurface of northern Belgium. The formation consists of marine clay and silt, alternating with more sandy layers. On top of this the lithology changes to limestone, siltstone and sandstone and the top of the formation is formed by a layer of glauconite bearing sand. The Hannut Formation was formed during the early to middle Thanetian age.
The Heers Formation is a geologic formation in the subsurface of Belgium. The formation consists of sand and marl and was deposited in the shallow sea that covered Belgium during the middle to late Selandian age of the Paleocene epoch.
The Landen Group is a lithostratigraphic unit in the Belgian subsurface. The group consists of two formations of Thanetian to Ypresian age. The Landen Group is named after the town of Landen in Flemish Brabant.
The Tienen Formation is a geologic formation in the subsurface of northern Belgium. The formation crops out in the province of Hainaut and the Hesbaye region in the province of Limburg. It has a late Thanetian (Paleocene) to early Ypresian (Eocene) age.
The Ieper Group is a group of rock strata in the subsurface of northwest Belgium. The group is subdivided into three marine formations, all formed during the Ypresian, a single age of the geologic timescale. Both age and group are named after the West Flemish town of Ypres, for which the Dutch name is "Ieper".
The Rupel Formation is a geologic formation in the subsurface of the Netherlands that consists of Oligocene marine sands and clays. The Rupel Formation is part of the Middle North Sea Group and correlates exactly with the Belgian Rupel Group.
The Rupel Group is a stratigraphic group of rock strata in the subsurface of Belgium. It is subdivided into three formations that are all marine deposits of Oligocene age.
The Breda Formation is a geologic formation in the subsurface of the Netherlands. The formation consists of marine glauconiferous sands and clays that were deposited during the Miocene epoch. Although the formation is not very rich in fossils, sometimes bones of fishes, mammals, shells and shark teeth are found.
The Tongeren Formation is a geologic formation in the subsurface of the Netherlands. The formation consists of shallow marine, epicontinental and continental sediments, predominantly clay and sand from the late Eocene and early Oligocene epochs. The Tongeren Formation is part of the Middle North Sea Group and correlates with the Tongeren Group from Belgian stratigraphy.
The Aalter Formation is a geologic formation in the subsurface of northwest Belgium. The formation consists of marine clay and sand, deposited in the shallow sea that covered northern and central Belgium in the Eocene epoch.
The Gentbrugge Formation is a geologic formation in the west of Belgium. The formation crops out in East Flanders and West Flanders and also occurs in the subsurface of the Province of Antwerp. It consists of marine clay, silt and sand, deposited in the shallow sea that covered northern Belgium during the Ypresian age.
The Tielt Formation is a geologic formation in the subsurface of Belgium. The formation crops out in the north of Hainaut, in the southern and central parts of West- and East Flanders and in Walloon and Flemish Brabant. It consists of marine very fine sand and silt, deposited in the shallow sea that covered Belgium during the middle and late Ypresian age.
The Kortrijk Formation is a geologic formation in the Belgian subsurface. This formation crops out in northern Hainaut, southern West and East Flanders and in Walloon Brabant. The formation consists of marine clay from the Ypresian age.
The Veldhoven Formation is a geologic formation in the subsurface of the Netherlands. The formation consists of an alternation of marine clay and sand from the Oligocene epoch.
The Voort Formation or Voort Member is a stratigraphic unit in the subsurface of north Belgium and the south of the Netherlands. The unit has the status of a formation in Belgium but is seen as a member of the Veldhoven Formation in the Netherlands. The Voort Formation consists of shallow marine sands with a late Oligocene age.
The Maldegem Formation is a geologic formation in the Belgian subsurface. The formation consists of alternating marine clay and sand strata, deposited during the late Eocene.
The Brussel Formation is a geologic formation in the subsurface of central Belgium. The formation is named after the Belgian capital, Brussels. It consists of shallow marine sandstone and calcareous sands, deposited in the sea that covered Belgium 45 million years ago, in the Eocene.
The Lede Formation is a geologic formation in the subsurface of Belgium. The formation is named after the town of Lede in East Flanders. It consists of shallow-marine limestone and sandstone, deposited in the former sea that covered Belgium during the Eocene.
The geology of Lithuania consists of ancient Proterozoic basement rock overlain by thick sequences of Paleozoic, Mesozoic and Cenozoic marine sedimentary rocks, with some oil reserves, abundant limestone, dolomite, phosphorite and glauconite. Lithuania is a country in the Baltic region of northern-eastern Europe.