The Dongen Formation ( nl, Formatie van Dongen; abbreviation: DO) is a geologic formation in the

subsurface In geology, bedrock is solid rock that lies under loose material (regolith) within the crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface material. An exposed portion of bedro ...

of the Netherlands. The formation consists of early Eocene

marine Marine is an adjective meaning of or pertaining to the sea or ocean. Marine or marines may refer to: Ocean * Maritime (disambiguation) * Marine art * Marine biology * Marine debris * Marine habitats * Marine life * Marine pollution Military * ...

clay and sand. It is named after the town of Dongen in North Brabant.

Lithology and stratigraphy

The Dongen Formation consists predominantly of marine clay, alternated with layers of fine sand or glauconiferous

marl Marl is an earthy material rich in carbonate minerals, clays, and silt. When hardened into rock, this becomes marlstone. It is formed in marine or freshwater environments, often through the activities of algae. Marl makes up the lower part o ...

. The clay can also contain glauconite and locally thin layers of

tuffite Tuffite is a tuff containing both pyroclastic and detrital materials, but predominantly pyroclasts. According to IUGS definition tuffite contains 75 to 25% volcanic (epiclastic) material. There are several classifications that define tuffite. ...

loam Loam (in geology and soil science) is soil composed mostly of sand (particle size > ), silt (particle size > ), and a smaller amount of clay (particle size < ). By weight, its mineral composition is about 40–40–20% concentration of sand–sil ...

can occur. The formation is subdivided into four members: *the Asse Member, clay with locally sandy layers, glauconite or/and nummulites; *the Brussels Member, fine glauconiferous sand, locally calcareous; *the Ieper Member, clay with layers of marl and limestone; *the Oosteind Member, clay with sand and tuffite layers. 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 The Zenne Group ( nl, Zenne Groep) is a group of rock strata in the subsurface of central and northwest Belgium. The group consists of three formations, all from the Ypresian and Lutetian ages (early Eocene, 50 to 40 million years old). These form ...

. 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 Ages may refer to: *Advanced glycation end-products, known as AGEs *Ages, Kentucky, census-designated place, United States * ''Ages'' (album) by German electronic musician Edgar Froese *The geologic time scale, a system of chronological measuremen ...

, when the

eustatic Mean sea level (MSL, often shortened to sea level) is an average surface level of one or more among Earth's coastal bodies of water from which heights such as elevation may be measured. The global MSL is a type of vertical datuma standardised g ...

sea level was relatively high after the

Paleocene–Eocene Thermal Maximum The Paleocene–Eocene thermal maximum (PETM), alternatively (ETM1), and formerly known as the "Initial Eocene" or "", was a time period with a more than 5–8 °C global average temperature rise across the event. This climate event o ...

. 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 The Landen Formation (abbreviation: LA) is a lithostratigraphic unit (a set of rock strata) 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 defin ...

in the Lower North Sea Group. The top of the Dongen Formation is formed by a

nonconformity Nonconformity or nonconformism may refer to: Culture and society * Insubordination, the act of willfully disobeying an order of one's superior * Dissent, a sentiment or philosophy of non-agreement or opposition to a prevailing idea or entity * ...

, over which younger formations, such as the

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

Rupel Formation The Rupel Formation (abbreviation: RU) 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 Belgi ...

or the Miocene

Breda Formation The Breda Formation ( nl, Formatie van Breda; abbreviation: BR) 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 ...

, are found.

References

* (''eds.''); 1993: ''Stratigraphic nomenclature of the Netherlands, revision and update by RGD and NOGEPA'', Mededelingen Rijks Geologische Dienst 50, pp. 1–39

External links

* ; 2003
Formatie van Dongen
TNO website () Geologic formations of the Netherlands Eocene Series of Europe Paleogene Netherlands

Formation Formation may refer to: Linguistics * Back-formation, the process of creating a new lexeme by removing or affixes * Word formation, the creation of a new word by adding affixes Mathematics and science * Cave formation or speleothem, a secondar ...

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