The Aachen Formation ( nl, Formatie van Aken, german: Aachen-Formation) is an

Upper Cretaceous The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...

geologic formation A geological formation, or simply formation, is a body of rock having a consistent set of physical characteristics ( lithology) that distinguishes it from adjacent bodies of rock, and which occupies a particular position in the layers of rock exp ...

in the southern

Netherlands ) , anthem = ( en, "William of Nassau") , image_map = , map_caption = , subdivision_type = Sovereign state , subdivision_name = Kingdom of the Netherlands , established_title = Before independence , established_date = Spanish Netherl ...

and northeastern

Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. The country is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeast, France to th ...

and adjacent

Germany Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...

.Aachen Formation
at

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ...

.org It is

stratigraphically Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostrati ...

equivalent to the middle part of the

Chalk Group The Chalk Group (often just called the Chalk) is the lithostratigraphic unit (a certain number of rock strata) which contains the Upper Cretaceous limestone succession in southern and eastern England. The same or similar rock sequences occur acr ...

of England, and named after the German city of

Aachen Aachen ( ; ; Aachen dialect: ''Oche'' ; French and traditional English: Aix-la-Chapelle; or ''Aquisgranum''; nl, Aken ; Polish: Akwizgran) is, with around 249,000 inhabitants, the 13th-largest city in North Rhine-Westphalia, and the 28th- ...

Geography

The formation crops out in southern Belgian and Dutch Limburg and adjacent areas in

. The formation can also be found 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 ...

West Flanders ) , settlement_type = Province of Belgium , image_flag = Flag of West Flanders.svg , flag_size = , image_shield = Wapen van West-Vlaanderen.svg , shield_size = , image_map ...

, where it forms an

aquifer An aquifer is an underground layer of water-bearing, permeable rock, rock fractures, or unconsolidated materials (gravel, sand, or silt). Groundwater from aquifers can be extracted using a water well. Aquifers vary greatly in their characterist ...

from which

drinking water Drinking water is water that is used in drink or food preparation; potable water is water that is safe to be used as drinking water. The amount of drinking water required to maintain good health varies, and depends on physical activity level, a ...

is won.

Geology

The Aachen Formation consists of glauconite bearing

sand Sand is a granular material composed of finely divided mineral particles. Sand has various compositions but is defined by its grain size. Sand grains are smaller than gravel and coarser than silt. Sand can also refer to a textural class of s ...

. It was deposited during the

Santonian The Santonian is an age in the geologic timescale or a chronostratigraphic stage. It is a subdivision of the Late Cretaceous Epoch or Upper Cretaceous Series. It spans the time between 86.3 ± 0.7 mya (million years ago) and 83.6 ± 0.7 mya. The ...

and Campanian ages (85.8 to 70.6 million years ago) of the Cretaceous Period. The formation rests

unconformably An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval o ...

on top of

Carboniferous The Carboniferous ( ) is a geologic period and system of the Paleozoic that spans 60 million years from the end of the Devonian Period million years ago ( Mya), to the beginning of the Permian Period, million years ago. The name ''Carbonifero ...

rocks of the

Limburg Group Limburg or Limbourg may refer to: Regions * Limburg (Belgium), a province since 1839 in the Flanders region of Belgium * Limburg (Netherlands), a province since 1839 in the south of the Netherlands * Diocese of Limburg, Roman Catholic Diocese in ...

, which are more than three times as old. Overlying the Aachen Formation is the Vaals Formation, equivalent to the upper part of the Chalk Group of England.

Fossil content

Among others, the following fossils have been reported from the formation:

Corals

* '' Cunnolites cancellata''Leloux, 1999

Flora

* '' Aachenosaurus multidens'' ;Pollen * '' Chrysotheca dentata''Dijkstra, 1949 * '' Chrysotheca quadriplicata'' * '' Chrysotheca striata'' * '' Chrysotheca tenuis'' * '' Geleenites fascinus'' * '' Spherites spinosus'' * '' Triletes aachenensis'' * '' Triletes carbunculus'' * '' Triletes compositi-punctatus'' * '' Triletes cristatus'' * '' Triletes diktyotus'' * '' Triletes dubius'' * '' Triletes lobatus'' * '' Triletes minimus'' * '' Triletes nanus'' * '' Triletes occultatus''Dijkstra, 1961 * '' Triletes persimilis'' * '' Triletes pupus'' * '' Triletes tenellus''

References

Bibliography

* * * * {{cite LSA , last=Dijkstra , first=S. J , year=1949 , title=Megaspores and some other fossils from the Aachenian (Senonian) in South Limburg, Netherlands , journal= Mededelingen Van de Geologische Stichting, Niewe Serie , volume=3 , pages=19–32 Geologic formations of Germany Geologic formations of Belgium Geologic formations of the Netherlands Upper Cretaceous Series of Europe Cretaceous Germany Cretaceous Netherlands Mesozoic Belgium Campanian Stage Santonian Stage Sandstone formations Shallow marine deposits Paleontology in Belgium Paleontology in the Netherlands Formations Formations Formations