|
Lede Formation
The Lede Formation ( nl, Formatie van Lede; abbreviation: Ld) 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 Lede Formation crops out in East Flanders, Flemish Brabant, Antwerp and parts of Hainaut, Walloon Brabant and West Flanders. It forms a laterally continuous unit of calcareous and glauconiferous sandstone, sandy limestone and calcareous sandstone, which reaches a thickness of up to 15 metres. The formation is characterised by fossils of the nummulite '' Nummulites variolarius''. It is not subdivided into members. The age of the Lede Formation is middle Lutetian (about 44 million years old) and it is part of the Zenne Group. On top of the Lede Formation is normally the younger Maldegem Formation (marine clays and sands of Bartonian The Bartonian is, in the ICS's geolog ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formation (stratigraphy)
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 exposed in a geographical region (the stratigraphic column). It is the fundamental unit of lithostratigraphy, the study of strata or rock layers. A formation must be large enough that it can be mapped at the surface or traced in the subsurface. Formations are otherwise not defined by the thickness (geology), thickness of their rock strata, which can vary widely. They are usually, but not universally, tabular in form. They may consist of a single lithology (rock type), or of alternating beds of two or more lithologies, or even a heterogeneous mixture of lithologies, so long as this distinguishes them from adjacent bodies of rock. The concept of a geologic formation goes back to the beginnings of modern scientific geology. The term was used by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glauconite
Glauconite is an iron potassium phyllosilicate ( mica group) mineral of characteristic green color which is very friable and has very low weathering resistance. It crystallizes with a monoclinic geometry. Its name is derived from the Greek () meaning 'bluish green', referring to the common blue-green color of the mineral; its sheen ( mica glimmer) and blue-green color. Its color ranges from olive green, black green to bluish green, and yellowish on exposed surfaces due to oxidation. In the Mohs scale it has hardness of 2. The relative specific gravity range is 2.4 - 2.95. It is normally found in dark green rounded brittle pellets, and with the dimension of a sand grain size. It can be confused with chlorite (also of green color) or with a clay mineral. Glauconite has the chemical formula . Glauconite particles are one of the main components of greensand, glauconitic siltstone and glauconitic sandstone. Glauconite has been called a marl in an old and broad sense of that word. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Formations Of Belgium
Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth sciences, including hydrology, and so is treated as one major aspect of integrated Earth system science and planetary science. Geology describes the structure of the Earth on and beneath its surface, and the processes that have shaped that structure. It also provides tools to determine the relative and absolute ages of rocks found in a given location, and also to describe the histories of those rocks. By combining these tools, geologists are able to chronicle the geological history of the Earth as a whole, and also to demonstrate the age of the Earth. Geology provides the primary evidence for plate tectonics, the evolutionary history of life, and the Earth's past climates. Geologists broadly study the properties and processes of Earth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aalter Formation
The Aalter Formation ( nl, Formatie van Aalter, abbreviation: Aa; named after the town of Aalter in East Flanders) 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 Aalter Formation crops out in the provinces of East Flanders and West Flanders and forms a maximally 30 meters thick layer in the subsurface. To the east, the formation wedges out and becomes thinner. Due to this wedging out, the formation does not occur anymore in the province of Antwerp. The base of the formation consists of glauconiferous clayey sand alternating with organic rich (humus and peat) layers (the Aalterbrugge Member). On top of this is a sequence of clay, sand and sandstone layers, rich in fossils (the Beernem Member). The top of the formation consists of fossil rich, glauconiferous fine sand (the Oedelem Member). The Aalter Formation was for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brussel Formation
The Brussel Formation ( nl, Formatie van Brussel; french: Formation de Bruxelles; abbreviation: Br) 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 Brussel Formation crops out in Walloon Brabant and the north of the provinces of Namur and Hainaut. It is normally about 30 metres in thickness. In Flemish Brabant and Antwerp the formation can be found in the subsurface. The Brussel Formation is subdivided into five members: the Archennes Member ( conglomerates), the Bois de la Houssière Member (quartzites), the Chaumont-Gistoux Member ( glauconiferous quartzites), the Diegem Member (glauconiferous quartzite) and the Neerijse Member (glauconiferous calcareous sand). The formation consists either of cross-bedded non-calcareous sands alternating with thin beds of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bartonian
The Bartonian is, in the ICS's geologic time scale, a stage or age in the middle Eocene Epoch or Series. The Bartonian Age spans the time between . It is preceded by the Lutetian and is followed by the Priabonian Age. Stratigraphic definition The Bartonian Stage was introduced by Swiss stratigrapher Karl Mayer-Eymar in 1857. The name derives from the coastal village Barton-on-Sea (part of New Milton) in southern England. The Barton Group, a lithostratigraphic unit from the south English Hampshire Basin, is of Bartonian age. The distinction between group and stage was made in the second part of the 20th century, when stratigraphers saw the need to distinguish between litho- and chronostratigraphy. The base of the Bartonian is at the first appearance of the calcareous nanoplankton species ''Reticulofenestra reticulata''. In 2009, an official reference profile (GSSP) for the base of the Bartonian had not yet been established. The top of the Bartonian Stage (the base of the Pria ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maldegem Formation
The Maldegem Formation ( nl, Formatie van Maldegem; old name: Kallo Complex) is a geologic formation in the Belgian subsurface. The formation consists of alternating marine clay and sand strata, deposited during the late Eocene. The Maldegem Formation crops out in the provinces of East Flanders and West Flanders and in the area between the Zenne and Dender rivers. In the northern parts of Flanders it forms an up to 50 meters thick sequence in the subsurface. Further south and to the east (in the Campine of the province of Antwerp) the formation pinches out and can be only a few meters in thickness. Lithology The Maldegem Formation is an alternating sequence of grey glauconiferous fine sands and greyish blue glauconiferous heavy clay. It was deposited during the late Lutetian and Bartonian ages (between 42 and 37 million years old). Stratigraphy Seven members can be recognized within the Maldegem Formation: Wemmel Member, Asse Member, Ursel Member, Onderdale Member, Zome ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 formation have their shallow marine facies in common. The three formations are: *the Aalter Formation, greenish sands and clays, found in East Flanders and West Flanders. *the Brussel Formation, marls and sands, found in Flemish and Walloon Brabant, Hainaut and Namur. *the Lede Formation, calcareous sands, found in almost all central Belgium. Stratigraphically on top of the Zenne Group are the late Eocene sands and clays of the Maldegem Formation The Maldegem Formation ( nl, Formatie van Maldegem; old name: Kallo Complex) is a geologic formation in the Belgian subsurface. The formation consists of alternating marine clay and sand strata, deposited during the late Eocene. The Maldegem For ..., which is not divided into a group. The Zenne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lutetian
The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the Middle Eocene Subepoch. Stratigraphic definition The Lutetian was named after Lutetia, the Latin name for the city of Paris. The Lutetian Stage was introduced in scientific literature by French geologist Albert de Lapparent in 1883 and revised by A. Blondeau in 1981. The base of the Lutetian Stage is at the first appearance of the nanofossil ''Blackites inflatus'', according to an official reference profile (GSSP) established in 2011. Of two candidates located in Spain, the Gorrondatxe section was chosen.See thwebsite of Eustoquio Molinafor these candidates. The top of the Lutetian (the base of the Bartonian) is at the first appearance of calcareous nanoplankton species ''Reticulofenestra reticulata''. The Lutetian overlaps with the Geisel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Member (stratigraphy)
A stratigraphic unit is a volume of rock of identifiable origin and relative age range that is defined by the distinctive and dominant, easily mapped and recognizable petrographic, lithologic or paleontologic features (facies) that characterize it. Units must be ''mappable'' and ''distinct'' from one another, but the contact need not be particularly distinct. For instance, a unit may be defined by terms such as "when the sandstone component exceeds 75%". Lithostratigraphic units Sequences of sedimentary and volcanic rocks are subdivided the basis of their shared or associated lithology. Formally identified lithostratigraphic units are structured in a hierarchy of lithostratigraphic rank, higher rank units generally comprising two or more units of lower rank. Going from smaller to larger in rank, the main lithostratigraphic ranks are Bed, Member, Formation, Group and Supergroup. Formal names of lithostratigraphic units are assigned by geological surveys. Units of formation or hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nummulite
A nummulite is a large lenticular fossil, characterized by its numerous coils, subdivided by septa into chambers. They are the shells of the fossil and present-day marine protozoan ''Nummulites'', a type of foraminiferan. Nummulites commonly vary in diameter from 1.3 cm (0.5 inches) to 5 cm (2 inches) and are common in Eocene to Miocene marine rocks, particularly around southwest Asia and the Mediterranean (e.g. Eocene limestones from Egypt). Fossils up to six inches wide are found in the Middle Eocene rocks of Turkey. They are valuable as index fossils. The ancient Egyptians used nummulite shells as coins and the pyramids were constructed using limestone that contained nummulites. It is not surprising then that the name "''Nummulites''" is a diminutive form of the Latin '' nummulus'' meaning "little coin", a reference to their shape. In 1913, naturalist Randolph Kirkpatrick published a book, ''The Nummulosphere: an account of the Organic Origin of so-called Igneous Ro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
