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Houthem Formation
The Houthem Formation, named after the Dutch town of Houthem, is a geological formation that crops out in the south of Belgian and Dutch Limburg. It has also been found in borings in the northeastern part of the Campine Basin. The formation consists of calcareous sandstone and was formed about 60 million years ago, in the Paleocene epoch. Lithology The Houthem Formation consists of maximally 30 metres of light grey to light yellow calcareous arenites. The arenite can contain calcareous concretions, fossils and hardgrounds with shell fragments. At other places lenses of boundstone occur, formed by red algae. The hardgrounds make it possible to subdivide the formation into three members: the Geleen Member, the Bunde Member and the Geulhem Member. Stratigraphy Dutch stratigraphers see the Houthem Formation as the youngest formation of the Chalk Group, because it has a similar lithology with the older formations in this group. Belgian stratigraphers see it as part of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 Netherlands , established_title2 = Act of Abjuration , established_date2 = 26 July 1581 , established_title3 = Peace of Münster , established_date3 = 30 January 1648 , established_title4 = Kingdom established , established_date4 = 16 March 1815 , established_title5 = Liberation Day (Netherlands), Liberation Day , established_date5 = 5 May 1945 , established_title6 = Charter for the Kingdom of the Netherlands, Kingdom Charter , established_date6 = 15 December 1954 , established_title7 = Dissolution of the Netherlands Antilles, Caribbean reorganisation , established_date7 = 10 October 2010 , official_languages = Dutch language, Dutch , languages_type = Regional languages , languages_sub = yes , languages = , languages2_type = Reco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Red Algae
Red algae, or Rhodophyta (, ; ), are one of the oldest groups of eukaryotic algae. The Rhodophyta also comprises one of the largest phyla of algae, containing over 7,000 currently recognized species with taxonomic revisions ongoing. The majority of species (6,793) are found in the Florideophyceae (class), and mostly consist of multicellular, marine algae, including many notable seaweeds. Red algae are abundant in marine habitats but relatively rare in freshwaters. Approximately 5% of red algae species occur in freshwater environments, with greater concentrations found in warmer areas. Except for two coastal cave dwelling species in the asexual class Cyanidiophyceae, there are no terrestrial species, which may be due to an evolutionary bottleneck in which the last common ancestor lost about 25% of its core genes and much of its evolutionary plasticity. The red algae form a distinct group characterized by having eukaryotic cells without flagella and centrioles, chloroplasts that l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 soil or soil type; i.e., a soil containing more than 85 percent sand-sized particles by mass. The composition of sand varies, depending on the local rock sources and conditions, but the most common constituent of sand in inland continental settings and non-tropical coastal settings is silica (silicon dioxide, or SiO2), usually in the form of quartz. Calcium carbonate is the second most common type of sand, for example, aragonite, which has mostly been created, over the past 500million years, by various forms of life, like coral and shellfish. For example, it is the primary form of sand apparent in areas where reefs have dominated the ecosystem for millions of years like the Caribbean. Somewhat more rarely, sand may be composed of calciu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clay
Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4). Clays develop plasticity when wet, due to a molecular film of water surrounding the clay particles, but become hard, brittle and non–plastic upon drying or firing. Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impurities, such as a reddish or brownish colour from small amounts of iron oxide. Clay is the oldest known ceramic material. Prehistoric humans discovered the useful properties of clay and used it for making pottery. Some of the earliest pottery shards have been dated to around 14,000 BC, and clay tablets were the first known writing medium. Clay is used in many modern industrial processes, such as paper making, cement production, and chemical filtering. Between one-half and two-thirds of the world's population live or work in buildings made with clay, often ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Opglabbeek Formation
The Opglabbeek Formation is a geologic formation in the subsurface of the eastern part of Belgian Limburg. The heterogeneous formation consists of clay and sand that was deposited lagoonally and fluvially during the early Selandian (Middle Paleocene, about 60 million years old). The formation is named after the town of Opglabbeek in Limburg. The Opglabbeek Formation is subdivided into two members: the Opoeteren Member (red clay with layers of lignite) and the Eisden Member (fine sand with crags). The Opglabbeek Formation's thickness ranges between and , reaching its greatest thickness as it abuts the Roer Valley Graben. It lies stratigraphically on top of the Houthem Formation (early Paleocene calcareous sandstone). It is the lateral equivalent of the Hainin Formation. On top of it lies the Heers Formation (Middle Paleocene sands and marls). The Opglabbeek Formation is part of the Hesbaye Group and can be correlated with parts of the Landen Formation of adjacent areas i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maastricht Formation
The Maastricht Formation (Dutch: ''Formatie van Maastricht''; abbreviation: MMa), named after the city of Maastricht in the Netherlands, is a geological formation in the Netherlands and Belgium whose strata date back to the Late Cretaceous, within 500,000 years of the Cretaceous–Paleogene boundary, now dated at . The formation is part of the Chalk Group and is between thick. It crops out in southern parts of Dutch and Belgian Limburg and adjacent areas in Germany. It can be found in the subsurface of northern Belgium and southeastern Netherlands, especially in the Campine Basin and Roer Valley Graben. Dinosaur remains are among the fossils that have been recovered from the formation.Weishampel, David B; et al. (2004). "Dinosaur distribution (Late Cretaceous, Europe)." In: Weishampel, David B.; Dodson, Peter; and Osmólska, Halszka (eds.): The Dinosauria, 2nd, Berkeley: University of California Press. Pp. 588-593. . Lithology The Maastricht Formation consists of soft, sand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of the entire Phanerozoic. The name is derived from the Latin ''creta'', "chalk", which is abundant in the latter half of the period. It is usually abbreviated K, for its German translation ''Kreide''. The Cretaceous was a period with a relatively warm climate, resulting in high eustatic sea levels that created numerous shallow inland seas. These oceans and seas were populated with now- extinct marine reptiles, ammonites, and rudists, while dinosaurs continued to dominate on land. The world was ice free, and forests extended to the poles. During this time, new groups of mammals and birds appeared. During the Early Cretaceous, flowering plants appeared and began to rapidly diversify, becoming the dominant group of plants across the Earth b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cretaceous–Paleogene Boundary
The Cretaceous–Paleogene (K–Pg) boundary, formerly known as the Cretaceous–Tertiary (K–T) boundary, is a geological signature, usually a thin band of rock containing much more iridium than other bands. The K–Pg boundary marks the end of the Cretaceous Period, the last period of the Mesozoic Era, and marks the beginning of the Paleogene Period, the first period of the Cenozoic Era. Its age is usually estimated at around 66 million years, with radiometric dating yielding a more precise age of 66.043 ± 0.011 Ma. The K–Pg boundary is associated with the Cretaceous–Paleogene extinction event, a mass extinction which destroyed a majority of the world's Mesozoic species, including all dinosaurs except for birds. Strong evidence exists that the extinction coincided with a large meteorite impact at the Chicxulub crater and the generally accepted scientific theory is that this impact triggered the extinction event. The word "Cretaceous" is derived from the Latin "creta" (ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hesbaye Group
The Hesbaye Group is a stratigraphic group (a set of sedimentary layers) in the subsurface of northeastern Belgium. This group was deposited during the early Paleocene epoch and is subdivided into two formations: the Houthem Formation (lower) and the Opglabbeek Formation (upper). The group is named after the region of Hesbaye in the south of Limburg. The Houthem Formation consists of shallow marine sandy limestones of early to middle Danian age (about 65-63 million years old). It is found in the province of Limburg and the north of the province of Antwerp. This formation also occurs in the Netherlands, where it is considered part of the Chalk Group. The Opglabbeek Formation is an alternation of continental to lagunary clay, sand and lignite layers of early Selandian age (about 60 million years old). This formation only occurs in the north and east of the province of Limburg. Corresponding deposits in the Netherlands are divided with the Landen Formation. The Hebaye Group lies s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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 across the wider northwest European chalk 'province'. It is characterised by thick deposits of chalk, a soft porous white limestone, deposited in a marine environment. Chalk is a limestone that consists of coccolith biomicrite. A biomicrite is a limestone composed of fossil debris ("bio") and calcium carbonate mud ("micrite"). Most of the fossil debris in chalk consists of the microscopic plates, which are called coccoliths, of microscopic green algae known as coccolithophores. In addition to the coccoliths, the fossil debris includes a variable, but minor, percentage of the fragments of foraminifera, ostracods and mollusks. The coccolithophores lived in the upper part of the water column. When they died, the microscopic calcium carbonate p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geulhem Member
Geulhem is a rural hamlet in the south-eastern Netherlands, part of the former Berg en Terblijt council, now Valkenburg aan de Geul council. It is situated between Houthem and Berg en Terblijt. History The name Geulhem was first mentioned in an act dating from 1360. The interpretation of the name is "hamlet on the river Geul". At the centre of Geulhem is its oldest building - the Geulhemmer watermill. This watermill existed before 1306. Geulhem is situated partially in a valley and partially on a hillside known as the Geulhemmerberg. Places of interest Next to the Geulhemer watermill, which is now in use as a cafe, one finds themself in the environs of an underground network of corridors under the "Geulhemmerberg" hill. In the past, parts of this network were used as cave dwellings due to 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, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
