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Viviparus Glacialis
†''Viviparus glacialis'' is an extinct species of fossil freshwater snail, an aquatic gastropod mollusks in the family Viviparidae, the river snails. Shell description This species of snail had an elongated, slim, rather thick-walled shell with approximately 6 ¼ flat whorls which are separated by a shallow suture. The apex is blunt. The aperture is slantingly oval and weakly angulated at the top. The peristome is simple, not thickened and not continuous. There is a narrow umbilicus that may be covered with callus. The surface of the shell is smooth and glossy and bears regular growing lines. Under a magnification of c. 50× a sculpture of fine spiral grooves can be observed. These 'grooves' are composed of densely spaced tiny holes. In most cases the periostracum has not been preserved but if still present this has a light brown to black color. Whether or not the shell had a color pattern, and if so what that might have been is unknown. The width of the shell is up to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in 2009 by the International Union of Geological Sciences, the cutoff of the Pleistocene and the preceding Pliocene was regarded as being 1.806 million years Before Present (BP). Publications from earlier years may use either definition of the period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology. The name is a combination of Ancient Greek grc, label=none, πλεῖστος, pleīstos, most and grc, label=none, καινός, kainós (latinized as ), 'new'. At the end of the preceding Pliocene, the previously isolated North and South American continents were joined by the Isthmus of Panama, causing Great American Interchang ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Periostracum
The periostracum ( ) is a thin, organic coating (or "skin") that is the outermost layer of the shell of many shelled animals, including molluscs and brachiopods. Among molluscs, it is primarily seen in snails and clams, i.e. in gastropods and bivalves, but it is also found in cephalopods such as ''Allonautilus scrobiculatus''. The periostracum is an integral part of the shell, and it forms as the shell forms, along with the other shell layers. The periostracum is used to protect the organism from corrosion. The periostracum is visible as the outer layer of the shell of many molluscan species from terrestrial, freshwater, and marine habitats, and may be seen in land snails, river mussels, and other kinds of freshwater bivalves, as well as in many kinds of marine shelled molluscs. The word ''periostracum'' means "around the shell", meaning that the periostracum is wrapped around what is usually the more calcareous part of the shell. Technically, the calcareous part of the shel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Index Fossil
Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock Stratum, strata by using the fossil assemblages contained within them.Hine, Robert. “Biostratigraphy.” ''Oxford Reference: Dictionary of Biology'', 8th ed., Oxford University Press, 2019. The primary objective of biostratigraphy is ''correlation'', demonstrating that a particular Horizon (geology), horizon in one geological section represents the same period of time as another horizon at a different section. Fossils within these strata are useful because sediments of the same age can look completely different, due to local variations in the Sedimentary depositional environment, sedimentary environment. For example, one section might have been made up of clays and marls, while another has more chalky limestones. However, if the fossil species recorded are similar, the two sediments are likely to have been laid down around the same time. Ideally these fossils are used to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Guide Fossil
Biostratigraphy is the branch of stratigraphy which focuses on correlating and assigning relative ages of rock Stratum, strata by using the fossil assemblages contained within them.Hine, Robert. “Biostratigraphy.” ''Oxford Reference: Dictionary of Biology'', 8th ed., Oxford University Press, 2019. The primary objective of biostratigraphy is ''correlation'', demonstrating that a particular Horizon (geology), horizon in one geological section represents the same period of time as another horizon at a different section. Fossils within these strata are useful because sediments of the same age can look completely different, due to local variations in the Sedimentary depositional environment, sedimentary environment. For example, one section might have been made up of clays and marls, while another has more chalky limestones. However, if the fossil species recorded are similar, the two sediments are likely to have been laid down around the same time. Ideally these fossils are used to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tiglian
The Tiglian, also referred to as the Tegelen, is a temperate complex stage in the glacial history of Northern Europe. It is preceded by the Praetiglian (stage). The stage was introduced by Zagwijn in 1957 based on geological formations in Tegelen in southern Netherlands. Originally, it was thought to be part of a sequence of glacials and interglacials, namely Praetiglian (cold), Tiglian (warm), Eburonian (cold), Waalian (warm), Menapian (cold), and Bavelian (warm). The Praetiglian and Tiglian are today regarded as corresponding to the Biber stage in the glacial history of the Alps and to the Gelasian (2.6-1.8 million years ago) in the global division of the Quaternary period. Deep sea core samples have identified approximately 40 marine isotope stages (MIS 103 – MIS 64) during the Gelasian. Thus, there have probably been about 20 glacial cycles of varying intensity during Praetiglian and Tiglian. The dominant trigger is believed to be the 41 000 year Milankovitch cycles of axia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interglacial
An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene interglacial began at the end of the Pleistocene, about 11,700 years ago. Pleistocene During the 2.5 million years of the Pleistocene, numerous glacials, or significant advances of continental ice sheets, in North America and Europe, occurred at intervals of approximately 40,000 to 100,000 years. The long glacial periods were separated by more temperate and shorter interglacials. During interglacials, such as the present one, the climate warms and the tundra recedes polewards following the ice sheets. Forests return to areas that once supported tundra vegetation. Interglacials are identified on land or in shallow epicontinental seas by their paleontology. Floral and faunal remains of species pointing to temperate climate and indicating a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Borehole
A borehole is a narrow shaft bored in the ground, either vertically or horizontally. A borehole may be constructed for many different purposes, including the extraction of water ( drilled water well and tube well), other liquids (such as petroleum), or gases (such as natural gas). It may also be part of a geotechnical investigation, environmental site assessment, mineral exploration, temperature measurement, as a pilot hole for installing piers or underground utilities, for geothermal installations, or for underground storage of unwanted substances, e.g. in carbon capture and storage. Importance Engineers and environmental consultants use the term ''borehole'' to collectively describe all of the various types of holes drilled as part of a geotechnical investigation or environmental site assessment (a so-called Phase II ESA). This includes holes advanced to collect soil samples, water samples or rock cores, to advance ''in situ'' sampling equipment, or to install monitoring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Limburg (Netherlands)
Limburg (, ) is the southernmost of the twelve provinces of the Netherlands. It is bordered by Gelderland to the north and by North Brabant to its west. Its long eastern boundary forms the international border with the state of North Rhine-Westphalia in Germany. To the west is the international border with the similarly named Belgian province of Limburg, part of which is delineated by the river Meuse. The Vaalserberg is on the extreme southeastern point, marking the tripoint of the Netherlands, Germany and Belgium. Limburg's main municipalities are the provincial capital Maastricht (population 120,837 as of January 2022), Venlo (population 102,176) in the northeast, as well as Sittard-Geleen (population 91,760, bordering both Belgium and Germany) and Heerlen (population 86,874) in the south. More than half of the population, approximately 650,000 people, live in the south of Limburg, which corresponds to roughly one-third of the province's area proper. In South Limburg, most peop ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tegelen
Tegelen ( li, Tegele) is a village in the municipality of Venlo, situated in the Netherlands. It was an independent municipality until 2001, when it was merged into the municipality of Venlo. Tiglian The name of the glacial stage of Tiglian (part of the Pleistocene) is derived from Tegelen because of the many fossils found there from this era in the local clay. History During excavations in Tegelen Roman pottery and tile ovens were found. The Sint-Martinus church is mentioned in diocesan and monasterial archives dating back to the year 800. Because of its strategic location, various castles and reinforced farms were soon established. The most important of these were the and the . During the Middle Ages, there were several battles in and around Tegelen, because of its proximity to the walled city of Venlo. Over time, a barracks was established in Venlo, and a fortification in neighbouring Blerick. As a result, from the 16th century until the 18th century Tegelen was regularl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
River Rhine
), Surselva, Graubünden, Switzerland , source1_coordinates= , source1_elevation = , source2 = Rein Posteriur/Hinterrhein , source2_location = Paradies Glacier, Graubünden, Switzerland , source2_coordinates= , source2_elevation = , source_confluence = Reichenau , source_confluence_location = Tamins, Graubünden, Switzerland , source_confluence_coordinates= , source_confluence_elevation = , mouth = North Sea , mouth_location = Netherlands , mouth_coordinates = , mouth_elevation = , progression = , river_system = , basin_size = , tributaries_left = , tributaries_right = , custom_label = , custom_data = , extra = The Rhine ; french: Rhin ; nl, Rijn ; wa, Rén ; li, Rien; rm, label= Sursilvan, Rein, rm, label= Sutsilvan and Surmiran, Ragn, rm, label=Rumantsch Grischun, Vallader and Puter, Rain; it, Reno ; gsw, Rhi(n), including i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Estuarine
An estuary is a partially enclosed coastal body of brackish water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries form a transition zone between river environments and maritime environments and are an example of an ecotone. Estuaries are subject both to marine influences such as tides, waves, and the influx of saline water, and to fluvial influences such as flows of freshwater and sediment. The mixing of seawater and freshwater provides high levels of nutrients both in the water column and in sediment, making estuaries among the most productive natural habitats in the world. Most existing estuaries formed during the Holocene epoch with the flooding of river-eroded or glacially scoured valleys when the sea level began to rise about 10,000–12,000 years ago. Estuaries are typically classified according to their geomorphological features or to water-circulation patterns. They can have many different names, such as bays, harb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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