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Varve
A varve is an annual layer of sediment or sedimentary rock. The word 'varve' derives from the Swedish word ''varv'' whose meanings and connotations include 'revolution', 'in layers', and 'circle'. The term first appeared as ''Hvarfig lera'' (varved clay) on the first map produced by the Geological Survey of Sweden in 1862. Initially, "varve" referred to each of the separate components comprising a single annual layer in glacial lake sediments, but at the 1910 Geological Congress, the Swedish geologist Gerard De Geer (1858–1943) proposed a new formal definition, where varve means the whole of any annual sedimentary layer. More recently introduced terms such as 'annually laminated' are synonymous with varve. Of the many rhythmites in the geological record, varves are one of the most important and illuminating in studies of past climate change. Varves are amongst the smallest-scale events recognised in stratigraphy. An annual layer can be highly visible because the particles w ...
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Gerard De Geer
Baron Gerard Jacob De Geer (20 November 1858 – 24 July 1943) was a Swedish geologist who made significant contributions to Quaternary geology, particularly geomorphology and geochronology. De Geer is best known for his work on varves. In 1890 De Geer was the first to apply the name Ancylus Lake to the Baltic paleolake discovered by Henrik Munthe. He subsequently participated the protracted scientific controversy surrounding this lake. Biography Baron Gerard Jacob De Geer comes from a well-known Swedish aristocratic family of Brabant origin, who had emigrated to Sweden in the early seventeenth century. His family included prominent industrialists and politicians. His father Louis and older brother Gerhard Louis served as the Prime Minister of Sweden. Gerard Jacob was born on October 2, 1858 in Stockholm in the family of Baron Louis Gerhard de Geer, at that time the first Minister of Justice in the Swedish government, and Carolina de Geer, née Countess Wachtmeister. Since ...
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Rhythmite
A rhythmite consists of layers of sediment or sedimentary rock which are laid down with an obvious periodicity and regularity. They may be created by annual processes such as seasonally varying deposits reflecting variations in the runoff cycle, by shorter term processes such as tides, or by longer term processes such as periodic floods. Rhythmites serve a significant role in unraveling prehistoric events, providing insights into sea level change, glaciation change, and earth's orbital variations which serve to answer questions about climate change. Annually-laminated rhythmites Annually-laminated deposits (varves) are rhythmites with annual periodicity: annual layers of sediment or sedimentary rock are laid down through seasonal variations that result from precipitation, or from temperature, which influences precipitation rates and debris loads in runoff. Of the many rhythmites found in the geological record, varves are among the most important and illuminating to studies of pa ...
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Carl Caldenius
Carl Caldenius (1887–1961), until 1920 known by the surname Carlzon, was a Swedish Quaterany geologist and geotechnical engineer. He is mostly known for his geochronological work in Patagonia. Caldenius worked as geotechnical engineer for the Swedish State Railways until 1922 when he started to work full-time with his Ph.D thesis "Ragundasjöns stratigrafi och geokronologi" (Stratigraphy and geochronology of Lake Ragunda) that he defended in 1924. In 1925 he travelled to Argentina as part of a Swedish-Argentine collaboration to extend the clay varve chronology of Gerard De Geer to the Southern Hemisphere. After returning to Swedsen in 1930 he joined an expedition to Australia and New Zealand where he applied knowledge of varves to study the Carboniferous Karoo Ice Age. See also *Carl Skottsberg *José María Sobral ''Alférez de Navío'' José María Sobral (April 14, 1880 – April 14, 1961) was an Argentine explorer, geologist, naval officer and author who rose t ...
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Sedimentary Rock
Sedimentary rocks are types of rock that are formed by the accumulation or deposition of mineral or organic particles at Earth's surface, followed by cementation. Sedimentation is the collective name for processes that cause these particles to settle in place. The particles that form a sedimentary rock are called sediment, and may be composed of geological detritus (minerals) or biological detritus (organic matter). The geological detritus originated from weathering and erosion of existing rocks, or from the solidification of molten lava blobs erupted by volcanoes. The geological detritus is transported to the place of deposition by water, wind, ice or mass movement, which are called agents of denudation. Biological detritus was formed by bodies and parts (mainly shells) of dead aquatic organisms, as well as their fecal mass, suspended in water and slowly piling up on the floor of water bodies (marine snow). Sedimentation may also occur as dissolved minerals precipitate from ...
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Dendrochronology
Dendrochronology (or tree-ring dating) is the scientific method of dating tree rings (also called growth rings) to the exact year they were formed. As well as dating them, this can give data for dendroclimatology, the study of climate and atmospheric conditions during different periods in history from wood. Dendrochronology derives from Ancient Greek (), meaning "tree", (), meaning "time", and (), "the study of". Dendrochronology is useful for determining the precise age of samples, especially those that are too recent for radiocarbon dating, which always produces a range rather than an exact date. However, for a precise date of the death of the tree a full sample to the edge is needed, which most trimmed timber will not provide. It also gives data on the timing of events and rates of change in the environment (most prominently climate) and also in wood found in archaeology or works of art and architecture, such as old panel paintings. It is also used as a check in radioc ...
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Stratigraphy
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: lithostratigraphy (lithologic stratigraphy), biostratigraphy (biologic stratigraphy), and chronostratigraphy (stratigraphy by age). Historical development Catholic priest Nicholas Steno established the theoretical basis for stratigraphy when he introduced the law of superposition, the principle of original horizontality and the principle of lateral continuity in a 1669 work on the fossilization of organic remains in layers of sediment. The first practical large-scale application of stratigraphy was by William Smith in the 1790s and early 19th century. Known as the "Father of English geology", Smith recognized the significance of strata or rock layering and the importance of fossil markers for correlating strata; he created the first geol ...
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Lake Timiskaming
Lake Timiskaming or Lake Temiskaming (french: Lac Témiscamingue) is a large freshwater lake on the provincial boundary between Ontario and Quebec, Canada. The lake, which forms part of the Ottawa River, is in length and covers an area of almost . Its water level ranges between and above sea-level, with a mean annual average of . The lake is in places up to deep. There are several islands on the lake, notably Mann and du Collège Islands. The name is from the Algonquin ''Temikami'' or ''Temikaming'', meaning "deep body of water with rapid winds” There are 30 species of fish in Lake Timiskaming, the best known are northern pike, sturgeon, lake trout, walleye, smallmouth bass, bullhead, carp, burbot, perch, and whitefish. The lake was shaped during the last ice age when glaciers carved into the rock. It is also the remnants of a huge basin called Lake Ojibway, which existed about 9,500 years ago. Between 1976 and 1981 the DuPagne Classic fishing tourney took plac ...
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Stockholm
Stockholm () is the capital and largest city of Sweden as well as the largest urban area in Scandinavia. Approximately 980,000 people live in the municipality, with 1.6 million in the urban area, and 2.4 million in the metropolitan area. The city stretches across fourteen islands where Lake Mälaren flows into the Baltic Sea. Outside the city to the east, and along the coast, is the island chain of the Stockholm archipelago. The area has been settled since the Stone Age, in the 6th millennium BC, and was founded as a city in 1252 by Swedish statesman Birger Jarl. It is also the county seat of Stockholm County. For several hundred years, Stockholm was the capital of Finland as well (), which then was a part of Sweden. The population of the municipality of Stockholm is expected to reach one million people in 2024. Stockholm is the cultural, media, political, and economic centre of Sweden. The Stockholm region alone accounts for over a third of the country's ...
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Ernst Antevs
Ernst Valdemar Antevs (November 20, 1888 – May 19, 1974) was a Swedish-American geologist and educator who made significant contributions to Quaternary geology, particularly geomorphology and geochronology. Ernst Valdemar Antevs was born on a farm in the Vartofta-Åsaka parish of Skaraborg, (now Västra Götaland), Sweden. He attended Stockholm University where in 1917, he was awarded his Ph.D. in geology. He was employed as a docent at the University of Stockholm from 1917 to 1935. He was also a research associate for the American Geographical Society (1921 to 1922), the Carnegie Institution of Washington (between 1922-1940), Geological Survey of Canada (between 1923- 1930), and Harvard University (1924-1926). He moved to the United States during the 1930s and joined investigators from the Gila Pueblo Archaeological Foundation in Globe, Arizona. In 1939, he became a citizen of the United States. Antevs joined the University of Arizona Departm ...
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Long Island
Long Island is a densely populated island in the southeastern region of the U.S. state of New York, part of the New York metropolitan area. With over 8 million people, Long Island is the most populous island in the United States and the 18th-most populous in the world. The island begins at New York Harbor approximately east of Manhattan Island and extends eastward about into the Atlantic Ocean and 23 miles wide at its most distant points. The island comprises four counties: Kings and Queens counties (the New York City boroughs of Brooklyn and Queens, respectively) and Nassau County share the western third of the island, while Suffolk County occupies the eastern two thirds of the island. More than half of New York City's residents (58.4%) lived on Long Island as of 2020, in Brooklyn and in Queens. Culturally, many people in the New York metropolitan area colloquially use the term "Long Island" (or "the Island") to refer exclusively to Nassau and Suffolk counties, a ...
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Patagonia
Patagonia () refers to a geographical region that encompasses the southern end of South America, governed by Argentina and Chile. The region comprises the southern section of the Andes Mountains with lakes, fjords, temperate rainforests, and glaciers in the west and deserts, tablelands and steppes to the east. Patagonia is bounded by the Pacific Ocean on the west, the Atlantic Ocean to the east, and many bodies of water that connect them, such as the Strait of Magellan, the Beagle Channel, and the Drake Passage to the south. The Colorado and Barrancas rivers, which run from the Andes to the Atlantic, are commonly considered the northern limit of Argentine Patagonia. The archipelago of Tierra del Fuego is sometimes included as part of Patagonia. Most geographers and historians locate the northern limit of Chilean Patagonia at Huincul Fault, in Araucanía Region.Manuel Enrique Schilling; Richard WalterCarlson; AndrésTassara; Rommulo Vieira Conceição; Gustavo Walter Berto ...
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