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Marine Reservoir Effect
The marine reservoir effect is a phenomenon affecting radiocarbon dating. Because much of the carbon consumed by organisms in the ocean is older than that consumed by organisms on land, samples from marine life and from organisms that consumed a lot of sea-based foods while alive may appear older when tested than they truly are. It is necessary to account for changes in the Earth's oceans to correct for the marine reservoir effect. The level of the effect on a particular sample varies significantly, depending on the body of water, and more locally on depths, upwelling currents, and freshwater discharges. Typically, affected radiocarbon dates appear c. 400 14C years older than they would if unaffected. But the effect is highly variable in space and time, and can reach 800 to 1200 14C years in Arctic regions. In 2013, archaeologists at the Gottorp Castle Museum tested the effects of fish prepared in a newly made clay vessel on their ability to accurately measure carbon-14 in the c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiocarbon Dating
Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon. The method was developed in the late 1940s at the University of Chicago by Willard Libby. It is based on the fact that radiocarbon () is constantly being created in the Earth's atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and thereafter the amount of it contains begins to decrease as the undergoes radioactive decay. Measuring the amount of in a sample from a dead plant or animal, such as a piece of wood or a fragment of bone, provides information that can be used to calc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon-14
Carbon-14, C-14, or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and colleagues (1949) to date archaeological, geological and hydrogeological samples. Carbon-14 was discovered on February 27, 1940, by Martin Kamen and Sam Ruben at the University of California Radiation Laboratory in Berkeley, California. Its existence had been suggested by Franz N. D. Kurie, Franz Kurie in 1934. There are three naturally occurring isotopes of carbon on Earth: carbon-12 (), which makes up 99% of all carbon on Earth; carbon-13 (), which makes up 1%; and carbon-14 (), which occurs in trace amounts, making up about 1 or 1.5 atoms per 1012 atoms of carbon in the atmosphere. Carbon-12 and carbon-13 are both stable, while carbon-14 is unstable and has a half-life of 5,730 ± 40 years. Carbon-14 decays into nitrogen-14 () through bet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Vikings
Vikings ; non, víkingr is the modern name given to seafaring people originally from Scandinavia (present-day Denmark, Norway and Sweden), who from the late 8th to the late 11th centuries raided, pirated, traded and settled throughout parts of Europe.Roesdahl, pp. 9–22. They also voyaged as far as the Mediterranean, North Africa, Volga Bulgaria, the Middle East, and North America. In some of the countries they raided and settled in, this period is popularly known as the Viking Age, and the term "Viking" also commonly includes the inhabitants of the Scandinavian homelands as a collective whole. The Vikings had a profound impact on the early medieval history of Scandinavia, the British Isles, France, Estonia, and Kievan Rus'. Expert sailors and navigators aboard their characteristic longships, Vikings established Norse settlements and governments in the Viking activity in the British Isles, British Isles, the Faroe Islands, Settlement of Iceland, Icela ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Great Heathen Army
The Great Heathen Army,; da, Store Hedenske Hær also known as the Viking Great Army,Hadley. "The Winter Camp of the Viking Great Army, AD 872–3, Torksey, Lincolnshire", ''Antiquaries Journal''. 96, pp. 23–67 was a coalition of Scandinavian warriors who invaded England in AD 865. Since the late 8th century, the Vikings had been engaging in raids on centres of wealth, such as monasteries. The Great Heathen Army was much larger and aimed to conquer and occupy the four kingdoms of East Anglia, Northumbria, Mercia and Wessex. The name ''Great Heathen Army'' is derived from the ''Anglo-Saxon Chronicle''. The force was led by three of the five sons of the semi-legendary Ragnar Lodbrok, including Halfdan Ragnarsson, Ivar the Boneless and Ubba. The campaign of invasion and conquest against the Anglo-Saxon kingdoms lasted 14 years. Surviving sources give no firm indication of its numbers, but it was described as amongst the largest forces of its kind. The invaders initially l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Bristol
, mottoeng = earningpromotes one's innate power (from Horace, ''Ode 4.4'') , established = 1595 – Merchant Venturers School1876 – University College, Bristol1909 – received royal charter , type = Public red brick research university , endowment = £91.3 million (2021) , budget = £752.0 million (2020–21) , chancellor = Paul Nurse , vice_chancellor = Professor Evelyn Welch , head_label = Visitor , head = Rt Hon. Penny Mordaunt MP , academic_staff = 3,385 (2020) , students = () , undergrad = () , postgrad = () , city = Bristol , country = England , coor = , campus = Urban , free_label = Students' Union , free = University of Bristol Union , colours = ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Radiocarbon Dating
Radiocarbon dating (also referred to as carbon dating or carbon-14 dating) is a method for determining the age of an object containing organic material by using the properties of radiocarbon, a radioactive isotope of carbon. The method was developed in the late 1940s at the University of Chicago by Willard Libby. It is based on the fact that radiocarbon () is constantly being created in the Earth's atmosphere by the interaction of cosmic rays with atmospheric nitrogen. The resulting combines with atmospheric oxygen to form radioactive carbon dioxide, which is incorporated into plants by photosynthesis; animals then acquire by eating the plants. When the animal or plant dies, it stops exchanging carbon with its environment, and thereafter the amount of it contains begins to decrease as the undergoes radioactive decay. Measuring the amount of in a sample from a dead plant or animal, such as a piece of wood or a fragment of bone, provides information that can be used to calc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Inventions ...
The following articles cover the timeline of United States inventions: *Timeline of United States inventions (before 1890), before the turn of the century * Timeline of United States inventions (1890–1945), before World War II *Timeline of United States inventions (1946–1991), for the post-war era *Timeline of United States inventions (after 1991), after the Fall of the Soviet Union {{DEFAULTSORT:Timeline of United States Inventions United States inventions United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conservation And Restoration Of Cultural Heritage
The conservation and restoration of cultural property focuses on protection and care of cultural property (tangible cultural heritage), including artworks, architecture, archaeology, and museum collections. Conservation activities include preventive conservation, examination, documentation, research, treatment, and education. This field is closely allied with conservation science, curators and registrars. Definition Conservation of cultural property involves protection and restoration using "any methods that prove effective in keeping that property in as close to its original condition as possible for as long as possible." Conservation of cultural heritage is often associated with art collections and museums and involves collection care and management through tracking, examination, documentation, exhibition, storage, preventive conservation, and restoration. The scope has widened from art conservation, involving protection and care of artwork and architecture, to conservatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
