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Jean-Claude Duplessy
Jean-Claude Duplessy, born in 1942, is a French geochemist. He is Director of Research Emeritus at the CNRS and a member of the French Academy of Sciences. Biography Jean-Claude Duplessy, a former student of the Ecole Normale Supérieure (Ulm), a physics graduate, is a geochemist. His work has contributed to a better understanding of how the ocean has functioned over the recent history of the Earth. He is a recognized pioneer in rebuilding ocean dynamics through the use of carbon isotopes and foraminiferous shell oxygen in marine sediments. He was one of the first to see the importance of a high quality chronology for a reliable interpretation of measurements related to climate variations in the Earth's past. Scientific work He began his research just as the foundations of isotopic geochemistry were beginning to be well established through the work of Harold Urey and Cesare Emiliani in Chicago. The analysis of stable isotopes and natural radioactive elements makes it possibl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geochemistry
Geochemistry is the science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems such as the Earth's crust and its oceans. The realm of geochemistry extends beyond the Earth, encompassing the entire Solar System, and has made important contributions to the understanding of a number of processes including mantle convection, the formation of planets and the origins of granite and basalt. It is an integrated field of chemistry and geology. History The term ''geochemistry'' was first used by the Swiss-German chemist Christian Friedrich Schönbein in 1838: "a comparative geochemistry ought to be launched, before geognosy can become geology, and before the mystery of the genesis of our planets and their inorganic matter may be revealed." However, for the rest of the century the more common term was "chemical geology", and there was little contact between geologists and chemists. Geochemistry emerged as a separate discipline af ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Carbon Dioxide
Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is transparent to visible light but absorbs infrared radiation, acting as a greenhouse gas. It is a trace gas in Earth's atmosphere at 421 parts per million (ppm), or about 0.04% by volume (as of May 2022), having risen from pre-industrial levels of 280 ppm. Burning fossil fuels is the primary cause of these increased CO2 concentrations and also the primary cause of climate change.IPCC (2022Summary for policy makersiClimate Change 2022: Mitigation of Climate Change. Contribution of Working Group III to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA Carbon dioxide is soluble in water and is found in groundwater, lakes, i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Greenland
Greenland ( kl, Kalaallit Nunaat, ; da, Grønland, ) is an island country in North America that is part of the Kingdom of Denmark. It is located between the Arctic and Atlantic oceans, east of the Canadian Arctic Archipelago. Greenland is the world's largest island. It is one of three constituent countries that form the Kingdom of Denmark, along with Denmark and the Faroe Islands; the citizens of these countries are all citizens of Denmark and the European Union. Greenland's capital is Nuuk. Though a part of the continent of North America, Greenland has been politically and culturally associated with Europe (specifically Norway and Denmark, the colonial powers) for more than a millennium, beginning in 986.The Fate of Greenland's Vikings , by Dale Mackenzie Brown, ''Archaeological Institute of America ... [...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 The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden experiments, Geiger–Marsden gold foil experiment. After th ... 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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mass Spectrometry
Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a '' mass spectrum'', a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is used in many different fields and is applied to pure samples as well as complex mixtures. A mass spectrum is a type of plot of the ion signal as a function of the mass-to-charge ratio. These spectra are used to determine the elemental or isotopic signature of a sample, the masses of particles and of molecules, and to elucidate the chemical identity or structure of molecules and other chemical compounds. In a typical MS procedure, a sample, which may be solid, liquid, or gaseous, is ionized, for example by bombarding it with a beam of electrons. This may cause some of the sample's molecules to break up into positively charged fragments or simply become positively charged without fragmenting. These ions (fragments) are then separated acco ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brown University
Brown University is a private research university in Providence, Rhode Island. Brown is the seventh-oldest institution of higher education in the United States, founded in 1764 as the College in the English Colony of Rhode Island and Providence Plantations. Brown is one of nine colonial colleges chartered before the American Revolution. Admissions at Brown is among the most selective in the United States. In 2022, the university reported a first year acceptance rate of 5%. It is a member of the Ivy League. Brown was the first college in the United States to codify in its charter that admission and instruction of students was to be equal regardless of their religious affiliation. The university is home to the oldest applied mathematics program in the United States, the oldest engineering program in the Ivy League, and the third-oldest medical program in New England. The university was one of the early doctoral-granting U.S. institutions in the late 19th century, adding ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Imbrie
John Imbrie (July 4, 1925 – May 13, 2016) was an American paleoceanographer best known for his work on the theory of ice ages. He was the grandson of William Imbrie, an American missionary to Japan. After serving with the 10th Mountain Division in Italy during World War II, Imbrie earned his bachelor's degree from Princeton University. He then went on to receive a Ph.D. from Yale University in 1951. He was elected to the National Academy of Sciences in 1978, and both the American Philosophical Society and the American Academy of Arts and Sciences in 1981. That same year, he was the recipient of a MacArthur Fellowship. He was awarded the Maurice Ewing Medal in 1986 by the AGU and the William H. Twenhofel Medal by the Society for Sedimentary Geology in 1991, the only time the Society has awarded it to a non-member. Imbrie was on the faculty of the Geological Sciences Department at Brown University from 1967, where he held the Henry L. Doherty chair of Oceanogra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
André Berger
André Léon Georges Chevalier Berger (born July 30, 1942, Acoz) is a Belgian climatologist and professor. He is best known for his significant contribution to the renaissance and further development of the astronomical theory of paleoclimates and as a cited pioneer of the interdisciplinary study of climate dynamics and history. Biography Trained in mathematics, Berger holds a PhD in sciences from the Université catholique de Louvain (1973) and a master of sciences in meteorology from Massachusetts Institute of Technology (1971). He has received honorary doctoral degrees from Paul Cézanne University Aix-Marseille III (1989), Toulouse III - Paul Sabatier University (1999) and the Faculté polytechnique de Mons (2004). He is presently emeritus professor and senior researcher at UCLouvain. Berger works in the field of paleoclimatology, and worked on the astronomical theory of paleoclimate (also known as the Milankovitch theory) in the 1970s, and to its promotion and developmen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milutin Milanković
Milutin Milanković (sometimes anglicised as Milankovitch; sr-Cyrl, Милутин Миланковић ; 28 May 1879 – 12 December 1958) was a Serbian mathematician, astronomer, climatologist, geophysicist, civil engineer and popularizer of science. Milanković gave two fundamental contributions to global science. The first contribution is the "Canon of the Earth's Insolation", which characterizes the climates of all the planets of the Solar System. The second contribution is the explanation of Earth's long-term climate changes caused by changes in the position of the Earth in comparison to the Sun, now known as Milankovitch cycles. This partly explained the ice ages occurring in the geological past of the Earth, as well as the climate changes on the Earth which can be expected in the future. He founded planetary climatology by calculating temperatures of the upper layers of the Earth's atmosphere as well as the temperature conditions on planets of the inner Solar System, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Salinity
Salinity () is the saltiness or amount of salt dissolved in a body of water, called saline water (see also soil salinity). It is usually measured in g/L or g/kg (grams of salt per liter/kilogram of water; the latter is dimensionless and equal to ‰). Salinity is an important factor in determining many aspects of the chemistry of natural waters and of biological processes within it, and is a thermodynamic state variable that, along with temperature and pressure, governs physical characteristics like the density and heat capacity of the water. A contour line of constant salinity is called an ''isohaline'', or sometimes ''isohale''. Definitions Salinity in rivers, lakes, and the ocean is conceptually simple, but technically challenging to define and measure precisely. Conceptually the salinity is the quantity of dissolved salt content of the water. Salts are compounds like sodium chloride, magnesium sulfate, potassium nitrate, and sodium bicarbonate which dissolve into ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Western Europe
Western Europe is the western region of Europe. The region's countries and territories vary depending on context. The concept of "the West" appeared in Europe in juxtaposition to "the East" and originally applied to the ancient Mediterranean world, the Roman Empire ( Western Roman Empire and Eastern Roman Empire), and medieval " Christendom" ( Western Christianity and Eastern Christianity). Beginning with the Renaissance and the Age of Discovery, roughly from the 15th century, the concept of ''Europe'' as "the West" slowly became distinguished from and eventually replaced the dominant use of "Christendom" as the preferred endonym within the region. By the Age of Enlightenment and the Industrial Revolution, the concepts of "Eastern Europe" and "Western Europe" were more regularly used. Historical divisions Classical antiquity and medieval origins Prior to the Roman conquest, a large part of Western Europe had adopted the newly developed La Tène culture. As the Roman ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gulf Stream
The Gulf Stream, together with its northern extension the North Atlantic Drift, is a warm and swift Atlantic ocean current that originates in the Gulf of Mexico and flows through the Straits of Florida and up the eastern coastline of the United States then veers east near 36 latitude (North Carolina) and moves toward Northwest Europe as the North Atlantic Current. The process of western intensification causes the Gulf Stream to be a northwards accelerating current off the east coast of North America. At about , it splits in two, with the northern stream, the North Atlantic Drift, crossing to Northern Europe and the southern stream, the Canary Current, recirculating off West Africa. The Gulf Stream influences the climate of the coastal areas of the east coast of the United States from Florida to southeast Virginia (near 36 north latitude), and to a greater degree the climate of Northwest Europe. There is consensus that the climate of northwest Europe is warmer than other ar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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