|
Marine Isotope Stages
Marine isotope stages (MIS), marine oxygen-isotope stages, or oxygen isotope stages (OIS), are alternating warm and cool periods in the Earth's paleoclimate, deduced from oxygen isotope data derived from deep sea core samples. Working backwards from the present, which is MIS 1 in the scale, stages with even numbers have high levels of oxygen-18 and represent cold glacial periods, while the odd-numbered stages are lows in the oxygen-18 figures, representing warm interglacial intervals. The data are derived from pollen and foraminifera (plankton) remains in drilled marine sediment cores, sapropels, and other data that reflect historic climate; these are called proxies. The MIS timescale was developed from the pioneering work of Cesare Emiliani in the 1950s, and is now widely used in archaeology and other fields to express dating in the Quaternary period (the last 2.6 million years), as well as providing the fullest and best data for that period for paleoclimatology or the stud ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Five Myr Climate Change
5 (five) is a number, numeral and digit. It is the natural number, and cardinal number, following 4 and preceding 6, and is a prime number. Humans, and many other animals, have 5 digits on their limbs. Mathematics 5 is a Fermat prime, a Mersenne prime exponent, as well as a Fibonacci number. 5 is the first congruent number, as well as the length of the hypotenuse of the smallest integer-sided right triangle, making part of the smallest Pythagorean triple ( 3, 4, 5). 5 is the first safe prime and the first good prime. 11 forms the first pair of sexy primes with 5. 5 is the second Fermat prime, of a total of five known Fermat primes. 5 is also the first of three known Wilson primes (5, 13, 563). Geometry A shape with five sides is called a pentagon. The pentagon is the first regular polygon that does not tile the plane with copies of itself. It is the largest face any of the five regular three-dimensional regular Platonic solid can have. A conic i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harold Urey
Harold Clayton Urey ( ; April 29, 1893 – January 5, 1981) was an American physical chemist whose pioneering work on isotopes earned him the Nobel Prize in Chemistry in 1934 for the discovery of deuterium. He played a significant role in the development of the Nuclear weapon, atom bomb, as well as contributing to theories on the Miller–Urey experiment, development of organic life from non-living matter. Born in Walkerton, Indiana, Urey studied thermodynamics under Gilbert N. Lewis at the University of California, Berkeley. After he received his PhD in 1923, he was awarded a fellowship by the American-Scandinavian Foundation to study at the Niels Bohr Institute in Copenhagen. He was a research associate at Johns Hopkins University before becoming an associate professor of chemistry at Columbia University. In 1931, he began work with the separation of isotopes that resulted in the discovery of deuterium. During World War II, Urey turned his knowledge of isotope separation to ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Milankovitch Cycles
Milankovitch cycles describe the collective effects of changes in the Earth's movements on its climate over thousands of years. The term was coined and named after the Serbian geophysicist and astronomer Milutin Milanković. In the 1920s, he provided a more definitive and quantitative analysis than James Croll's earlier hypothesis that variations in eccentricity, axial tilt, and precession combined to result in cyclical variations in the intra-annual and latitudinal distribution of solar radiation at the Earth's surface, and that this orbital forcing strongly influenced the Earth's climatic patterns. Earth movements The Earth's rotation around its axis, and revolution around the Sun, evolve over time due to gravitational interactions with other bodies in the Solar System. The variations are complex, but a few cycles are dominant. The Earth's orbit varies between nearly circular and mildly elliptical (its eccentricity varies). When the orbit is more elongated, there is more ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Sheet
In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacier, glacial ice that covers surrounding terrain and is greater than . The only current ice sheets are the Antarctic ice sheet and the Greenland ice sheet. Ice sheets are bigger than ice shelf, ice shelves or alpine glaciers. Masses of ice covering less than 50,000 km2 are termed an ice cap. An ice cap will typically feed a series of glaciers around its periphery. Although the surface is cold, the base of an ice sheet is generally warmer due to Geothermal activity, geothermal heat. In places, melting occurs and the melt-water lubricates the ice sheet so that it flows more rapidly. This process produces fast-flowing channels in the ice sheet — these are ice streams. Even stable ice sheets are continually in motion as the ice gradually flows outward from the central plateau, which is the tallest point of the ice sheet, and towards the margins. The ice sheet slope is low around the plate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plio-Pleistocene
The Plio-Pleistocene is an informally described geological pseudo-period, which begins about 5 million years ago (Mya) and, drawing forward, combines the time ranges of the formally defined Pliocene and Pleistocene epochs—marking from about 5 Mya to about 12 kya. Nominally, the Holocene epoch—the last 12 thousand years—would be excluded, but most Earth scientists would probably treat the current times as incorporated into the term "Plio-Pleistocene"; see below. In the contexts of archaeology, paleontology, and paleoanthropology, the Plio-Pleistocene is a very useful period to which scientists may assign the long and continuous run in East Africa of datable sedimentary layers and their contents (e.g. the Bouri Formation). These contents collectively present a focused view of the continuous evolution of the region's large vertebrates, especially the evolution of some African apes ( hominids) to the earliest hominins; and then the development of the early humans and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Core
An ice core is a core sample that is typically removed from an ice sheet or a high mountain glacier A glacier (; or ) is a persistent body of dense ice, a form of rock, that is constantly moving downhill under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires .... Since the ice forms from the incremental buildup of annual layers of snow, lower layers are older than upper ones, and an ice core contains ice formed over a range of years. Cores are Ice drilling, drilled with hand Auger (drill), augers (for shallow holes) or powered drills; they can reach depths of over two miles (3.2 km), and contain ice up to 800,000 years old. The physical properties of the ice and of material trapped in it can be used to reconstruct the climate over the age range of the core. The proportions of different oxygen and hydrogen isotopes provide information about Paleothermometer, ancient temperatures, a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stadial
Stadials and interstadials are phases dividing the Quaternary period, or the last 2.6 million years. Stadials are periods of colder climate, and interstadials are periods of warmer climate. Each Quaternary climate phase has been assigned with a marine isotope stage (MIS) number, which describes the alternation between warmer and cooler temperatures, as measured by oxygen isotope data. Stadials have even MIS numbers, and interstadials have odd MIS numbers. The current Holocene interstadial is MIS 1, and the Last Glacial Maximum stadial is MIS 2. Marine isotope stages are sometimes subdivided into stadials and interstadials by minor climate fluctuations within the overall stadial or interstadial, which are indicated by letters. The odd-numbered interstadial MIS 5, also known as the Sangamonian interglacial, contains two periods of relative cooling, and so is subdivided into three interstadials (5a, 5c, 5e) and two stadials (5b, 5d). A stadial isotope stage like MIS 6 woul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ecoregion
An ecoregion (ecological region) is an ecological and geographic area that exists on multiple different levels, defined by type, quality, and quantity of environmental resources. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural communities and species. The biodiversity of flora, fauna and ecosystems that characterise an ecoregion tends to be distinct from that of other ecoregions. In theory, biodiversity or conservation ecoregions are relatively large areas of land or water where the probability of encountering different species and communities at any given point remains relatively constant, within an acceptable range of variation (largely undefined at this point). Ecoregions are also known as "ecozones" ("ecological zones"), although that term may also refer to biogeographic realms. Three caveats are appropriate for all bio-geographic mapping approaches. Firstly, no single bio-geographic fram ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nicholas Shackleton
Sir Nicholas John Shackleton (23 June 1937 – 24 January 2006) was an English geologist and paleoclimatologist who specialised in the Quaternary Period. He was the son of the distinguished field geologist Robert Millner Shackleton and great-nephew of the explorer Ernest Shackleton. Education and employment Educated at Cranbrook School, Kent (thanks to the generosity of a person he called his "fairy godmother" as she paid his school fees) Shackleton went on to read Natural Sciences (Cambridge), natural sciences at Clare College, Cambridge. He graduated with the Bachelor of Arts degree in 1961, promoted in 1964 to Master of Arts (Oxbridge and Dublin), Master of Arts. In 1967 Cambridge awarded him a PhD degree, for a thesis entitled "The Measurement of Paleotemperatures in the Quaternary Era". Apart from periods abroad as Visiting Professor or Research Associate, Shackleton's entire scientific career was spent at Cambridge. He became Ad hominem Professor in 1991, in the Univer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caribbean
The Caribbean ( , ; ; ; ) is a region in the middle of the Americas centered around the Caribbean Sea in the Atlantic Ocean, North Atlantic Ocean, mostly overlapping with the West Indies. Bordered by North America to the north, Central America to the west, and South America to the south, it comprises numerous List of Caribbean islands, islands, cays, islets, reefs, and banks. It includes the Lucayan Archipelago, Greater Antilles, and Lesser Antilles of the West Indies; the Quintana Roo Municipalities of Quintana Roo#Municipalities, islands and Districts of Belize#List, Belizean List of islands of Belize, islands of the Yucatán Peninsula; and the Bay Islands Department#Islands, Bay Islands, Miskito Cays, Archipelago of San Andrés, Providencia and Santa Catalina, Archipelago of San Andrés, Providencia, and Santa Catalina, Corn Islands, and San Blas Islands of Central America. It also includes the coastal areas on the Mainland, continental mainland of the Americas bordering the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Miami
The University of Miami (UM, UMiami, Miami, U of M, and The U) is a private university, private research university in Coral Gables, Florida, United States. , the university enrolled 19,852 students in two colleges and ten schools across over 350 academic majors and programs, including the Miller School of Medicine in Health District (Miami), Miami's Health District, the University of Miami School of Law, law school on the main campus, the Rosenstiel School of Marine, Atmospheric, and Earth Science on Virginia Key, and additional research facilities in southern Miami-Dade County, Florida, Miami-Dade County. The University of Miami offers 151 undergraduate, 149 master's, and 68 doctoral degree programs. With over 20,000 faculty and staff as of 2024, the University of Miami is the second-largest employer in Miami-Dade County. The university's main campus in Coral Gables spans , has over of buildings, and is located southwest of Greater Downtown Miami, downtown Miami, the heart ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
