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Meltwater Pulse 1B
Meltwater pulse 1B (MWP1b) is the name used by Quaternary geologists, paleoclimatologists, and oceanographers for a period of either rapid or just accelerated post-glacial sea level rise that some hypothesize to have occurred between 11,500 and 11,200 calendar years ago at the beginning of the Holocene and after the end of the Younger Dryas. Meltwater pulse 1B is also known as catastrophic rise event 2 (CRE2) in the Caribbean Sea. Other named, postglacial meltwater pulses are known most commonly as meltwater pulse 1A0 (meltwater pulse19ka), meltwater pulse 1A, meltwater pulse 1C, meltwater pulse 1D, and meltwater pulse 2. It and these other periods of proposed rapid sea level rise are known as ''meltwater pulses'' because the inferred cause of them was the rapid release of meltwater into the oceans from the collapse of continental ice sheets.Cronin, T.M. (2012) ''Rapid sea-level rise.'' Quaternary Science Reviews. 56:11-30. Sea level There is considerable unresolved disagreemen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Postglacial Sea Level Rise Curve And Meltwater Pulses (MWP)
The Holocene ( ) is the current Geologic time scale, geological epoch. It began approximately 11,650 radiocarbon calibration, cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene together form the Quaternary period. The Holocene has been identified with the current warm period, known as Marine isotope stage, MIS 1. It is considered by some to be an interglacial period within the Pleistocene Epoch, called the Flandrian interglacial.Oxford University Press – Why Geography Matters: More Than Ever (book) – "Holocene Humanity" section https://books.google.com/books?id=7P0_sWIcBNsC The Holocene corresponds with the rapid proliferation, growth and impacts of the human species worldwide, including Recorded history, all of its written history, technological revolutions, development of major civilizations, and overall significant transition towards urban culture, urban living in the p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deglaciation
Deglaciation is the transition from full glacial conditions during ice ages, to warm interglacials, characterized by global warming and sea level rise due to change in continental ice volume. Thus, it refers to the retreat of a glacier, an ice sheet or frozen surface layer, and the resulting exposure of the Earth's surface. The decline of the cryosphere due to ablation can occur on any scale from global to localized to a particular glacier. After the Last Glacial Maximum (ca. 21,000 years ago), the last deglaciation begun, which lasted until the early Holocene. Around much of Earth, deglaciation during the last 100 years has been accelerating as a result of climate change, partly brought on by anthropogenic changes to greenhouse gases. The previous deglaciation took place from approximately 22 ka until 11.5 ka. This occurred when there was an annual mean atmospheric temperature on the earth that increased by roughly 5 °C, which was also accompanied by regional hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sverdrup
In oceanography, the sverdrup (symbol: Sv) is a non- SI metric unit of volumetric flow rate, with equal to . It is equivalent to the SI derived unit cubic hectometer per second (symbol: hm3/s or hm3⋅s−1): 1 Sv is equal to 1 hm3/s. It is used almost exclusively in oceanography to measure the volumetric rate of transport of ocean currents. It is named after Harald Sverdrup. One sverdrup is about five times what is carried by the world’s largest river, the Amazon. In the context of ocean currents, a volume of one million cubic meters may be imagined as a "slice" of ocean with dimensions × × (width × length × thickness). At this scale, these units can be more easily compared in terms of width of the current (several km), depth (hundreds of meters), and current speed (as meters per second). Thus, a hypothetical current wide, 500 m (0.5 km) deep, and moving at 2 m/s would be transporting of water. The sverdrup is distinct from the SI sievert unit or th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gulf Of Mexico
The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States; on the southwest and south by the Mexico, Mexican States of Mexico, states of Tamaulipas, Veracruz, Tabasco, Campeche, Yucatan, and Quintana Roo; and on the southeast by Cuba. The Southern United States, Southern U.S. states of Texas, Louisiana, Mississippi, Alabama, and Florida, which border the Gulf on the north, are often referred to as the "Third Coast" of the United States (in addition to its Atlantic and Pacific Ocean, Pacific coasts). The Gulf of Mexico took shape approximately 300 million years ago as a result of plate tectonics.Huerta, A.D., and D.L. Harry (2012) ''Wilson cycles, tectonic inheritance, and rifting of the North American Gulf of Mexico continental margin.'' Geosphere. 8(1):GES00725.1, first p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orca Basin
The Orca Basin is a mid-slope, silled, mini-basin in the northern Gulf of Mexico some 300 km southwest of the Mississippi River mouth on the Louisiana continental slope.Meckler, A. N., et al.''Glacial to Holocene terrigenous organic matter input to sediments from Orca Basin, Gulf of Mexico,''Earth and Planetary Science Letters 272 (2008) 251–263. It is unique amongst the mini-basins in this area, in containing a large brine pool of anoxic salt brine. The pool is approximately in area and up to deepPilcher, R.S. and Blumstein, R.D. 2007. Brine volume and salt dissolution rates in Orca Basin, northeast Gulf of Mexico. AAPG Bulletin; 91; no. 6; p. 823-833. Abstract under depth of Gulf water and is derived from dissolution of underlying Jurassic age Louann Salt. With a volume of the pool results from the dissolution of about 3.62 billion tonnes of the Louann Salt bed into seawater. The basin owes its shape to ongoing salt tectonics and is surrounded by salt diapirs. Gas hydr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand and silt can be carried in suspension in river water and on reaching the sea bed deposited by sedimentation; if buried, they may eventually become sandstone and siltstone (sedimentary rocks) through lithification. Sediments are most often transported by water (fluvial processes), but also wind (aeolian processes) and glaciers. Beach sands and river channel deposits are examples of fluvial transport and deposition, though sediment also often settles out of slow-moving or standing water in lakes and oceans. Desert sand dunes and loess are examples of aeolian transport and deposition. Glacial moraine deposits and till are ice-transported sediments. Classification Sediment can be classified based on its grain size, grain shape, and c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mississippi River
The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it flows generally south for to the Mississippi River Delta in the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains all or parts of 32 U.S. states and two Canadian provinces between the Rocky and Appalachian mountains. The main stem is entirely within the United States; the total drainage basin is , of which only about one percent is in Canada. The Mississippi ranks as the thirteenth-largest river by discharge in the world. The river either borders or passes through the states of Minnesota, Wisconsin, Iowa, Illinois, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana. Native Americans have lived along the Mississippi River and its tributaries for thousands of years. Most were hunter-ga ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proxy (climate)
In the study of past climates ("paleoclimatology"), climate proxies are preserved physical characteristics of the past that stand in for direct meteorological measurements and enable scientists to reconstruct the climatic conditions over a longer fraction of the Earth's history. Reliable global records of climate only began in the 1880s, and proxies provide the only means for scientists to determine climatic patterns before record-keeping began. A large number of climate proxies have been studied from a variety of geologic contexts. Examples of proxies include stable isotope measurements from ice cores, growth rates in tree rings, species composition of sub-fossil pollen in lake sediment or foraminifera in ocean sediments, temperature profiles of boreholes, and stable isotopes and mineralogy of corals and carbonate speleothems. In each case, the proxy indicator has been influenced by a particular seasonal climate parameter (e.g., summer temperature or monsoon intensity) at the t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laurentide Ice Sheet
The Laurentide Ice Sheet was a massive sheet of ice that covered millions of square miles, including most of Canada and a large portion of the Northern United States, multiple times during the Quaternary glacial epochs, from 2.58 million years ago to the present. The last advance covered most of northern North America between c. 95,000 and c. 20,000 years before the present day and, among other geomorphological effects, gouged out the five Great Lakes and the hosts of smaller lakes of the Canadian Shield. These lakes extend from the eastern Northwest Territories, through most of northern Canada, and the upper Midwestern United States (Minnesota, Wisconsin, and Michigan) to the Finger Lakes, through Lake Champlain and Lake George areas of New York, across the northern Appalachians into and through all of New England and Nova Scotia. At times, the ice sheet's southern margin included the present-day sites of coastal towns of the Northeastern United States, and cities such as Bos ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
East Antarctic Ice Sheet
The East Antarctic Ice Sheet (EAIS) is one of two large ice sheets in Antarctica, and the largest on the entire planet. The EAIS lies between 45° west and 168° east longitudinally. The EAIS holds enough ice to raise global sea levels by and is considerably larger in area and mass than the West Antarctic Ice Sheet (WAIS). It is separated from the WAIS by the Transantarctic Mountains. The EAIS is the driest, windiest, and coldest place on Earth, with temperatures reported down to nearly -100°C. The EAIS holds the thickest ice on Earth, at . It is home to the geographic South Pole and the Amundsen–Scott South Pole Station. Temperature changes Cooling in East Antarctica during the decades of the 1980s and 1990s partially offset the impact of climate change on the West Antarctic Ice Sheet, which has warmed by more than 0.1 °C/decade in the last 50 years. The continent-wide average surface temperature trend of Antarctica is positive and statistically significant at >0.0 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nunatak
A nunatak (from Inuit ''nunataq'') is the summit or ridge of a mountain that protrudes from an ice field or glacier that otherwise covers most of the mountain or ridge. They are also called glacial islands. Examples are natural pyramidal peaks. When rounded by glacial action, smaller rock promontories may be referred to as rognons. The word is of Greenlandic origin and has been used in English since the 1870s. Description The term is typically used in areas where a permanent ice sheet is present and the nunataks protrude above the sheet.J. J. Zeeberg, ''Climate and Glacial History of the Novaya Zemlya Archipelago, Russian Arctic''. pp. 82–84 Nunataks present readily identifiable landmark reference points in glaciers or ice caps and are often named. While some nunataks are isolated, sometimes they form dense clusters, such as Queen Louise Land in Greenland. Nunataks are generally angular and jagged, which hampers the formation of glacial ice on their tops, although snow can a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glacial Erratic
A glacial erratic is glacially deposited rock differing from the type of rock native to the area in which it rests. Erratics, which take their name from the Latin word ' ("to wander"), are carried by glacial ice, often over distances of hundreds of kilometres. Erratics can range in size from pebbles to large boulders such as Big Rock () in Alberta. Geologists identify erratics by studying the rocks surrounding the position of the erratic and the composition of the erratic itself. Erratics are significant because: *They can be transported by glaciers, and they are thereby one of a series of indicators which mark the path of prehistoric glacier movement. Their lithographic origin can be traced to the parent bedrock, allowing for confirmation of the ice flow route. *They can be transported by ice rafting. This allows quantification of the extent of glacial flooding resulting from ice dam failure which release the waters stored in proglacial lakes such as Lake Missoula. Erratics ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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