|
Younger Dryas Impact Hypothesis
The Younger Dryas impact hypothesis (YDIH) or Clovis comet hypothesis is a speculative attempt to explain the onset of the Younger Dryas (YD) as an alternative to the long standing and widely accepted cause due to a significant reduction or shutdown of the North Atlantic "Conveyor" in response to a sudden influx of fresh water from Lake Agassiz and deglaciation in North America. The YDIH posits that fragments of a large (more than 4 kilometers in diameter), disintegrating asteroid or comet struck North America, South America, Europe, and western Asia around 12,850 years ago, coinciding with the beginning of the Younger Dryas cooling event. Multiple meteor air bursts and/or impacts are said to have produced the Younger Dryas boundary layer (YDB), depositing peak concentrations of platinum, high-temperature spherules, meltglass, and nanodiamonds, forming an isochronous datum at more than 50 sites across about 50 million km2 of Earth's surface. Some scientists have proposed that ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Younger Dryas
The Younger Dryas (c. 12,900 to 11,700 years BP) was a return to glacial conditions which temporarily reversed the gradual climatic warming after the Last Glacial Maximum (LGM, c. 27,000 to 20,000 years BP). The Younger Dryas was the last stage of the Pleistocene epoch (c. 2,580,000 to 11,700 years BP) and it preceded the current, warmer Holocene epoch. The Younger Dryas was the most severe and long lasting of several interruptions to the warming of the Earth's climate, and it was preceded by the Late Glacial Interstadial (c. 14,670 to 12,900 BP). The change was relatively sudden, taking place in decades, and it resulted in a decline of temperatures in Greenland by 4~10 °C (7.2~18 °F), and advances of glaciers and drier conditions over much of the temperate Northern Hemisphere. A number of theories have been put forward about the cause, and the most widely supported by scientists is that the Atlantic meridional overturning circulation, which transports warm water ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clovis Culture
The Clovis culture is a prehistoric Paleoamerican culture, named for distinct stone and bone tools found in close association with Pleistocene fauna, particularly two mammoths, at Blackwater Locality No. 1 near Clovis, New Mexico, in 1936 and 1937 (though Paleoindian artifacts had been found at the site since the 1920s). It appears around 11,500–11,000 uncalibrated years before present (YBP)"Clovis Culture" entry in the ''Concise Oxford Dictionary of Archaeology'': "9,500–9,000 BC". at the end of the last glacial period and is characterized by the manufacture of " Clovis points" and distinctive bone and ivory tools. Archaeologists' most precise determinations at present suggest this radiocarbon age is equal to roughly 13,200 to 12,900 calendar years ago. The only human burial that has been directly associated with tools from the Clovis culture included the remains of an infant boy researchers named Anzick-1. Paleogenetic analyses of Anzick-1's ancient nuclear, mitoch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
World Archaeology
''World Archaeology'' is a peer-reviewed academic journal covering all aspects of archaeology. It was established in 1969 and originally published triannually by Routledge & Kegan Paul. In 2004 it changed to a quarterly publication schedule while remaining under the Routledge imprint. Each of the year's first three issues within a volume are dedicated to specific individual themes and topics within archaeology Archaeology or archeology is the scientific study of human activity through the recovery and analysis of material culture. The archaeological record consists of artifacts, architecture, biofacts or ecofacts, sites, and cultural landsca ..., and contributions address the topic from a variety of perspectives. The fourth and last issue of the year has been given over to coverage of current debates within archaeology, in which papers discuss significant issues and global concerns in the field. Abstracting and indexing The journal is abstracted and indexed in: ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arctodus
''Arctodus'' is an extinct genus of short-faced bear that inhabited North America during the Pleistocene (~2.5 Mya until 12,000 years ago). There are two recognized species: the lesser short-faced bear (''Arctodus pristinus'') and the giant short-faced bear (''Arctodus simus''). Both species are relatively rare in the fossil record- ''A. pristinus'' was largely restricted to the Early Pleistocene of the eastern United States, whereas ''A. simus'' had a cosmopolitan range, with most finds being from the Late Pleistocene of the US, Mexico and Canada. ''A. simus'' evolved from ''A. pristinus'', but both species likely overlapped in the Middle Pleistocene. Of these species, ''A. simus'' was larger, is known from more complete remains, and is considered one of the most charismatic of North America's megafauna. Today considered to be an enormous omnivore, ''Arctodus simus'' is believed to be one of the largest known terrestrial mammalian carnivorans that has ever existed. However, ''Arc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mammoth
A mammoth is any species of the extinct elephantid genus ''Mammuthus'', one of the many genera that make up the order of trunked mammals called proboscideans. The various species of mammoth were commonly equipped with long, curved tusks and, in northern species, a covering of long hair. They lived from the Pliocene epoch (from around 5 million years ago) into the Holocene at about 4,000 years ago, and various species existed in Africa, Europe, Asia, and North America. They were members of the family Elephantidae, which also contains the two genera of modern elephants and their ancestors. Mammoths are more closely related to living Asian elephants than African elephants. The oldest representative of ''Mammuthus'', the South African mammoth (''M. subplanifrons''), appeared around 5 million years ago during the early Pliocene in what is now southern and eastern Africa. Descendant species of these mammoths moved north and continued to propagate into numerous subsequen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Camel
A camel (from: la, camelus and grc-gre, κάμηλος (''kamēlos'') from Hebrew or Phoenician: גָמָל ''gāmāl''.) is an even-toed ungulate in the genus ''Camelus'' that bears distinctive fatty deposits known as "humps" on its back. Camels have long been domesticated and, as livestock, they provide food (milk and meat) and textiles (fiber and felt from hair). Camels are working animals especially suited to their desert habitat and are a vital means of transport for passengers and cargo. There are three surviving species of camel. The one-humped dromedary makes up 94% of the world's camel population, and the two-humped Bactrian camel makes up 6%. The Wild Bactrian camel is a separate species and is now critically endangered. The word ''camel'' is also used informally in a wider sense, where the more correct term is "camelid", to include all seven species of the family Camelidae: the true camels (the above three species), along with the "New World" camelids: the lla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
University Of Mainz
The Johannes Gutenberg University Mainz (german: Johannes Gutenberg-Universität Mainz) is a public research university in Mainz, Rhineland Palatinate, Germany, named after the printer Johannes Gutenberg since 1946. With approximately 32,000 students (2018) in about 100 schools and clinics, it is among the largest universities in Germany. Starting on 1 January 2005 the university was reorganized into 11 faculties of study. The university is a member of the German U15, a coalition of fifteen major research-intensive and leading medical universities in Germany. The Johannes Gutenberg University is considered one of the most prestigious universities in Germany. The university is part of the IT-Cluster Rhine-Main-Neckar. The Johannes Gutenberg University Mainz, the Goethe University Frankfurt and the Technische Universität Darmstadt together form the Rhine-Main-Universities (RMU). History The first University of Mainz goes back to the Archbishop of Mainz, Prince-elector and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Laacher See
Laacher See (), also known as Lake Laach or Laach Lake, is a volcanic caldera lake with a diameter of in Rhineland-Palatinate, Germany, about northwest of Koblenz, south of Bonn, and west of Andernach. It is in the Eifel mountain range, and is part of the East Eifel volcanic field within the larger Volcanic Eifel. The lake was formed by a Plinian eruption approximately 13,000 years BP with a Volcanic Explosivity Index (VEI) of 6, on the same scale as the Pinatubo eruption of 1991. Description The lake is oval in shape and surrounded by high banks. The lava was quarried for millstones from the Roman period until the introduction of iron rollers for grinding grain. On the western side lies the Benedictine Maria Laach Abbey ('), founded in 1093 by Henry II of Laach of the House of Luxembourg, first Count Palatine of the Rhine, who had his castle opposite to the monastery above the eastern lakeside. The lake has no natural outlet but is drained by a tunnel dug before 1170 a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Baylor University
Baylor University is a private Baptist Christian research university in Waco, Texas. Baylor was chartered in 1845 by the last Congress of the Republic of Texas. Baylor is the oldest continuously operating university in Texas and one of the first educational institutions west of the Mississippi River in the United States. Located on the banks of the Brazos River next to I-35, between the Dallas–Fort Worth Metroplex and Austin, the university's campus is the largest Baptist university in the world. As of fall, 2021, Baylor had a total enrollment of 20,626 (undergraduate 15,191, graduate 5,435). It is classified among "R1: Doctoral Universities – Very High Research Activity". The university grants undergraduate and graduate degrees, including doctoral and professional degrees. Baylor University's athletic teams, known as the Bears, participate in 19 intercollegiate sports. The university is a member of the Big 12 Conference in the NCAA Division I. History In 184 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermohaline Circulation
Thermohaline circulation (THC) is a part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes. The adjective ''thermohaline'' derives from '' thermo-'' referring to temperature and ' referring to salt content, factors which together determine the density of sea water. Wind-driven surface currents (such as the Gulf Stream) travel polewards from the equatorial Atlantic Ocean, cooling en route, and eventually sinking at high latitudes (forming North Atlantic Deep Water). This dense water then flows into the ocean basins. While the bulk of it upwells in the Southern Ocean, the oldest waters (with a transit time of about 1000 years) upwell in the North Pacific. Extensive mixing therefore takes place between the ocean basins, reducing differences between them and making the Earth's oceans a global system. The water in these circuits transport both energy (in the form of heat) and mass (dissolved solids an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jet Stream
Jet streams are fast flowing, narrow, meandering air currents in the atmospheres of some planets, including Earth. On Earth, the main jet streams are located near the altitude of the tropopause and are westerly winds (flowing west to east). Jet streams may start, stop, split into two or more parts, combine into one stream, or flow in various directions including opposite to the direction of the remainder of the jet. Overview The strongest jet streams are the polar jets around the polar vortices, at above sea level, and the higher altitude and somewhat weaker subtropical jets at . The Northern Hemisphere and the Southern Hemisphere each have a polar jet and a subtropical jet. The northern hemisphere polar jet flows over the middle to northern latitudes of North America, Europe, and Asia and their intervening oceans, while the southern hemisphere polar jet mostly circles Antarctica, both all year round. Jet streams are the product of two factors: the atmospheric heating b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
_(white_background).jpg "Click for more on -> Arctodus")
