| Discipline | Geochronology of the Quaternary period |
|---|---|
| Language | English |
| Edited by | R. Grün |
| Publication details | |
| History | 2006-present |
| Publisher | |
| Frequency | Bimonthly |
| 2.853 (2009) | |
| Standard abbreviations | |
| ISO 4 | Quat. Geochronol. |
| Indexing | |
| ISSN | 1871-1014 |
| Links | |
Quaternary Geochronology is a peer-reviewed scientific journal addressing methods and results in the dating of samples from the Quaternary Period.
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The Neogene is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period 23.03 million years ago (Mya) to the beginning of the present Quaternary Period 2.58 Mya. The Neogene is sub-divided into two epochs, the earlier Miocene and the later Pliocene. Some geologists assert that the Neogene cannot be clearly delineated from the modern geological period, the Quaternary. The term "Neogene" was coined in 1853 by the Austrian palaeontologist Moritz Hörnes (1815–1868).
The Pleistocene is the geological epoch that lasted from c. 2.58 million to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was finally confirmed in 2009 by the International Union of Geological Sciences, the cutoff of the Pleistocene and the preceding Pliocene was regarded as being 1.806 million years Before Present (BP). Publications from earlier years may use either definition of the period. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology. The name is a combination of Ancient Greek πλεῖστος (pleîstos), meaning "most", and καινός, meaning "new".
The Quaternary is the current and most recent of the three periods of the Cenozoic Era in the geologic time scale of the International Commission on Stratigraphy (ICS). It follows the Neogene Period and spans from 2.58 million years ago to the present. The Quaternary Period is divided into two epochs: the Pleistocene and the Holocene although a third epoch, the Anthropocene, has been proposed but is not officially recognised by the ICS.
Protein quaternary structure is the fourth classification level of protein structure. Protein quaternary structure refers to the structure of proteins which are themselves composed of two or more smaller protein chains. Protein quaternary structure describes the number and arrangement of multiple folded protein subunits in a multi-subunit complex. It includes organizations from simple dimers to large homooligomers and complexes with defined or variable numbers of subunits. In contrast to the first three levels of protein structure, not all proteins will have a quaternary structure since some proteins function as single units. Protein quaternary structure can also refer to biomolecular complexes of proteins with nucleic acids and other cofactors.
A quaternary numeral system is base-4. It uses the digits 0, 1, 2 and 3 to represent any real number. Conversion from binary is straightforward.
The Last Glacial Period (LGP), also known colloquially as the last ice age or simply ice age, occurred from the end of the Eemian to the end of the Younger Dryas, encompassing the period c. 115,000 – c. 11,700 years ago. The LGP is part of a larger sequence of glacial and interglacial periods known as the Quaternary glaciation which started around 2,588,000 years ago and is ongoing. The definition of the Quaternary as beginning 2.58 million years ago (Mya) is based on the formation of the Arctic ice cap. The Antarctic ice sheet began to form earlier, at about 34 Mya, in the mid-Cenozoic. The term Late Cenozoic Ice Age is used to include this early phase. The previous ice age, the Saale glaciation, which ended about 128,000 years ago, was more severe than the Last Glacial Period in some areas such as Britain, but less severe in others.
The quaternary sector of the economy is based upon the economic activity that is associated with either the intellectual or knowledge-based economy. This consists of information technology; media; research and development; information-based services such as information-generation and information-sharing; and knowledge-based services such as consultation, education, financial planning, blogging, and designing. Other definitions describe the quaternary sector as pure services. This may consist of the entertainment industry, to describe media and culture, and government. This may be classified into an additional quinary sector.
An active fault is a fault that is likely to become the source of another earthquake sometime in the future. Geologists commonly consider faults to be active if there has been movement observed or evidence of seismic activity during the last 10,000 years.
Before Present (BP) years, also known as "time before present" or "years before present (YBP)", is a time scale used mainly in archaeology, geology and other scientific disciplines to specify when events occurred relative to the origin of practical radiocarbon dating in the 1950s. Because the "present" time changes, standard practice is to use 1 January 1950 as the commencement date (epoch) of the age scale. The abbreviation "BP" has been interpreted retrospectively as "Before Physics", which refers to the time before nuclear weapons testing artificially altered the proportion of the carbon isotopes in the atmosphere, which scientists must now account for.
There have been five or six major ice ages in the history of Earth over the past 3 billion years. The Late Cenozoic Ice Age began 34 million years ago, its latest phase being the Quaternary glaciation, in progress since 2.58 million years ago.
The Anglian Stage is the name used in the British Isles for a middle Pleistocene glaciation. It precedes the Hoxnian Stage and follows the Cromerian Stage in the British Isles. The Anglian Stage is correlated to Marine Isotope Stage 12, which started about 478,000 years ago and ended about 424,000 years ago.
In chemistry, quaternary ammonium cations, also known as quats, are positively-charged polyatomic ions of the structure [NR4]+, where R is an alkyl group, an aryl group or organyl group. Unlike the ammonium ion and the primary, secondary, or tertiary ammonium cations, the quaternary ammonium cations are permanently charged, independent of the pH of their solution. Quaternary ammonium salts or quaternary ammonium compounds are salts of quaternary ammonium cations. Polyquats are a variety of engineered polymer forms which provide multiple quat molecules within a larger molecule.
The Illinoian Stage is the name used by Quaternary geologists in North America to designate the period c.191,000 to c.130,000 years ago, during the Chibanian stage of the Pleistocene, when sediments comprising the Illinoian Glacial Lobe were deposited. It precedes the Sangamonian Stage and follows the Pre-Illinoian Stage in North America. The Illinoian Stage is defined as the period of geologic time during which the glacial tills and outwash, which comprise the bulk of the Glasford Formation, accumulated to create the Illinoian Glacial Lobe. It occurs at about the same time as the penultimate glacial period.
The Chibanian, widely known as the Middle Pleistocene, is an age in the international geologic timescale or a stage in chronostratigraphy, being a division of the Pleistocene Epoch within the ongoing Quaternary Period. The Chibanian name was officially ratified in January 2020. It is currently estimated to span the time between 0.770 Ma and 0.126 Ma, also expressed as 770–126 ka. It includes the transition in palaeoanthropology from the Lower to the Middle Paleolithic over 300 ka.
The Late Pleistocene is an unofficial age in the international geologic timescale in chronostratigraphy, also known as Upper Pleistocene from a stratigraphic perspective. It is intended to be the fourth division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently defined as the time between c. 129,000 and c. 11,700 years ago. The Late Pleistocene equates to the proposed Tarantian Age of the geologic time scale, preceded by the officially ratified Chibanian and succeeded by the officially ratified Greenlandian. The estimated beginning of the Tarantian is the start of the Eemian interglacial period. It is held to end with the termination of the Younger Dryas, some 11,700 years ago when the Holocene Epoch began.
The Quaternary glaciation, also known as the Pleistocene glaciation, is an alternating series of glacial and interglacial periods during the Quaternary period that began 2.58 Ma and is ongoing. Although geologists describe this entire period up to the present as an "ice age", in popular culture this term usually refers to the most recent glacial period, or to the Pleistocene epoch in general. Since Earth still has polar ice sheets, geologists consider the Quaternary glaciation to be ongoing, though currently in an interglacial period.
From 1948 to 1975, the U.S. Army Chemical Corps conducted classified human subject research at the Edgewood Arsenal facility in Maryland. The purpose was to evaluate the impact of low-dose chemical warfare agents on military personnel and to test protective clothing, pharmaceuticals, and vaccines. A small portion of these studies were directed at psychochemical warfare and grouped under the prosaic title of the "Medical Research Volunteer Program" (1956–1975). The MRVP was also driven by intelligence requirements and the need for new and more effective interrogation techniques.
The genus Cathartes includes medium-sized to large carrion-feeding birds in the New World vulture (Cathartidae) family. The three extant species currently classified in this genus occur widely in the Americas. There is one extinct species known from the Quaternary of Cuba.
Quaternary science is the study which represents the systematic study of the Quaternary Period commonly known as the ice age. The Quaternary Period is a time period that started around 2.58 million years ago and continues today. This period is divided into two epochs – the Pleistocene Epoch and the Holocene Epoch. The aim of Quaternary science is to understand everything that happened during the Pleistocene Epoch and the Holocene Epoch to be able to acquire fundamental knowledge about Earth's environment, ecosystem, climate changes, etc. Quaternary science was first studied during the nineteenth century by Georges Cuvier, a French scientist. Most Quaternary scientists have studied the history of the Quaternary to predict future changes in climate.
A Zungenbecken, also called a tongue basin or tongue-basin, is part of a succession of ice age geological landforms, known as a glacial series. It is a hollow that is left behind by the ice mass, as the snout of the glacier recedes, which initially fills with meltwater, forming a proglacial lake, and later may be filled with surface water from streams or precipitation. When the glacier has more fully retreated this produces a finger lake or glacial piedmont lake. The term Zungenbecken is of German origin, but used in English language sources.
