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Eocene Thermal Maximum 3
Eocene Thermal Maximum 3 (ETM3), also known as the K or X event, was a hyperthermal event that occurred during the middle of the Ypresian stage of the Eocene epoch. Timing ETM3 has been dated to about 52.5 Ma. It is demarcated in the chronostratigraphic record by a marked negative δ13C and δ18O excursion. Causes ETM3 was caused by a massive input of isotopically light carbon into the atmosphere. It has been suggested that methane hydrate reservoirs, recharged over millennia after melting during previous Eocene hyperthermals, were the source of this light carbon during ETM3. Effects ETM3, in conjunction with the other hyperthermal events of the Early Eocene, led to the onset of the Early Eocene Climatic Optimum (EECO), the warmest long-term climatic interval of the Cenozoic. The diversity of benthic foraminifera decreased in the southeastern Atlantic Ocean during ETM3. See also * Latest Danian Event * Palaeocene-Eocene Thermal Maximum * Eocene Thermal Maximum 2 Eoc ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hyperthermal Event
A hyperthermal event corresponds to a sudden warming of the planet on a geologic time scale. The consequences of this type of event are the subject of numerous studies because they can constitute an analogue of current global warming. Hyperthermal events The first event of this type was described in 1991 from a sediment core extracted from a drilling of the Ocean Drilling Program (ODP) carried out in Antarctica in the Weddell Sea. This event occurs at the boundary of the Paleocene and Eocene epochs approximately 56 million years ago. It is now called the Paleocene-Eocene Thermal Maximum (PETM). During this event, the temperature of the oceans increased by more than 5 °C in less than 10,000 years. Since this discovery, several other hyperthermal events have been identified in this lower part of the Paleogene geological period: * the Dan-C2 event at the beginning of the Danian stage of the Paleocene, about 65.2 million years ago, quite the basis of the Cenozoic era; * the D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ypresian
In the geologic timescale the Ypresian is the oldest age (geology), age or lowest stage (stratigraphy), stratigraphic stage of the Eocene. It spans the time between , is preceded by the Thanetian Age (part of the Paleocene) and is followed by the Eocene Lutetian Age. The Ypresian is consistent with the Lower Eocene (Early Eocene). Events The Ypresian Age begins during the throes of the Paleocene–Eocene Thermal Maximum (PETM). The Fur Formation in Denmark, the Messel shales in Germany, the Oise amber of France and Cambay amber of India are of this age. The Eocene Okanagan Highlands are an uplands subtropical to temperate series of lakes from the Ypresian. The Ypresian is additionally marked by another warming event called the Early Eocene Climatic Optimum (EECO). The EECO is the longest sustained warming event in the Cenozoic record, lasting about 2–3 million years between 53 and 50 Ma. The interval is characterized by low oxygen-18 isotopes, high levels of atmospheric pCO2 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stage (stratigraphy)
In chronostratigraphy, a stage is a succession of rock strata laid down in a single age on the geologic timescale, which usually represents millions of years of deposition. A given stage of rock and the corresponding age of time will by convention have the same name, and the same boundaries. Rock series are divided into stages, just as geological epochs are divided into ages. Stages are divided into smaller stratigraphic units called chronozones or substages, and added together into superstages. The term faunal stage is sometimes used, referring to the fact that the same fauna (animals) are found throughout the layer (by definition). Definition Stages are primarily defined by a consistent set of fossils ( biostratigraphy) or a consistent magnetic polarity (see paleomagnetism) in the rock. Usually one or more index fossils that are common, found worldwide, easily recognized, and limited to a single, or at most a few, stages are used to define the stage's bottom. Thus, f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Eocene
The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes from the Ancient Greek (''Ēṓs'', 'Eos, Dawn') and (''kainós'', "new") and refers to the "dawn" of modern ('new') fauna that appeared during the epoch.See: *Letter from William Whewell to Charles Lyell dated 31 January 1831 in: * From p. 55: "The period next antecedent we shall call Eocene, from ήως, aurora, and χαινος, recens, because the extremely small proportion of living species contained in these strata, indicates what may be considered the first commencement, or ''dawn'', of the existing state of the animate creation." The Eocene spans the time from the end of the Paleocene Epoch to the beginning of the Oligocene Epoch. The start of the Eocene is marked by a brief period in which the concentration of the carbon isoto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epoch (geology)
The geologic time scale or geological time scale (GTS) is a representation of time based on the rock record of Earth. It is a system of chronological dating that uses chronostratigraphy (the process of relating strata to time) and geochronology (a scientific branch of geology that aims to determine the age of rocks). It is used primarily by Earth scientists (including geologists, paleontologists, geophysicists, geochemists, and paleoclimatologists) to describe the timing and relationships of events in geologic history. The time scale has been developed through the study of rock layers and the observation of their relationships and identifying features such as lithologies, paleomagnetic properties, and fossils. The definition of standardised international units of geological time is the responsibility of the International Commission on Stratigraphy (ICS), a constituent body of the International Union of Geological Sciences (IUGS), whose primary objective is to precis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paleoceanography And Paleoclimatology
''Paleoceanography and Paleoclimatology'' is a peer-reviewed scientific journal published by the American Geophysical Union. It publishes original research articles dealing with all aspects of understanding and reconstructing Earth's past climate and environments from the Precambrian to modern analogs. Until the first of January 2018 the name of the journal was ''Paleoceanography''. The founding editor-in-chief was James P. Kennett and the journal is currently edited by Matthew Huber (Purdue University) . Abstracting and indexing The journal is abstracted and indexed by GEOBASE, GeoRef, Scopus, and several CSA indexes. According to the ''Journal Citation Reports'', the journal has a 2021 impact factor The impact factor (IF) or journal impact factor (JIF) of an academic journal is a type of journal ranking. Journals with higher impact factor values are considered more prestigious or important within their field. The Impact Factor of a journa ... of 3.990. Notable article ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Δ13C
In geochemistry, paleoclimatology, and paleoceanography ''δ''13C (pronounced "delta thirteen c") is an isotopic signature, a measure of the ratio of the two stable isotopes of carbon—Carbon-13, 13C and Carbon-12, 12C—reported in parts per thousand (per mil, ‰). The measure is also widely used in archaeology for the reconstruction of past diets, particularly to see if marine foods or certain types of plants were consumed. The definition is, in per mille: :\delta \ce = \left( \frac - 1 \right) \times 1000 where the standard is an established Reference materials for stable isotope analysis, reference material. ''δ''13C varies in time as a function of productivity, the signature of the inorganic source, Oceanic carbon cycle#Burial, organic carbon burial, and vegetation type. Biological processes preferentially take up the lower mass isotope through kinetic fractionation. However some abiotic processes do the same. For example, methane from hydrothermal vents can be depleted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Δ18O
In geochemistry, paleoclimatology and paleoceanography ''δ''18O or delta-O-18 is a measure of the deviation in ratio of stable isotopes oxygen-18 (18O) and oxygen-16 (16O). It is commonly used as a measure of the temperature of precipitation, as a measure of groundwater/mineral interactions, and as an indicator of processes that show isotopic fractionation, like methanogenesis. In paleosciences, 18O:16O data from corals, foraminifera and ice cores are used as a proxy for temperature. It is defined as the deviation in "per mil" (‰, parts per thousand) between a sample and a standard: :\delta \ce = \left( \frac - 1 \right) \times 1000 ‰ where the standard has a known isotopic composition, such as Vienna Standard Mean Ocean Water (VSMOW). The fractionation can arise from kinetic, equilibrium, or mass-independent fractionation. Mechanism Foraminifera shells are composed of calcium carbonate (CaCO3) and are found in many common geological environments. The rat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methane Clathrate
Methane clathrate (CH4·5.75H2O) or (4CH4·23H2O), also called methane hydrate, hydromethane, methane ice, fire ice, natural gas hydrate, or gas hydrate, is a solid clathrate compound (more specifically, a clathrate hydrate) in which a large amount of methane is trapped within a crystal structure of water, forming a solid similar to ice. Originally thought to occur only in the outer regions of the Solar System, where temperatures are low and water ice is common, significant deposits of methane clathrate have been found under sediments on the ocean floors of the Earth (around 1100m below the sea level). Methane hydrate is formed when hydrogen-bonded water and methane gas come into contact at high pressures and low temperatures in oceans. Methane clathrates are common constituents of the shallow marine geosphere and they occur in deep sedimentary structures and form outcrops on the ocean floor. Methane hydrates are believed to form by the precipitation or crystallisation of metha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Early Eocene Climatic Optimum
The Early Eocene Climatic Optimum (EECO), also referred to as the Early Eocene Thermal Maximum (EETM), was a period of extremely warm greenhouse climatic conditions during the Eocene epoch. The EECO represented the hottest sustained interval of the Cenozoic era and one of the hottest periods in all of Earth's history. Duration The EECO lasted from about 54 to 49 Ma. The EECO's onset is signified by a major geochemical enrichment in isotopically light carbon, commonly known as a negative ''δ''13C excursion, that demarcates the hyperthermal Eocene Thermal Maximum 3 (ETM3). Climate Following some climate models, the EECO was marked by an extremely high global mean surface temperature, which has been estimated to be anywhere between 23.2 and 29.7 °C, with the mean estimate being around 27.0 °C. In North America, the mean annual temperature was 23.0 °C, while the continent's overall mean annual precipitation (MAP) was about 1500 mm. The mean annual temperature range (MATR) o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
New Zealand Journal Of Geology And Geophysics
The ''New Zealand Journal of Geology and Geophysics'' is a peer-reviewed academic journal published by Taylor & Francis on behalf of the Royal Society Te Apārangi. The journal is issued quarterly in print, with additional open access and other material published online. First published in 1958 by New Zealand's former Department of Scientific and Industrial Research, it covers topics in the earth sciences relevant to New Zealand and its surrounding regions in Antarctica and the Pacific Rim The Pacific Rim comprises the lands around the rim of the Pacific Ocean. The '' Pacific Basin'' includes the Pacific Rim and the islands in the Pacific Ocean. The Pacific Rim roughly overlaps with the geological Pacific Ring of Fire. List .... References 1958 establishments in New Zealand English-language journals Earth and atmospheric sciences journals Open access journals Science and technology in New Zealand Publications established in 1958 Quarterly journals { ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Latest Danian Event
The Latest Danian Event (LDE) was a hyperthermal event that occurred at the end of the Danian stage. Timing The LDE is believed to have been approximately 170-230 kyr in duration and occurred about 62.18 Ma. The LDE consisted of two distinct ''δ''13C excursions, which are referred to as LDE1 and LDE2, respectively. Effects The LDE was similar in essence to the Palaeocene-Eocene Thermal Maximum (PETM), although significantly smaller in magnitude. Seawater warmed by about 2-3 °C in both the surface oceans and the deep oceans. The LDE led to a significant shoaling of the oceanic lysocline, which is evidenced by the greatly reduced calcium carbonate preservation that occurred during the event. Significant black shale deposition occurred during the LDE, a consequence of sea level rise and clastic starvation combined with enhanced nutrient input into the ocean and anoxia. The planktonic foraminifer genus ''Morozovella'', especially the species ''M. angulata'', increased in abu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
