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Holocene
The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene together form the Quaternary period. The Holocene is an interglacial period within the ongoing Ice age, glacial cycles of the Quaternary, and is equivalent to Marine isotope stages, Marine Isotope Stage 1. The Holocene correlates with the last maximum axial tilt towards the Sun of the Earth#Axial tilt and seasons, Earth's obliquity. 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 present. The human impact on modern-era Earth and its ecosystems may be considered of global significance for th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holocene Extinction
The Holocene extinction, also referred to as the Anthropocene extinction or the sixth mass extinction, is an ongoing extinction event caused exclusively by human activities during the Holocene epoch. This extinction event spans numerous families of plants and animals, including mammals, birds, reptiles, amphibians, fish, and invertebrates, impacting both terrestrial and marine life, marine species. Widespread degradation of biodiversity hotspots such as coral reefs and rainforests has exacerbated the crisis. Many of these extinctions are undocumented, as the species are often undiscovered before their extinctions. Current extinction rates are estimated at 100 to 1,000 times higher than natural background extinction rates and are accelerating. Over the past 100–200 years, biodiversity loss has reached such alarming levels that some conservation biologists now believe humankind, human activities have triggered a mass extinction, or are on the cusp of doing so. As such, after the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Pleistocene Extinctions
The Late Pleistocene to the beginning of the Holocene saw the extinction of the majority of the world's megafauna, typically defined as animal species having body masses over , which resulted in a collapse in faunal density and diversity across the globe. The extinctions during the Late Pleistocene are differentiated from previous extinctions by their extreme size bias towards large animals (with small animals being largely unaffected), and widespread absence of ecological succession to replace these extinct megafaunal species, and the regime shift of previously established faunal relationships and habitats as a consequence. The timing and severity of the extinctions varied by region and are generally thought to have been driven by humans, climatic change, or a combination of both. Human impact on megafauna populations is thought to have been driven by hunting ("overkill"), as well as possibly environmental alteration. The relative importance of human vs climatic factors in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Younger Dryas
The Younger Dryas (YD, Greenland Stadial GS-1) was a period in Earth's geologic history that occurred circa 12,900 to 11,700 years Before Present (BP). It is primarily known for the sudden or "abrupt" cooling in the Northern Hemisphere, when the North Atlantic Ocean cooled and annual air temperatures decreased by ~ over North America, in Europe and up to in Greenland, in a few decades. Cooling in Greenland was particularly rapid, taking place over just 3 years or less. At the same time, the Southern Hemisphere experienced warming. This period ended as rapidly as it began, with dramatic warming over ~50 years, the transition from the glacial Pleistocene epoch into the current Holocene. The Younger Dryas onset was not fully synchronized; in the tropics, the cooling was spread out over several centuries, and the same was true of the early-Holocene warming. Even in the Northern Hemisphere, temperature change was highly seasonal, with much colder winters, cooler springs, yet no cha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holocene Glacial Retreat
The Holocene glacial retreat is a geographical phenomenon that involved the global retreat of glaciers ( deglaciation) that previously had advanced during the Last Glacial Maximum. Ice sheet retreat initiated ca. 19,000 years ago and accelerated after ca. 15,000 years ago. The Holocene, starting with abrupt warming 11,700 years ago, resulted in rapid melting of the remaining ice sheets of North America and Europe. Geographical alterations Antarctica Radiocarbon dating has been used to date the start of glacial retreat on Alexander Island 18,000 years ago. The outermost locations like Marguerite Bay were fully deglaciated 12,000 years ago and the further inland locations continued deglaciating for an additional 3,000 years. The Larsen ice shelf was formed in the early Holocene at the latest estimation of 10,700 years ago. Certain segments of the ice shelf have collapsed as recently as 1995 for Larsen A and a large segment of Larsen B collapsed in 2002. Europe The many valley ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pleistocene
The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from 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 () 'most' and (; Latinized as ) 'new'. The aridification and cooling trends of the preceding Neogene were continued in the Pleistocene. The climate was strongly variable depending on the glacial cycle, oscillating between cold Glacial period, glacial periods and warmer Interglacial, int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Time Scale
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 preci ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Late Pleistocene
The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as the Upper Pleistocene from a Stratigraphy, 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 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 (commonly known as the Middle Pleistocene). The beginning of the Late Pleistocene is the transition between the end of the Penultimate Glacial Period and the beginning of the Last Interglacial around 130,000 years ago (corresponding with the beginning of Marine Isotope Stage 5). The Late Pleistocene ends with the termination of the Younger Dryas, some 10th millennium BC, 11,700 years ago when the Holocene Epoch began. The term Upper Pleistocene is currently in use as a p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ice Age
An ice age is a long period of reduction in the temperature of Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers. Earth's climate alternates between ice ages, and greenhouse periods during which there are no glaciers on the planet. Earth is currently in the ice age called Quaternary glaciation. Individual pulses of cold climate within an ice age are termed '' glacial periods'' (''glacials, glaciations, glacial stages, stadials, stades'', or colloquially, ''ice ages''), and intermittent warm periods within an ice age are called '' interglacials'' or ''interstadials''. In glaciology, the term ''ice age'' is defined by the presence of extensive ice sheets in the northern and southern hemispheres. By this definition, the current Holocene epoch is an interglacial period of an ice age. The accumulation of anthropogenic greenhouse gases is projected to delay the next glacial period. History of research ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Interglacial
An interglacial period (or alternatively interglacial, interglaciation) is a geological interval of warmer global average temperature lasting thousands of years that separates consecutive glacial periods within an ice age. The current Holocene interglacial began at the end of the Pleistocene, about 11,700 years ago. Pleistocene During the 2.5 million years of the Pleistocene, numerous glacials, or significant advances of continental ice sheets, in North America and Europe, occurred at intervals of approximately 40,000 to 100,000 years. The long glacial periods were separated by more temperate and shorter interglacials. During interglacials, such as the present one, the climate warms and the tundra recedes polewards following the ice sheets. Forests return to areas that once supported tundra vegetation. Interglacials are identified on land or in shallow epicontinental seas by their paleontology. Floral and faunal remains of species pointing to temperate climate and indicating a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Human Species
Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are great apes characterized by their hairlessness, bipedalism, and high intelligence. Humans have large brains, enabling more advanced cognitive skills that facilitate successful adaptation to varied environments, development of sophisticated tools, and formation of complex social structures and civilizations. Humans are highly social, with individual humans tending to belong to a multi-layered network of distinct social groups — from families and peer groups to corporations and political states. As such, social interactions between humans have established a wide variety of values, social norms, languages, and traditions (collectively termed institutions), each of which bolsters human society. Humans are also highly curious: the desire to understand and influence phenomena has motivated humanity's development of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Quaternary
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), as well as the current and most recent of the twelve periods of the Phanerozoic eon. 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 (2.58 million years ago to 11.7 thousand years ago) and the Holocene (11.7 thousand years ago to today); a proposed third epoch, the Anthropocene, was rejected in 2024 by IUGS, the governing body of the ICS. The Quaternary is typically defined by the Quaternary glaciation, the cyclic growth and decay of continental ice sheets related to the Milankovitch cycles and the associated climate and environmental changes that they caused. Research history In 1759 Giovanni Arduino proposed that the geological strata of northern Italy could be divided into four succ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
