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8th Millennium BC
The 8th millennium BC spanned the years 8000 BC to 7001 BC (c. 10 ka to c. 9 ka). In chronological terms, it is the second full millennium of the current Holocene epoch and is entirely within the Pre-Pottery Neolithic B (PPNB) phase of the Early Neolithic. It is impossible to precisely date events that happened around the time of this millennium and all dates mentioned here are estimates mostly based on geological and anthropological analysis, or by radiometric dating. Global environment In the geologic time scale, the first stratigraphic stage of the Holocene epoch is the " Greenlandian" from about 9700 BC to the fixed date 6236 BC and so including the whole of the 8th millennium. The Greenlandian followed the Younger Dryas and essentially featured a climate shift from near-glacial to interglacial, causing glaciers to retreat and sea levels to rise. ''This proposal on behalf of the SQS has been approved by the International Commission on Stratigraphy (ICS) and for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kuril Islands
The Kuril Islands or Kurile Islands are a volcanic archipelago administered as part of Sakhalin Oblast in the Russian Far East. The islands stretch approximately northeast from Hokkaido in Japan to Kamchatka Peninsula in Russia, separating the Sea of Okhotsk from the north Pacific Ocean. There are 56 islands and many minor islets. The Kuril Islands consist of the Greater Kuril Chain and, at the southwest end, the parallel Lesser Kuril Chain. The group termed the 'South Kurils' consists of those of the Lesser Kuril Chain together with Kunashir and Iturup in the Greater Kuril Chain. The Vries Strait between Iturup and Urup forms the Miyabe Line dividing the North and South Kurils. The Kuril Islands cover an area of around , with a population of roughly 20,000. The islands have been under Russian administration since their Invasion of the Kuril Islands, 1945 invasion by the Soviet Union near the end of World War II. Japan claims the four southernmost islands, including two of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Terra Nova (journal)
''Terra Nova'' is a peer-reviewed scientific journal about geology and planetary science published by John Wiley & Sons Ltd. As of 2023, it had an 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 2.2. References Geology journals {{Geology-journal-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comet
A comet is an icy, small Solar System body that warms and begins to release gases when passing close to the Sun, a process called outgassing. This produces an extended, gravitationally unbound atmosphere or Coma (cometary), coma surrounding the nucleus, and sometimes a Comet tail, tail of gas and dust gas blown out from the coma. These phenomena are due to the effects of solar radiation and the outstreaming solar wind plasma acting upon the nucleus of the comet. Comet nuclei range from a few hundred meters to tens of kilometers across and are composed of loose collections of ice, dust, and small rocky particles. The coma may be up to 15 times Earth's diameter, while the tail may stretch beyond one astronomical unit. If sufficiently close and bright, a comet may be seen from Earth without the aid of a telescope and can Subtended angle, subtend an arc of up to 30° (60 Moons) across the sky. Comets have been observed and recorded since ancient times by many cultures and religion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asteroid
An asteroid is a minor planet—an object larger than a meteoroid that is neither a planet nor an identified comet—that orbits within the Solar System#Inner Solar System, inner Solar System or is co-orbital with Jupiter (Trojan asteroids). Asteroids are rocky, metallic, or icy bodies with no atmosphere, and are broadly classified into C-type asteroid, C-type (carbonaceous), M-type asteroid, M-type (metallic), or S-type asteroid, S-type (silicaceous). The size and shape of asteroids vary significantly, ranging from small rubble piles under a kilometer across to Ceres (dwarf planet), Ceres, a dwarf planet almost 1000 km in diameter. A body is classified as a comet, not an asteroid, if it shows a coma (tail) when warmed by solar radiation, although recent observations suggest a continuum between these types of bodies. Of the roughly one million known asteroids, the greatest number are located between the orbits of Mars and Jupiter, approximately 2 to 4 astronomical unit, AU ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deluge (mythology)
A flood myth or a deluge myth is a myth in which a great flood, usually sent by a deity or deities, destroys civilization, often in an act of divine retribution. Parallels are often drawn between the flood waters of these myths and the primeval cosmic ocean which appear in certain creation myths, as the flood waters are described as a measure for the cleansing of humanity, for example in preparation for rebirth. Most flood myths also contain a culture hero, who "represents the human craving for life". The oldest known narrative of a divinely inititated flood originates from the Sumerian culture in Mesopotamia, among others expressed in the Akkadian Athra-Hasis epic, which dates to the 18th century BCE. Comparable flood narratives appear in many other cultures, including the biblical Genesis flood narrative, ''manvantara-sandhya'' in Hinduism, Deucalion and Pyrrha in Greek mythology, also the Cheyenne, Blackfeet and Puebloan traditions. Mythologies The ''Epic of Gilgam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Disaster
A disaster is an event that causes serious harm to people, buildings, economies, or the environment, and the affected community cannot handle it alone. '' Natural disasters'' like avalanches, floods, earthquakes, and wildfires are caused by natural hazards. ''Human-made disasters'' like oil spills, terrorist attacks and power outages are caused by people. Nowadays, it is hard to separate natural and human-made disasters because human actions can make natural disasters worse. Climate change also affects how often disasters due to extreme weather hazards happen. Disasters usually hit people in developing countries harder than people in wealthy countries. Over 95% of deaths from disasters happen in low-income countries, and those countries lose a lot more money compared to richer countries. For example, the damage from natural disasters is 20 times greater in developing countries than in industrialized countries. This is because low-income countries often do not have well-bu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tollmann's Hypothetical Bolide
Tollmann's bolide hypothesis is a hypothesis presented by Austrian palaeontologist Edith Kristan-Tollmann and geologist Alexander Tollmann in 1994. The hypothesis postulates that one or several bolides (asteroids or comets) struck the Earth around 7640 ± 200 years BCE, and a much smaller one approximately 3150 ± 200 BCE. The hypothesis tries to explain early Holocene extinctions and possibly legends of the Universal Deluge. The claimed evidence for the event includes stratigraphic studies of tektites,Glass, B.P., 1978, "Australasian Microtektites and the Stratigraphic Age of the Australites" ''Bulletin of the Geological Society of America''. v. 89, no. 10, pp. 1455–1458.Izokh, E.P., 1988, "Age-paradox and the Origin of Tektites" in J. Konta, ed., ''2nd international conference on natural glasses'' Abstracts – International Conference on Natural Glasses-Prague, Czechoslovakia, 1988. v. 2, pp. 379–384.Prasad, N.S. and P.S. Rao, 1990, "Tektites Far and Wide". ''Nature'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tephra
Tephra is fragmental material produced by a Volcano, volcanic eruption regardless of composition, fragment size, or emplacement mechanism. Volcanologists also refer to airborne fragments as pyroclasts. Once clasts have fallen to the ground, they remain as tephra unless hot enough to fuse into pyroclastic rock or tuff. When a volcano explodes, it releases a variety of tephra including ash, cinders, and blocks. These layers settle on the land and, over time, sedimentation occurs incorporating these tephra layers into the geologic record. Tephrochronology is a geochronological technique that uses discrete layers of tephra—volcanic ash from a single eruption—to create a chronological framework in which Paleoecology, paleoenvironmental or Archaeology, archaeological records can be placed. Often, when a volcano explodes, biological organisms are killed and their remains are buried within the tephra layer. These fossils are later dated by scientists to determine the age of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aleutians
The Aleutian Islands ( ; ; , "land of the Aleuts"; possibly from the Chukchi ''aliat'', or "island")—also called the Aleut Islands, Aleutic Islands, or, before 1867, the Catherine Archipelago—are a chain of 14 main, larger volcanic islands and 55 smaller ones. Most of the Aleutian Islands belong to the U.S. state of Alaska, with the archipelago encompassing the Aleutians West Census Area and the Aleutians East Borough. The Commander Islands, located further to the west, belong to the Russian federal subject of Kamchatka Krai, of the Russian Far East. The islands form part of the Aleutian Arc of the Northern Pacific Ocean, and occupy a land area of 6,821 sq mi (17,666 km2) that extends westward roughly from the Alaskan Peninsula mainland, in the direction of the Kamchatka Peninsula; the archipelago acts as a border between the Bering Sea to the north and the Pacific Ocean to the south. Crossing longitude 180°, at which point east and west longitude end, the archip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Unimak Island
Unimak Island (, ) is the largest island in the Aleutian Islands chain of the U.S. state of Alaska. Geography It is the easternmost island in the Aleutians and, with an area of , the 9th largest island in the United States and the 134th largest island in the world. It is home to Mount Shishaldin, one of the ten most active volcanoes in the world. According to the United States Census Bureau, 64 people were living on Unimak as of the 2000 census, all of them in the city of False Pass at the eastern end of the island. Cape Lutke is a headland on the island. Cape Pankof is located at the extreme southwest of the island. The Fisher Caldera is a volcanic crater in the west-central part of Unimak. Some characteristics include many volcanic cones and undrained lakes. It is named for Bernard Fisher, a U.S. Geological Survey geologist who was killed in Umnak Pass. Mount Westdahl, in elevation, is a stratovolcano of the Aleutian Range on the island situated at its western end. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fisher Caldera
Fisher Caldera, also known as Mount Fisher and Fisher Volcano, is a large volcanic caldera, measuring about by , located on Unimak Island in the Aleutian Islands of Alaska. Formed by the destructive eruption of an Andesite, andesitic stratovolcano about 9,100 years ago, it contains three Volcanic crater lake, crater lakes, one wide and two others about wide. Small peaks rising and are also present in the caldera. Fisher Caldera is located just from the Mount Westdahl volcano. The largest volcanic eruption on Earth during the Holocene Epoch (geology), Epoch (the last 11,700 years) occurred at Fisher Caldera in 8700 BCE. References External links * See also * List of volcanic craters in Alaska * List of volcanoes in the United States Volcanoes of Alaska Unimak Island Volcanoes of Aleutians East Borough, Alaska VEI-6 volcanoes Calderas of Alaska Stratovolcanoes of the United States Holocene calderas {{AleutiansEastAK-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
