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Australasian Strewnfield
The Australasian strewnfield is the youngest and largest of the tektite strewnfields, with recent estimates suggesting it might cover 10%–30% of the Earth's surface.Glass, B.P. and Wu, J., 1993. ''Coesite and shocked quartz discovered in the, Australasian and North American, microtektite layers.'' ''Geology'', 21(5), pp.435-438.Prasad, M.S., Gupta, S.M. and Kodagali, V.N., 2003. ''Two layers of Australasian impact ejecta in the Indian Ocean?.'' ''Meteoritics & Planetary Science'', 38(9), pp.1373-1381.Prasad, M.S., Mahale, V.P. and Kodagali, V.N., 2007. ''New sites of Australasian microtektites in the central Indian Ocean: Implications for the location and size of source crater.'' ''Journal of Geophysical Research: Planets'', 112, no. E06007, 11 pp. Research indicates that the impact forming the tektites occurred around 788,000 years ago, most likely in Southeast Asia.Jourdan, F., Nomade, S., Wingate, M.T., Eroglu, E. and Deino, A., 2019. ''Ultraprecise age and formation temperatur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Australasian Strewnfield
The Australasian strewnfield is the youngest and largest of the tektite strewnfields, with recent estimates suggesting it might cover 10%–30% of the Earth's surface.Glass, B.P. and Wu, J., 1993. ''Coesite and shocked quartz discovered in the, Australasian and North American, microtektite layers.'' ''Geology'', 21(5), pp.435-438.Prasad, M.S., Gupta, S.M. and Kodagali, V.N., 2003. ''Two layers of Australasian impact ejecta in the Indian Ocean?.'' ''Meteoritics & Planetary Science'', 38(9), pp.1373-1381.Prasad, M.S., Mahale, V.P. and Kodagali, V.N., 2007. ''New sites of Australasian microtektites in the central Indian Ocean: Implications for the location and size of source crater.'' ''Journal of Geophysical Research: Planets'', 112, no. E06007, 11 pp. Research indicates that the impact forming the tektites occurred around 788,000 years ago, most likely in Southeast Asia.Jourdan, F., Nomade, S., Wingate, M.T., Eroglu, E. and Deino, A., 2019. ''Ultraprecise age and formation temperatur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hainan
Hainan (, ; ) is the smallest and southernmost province of the People's Republic of China (PRC), consisting of various islands in the South China Sea. , the largest and most populous island in China,The island of Taiwan, which is slightly larger, is claimed but not controlled by the PRC. It is instead controlled by the Republic of China, a ''de facto'' separate country. makes up the vast majority (97%) of the province. The name means "south of the sea", reflecting the island's position south of the Qiongzhou Strait, which separates it from Leizhou Peninsula. The province has a land area of , of which Hainan the island is and the rest is over 200 islands scattered across three archipelagos: Zhongsha, Xisha and Nansha. It was part of Guangdong from 1950–88, after which it resumed as a top-tier entity and almost immediately made the largest Special Economic Zone by Deng Xiaoping as part of the then-ongoing Chinese economic reform program. Indigenous peoples like th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brunhes–Matuyama Reversal
The Brunhes–Matuyama reversal, named after Bernard Brunhes and Motonori Matuyama, was a geologic event, approximately 781,000 years ago, when the Earth's magnetic field last underwent reversal. Estimations vary as to the abruptness of the reversal. A 2004 paper estimated that it took over several thousand years; a 2010 paper estimated that it occurred more quickly, perhaps within a human lifetime; a 2019 paper estimated that the reversal lasted 22,000 years. The apparent duration at any particular location can vary by an order of magnitude, depending on geomagnetic latitude and local effects of non-dipole components of the Earth's field during the transition. The Brunhes–Matuyama reversal is a marker for the Global Boundary Stratotype Section and Point (GSSP) defining the base of the Chibanian Stage and Middle Pleistocene Subseries at the Chiba section, Japan, which was officially ratified in 2020 by the International Union of Geological Sciences. It is useful in dating ocea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Siberia
Siberia ( ; rus, Сибирь, r=Sibir', p=sʲɪˈbʲirʲ, a=Ru-Сибирь.ogg) is an extensive geographical region, constituting all of North Asia, from the Ural Mountains in the west to the Pacific Ocean in the east. It has been a part of Russia since the latter half of the 16th century, after the Russians conquered lands east of the Ural Mountains. Siberia is vast and sparsely populated, covering an area of over , but home to merely one-fifth of Russia's population. Novosibirsk, Krasnoyarsk and Omsk are the largest cities in the region. Because Siberia is a geographic and historic region and not a political entity, there is no single precise definition of its territorial borders. Traditionally, Siberia extends eastwards from the Ural Mountains to the Pacific Ocean, and includes most of the drainage basin of the Arctic Ocean. The river Yenisey divides Siberia into two parts, Western and Eastern. Siberia stretches southwards from the Arctic Ocean to the hills of north-ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lake Elgygytgyn
Lake El'gygytgyn (Russian and Chukchi: Эльгыгытгын) is an impact crater lake located in the Chukotka Autonomous Okrug in northeast Siberia, about southeast of Chaunskaya Bay. The word "Elgygytgyn" means "white lake" in the Chukchi language. The lake is of particular interest to scientists because it has never been covered by glaciers. This has allowed the uninterrupted build-up of of sediment at the bottom of the lake, recording information on prehistoric climate change. Geography Lake El'gygytgyn is located in the Anadyr Plateau, part of the Anadyr Highlands. It is drained to the southeast by the Enmyvaam, a tributary of the Belaya. It is approximately in diameter and has a maximum depth of . The lake is centered within an impact crater with a rim diameter of that formed 3.6 million years ago during the Pliocene. Before it was reliably dated, preliminary papers in the late 1970s suggested either Elgygytgyn or Zhamanshin as the source of the young Austra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kazakhstan
Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbekistan to the south, and Turkmenistan to the southwest, with a coastline along the Caspian Sea. Its capital is Astana, known as Nur-Sultan from 2019 to 2022. Almaty, Kazakhstan's largest city, was the country's capital until 1997. Kazakhstan is the world's largest landlocked country, the largest and northernmost Muslim-majority country by land area, and the ninth-largest country in the world. It has a population of 19 million people, and one of the lowest population densities in the world, at fewer than 6 people per square kilometre (15 people per square mile). The country dominates Central Asia economically and politically, generating 60 percent of the region's GDP, primarily through its oil and gas industry; it also has vast mineral ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zhamanshin Crater
Zhamanshin is a meteorite crater in Kazakhstan. It is in diameter and the age is estimated to be 900,000 ± 100,000 years (Pleistocene). The crater is exposed at the surface. Description It is believed that the Zhamanshin crater is the site of the most recent meteorite impact event of the magnitude that could have produced a disruption comparable to that of a nuclear winter, but it was not sufficiently large enough to have caused a mass extinction. Preliminary papers in the late 1970s suggested either Elgygytgyn, or Zhamanshin,B.P. Glass (1979), Zhamanshin crater, a possible source of Australasian tektites? Geology, July 1979, v. 7, p. 351-353 as the source of the Australasian strewnfield The Australasian strewnfield is the youngest and largest of the tektite strewnfields, with recent estimates suggesting it might cover 10%–30% of the Earth's surface.Glass, B.P. and Wu, J., 1993. ''Coesite and shocked quartz discovered in the, A .... References Impact craters of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wilkes Land Crater
Wilkes Land crater is an informal term that may apply to two separate cases of conjectured giant impact craters hidden beneath the ice cap of Wilkes Land, East Antarctica. These are separated below under the heading Wilkes Land anomaly and Wilkes Land mascon (mass concentration), based on terms used in their principal published reference sources. Wilkes Land anomaly A giant impact crater beneath the Wilkes Land ice sheet was first proposed by Richard A. Schmidt in 1962 on the basis of the seismic and gravity discovery of the feature made by the U.S. Victoria Land Traverse in 1959–60 (VLT), and the data provided to Schmidt by John G. Weihaupt, geophysicist of the VLT (Geophysical Studies in Victoria Land, Antarctica, Report No. 1, Geophysical and Polar Research Center, University of Wisconsin, 1–123). Schmidt further considered the possibility that it might be the elusive source of the tektites of the Australasian strewnfield (which is only 790,000 years old). The hypothesis ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bolaven Plateau
The Bolaven Plateau is an elevated region in southern Laos. Most of the plateau is located within Champasak Province of Laos, though the edges of the plateau are also located in Salavan, Sekong and Attapeu Provinces. It is located between the Annamite Mountain Range, along which runs Laos' eastern border with Vietnam, and the Mekong River to the west, at about . The plateau's elevation ranges approximately from above sea level. The plateau is crossed by several rivers and has many scenic waterfalls. The name Bolaven makes reference to the Laven ethnic group which has historically dominated the region. However, domestic migrations by the Lao ethnic group (which comprises approximately 50 to 60 percent of the population of Laos) has resulted in widespread interethnic marriage, thus modifying the ethnic composition of the region. Historical significance The Bolaven Plateau has had an important role in the greater history of Laos. The three most significant historical period ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gulf Of Tonkin
The Gulf of Tonkin is a gulf at the northwestern portion of the South China Sea, located off the coasts of Tonkin (northern Vietnam) and South China. It has a total surface area of . It is defined in the west and northwest by the northern coastline of Vietnam down to the Hòn La Island, in the north by China's Guangxi Zhuang Autonomous Region, and to the east by the Leizhou Peninsula and Hainan Island. Etymology The name ''Tonkin'', written "" in Hán-Nôm characters and in the Vietnamese alphabet, means "eastern capital", and is the former toponym for Hanoi, the present capital of Vietnam. It should not to be confused with Tokyo, which is also written "" and also means "eastern capital". During the French colonial era, the northern region of today’s Vietnam was called ''Tonkin''. ''Bắc Bộ'' is the native Vietnamese name of Tonkin. The bay's Vietnamese and Chinese names – and , respectively – both mean "Northern Bay". History Gulf of Tonkin incident On 4 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tonlé Sap
Tonlé Sap (; km, ទន្លេសាប, ; or commonly translated as 'Great Lake'; vi, Biển Hồ, Chữ Hán: 湖海/壺海) is a lake in the northwest of Cambodia. It belongs to the Mekong, Mekong River system. It is the largest freshwater lake in Southeast Asia and one of the most diverse and productive ecosystems in the world, designated as a Biosphere Reserve by UNESCO in 1997 due to its high biodiversity. Entering the 21st century, the lake and its surrounding ecosystems are under increasing pressure from Deforestation in Cambodia, deforestation, infrastructure development and Climate change in Cambodia, climate change. Geography Tonlé Sap Lake is located in the northwest of the lower Mekong plain, formed by the collision and collapse of the Indian Plate and the Eurasian Plate. The lower Mekong plain used to be a bay, and the sea level rose rapidly at the end of the last glacial period. About high, cores from this period found near Angkor contain tidal deposits ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mekong
The Mekong or Mekong River is a trans-boundary river in East Asia and Southeast Asia. It is the world's List of rivers by length, twelfth longest river and List of longest rivers of Asia, the third longest in Asia. Its estimated length is , and it drains an area of , discharging of water annually. From the Tibetan Plateau the river runs through China, Myanmar, Laos, Thailand, Cambodia, and Vietnam. The extreme seasonal variations in flow and the presence of rapids and waterfalls in the Mekong make navigation difficult. Even so, the river is a major trade route between western China and Southeast Asia. Names The Mekong was originally called ''Mae Nam Khong'' from a contracted form of Tai language, Tai shortened to ''Mae Khong''. In Thai and Lao, ''Mae Nam'' ("Mother of Water[s]") is used for large rivers and ''Khong'' is the proper name referred to as "River Khong". However, ''Khong'' is an archaic word meaning "river", loaned from Austroasiatic languages, such as Vietnamese ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
