| 词条 | Tswaing crater |
| 释义 |
| name = Tswaing crater | other_name = | photo = Tswaing, Salt Pan Crater.jpg | photo_caption = Tswaing crater as seen from above | map = Africa | map_caption = Asteroid impact location in Africa | coordinates = | confidence = Confirmed | diameter = {{cvt| 1.13|km|||}} | depth = {{cvt|100|m||}} | age = 220 ± 52 Ka | exposed = | drilled = | imp_size = {{cvt|30|to|50|m||}} | bolide = | country = South Africa | state = }} Tswaing is an impact crater in South Africa that is accompanied by a museum. It is situated 40 km to the north-west of Pretoria. This astrobleme is 1.13 km in diameter and 100 m deep[1] and the age is estimated to be 220,000 ± 52,000 years (Pleistocene).[2] The impactor is believed to have been a chondrite or stony meteorite some 30 to 50 m in diameter that was vaporized during the impact event.[2][3] Morokweng crater, another crater of chondrite origin, lies north-west of Vryburg. EtymologyThe name Tswaing means "place of salt" in Tswana and the crater was also formerly known in English as Pretoria Saltpan crater and in Afrikaans as Soutpankrater. HistoryStone tools from the Middle Stone Age show that the crater was regularly visited by people from as far back as 100,000 years ago in order to hunt and collect salt. Water in the crater comes from surface springs, ground water and rain water and is rich in dissolved carbonates and sodium chlorides. Tswana and Sotho people harvested the salt by filtering and decoction between 1200 and 1800. Between 1912 and 1956 brine was pumped from the floor of the crater by the company SA Alkali Ltd. in order to extract soda and salt.[4] A scientific dispute was ongoing regarding the origin of the crater between supporters of volcanic origin (Wagner, 1922) and those who believed it is an impact crater (Rohleder, 1933) until 1990, when examination of the core from a borehole proved that it is an impact crater.[5] Museum{{Infobox museum| name = Tswaing Meteorite Crater | native_name = "Place of Salt" | native_name_lang = Setswana | image = Tswaing crater - panoramio.jpg | imagesize = 270px | caption = Crater seen from its eastern rim | alt = | map_type = South Africa Gauteng | map_relief = | map_size = | map_caption = The museum in relation to Gauteng | map_dot_label = | coordinates = {{coord|-25.408486|28.082529|display=inline}} | established = | dissolved = | location = Pretoria, Gauteng, {{RSA}} | type = Natural history | accreditation = | key_holdings = | collections = | collection_size = | visitors = | founder = | director = | president = | curator = | owner = | publictransit = Onderstepoort Road ( M35), Soshanguve, Pretoria | car_park = | parking = | network = | website = http://www.ditsong.org.za/tswaing.htm }} The impact crater is accompanied by a museum. Status of protectionTswaing is currently on the tentative list for consideration as a World Heritage Site.[6] See also{{Portal|South Africa}}{{commons category|Tswaing crater}}
References1. ^{{cite web |url= http://www.saao.ac.za/~wgssa/as2/reimold.html|title=Meteorites and Meteorite Craters|last=Reimold|first=W.U. |date=1998-04-27 |publisher= South African Astronomical Observatory (SAAO)|accessdate=2008-08-23}} 2. ^1 {{cite web |url= http://www.lpi.usra.edu/science/kring/epo_web/impact_cratering/enviropages/Tswaing/Tswaingintropage.html|title=Tswaing and its environmental effects|publisher=Lunar and Planetary Institute|accessdate=2008-08-23}} 3. ^{{cite Earth Impact DB | name = Tswaing| accessdate = 2009-08-16}} 4. ^Tswaing information leaflet 5. ^{{cite web|url=http://www.wondermondo.com/Countries/Af/SouthAfrica/Gauteng/TswaingCrater.htm|title=Tswaing crater|publisher=Wondermondo}} 6. ^{{cite web|url=http://whc.unesco.org/en/search/?criteria=tswaing&x=0&y=0|title=Tentative Lists, Tswaing Meteorite Crater|date=2004-05-15|publisher=UNESCO|accessdate=2008-08-23}} External links
4 : Impact craters of South Africa|Pleistocene impact craters|Natural history museums in South Africa|Museums in Pretoria |
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