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 and the age is estimated to be 220,000 ± 52,000 years (Pleistocene). The impactor is believed to have been a chondrite or stony meteorite some 30 to 50 m in diameter that was vapourised during the impact event. Morokweng impact structure, another crater of chondrite origin, lies north-west of Vryburg.
The 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.
Stone 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.
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.
"Place of Salt"
Crater seen from its eastern rim
The museum in relation to Gauteng
|Location||Pretoria, Gauteng, South Africa|
|Coordinates||25°24′31″S 28°04′57″E / 25.408486°S 28.082529°E / -25.408486; 28.082529|
|Public transit access||Onderstepoort Road ( M35), Soshanguve, Pretoria|
The impact crater is accompanied by a museum.
Status of protection
- ^ Reimold, W.U. (1998-04-27). "Meteorites and Meteorite Craters". South African Astronomical Observatory (SAAO). Retrieved 2008-08-23.
- ^ a b "Tswaing and its environmental effects". Lunar and Planetary Institute. Retrieved 2008-08-23.
- ^ "Tswaing". Earth Impact Database. Planetary and Space Science Centre University of New Brunswick Fredericton. Retrieved 2009-08-16.
- ^ Tswaing information leaflet
- ^ "Tswaing crater". Wondermondo.
- ^ "Tentative Lists, Tswaing Meteorite Crater". UNESCO. 2004-05-15. Retrieved 2008-08-23.
- Tswaing Meteorite Crater
- Hartebeesthoek Radio Astronomy Observatory writeup on the crater
- City of Tswhane - Tswaing Meteorite Crater
Coordinates: 25°24′32″S 28°4′58″E / 25.40889°S 28.08278°E / -25.40889; 28.08278
- Amelia Creek
- Chesapeake Bay
- Clearwater East and West
- Gosses Bluff
- Nördlinger Ries
- Saint Martin
- Siljan Ring
- Slate Islands
- Steen River
- Alvarez hypothesis
- Complex crater
- Cretaceous–Paleogene boundary
- Ejecta blanket
- Impact crater
- Impact structure
- Late Heavy Bombardment
- Ordovician meteor event
- Planar deformation features
- Shatter cone
- Shock metamorphism
- Shocked quartz