Lake Bosumtwi

Lake Bosomtwe<ref>Template:Cite web</ref> is the only natural lake in Ghana. It is situated within an ancient impact crater that is about Template:Convert in diameter.<ref name="LakeNet"/> It is about Template:Cvt south-east of Kumasi, the capital of Ashanti, and is a popular recreational area. There are about 30 villages near the crater lake of Lake Bosomtwe, with a combined population of about 70,000.<ref>Template:Cite web</ref> The most popular amongst the villages where tourists usually settle is Abono.<ref name="auto">Template:Cite journal</ref><ref>Template:Cite web</ref>

The Ashanti consider Bosomtwe a sacred lake. According to traditional belief, the souls of the dead come here to bid farewell to the goddess Asase Ya. Because of this, it is considered permissible to fish in the lake only from wooden planks. Among the fish species in the lake is the endemic cichlid Hemichromis frempongi, and the near-endemic cichlids Tilapia busumana and T. discolor.<ref>Template:FishBase</ref><ref>Template:FishBase</ref><ref>Template:FishBase</ref>

Impact crater

Planar deformation features from the Bosumtwi impact crater visible under the optical and scanning electron microscope.<ref>Template:Cite journal</ref>

The Lake Bosomtwe impact crater is Template:Convert in diameter, slightly larger than the present lake which is approximately Template:Convert across, and is estimated to be 1.07 million years old (Pleistocene period).<ref name=EIDB>Template:Cite Earth Impact DB</ref><ref name=Koeberl2007>Template:Cite journal</ref>

The depth of crater is approximately Template:Convert, but, if counted together with the depth of lake sediments - Template:Convert.<ref>Template:Cite web</ref>

The crater has been partly eroded, and is situated in dense rainforest, making it difficult to study and confirm its origin by meteorite impact. Shock features such as shatter cones are largely overgrown by vegetation or covered by the lake. However, drilling of the crater's central uplift beneath the lake floor has recently provided an abundance of shocked materials for scientific study.<ref name="Koeberl2007" /> Tektites, believed to be from this impact, are found in the neighbouring country of Ivory Coast, and related microtektites have been found in deep sea sediments west of the African continent.<ref name="Koeberl2007" />

A work based on a statistical study of past numerical orbital simulations of the impact event<ref name=Artemievaetal2004>Template:Cite journal</ref> asserts that the possible origin of the impactor is an asteroid coming from the middle main-belt at a high inclination (>17 degrees).<ref name=Galiazzoetal2013>Template:Cite journal</ref>

Climate history

Before the asteroid impact, the area was a lush rainforest filled with animals. Following the impact, the resulting crater filled with water forming Lake Bosomtwe.<ref name=bbc> Template:Cite news </ref>

Periods of heavy rainfall filled the crater with water, causing the lake level to rise above the lowest points of the rim. Such periods are evidenced from fossils of fish found on hilltops. Water even flowed from the basin through an overflow channel. However, there were also times when the water level was so low that the rainforest entered the basin rendering the lake only a small pond. Such a period, according to legend and now proved by paleoclimate records, lasted until about 300 years ago.<ref>Shanahan et al. 2009</ref><ref>Template:Cite journal</ref>

See also

• Lake Iro – another African lake suspected to be an impact crater

References

• Template:Cite journal

External links

• Lake Bosomtwe Ecotourism Map and Guide (notice: "Bosomtwe" is the correct spelling according to Kumasi University) Template:Webarchive
• Lake Bosomtwe Drilling Project Template:Webarchive