Kalahari Desert

A large desert located in southern Africa near the Tropic of Capricorn. It is mainly located in the area excluding eastern Botswana, and extends over eastern Namibia, the western tip of Zimbabwe, western Zambia, and northern South Africa. It is an inland dry basin with an average elevation of 900 to 1,200 meters, and a total area of ​​about 1.6 million square kilometers. There are regional differences from north to south, with the northern part showing savanna scenery, annual precipitation of 600 to 1,100 mm, and rivers of the Zambezi River system and Cubango River system flowing through it. The central part is at the bottom of the basin, and is dotted with wetlands such as the Cubango Marsh. The southern part is dry and sand dunes have developed. These sand dunes originate from Precambrian bedrock, and the sand layer is generally thin, less than 100 meters thick. Currently, there is vegetation on the sand dunes, and most of them are fixed, but it has been pointed out that during the last glacial period about 20,000 years ago, the dry area was wider than it is today, and the distribution area of ​​the sand dunes also expanded. The annual rainfall is about 120-400 mm, and this rain falls mainly in February and March due to the Kalahari low that develops around January. The rivers are intermittent, and the vegetation is mainly short herbaceous plants, including thorny acacias, bushman grass, and the watermelon variety, tsarma melon.

The southwestern part is a national park, and is the main habitat of the indigenous San people, as well as the Khoi people. However, this is not because they historically preferred to live in arid regions, but because they fled there after being chased by surrounding ethnic groups and adapted to the climate.

[Nobuyuki Hori]

Source: Shogakukan Encyclopedia Nipponica About Encyclopedia Nipponica Information | Legend

アフリカ南部、南回帰線付近にある大砂漠。ボツワナの東部を除いた地域が中心で、ナミビア東部、ジンバブエ西端部、ザンビア西部、南アフリカ共和国北部にまたがる。内陸の乾燥盆地で、平均標高900～1200メートル、総面積は約160万平方キロメートルにわたる。南北方向に地域差があり、北部はサバンナ景観を示し、年降水量は600～1100ミリメートル、ザンベジ川水系やクバンゴ川水系の河川が流れる。中部は盆地の低部にあたり、クバンゴ低湿地をはじめ湿地帯が点在する。南部は乾燥し砂丘が発達する。この砂丘は先カンブリア系の基盤岩類に由来し、砂層の厚さは100メートル以下で全体に薄い。現在は砂丘に植生があり、固定されたものが多いが、約2万年前の最終氷期には、現在よりも乾燥域が広くなり、砂丘も分布域が拡大したことが指摘されている。年降水量は120～400ミリメートル程度で、この雨はおもに1月ごろ発達するカラハリ低気圧により2～3月に降るものである。河川は間欠河川となり、植生は刺(とげ)の多いアカシア類をはじめ、イネ科のブッシュマングラスや、スイカの変種のツァーマメロンなど、短い草本が主体をなす。

　南西部は国立公園で、先住民サン人のおもな居住地であり、ほかにコイ人らが住んでいる。ただこれは歴史的には彼らが乾燥地域を好んで住んでいるというよりは、周辺民族に追われる形で逃げ込み、適応していったものである。

［堀　信行］

出典　小学館　日本大百科全書(ニッポニカ)日本大百科全書(ニッポニカ)について　情報 | 凡例