Permafrost by permafrost. Of this area slightly more than half is underlain by continuous permafrost, around 20 percent by discontinuous permafrost, and a little less than 30 percent by sporadic permafrost. Most of this area is found in Siberia, northern Canada, Alaska and Greenland. Beneath the active layer annual temperature swings of permafrost become smaller with depth. The deepest depth of permafrost occurs where geothermal heat maintains a temperature above freezing. Above that bottom limit there may be permafrost, whose temperature doesn't change annually—"isothermal permafrost". Permafrost typically forms in any climate where the mean annual air temperature is less than the
Luarica diamond mine Luarica diamond mine The Luarica diamond mine is a diamond mine located in Angola. The mine is owned by a consortium of diamond mining companies, the two largest holders being Endiama with 38 percent ownership and Trans Hex with 32 percent ownership. In 2004, the Luarica mine produced about 95,000 carats (19 kg) of diamond from over 632,000 cubic meters of ore processed. 84,000 carats (16.8 kg) of the production was sold in 2004, at an average price of over US$300 per carat (1500 $/g), a new high mark for Angolan diamond production. Probable reserves are 1.3 million cubic meters