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
Diamond Mine (video game) Diamond Mine (video game) Diamond Mine is a video game first published by MRM Software for the Acorn Electron and BBC Micro home computers in 1984. It was reissued by Blue Ribbon in 1985 and ported to other systems in 1985 and 1986. Blue Ribbon also released a sequel Diamond Mine II at the same time. Both games are similar to the 1982 arcade game "Anteater". While the maze design, limited pipe length and non-stop movement make the first game more original, "Diamond Mine II" could be considered an "Anteater" clone. The aim of the game is to guide a