Retreat of glaciers since 1850 doing so due to transient local weather conditions, which have brought more precipitation and cloudier, cooler summers since 2002. Tropical glaciers are located between the Tropic of Cancer and the Tropic of Capricorn, in the region that lies 23° 26′ 22″ north or south of the equator. Strictly, a tropical glacier is located within the astronomical tropics; the area where the annual temperature variation is less than the daily variation, and is within the oscillation area of the Intertropical Convergence Zone. Tropical glaciers are the most uncommon of all glaciers for a variety of reasons. Firstly, the regions are the
Geology of the North Sea Red Sandstone' continent at the joining of the tectonic plates. The Rheic Ocean began to open to the south. The Acadian orogeny occurred in the Lower Devonian period (Paleozoic era), about 500 Ma. The continents of Laurentia and Baltica collided. The Iapetus Ocean disappeared under this continental collision. These plate tectonic forces built up a mountain range extending from what is now termed the Adirondacks north through Nova Scotia, the British Isles, Norway and the eastern margin of Greenland. Greenland and Scandinavia were situated at the amid the equator and mid tropics (20 to 20 degrees north). The area now