Age of Glaciation

During the Pleistocene more than one-third of the world's land surface was covered by snow and ice. Northern Hemisphere glaciation actually began in the Pliocene and expanded in the Pleistocene. The glacial maxima and minima caused Northern Hemisphere climatic zones to shift southward by around 20 degrees latitude in North America and Europe; Asia was mostly free of ice, but it became a cold desert. Also as a result, tropical zones shrank and rain forests in Africa were fragmented into islands of forests amid savannas, and the Sahara Desert greatly expanded its boundaries.

The Pleistocene expansions of continental ice sheets in North America, Greenland, and Scandinavia caused the lowering of sea level by more than 100 m (roughly 330 ft). Vast quantities of water remained as ice and snow that was added to the glaciers. At this time, the continental shelves were exposed above sea level. Marine sediments were now exposed to weathering, erosion, and pedogenic processes. Rivers flowed across the shelves, cut downward, and produced large valleys, while soils formed between valley systems. Sediments that passed through these rivers were eventually deposited in the deep sea. The remnants of these systems today exist as submarine canyons.

Worm Farming

Worm Farming

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