Pleistocene (1.8 Ma-0.01 Ma = 1.79 My): According to the International Union of Geological Sciences the Pleistocene spans from 1.8 to 2.588 My before the Present. The recent period of repeated glaciation forms part of the Pleistocene. The glaciation in some parts advanced to 400 latitude; when at its peak, ice covered about 30% of the Earth surface. The permafrost zone extended southward, the mean annual temperature at the edge of the ice was -60 C and at the edge of permafrost was 00 C. Each glacial episode locked up huge quantity of water in continental ice sheets measuring 1500-3000 m in thickness, which led to fall of sea level by 100 m or even more over the entire surface of the Earth. The interglacial (pluvial) periods resulted in melting of the ice sheets and consequent rise in sea level. Southern part of the Andes had ice cap, glaciers abounded in New Zealand, Tasmania, Mt Kenya, Mt Kilimanjaro, Ruwenzori Range, central Africa, in mountains of Ethiopia and Atlas mountains. In t

The Himalaya became abode of valley glaciers which in many areas descended up to an altitude of about 1000 m. South of the ice sheets due to choked outlets and cooler air retarded the evaporation though large lakes still existed. Deserts were drier and more extensive as the rainfall decreased due to diminished oceanic and other evaporation.

Over 11 major and as many minor glacial events, interspersed with warmer pluvial (inter-glacial) periods have been identified. The glacial range and period for each continent varied as per its latitudes. The glacial periods in the Himalaya and elsewhere are presented in Tables 3 a, b. Table 3a. Names of interglacial in Europe and Midwest U.S. Region Interglacial 1 Interglacial 2 Interglacial 3 Alps Ghz-Mindel Mindel-Riss Riss-Wrm North Europe Waalian Holsteinian Eemian British Isles Cromerian Hoxnian Ipswichian Midwest U.S. Aftonian Yarmouthian Sangamonian 20 Table 3b. Historical names of the four major glacials in four regions. Region Glacial 1 Glacial 2 Glacial 3 Glacial 4 Alps Ghz Mindel Riss Wrm North Europe Eburomian Elasterian Saalian Weichselian British Isles Bestomian Anglian Wolstonian Devensian Midwest U.S. Nebraskan Kamsan

Illinoian Wisconsinan The climate cycles depend on regional solar radiation that is caused by the sum of many repeating changes in the Earths motion. The Milankovitch Cycle, based on the Earths orbital variation envisages glaciation once every 100,000, 40,000 and 10,000 years (Tables 3 a,b). Such a pattern seems to fit the information on climate change found in oxygen isotope cores. Though these pattern cannot be the only reason to control the ice ages. The timing of our present interglacial interval (the Holocene) to that of the previous interglacial beginning about 130,000 years ago (Sangamon), suggests that the next glacial will begin in about 3,000 years. Both marine and continental faunas were quite similar to the modern fauna (Fig. 40) Fig. 40. Early Pleistocene animals (modified after