Pleistocene Epoche

Pleistocene Epoch, courtesy The American Museum of Natural History. c Fossilized specimen, courtesy The American Museum of Natural History. d Collagenous material extracted with boiling water for 2 hrs. 

The Quaternary Period is subdivided into the Pleistocene Epoch and, commencing at 10,000 years ago, the Holocene Epoch. The Holocene is synonymous with the Postglacial or present interglaciation. ... 

It is important to realise that clay can be exposed to many processes after it has been depos-ited. The periods are the Miocene Epoch (26 - 7 million years old), the Pliocene Epoch (7-2 millions years old), the Pleistocene Epoch (2 million to 15,000 years old) and the Holocene Epoch (up to approximately 15,000 years old). In The Netherlands no primary clay deposits are found, i.e. all clay is secondary, i.e. formed elsewhere and transported by wind, ice or water. 

Modern estuaries are recent features that only formed over the past 5000 to 6000 years during the stable interglacial period of the middle-to-late Holocene epoch (0-10,000 y BP), which followed an extensive rise in sea level at the end of the Pleistocene epoch (1.8 My to 10,000 y BP). 

A glacial epoch or time of extensive glacial activity. Also, as Ice Age, which refers to the latest glacial epoch, the Pleistocene Epoch, ice and snow albedo... 

A glacier of considerable thickness and more than 50,000 sq km in area. It forms a continuous cover of ice and snow over a land surface. An ice sheet is not confined by the underlying topography but spreads outward in all directions. During the Pleistocene Epoch, ice sheets covered large parts of North America and northern Europe but they are now confined to polar regions (e.g., Greenland and Antarctica), ice shelf... 

Quaternary 1) Time The second and last period in the Cenozoic Era. Normally, it is subdivided into the Holocene (Recent) and Pleistocene Epochs. The short chronology places its beginning at the traditionally defined boundary atroughly 1.78 Ma, while the long chronology places it at the start of the Matuyama Magnetochron at approximately 2.48 Ma. 2) Rocks The sediment and rocks formed during the Quaternary Period. 

Fig. 17.31 The history of temperature fluctuations based on the isotope composition of oxygen and hydrogen in the ice core drilled by the European Project for Ice Coring in Antarctica (EPICA) at Concordia Station on Dome C (75°06 S, 123°21 SE) is closely correlated with the concentrations of carbon dioxide in the ice, both of which can be indexed to the marine isotope stages in Fig. 17.30. The correlation of these parameters confirms the scope of the chmate fluctuations which include nine cold spells that terminated abruptly during the Pleistocene Epoch (i.e., Tj-Tjj, etc.). The temperature profile (black curve) is based on measurements of 6D and was plotted on the EDC3...

Four ice age episodes were recognized in the Pleistocene Epoch that commenced about 2 million years ago and ended about 10,000 years ago. Each was succeeded by warmer episodes and there were an estimated 22 ice episodes during this time interval. Numerous possible causes for this last ice age and earlier ones have been put forward. One is a decrease in solar energy output. Another is variations in the geometry of the Earth s orbit and precessional cycle. 

Early in the Pleistocene epoch much of the present Netherlands was submerged. With time marine and fluvial deposits built up the land. Around 5000 years ago the coastline consisted of a sandy coastal zone, mud flats, salt marshes, and peat bogs. The subsequent formation of coastal dunes closed off the area of mud flats and salt marshes resulting in an increase of peat growth. Figure 84.1 shows the coastline around 800 A.D. when the shape was a result of natural forces only. Note Lake Almere in the center of the region. 

The present glaciation of the Arctic is small compared with that during the Pleistocene epoch (2-0.01 Ma). During that epoch, four major - or six according to some authors - ice-sheets invaded Europe and North America, their deposits being most readily studied at the southern peripheries of the glaciated areas. 

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