NRES 201 Lecture 5 Outline of Last Lecture I Nature of soil genesis II Rocks the basic ingredient of soils III Parent Materials a Residuum b Colluvium c Alluvium d Marine sediments Outline of Current Lecture IV The Pleistocene Ice Age V Parent materials a Glacial drif b Eolian deposits VI Climate Current Lecture The Pleistocene Ice Age o Estimated extent Up to 20 of the world s land area covered by great ice sheets including Canada Southern Alaska and Northern parts of the USA Most of Illinois was glaciated during the pre Illinoisan and Illinoisan periods o Glacial impacts Massive ice sheets up to more than 1 km thick acted like a giant bulldozer The existing soil and regolith were swept away New soils began to form from fresh parent materials o Glacial drif All materials of glacial origin Two types Glacial till Materials deposited directly by the ice Ofen deposited in irregular ridges Associated landforms o End moraine Till placed at a terminal or recessional edge of glacier These notes represent a detailed interpretation of the professor s lecture GradeBuddy is best used as a supplement to your own notes not as a substitute o Ground moraine Level till plain formed beneath the glacier The campus is built on one o Drumlin Large elongated hill oriented with the direction of ice movement o Glacial outwash Materials carried by torrents of melt water Outwash deposits are stratified by water ofen over or underlain by stratified till Eolian deposits Transported by wind and important parent materials in many areas o Loess Wind blown silt important term 4 types of Aeolian deposits o Dune Sand o Loess o Aerosolic dust o Volcanic ash Organic deposits o Accumulate in marshes and swamps lack of oxygen slows decomposition o May be mixed with inorganic material o Two types Peat un decomposed Muck partially decomposed o Organic soils are naturally wet highly productive if drained and subject to fire and subsidence 5 Soil forming factors o Climate o Topography o Time o Plants and Animals o Parent Material
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