,educational ,series #i ,,inside ,,illinois ,mineral ,resources ,illinois ,state ,geological ,survey ,illustration3 ,,seal ,,of ,,the ,,state ,,of ,,illinois ,,aug4 #bf,,th #ahah ,,state of ,,illinois ,,department of ,,registration and ,,education #aife ,,illinois ,,state ,,geological ,,survey ,john ,c4 ,frye1 ,chief ,,urbana1 ,,illinois ,printed by ,authority of ,state of ,illinois1 ,ch4 #abg1 ,,irs1 ,par4 #eh4be4 ,,inside ,,illinois-- ,mineral ,resources ,although ,illinois has been nicknamed the 8,prairie ,state10 many parts of it are hilly and scenic4 ,the idea of large areas of the state being nothing more than broad1 flat prairies has come about because the major highways have been built to take advantage of the comparatively low1 gently rolling landscape rather than the rougher more scenic areas4 ,physiography is the study of the creation and gradual change of land surface forms 7the landscape74 ,thus1 the land surface as we see it today in each of the physiographic provinces 7fig4 #a7 has had a particular history of development4 ,illinois is about #che miles long from north to south and about #bah miles wide4 ,it has an area of #ee1idg square miles4 ,the average elevation of the state is about #fjj feet above sea level4 ,charles ,mound1 however1 in the northern part of ,jo ,daviess ,county in extreme northwestern ,illinois1 has an elevation of #a1bda feet above sea level and is the highest point in the state4 ,cheap water transportation is available to ,illinois industry through ,lake ,michigan1 the ,illinois ,waterway1 and the ,mississippi1 ,ohio1 and ,wabash ,rivers4 ,these major rivers of ,illinois collect the surface drainage of the state from a network of about #ejj streams4 ,,what ,,is ,,the ,,earth ,,made ,,of ,,beneath ,,the ,,ground ,,surface8 ,the earth is made of a large number of different rocks and minerals 7limestone1 sandstone1 shale1 coal1 iron1 granite1 and many others74 ,these materials are divided into three zones3 core1 mantle1 and crust 7fig4 #b74 ,illustration3 ,figure #a--,physiographic provinces of ,illinois4 ,,driftless ,,area ,,wisconsinan ,,moraines ,,illinoian ,,till ,,plain ,,mississippi ,,river ,,wabash ,,river ,,shawnee ,,hills ,,ohio ,,river ,illustration3 ,figure #b--,the earth with a segment removed to show supposed internal zones4 ,crust 7#f-cj miles7 ,mantle 7#ahjj miles7 ,outer core 7#adjj miles7 ,inner core 7#gej miles7 ,,what ,,is ,,core8 ,the core is the innermost zone of the earth4 ,it is mainly iron with some nickel and cobalt4 ,the inner core probably is solid1 but the outer core may consist of the same elements in a molten form4 ,the core is the most dense 7heaviest7 of the three zones4 ,,how ,,does ,,the ,,mantle ,,differ ,,from ,,the ,,core8 ,the mantle1 which surrounds the core1 is a rigid zone of materials rich in iron and magnesium4 ,these materials are not as dense as those found in the core4 ,,what ,,is ,,the ,,crust ,,of ,,the ,,earth ,,and ,,how ,,is ,,it ,,distinguished ,,from ,,the ,,mantle ,,and ,,the ,,core8 ,the crust1 the top part of which includes the ground we walk on1 is the hard1 outer surface layer of the earth4 ,although the crust is about #f to #cj miles deep1 the scale 7size7 of figure #b allows it to be drawn only as the thin outer line4 ,the rocks and minerals that we are all acquainted with are found in the crust4 ,these rocks are not as dense and do not have as high an iron content as do the rocks of the mantle and the core4 ,,what ,,is ,,the ,,earth',s ,,crust ,,under ,,illinois ,,made ,,of8 ,the earth's crust under ,illinois is made of3 sedimentary rocks deposited by water1 wind1 or glaciers 7limestone1 sandstone1 shale1 glacial drift72 igneous1 or melted rocks 7granite1 gabbro72 and metamorphic1 or altered sedimentary and igneous rocks 7quartzite1 gneiss74 ,these various types of rocks have a relatively thin covering of broken or weathered material called mantle rock and soil4 ,,when ,,and ,,how ,,was ,,the ,,land ,,surface ,,of ,,illinois ,,formed8 ,the ground surface over most of ,illinois was formed during the ice age 7,quaternary ,period7 which lasted from about one million years ago up to nearly #e1jjj years ago4 ,as much as #ij percent of the state was covered by one of several sheets of glacial ice 7fig4 #c74 ,the glaciers smoothed down and covered much of the old1 rocky1 hilly land surface and filled old valleys with loose1 unconsolidated deposits4 ,,where ,,did ,,the ,,loose1 ,,unconsolidated ,,deposits ,,come ,,from ,,and ,,what ,,are ,,they ,,made ,,of8 ,in ,canada vast thicknesses of snow and ice accumulated until the weight of the ice finally caused it to flow slowly outward1 mainly to the south 7fig4 #d74 ,rocks and surface materials of all types were picked up and carried by the glaciers for great distances before being deposited4 ,pieces of granite1 quartzite1 and native copper among the many local rocks and minerals are found in glacial deposits and indicate that at least part of these deposits came from the ,great ,lakes ,region4 ,the materials deposited range from clay-size minerals to large boulders4 ,illustration3 ,figure #c--;,extent of the main glacial advances which began with the ,nebraskan 7a--the oldest7 and ended with the late ,wisconsinan 7f--the youngest74 ,diagram 8d0 shows the major stream development during the time between the ,illinoian and the earliest ,wisconsinan glaciers4 ,the heavy lines on the diagrams indicate major stream valleys that were present during these times4 a4 ,inferred limit of ,,nebraskan glaciation b4 ,inferred limit of ,,kansan glaciation c4 ,,illinoian glacial advance d4 ,,sangamonian major drainage e4 ,maximum ,,wisconsinan glacial advance f4 ,late ,,wisconsinan ,valparaiso front and ,kankakee ,flood ,,how ,,did ,,illinois ,,get ,,its ,,soils8 ,illustration3 ,figure #d--,limits of ice age glaciers4 ,weathering and bacterial decay action have modified many of the loose1 unconsolidated surface materials into soils4 ,the present soils of ,illinois are fertile partly because they have minerals and trace elements 7minute amounts of elements such as copper1 zinc1 manganese7 brought in by the glaciers from adjacent parts of the country4 ,the youngest and most fertile soils occur in the northeastern part of the state and along the ,illinois and ,mississippi ,river valleys4 ,these young soils are more fertile because the glacial deposits and loess 7wind-blown silt7 upon which they have developed are younger and fresher4 ,the minerals and trace elements in these deposits have not been dissolved out to the extent that they have in the older glacial deposits and soils in other parts of the state4 ,illustration3 ,figure #e--,woolly mammoth 7after ,c4 ,r4 ,knight74 ,,are ,,animal ,,and ,,plant ,,remains ,,found ,,in ,,the ,,glacial ,,deposits ,,of ,,illinois8 ,scattered mammoth 7fig4 #e7 and mastodon remains have been found in glacial deposits at various localities in the state4 ,peat1 which is an accumulation of partially decomposed plant materials1 has been found1 especially in the northern part of the state4 ,it is marketed as an organic soil conditioner4 ,,mineral ,,wealth ,,how ,,wealthy ,,is ,,illinois ,,in ,,mineral ,,production8 ,in #aifc1 ,illinois mineral production totaled approximately #fae1jjj1jjj4 ,this placed the state first as a mineral producer in the ,upper ,mississippi ,valley and eighth in the nation4 ,,what ,,mineral ,,commodities ,,are ,,produced ,,in ,,illinois8 ,coal and petroleum1 two of the world's most important mineral resources1 are produced in ,illinois4 ,iron ore1 another mineral of extreme importance1 is brought into the steel mills of the ,chicago and ,east ,st4 ,louis areas from deposits in ,minnesota and ,missouri4 ,some ore from foreign countries is also processed in these mills4 ,a great variety of mineral commodities are produced in ,illinois4 ,in the order of their #aifc value 7fig4 #f7 they are 7#a7 crude oil and natural gas1 7#b7 coal1 7#c7 clay products1 7#d7 crushed stone and cement1 7#e7 common sand and gravel1 7#f7 special sands1 7#g7 fluorspar1 and 7#h7 metals--zinc and lead4 ,,how ,,many ,,illinois ,,counties ,,produce ,,mineral ,,commodities8 ,in #aifc1 #ii of the #ajb counties of ,illinois reported mineral production of one kind or another4 ,illustration3 ,figure #f--,percentage diagram of ,illinois mineral production value for #aifc4 ,petroleum and ,natural ,gas #cf4c ,coal #ca4i ,stone ,products #ae4b ,clay ,products #h4h ,sand and ,gravel #e4i ,fluorspar and ,metals #a4i ,,how ,,many ,,people ,,work ,,in ,,the ,,mineral ,,industries ,,of ,,illinois8 ,in #aifc1 approximately #bg1jjj people worked in mines1 quarries1 oil fields1 and direct processing operations such as cement and clay products plants and oil refineries4 ,many other persons were employed in transporting the materials and in plants and general offices4 ,,how ,,does ,,the ,,farmer ,,in ,,illinois ,,benefit ,,from ,,mineral ,,production8 ,the farmers of the state are among those receiving direct and indirect benefits from ,illinois minerals4 ,in #aifc1 more than #d1hjj1jjj tons of agstone 7crushed limestone and dolomite7 were spread on ,illinois fields to reduce acidity1 maintain soil fertility1 and improve crop production4 ,other stone and stone products are used in constructing farm buildings and facilities and in the maintenance of farm-to-market roads4 ,in addition1 petroleum products and coal provide energy to power the laborsaving devices that enable the farmer to increase his production and scale of operations4 ,,petroleum ,,what ,,is ,,petroleum ,,and ,,how ,,is ,,it ,,formed8 ,petroleum is a dark1 oily fluid that is irregularly distributed in sedimentary rocks throughout the world4 ,there are several ideas about the origin of petroleum4 ,the most widely accepted of these is that billions of plants and animals lived and died in widespread seas and their remains decomposed and released fluid1 fatty particles4 ,these were distilled into 8hydrocarbons0 7a mixture of the elements hydrogen and carbon1 such as gas and oil74 ,,how ,,and ,,where ,,did ,,oil ,,collect ,,in ,,rocks8 ,the hydrocarbons1 or oil and gas droplets1 were buried by countless tons of sediments that accumulated on ancient sea bottoms4 ,as these sediments hardened into sedimentary rocks1 the hydrocarbons were squeezed into whatever empty spaces were available in the rocks4 ,as the layers of sedimentary rocks later became folded and broken1 oil and gas droplets and salt water moved upward through any interconnecting open spaces4 ,some droplets escaped to the surface as 8seeps10 but many were trapped when they came up against a nonporous barrier4 ,gas1 being lighter than either oil or water1 was trapped at the top1 and oil was stopped in the middle1 above the salt water4 ,an accumulation of this kind is termed a 8pool0 or a 8field40 ,,where ,,did ,,oil ,,accumulate ,,in ,,illinois8 ,conditions under which oil is found in ,illinois 7fig4 #g7 are as follows3 7a7 coral reefs1 7b7 anticlines 7upfolds or arches of rock layers71 7c7 8pinching0 or 8lensing0 out of dipping1 overlapping porous rock layers1 and 7d7 buried sandstone-filled ancient stream channels4 ,,are ,,there ,,lakes ,,or ,,rivers ,,of ,,oil ,,underground8 ,no4 ,oil and gas accumulate in the pores 7openings7 between silt and sand grains and in small openings in limestone and dolomite4 ,illustration3 ,figure #g--,places where oil is found in ,illinois3 7a7 coral reefs1 7b7 anticlines1 7c7 pinch-outs1 and 7d7 channel sandstones4 ,,explanation ,glacial drift ,dolomite ,shale ,gas saturated zone ,sandstone ,oil saturated zone ,limestone ,water saturated zone ,,how ,,is ,,oil ,,discovered8 ,although prospect 7test7 drilling is still the only way to prove the presence or absence of commercial quantities of oil beneath the surface1 careful study by a geologist of all available information may indicate the most favorable places for testing4 ,since oil and gas migrate to the highest parts of the porous rock zones1 the geologist tries to find these high places even though they may be several hundred feet underground4 ,sometimes dipping rocks can be seen in outcrops1 and several geophysical methods have been used to indicate where such high places may occur underground4 ,at other times1 high places are found by studying with a microscope samples of rocks collected from wells already drilled in the surrounding area4 ,the geologist notes the type and order of the formations which have been drilled4 ,many holes have been drilled based on such information4 ,whether or not the test drilling is successful as a producing well1 small samples of cuttings of the rock being drilled are collected and saved to be studied at a later time4 ,various instruments are also put down into the hole to record temperatures1 pressures1 electrical properties1 and other characteristics of the rocks4 ,this type of information1 when carefully plotted on maps1 serves to locate new areas for test drilling4 ,,how ,,much ,,oil ,,can ,,be ,,obtained ,,from ,,an ,,oil ,,pool8 ,there is no way to tell before a hole is drilled whether or not oil will be found1 how much oil is present1 or what will be the best way to get it to the surface4 ,where subsurface pressures are great enough1 oil may flow to the surface4 ,generally speaking1 about one-third of the oil actually present in the rocks can be pumped before the well becomes uneconomical to operate4 ,this is called primary production4 ,oil operators have learned that by pumping water or gas down some wells into the oil-bearing formation1 another third of the oil may be forced out through neighboring wells4 ,this is called secondary production4 ,experiments that use steam or that burn some of the oil underground in an oil-bearing formation are attempts to recover the remaining third4 ,these methods using heat are often referred to as tertiary production methods4 ,,what ,,is ,,the 8,,biggest0 ,,oil ,,well ,,on ,,record ,,in ,,illinois8 ,illinois' largest well1 near ,centralia1 flowed #ab1jjj barrels of oil in a #bd-;hour period4 ,most ,illinois oil wells1 however1 have to be pumped1 and the majority of them are now producing #aj barrels or less a day4 ,the deepest producing well1 #e1ced feet1 was drilled in #aifj in ,wayne ,county1 near ,fairfield4 ,in the same year the deepest oil test was drilled to a depth of #h1faf feet and was stopped in granite4 ,this test is located in ,fayette ,county near ,beecher ,city and has its oil production from a zone over #d1jjj feet above the bottom of the hole4 ,,how ,,much ,,oil ,,is ,,produced ,,in ,,illinois ,,and ,,how ,,valuable ,,is ,,it8 ,in #aifc1 about #ge million barrels of oil1 #b4g percent of the nation's total1 were produced in ,illinois 7fig4 #h74 ,this oil is valued at over #bba1jjj1jjj4 ,,is ,,oil ,,production ,,increasing ,,or ,,decreasing ,,in ,,illinois8 ,in #aidj1 our state had its highest yield of oil when #adg1fdg1jjj barrels were produced4 ,although production figures remained fairly high for some time1 they have declined in the past few years4 ,since no new large oil discoveries have been made recently1 ,illinois' total known oil reserves are decreasing yearly4 ,in #aifc1 ,illinois ranked eighth among the oil-producing states1 with #dbj oil fields consisting of #cj1adi wells4 ,,coal ,,what ,,is ,,coal ,,and ,,how ,,is ,,it ,,formed8 ,coal is a combustible rock that was formed by the accumulation and partial decay of vegetation4 ,when coal was forming millions of years ago1 most of the state was a low coastal plain bordered on the west and southwest by a shallow sea4 ,a large variety of plants grew in great swamps which covered this coastal plain 7fig4 #i74 ,when the plants died1 they accumulated in the swamps to form thick masses of peat that were eventually covered by shallow seas and buried beneath mud and sand4 ,periodically1 the region was above sea level1 new swamps developed1 new peat deposits accumulated1 and more sediments were laid down4 ,this process occurred repeatedly until over #c1jjj feet of sediments had been deposited4 ,then the sediments were slowly compacted and hardened so that sandstones1 shales1 limestones1 and coals were formed4 ,illustration3 ,figure #h--;,estimated total oil production by counties from #ahhh through #aifc4 ,counties producing oil in ,january #aife ,total ,production #b1dfd1geh1jjj barrels #df counties producing ,illustration3 ,figure #i--,reconstruction of coal-forming swamp4 ,,how ,,do ,,we ,,know ,,that ,,coal ,,was ,,derived ,,from ,,plant ,,materials8 ,although plant impressions or fossilized wood can be seen in coal1 they are more common in shales and sandstones associated with the coal4 ,often roots can be seen in the clay that lies just under the coal1 and in some places stumps of trees from the coal swamp forest are preserved in the sediments adjacent to the coal 7fig4 #aj74 ,when pieces of coal are examined with a microscope1 carbonized plant remains can be seen4 ,,how ,,many ,,coal ,,seams ,,are ,,present ,,in ,,illinois8 ,there are at least #dj different coal seams in ,illinois1 but most are relatively thin4 ,seven coal seams have been mined extensively1 and all together #bj or more have been mined4 ,illustration3 ,figure #aj--,some root1 stem1 and leaf fossils found in ,illinois coal-bearing rocks4 ,neuropteris ,nosopteris stem ,neuropteris ,lepidodendron ,pecopteris ,stigmaria ,annularia ,spiropteris ,sphenophyllum #a ,,how ,,is ,,illinois ,,coal ,,mined8 ,in ,illinois there are two main ways of mining coal3 strip 7open-cut7 and underground4 ,strip or open-cut mines 7fig4 #aa7 usually operate where the coal is at very shallow depths1 although such mining is done as much as #ajj feet deep or more in some places4 ,many old underground mines produced coal from seams that were less than #ajj feet deep because they did not have the large machinery for strip mining when these mines were started4 ,an abandoned mine1 #a1jjd feet deep1 near ,assumption is the deepest underground coal mine in the state4 ,coal is now being mined at depths somewhat over #hjj feet in ,jefferson ,county4 ,,how ,,does ,,illinois ,,rank ,,as ,a ,,coal ,,producer8 ,illinois ranks fourth in production of coal in the ,united ,states4 ,it is exceeded only by ,west ,virginia1 ,kentucky1 and ,pennsylvania4 ,some of the largest and most efficient mines in the country are operated in ,illinois4 ,underground mines in ,illinois have the highest rate of tons mined per man each day in the country1 and this rate is increasing4 ,increased mining efficiency has made it possible to hold the price of coal low enough so that it can successfully compete against other fuels for many uses4 ,illustration3 ,figure #aa--;,diagram of strip mine showing3 7a7 stripping shovel1 and 7b7 coal-loading shovel4 ,,how ,,much ,,coal ,,is ,,produced ,,in ,,illinois ,,annually ,,and ,,how ,,valuable ,,is ,,it8 ,in the last #aj years1 an average of about #df million tons of coal has been mined each year 7fig4 #ab74 ,in #aifc1 approximately #ea4f million tons were produced1 which were valued at about #aif1jjj1jjj at the mine4 ,since #aifa1 strip mines have produced over half of the coal mined in ,illinois4 ,,how ,,long ,,will ,,our ,,coal ,,supplies ,,last8 ,it will take well over #a1jjj years at the present rate of mining in ,illinois to exhaust our coal reserves4 ,an estimated #adj billion tons of coal in seams of minable thickness remain in the ground in our state2 these are the largest known reserves of bituminous coal of any state in the ,united ,states4 ,,what ,,is ,,coal ,,used ,,for8 ,electric power generation consumes the greater part of the annual coal production in ,illinois4 ,coal is also used for home and commercial heating1 for production of coke1 and for manufacturing various chemical compounds from coal tar4 ,products derived from coal tar include drugs and medicines1 plastics1 synthetic fibres1 perfumes1 flavorings1 dyes1 synthetic rubbers1 explosives1 specialized oils1 solvents1 wood preservatives1 tarlike paving and roofing materials1 and some gas4 ,the gas is both produced and utilized in the coke industry4 ,,what ,,is ,,coke8 ,coke is a material produced by burning coal in the absence of air so that most of the gases and water are driven off without consuming the solid portion4 ,the resulting solid coke is a strong1 porous1 combustible substance4 ,,how ,,important ,,is ,,coke ,,and ,,how ,,is ,,it ,,used8 ,the structure and nature of coke make it a valuable fuel for blast furnace use in the production of steel4 ,in the past1 most of the coal used in the manufacture of coke has come from areas of higher quality coal outside of our state4 ,however1 at present1 over #a1jjj1jjj tons of ,illinois coal are mined annually for the production of metallurgical coke4 ,illustration3 ,figure #ab--;,estimated total coal production by counties from #ahhb through #aifc4 ,area underlain by coal-bearing rocks ,counties producing coal in ,january #aife ,total ,production #c1gdi1dbc1ecd tons #ga counties producing ,,stone ,,and ,,stone ,,products ,,what ,,types ,,of ,,stone ,,are ,,produced ,,in ,,illinois8 ,limestone and dolomite are the most abundant rocks quarried in ,illinois4 ,small amounts of marble1 limestone1 and sandstone for building stone are also produced4 ,in addition1 some glacial boulders and cobbles are used for rock gardens and in home construction4 ,the crushed limestone industry is ,illinois' most important rock products industry4 ,,what ,,are ,,limestone ,,and ,,dolomite8 ,limestone is a sedimentary rock that consists chiefly of calcite1 which is composed of calcium1 carbon1 and oxygen4 ,dolomite is a variety of limestone that contains considerable magnesium in addition to the other elements4 ,limestones were deposited on the floors of ancient seas that repeatedly covered most parts of ,illinois4 ,shelled creatures1 corals1 and coral reefs helped build up the thick limestone deposits 7figs4 #ac and #ad74 ,illustration3 ,figure #ac--,piece of limestone largely made up of fossil brachiopod shells4 ,,where ,,are ,,limestone ,,and ,,dolomite ,,quarries ,,located ,,in ,,illinois8 ,limestone and dolomite quarries are located along the southern1 western1 and northern margins of the state where the thick deposits of these rocks crop out at the surface4 ,although bedrock was deposited in horizontal layers1 it has since been downfolded into the ,illinois ,basin whose center is in southeastern ,illinois4 ,thus1 the thick limestones and dolomites that are quarried along the margins of the state are too deeply buried to be quarried in the central part of this basin 7fig4 #ae74 ,illustration3 ,figure #ad--;,fossils commonly found in ,illinois rocks4 ,strophomena #a ,paleoneilo #a ,ctenodonta ,dolmanites ,archimedes #a ,hormotoma ,polygyra #a ,mucrospirifer #a ,atrypa ,crinoid ,columnais #a ,halysites ,hexagonaria #a ,microcylus #a ,streptelasma ,lithostrationella ,lophophyllum #a ,illustration3 ,figure #ae--;,diagrammatic cross section of the ,illinois ,basin4 ,,miss4 ,,river ,waterloo ,mt4 ,vernon ,,illinois ,,wabash ,,river ,,indiana ,new ,albany ,,ohio ,,river ,,are ,,any ,,stone ,,quarries ,,located ,,in ,,the ,,area ,,underlain ,,by ,,the ,,illinois ,,basin8 ,yes4 ,in the area underlain by the basin1 stone quarries are operated in younger1 thinner rock strata of ,pennsylvanian age4 ,these strata also overlie the thick limestones and dolomites quarried along the margins of the state4 ,the quarries located within the basin area produce stone for agricultural limestone1 roads1 and other purposes4 ,,how ,,and ,,where ,,are ,,limestone ,,and ,,dolomite ,,used8 ,millions of tons of stone are crushed annually to produce aggregate for use in making concrete roads and buildings1 for road surfacing1 and for agricultural limestone4 ,agstone is applied to farmlands to neutralize soil acidity1 improve soil structure1 add calcium and magnesium1 and promote conditions favorable for the utilization of soil materials by plants4 ,large quantities of limestone are used in making lime and cement4 ,there are three cement plants in northern ,illinois--two at ,la,salle and one at ,dixon--and one in southern ,illinois1 at ,joppa4 ,small amounts of stone are used for making alkalies and glass1 for railroad ballast1 for building stone1 for dusting coal mines to prevent coal dust explosions1 and for ingredients in mineral feeds for livestock4 ,,how ,,much ,,stone ,,does ,,illinois ,,produce8 ,a production of about #cf million tons of stone in #aifc was valued at almost #dh1jjj1jjj4 ,the cement made from ,illinois limestone in the same year was valued at #cb1jjj1jjj4 ,,clay ,,what ,,is ,,clay ,,and ,,how ,,is ,,it ,,formed8 ,weathering or alteration of some rocks produces clay which is a very fine-grained1 unconsolidated rock4 ,clay is made up of a group of minerals1 of which illite1 montmorillonite1 kaolinite1 and chlorite are the most abundant4 ,,how ,,extensive ,,are ,,clay ,,deposits ,,in ,,illinois8 ,clay deposits in ,illinois consist of ,quaternary clays1 which were deposited by glaciers1 lakes1 and winds2 and of fireclay1 shale1 kaolin1 and 8fuller's earth10 all of which are bedrock deposits4 ,quaternary clay1 fireclay1 and shale resources occur widely in very large quantities2 8fuller's earth0 and kaolin deposits are small in relation to other clay resources4 ,,how ,,is ,,illinois ,,clay ,,used8 ,surface clay1 shale1 and fireclay are used in the manufacture of structural clay products1 such as brick1 drain tile1 and hollow block 7fig4 #af74 ,fireclay is used for a bonding agent in molding sand1 for the making of stoneware vessels1 for a plaster on the walls of industrial furnaces1 and for making refractory brick4 ,refractory brick must be able to withstand very high temperatures and is used to line industrial furnaces1 boilers1 kilns1 and ladles for molten steel4 ,shale and clay are ground up and mixed with limestone in the manufacture of cement4 ,crucibles1 refractories1 china1 and porcelain are made from kaolin4 8,fuller's earth0 is used as a sweeping compound and as an animal litter4 ,illustration3 ,figure #af--,typical ,illinois bee-hive kiln4 ,,what ,,is ,,the ,,value ,,of ,,the ,,clay ,,products ,,manufactured ,,in ,,illinois8 ,about #ec1ijj1jjj worth of clay products were manufactured in ,illinois in #aifc4 ,,sand ,,and ,,gravel ,,where ,,do ,,sand ,,and ,,gravel ,,come ,,from8 ,glacial deposits of sand and gravel are the chief source of these materials in ,illinois1 but chert or flint gravels that are older than the glacial deposits are known and utilized locally in western and extreme southern ,illinois4 ,sands of recent origin are dredged from deposits in the larger rivers and streams 7fig4 #ag71 and commercial silica sand is produced from sandstone bedrock4 ,illustration3 ,figure #ag--;,dredge equipment used in producing sand and gravel4 ,,what ,,is ,,the ,,value ,,of ,,common ,,illinois ,,sand ,,and ,,gravel ,,production8 ,production of common sand and gravel totaled #bg1aae1jjj tons at a value of #bd1hjj1jjj in #aifc4 ,,silica ,,sand ,,what ,,is ,,silica ,,sand8 ,although natural sands are aggregations of many kinds of small rock and mineral fragments1 silica sand consists almost entirely of fine grains of a single mineral1 quartz4 ,the principal sources of ,illinois silica sand are in ,la,salle 7,ottawa1 ,utica1 ,wedron1 and ,troy ,grove areas7 and ,ogle 7,oregon area7 ,counties4 ,,how ,,is ,,silica ,,sand ,,used8 ,silica sand1 produced in northern ,illinois1 is famous for its high purity1 and is widely used in making glass4 ,more than two-thirds of the raw material in common glass is silica sand4 ,quantities of silica sand are used as molding sand1 because it can withstand the high temperatures produced in casting steel and other metals4 ,it also is used for grinding and smoothing plate glass1 for sand blasting1 and for fracturing sand used to increase the production of oil wells4 ,some silica sand is ground to a fine powder and utilized as an ingredient in scouring compounds1 paint fillers1 pottery1 glazes1 and enamels4 ,a specially sized sand is produced from the ,st4 ,peter ,sandstone ,formation 7,ordovician in age7 that is used in testing the strength of cements and as a laboratory standard in various kinds of tests4 ,,how ,,valuable ,,is ,,silica ,,sand ,,to ,,the ,,economy ,,of ,,the ,,state8 ,illinois is a major producer of silica sand1 having produced #b1ijj1jjj tons in #aifc4 ,the silica sand and ground silica produced in the same year was valued at #aa1djj1jjj4 ,,tripoli ,,what ,,is ,,tripoli ,,and ,,where ,,is ,,it ,,found8 ,tripoli1 also known as amorphous silica1 is mined in ,alexander ,county in southern ,illinois4 ,it is prepared for market by being ground to a fine powder4 ,it consists of tiny particles of quartz4 ,,what ,,are ,,some ,,of ,,the ,,uses ,,for ,,tripoli8 ,tripoli is used as 8white rouge0 in optical lens polishing1 as a paint filler1 as a fine abrasive1 in the ceramic industry1 and for many other purposes4 ,,fluorspar ,,what ,,is ,,fluorspar8 ,fluorspar1 or fluorite1 is a glassy mineral that is commonly gray1 white1 or colorless1 but may be green1 blue1 purple1 yellow1 or black4 ,it is composed of calcium and fluorine4 ,fluorite is not a gem because it is too fragile and soft4 ,mineral collectors seek it because it is attractive and because some varieties have the ability to glow under invisible ultraviolet light 7hence the term 8fluorescence074 ,,where ,,are ,,fluorspar ,,deposits ,,located ,,and ,,how ,,important ,,is ,,illinois ,,production8 ,fluorspar produced in the ,united ,states comes chiefly from a small area in ,illinois and ,kentucky where it has been mined since #ahdb4 ,illinois produced about #ff percent of the nation's total in #aifc4 ,the state's production amounted to more than #acb1jjj tons1 valued at about #f1edg1jjj4 ,the crude ore is extracted from nearly horizontal bedded deposits and from nearly vertical veins in mines up to #hjj feet deep in ,pope and ,hardin ,counties4 ,finished fluorspar is produced from the crude ore by separating and concentrating methods4 ,,what ,,are ,,fluorspar ,,pellets8 ,in the separation of fluorspar from the other materials with which it naturally occurs1 a process is used that involves grinding the spar to a very fine powder4 ,the powdered spar has a number of uses1 but to suit it for use as a flux 7a substance which promotes fusion7 it is made into pellets by the use of a binder4 ,,what ,,is ,,fluorspar ,,used ,,for8 ,fluorspar is used extensively as a flux in the steel industry1 but over #ej percent of the spar produced in ,illinois in #aifc was consumed in the manufacture of hydrofluoric acid4 ,a large portion of this acid production is used in the aluminum industry4 ,hydrofluoric acid is also employed in the preparation of many fluorine compounds1 particularly those used in the production of fluorocarbons 7refrigerants1 plastics1 aerosols71 insecticides1 and high-energy fuels for rockets and missiles4 ,the fluorocarbons utilize about #dj percent of the hydrofluoric acid production4 ,,lead ,,and ,,zinc ,,what ,,ores ,,yield ,,lead ,,and ,,zinc ,,in ,,illinois8 ,the mineral galena is the principal ore of lead4 ,galena is gray in color1 very heavy1 has a bright metallic luster1 and breaks into cubes along steplike cleavage surfaces 7fig4 #ah74 ,it is composed of lead and sulfur4 ,the chief ore of zinc is the mineral sphalerite4 ,it may be brown1 yellow1 or black4 ,sphalerite is a combination of zinc and sulfur1 has a resinous luster1 and is not as heavy as galena4 ,,where ,,are ,,lead ,,and ,,zinc ,,mines ,,located ,,and ,,how ,,long ,,have ,,these ,,ores ,,been ,,mined8 ,although the lead deposits of extreme northwestern ,illinois 7now ,jo ,daviess ,county7 were reported by the ,french explorers in #afeh and are said to have been worked by the ,indians1 the influx of white settlers in the early #ahjj's marked the beginning of an extensive mining industry1 which was an important factor in the early development of that part of the state4 ,the town of ,galena takes its name from the mineral galena1 which was the principal ore mined4 ,illustration3 ,figure #ah--;,galena cubes4 ,in #ahde1 the ,upper ,mississippi ,valley produced #fj percent of all lead mined in the ,united ,states1 which then ranked first in world lead production4 ,until about #ahfj1 the zinc ore was considered useless1 but today its total value is several times that of lead4 ,lead mining began in southern ,illinois in #ahdb4 ,lead and zinc production in this area is a by-product of fluorspar mining4 ,,what ,,is ,,the ,,value ,,of ,,these ,,metals ,,produced ,,in ,,illinois8 ,in #aifc1 ,illinois produced #bj1cgg tons of zinc valued at about #d1fgg1ejj and #b1ija tons of lead worth about #fbf1fjj4 ,,ground ,,water ,,what ,,is ,,ground ,,water8 ,ground water is water that fills all openings in earth materials in the zone of permanent saturation4 ,the top of the zone of saturation is called the water table4 ,the source of ground water is precipitation 7rain and snow7 that seeps into the soil and percolates downward4 ,below the water table1 ground water moves slowly toward places of discharge such as springs1 lakes1 rivers1 marshes1 and wells4 ,water falls to the ground1 moves through the rocks1 returns to the surface1 and finally gets back to the atmosphere by evaporation and from plants 7fig4 #ai74 ,this cycle is continuously repeated4 ,,what ,,kinds ,,of ,,rocks ,,yield ,,ground ,,water8 ,ground water is most readily obtained from saturated rocks that have fairly large openings between grains 7such as sand1 gravel1 and sandstone7 or have interconnected cracks or channels 7such as limestones74 ,rocks that contain ground water and that will yield it to wells are called aquifers4 ,sand and gravel beds are widely used aquifers in ,illinois4 ,illustration3 ,figure #ai--,source1 movement1 and occurrence of ground water4 ,arrows in aquifers show direction of flow of water4 ,,evaporation ,,sand ,,and ,,gravel ,,well ,water ,table ,river sand and gravel ,,artesian ,,wells ,,evaporation ,river ,,well ,,collecting ,,area ,,for ,,artesian ,,water ,,precipitation ,crater ,,water ,,table ,,well ,lake ,glacial pebbly clay ,glacial sand and aquifer ,shale ,sandstone aquifer ,limestone aquifer ,shale ,,ground-,,water ,,reservoir ,,is ,,water ,,found ,,in ,,underground ,,lakes ,,and ,,rivers ,,in ,,illinois8 ,no4 ,there are a few large springs that flow from rocks along river bluffs in ,illinois1 but most ground water occurs in tiny openings within the rocks4 ,ground water reservoirs may be regarded as similar to sponges rather than as underground lakes or rivers4 ,,why ,,do ,,wells ,,sometimes ,,go ,,dry8 ,the water table rises and falls seasonally and from year to year1 depending upon the amount of precipitation4 ,sometimes the water table may fall below the bottom of the well or below the pump4 ,sometimes overpumping the well or pumping too many wells in a small area lowers the water table sufficiently to check the yield of the well4 ,,what ,,is ,,an ,,artesian ,,well8 ,an artesian well is one in which pressure forces water to rise in the well above the level where it was found4 ,in some artesian wells water flows out at the surface4 ,conditions for artesian wells are illustrated in figure #ai4 ,the shale above the sandstone and limestone aquifers in the figure is 8tight0 and does not permit water to escape upward to the level at which it enters the aquifers in the intake areas4 ,the water is under natural pressure4 ,when a well is drilled through the shale and into the aquifers1 water rises1 seeking its own level4 ,most of the deep wells in northern ,illinois are artesian wells1 though few of them flow at the surface anymore4 ,,will ,,you ,,always ,,find ,,water ,,if ,,you ,,go ,,deep ,,enough8 ,this is generally true4 ,however1 in much of the southern two-thirds of ,illinois the deeper waters are quite salty4 ,therefore1 only the upper few hundred feet of rocks are worth exploring for water4 ,in the northern third of ,illinois1 where the deepest water wells are located1 fresh water extends in some places to more than #b1jjj feet4 ,,how ,,can ,,ground ,,water ,,be ,,found8 ,the most effective way of locating a ground water supply is by using knowledge of the geology and ground water conditions--gained partly from study of existing well records--to determine the most favorable areas and depths to drill to4 ,an additional tool that has been used successfully in ,illinois is the electrical earth resistivity survey4 ,the resistivity survey attempts to locate buried sand and gravel layers that commonly are sources of ground water4 ,test drilling is recommended at sites that appear to be underlain by sand and gravel4 ,there is no known method that will positively 8find0 ground water without drilling4 ,,illinois ,,state ,,geological ,,survey ,,why ,,is ,,geology ,,important8 ,geology and allied sciences are being called upon increasingly to aid in more intelligent and efficient discovery and utilization of mineral wealth4 ,our national life and welfare are more and more dependent upon the further discovery and proper use of the earth's natural resources4 ,illinois is widely recognized by scientists1 industrialists1 and educators as being outstanding in its promotion of research and industrial development4 ,,what ,,are ,,some ,,of ,,the ,,services ,,available ,,from ,,the ,,survey8 ,the occurrence and distribution of rock and mineral deposits in ,illinois are studied by the ,state ,geological ,survey ,division of the ,department of ,registration and ,education 7fig4 #bj74 ,in seeking new information concerning the state's natural mineral resources1 physical and chemical studies of useful rocks1 minerals1 and mineral products are made4 ,techniques and methods are developed and experiments are conducted to find and prepare ,illinois' mineral substances for use4 ,the results of the ,survey's field and laboratory findings are published and made available to all citizens upon request4 ,much information that has not been published is in the open files of the ,geological ,survey where it may be examined by the public4 ,members of the ,survey's scientific and technical staff answer requests for information received by letter1 telegram1 telephone1 or personal interview4 ,since the main ideas of geology are easy to understand and greatly increase one's enjoyment and appreciation of the world in which we live1 the ,geological ,survey publishes popular and educational booklets designed for the use of ,illinois teachers and students4 ,the ,survey also distributes a labeled collection of rocks and minerals for class use in ,illinois schools4 ,six geological science field trips are conducted each year throughout various sections of the state for teachers and interested laymen4 ,members of the ,survey staff give illustrated lectures to organized groups about the geology and mineral resources of the state4 ,illustration3 ,figure #bj--;,geological ,survey offices are located in the ,natural ,resources ,building1 ,urbana1 ,illinois4 ,,what ,,is ,,the ,,charge ,,for ,,these ,,services8 ,all of the ,survey's publications are distributed free to schools and teachers4 ,only topographic maps and certain base maps1 which are prepared and printed by the ,u4,s4 ,geological ,survey in ,washington1 are sold at nominal prices4 ,illustration3 uncaptioned ,illustration3 ,geologic column ,era ,general ,types of ,rocks ,period or ,system and ,thickness ,epoch ,,cenozoic 8,recent ,life0 ,age of ,mammals ,quaternary #j-ejj ,pleistocene or ,glacial ,age ,recent--alluvium in river valleys ,glacial till1 glacial outwash1 gravel1 sand1 silt lake deposits of clay and silt1 loess and sand dunes2 covers nearly all of state except northwest corner and southern tip ,tertiary #j-ejj ,pliocene ,chert gravel2 present in northern1 southern1 and western ,illinois ,eocene ,mostly micaceous sand with some silt and clay2 present only in southern ,illinois ,paleocene ,mostly clay1 little sand2 present only in southern ,illinois ,,mesozoic 8,middle ,life0 ,age of ,reptiles ,cretaceous ,mostly sand1 some thin beds of clay and1 #j-cjj locally1 gravel2 present only in southern ,illinois ,,paleozoic 8,ancient ,life0 ,age of ,amphibians and ,early ,plants ,pennsylvanian ,largely shale and sandstone with beds of coal1 #j-c1jjj limestone1 and clay 78,coal ,measures07 ,mississippian ,black and gray shale at base2 middle zone of #j-c1ejj thick limestone that grades to siltstone1 chert1 and shale2 upper zone of interbedded sandstone1 shale and limestone ,age of ,fishes ,devonian ,thick limestone1 minor sandstones and shales2 #j-a1ejj largely chert and cherty limestone in southern ,illinois ,age of ,invertebrates ,silurian ,principally dolomite and limestone #j-a1jjj ,ordovician ,largely dolomite and limestone but contains #ejj-b1jjj sandstone1 shale1 and siltstone formations ,cambrian ,chiefly sandstones with some dolomite and shale2 #a1ejj-c1jjj exposed only in small areas in north-central ,illinois ,,archeozoic and ,,proterozoic ,igneous and metamorphic rocks2 known in ,illinois only from deep wells ,illustration3 uncaptioned ,illinois ,state ,geological ,survey ,educational ,series #i ,transcriber's ,notes --,silently corrected a few typos4 --,retained publication information from the printed edition3 this e,book is public-domain in the country of publication4 --,in the text versions only1 text in italics is delimited by underscores4