lllKll»f° L °°'CAL Digitized by the Internet Archive in 2012 with funding from University of Illinois Urbana-Champaign http://archive.org/details/subsurfacedolomi04ostr r: ■f \ »c . ; ILLINOIS STATE GEOLOGICAL SURVEY Urbana, Illinois John C. Frye, Chief { ILLINOIS INDUSTRIAL MINERAL NOTES Number 4, September) 1, 1956 Prepared by the Industrial Minerals Division J. E. Lamar, Head Hew Publications n -*< Sin 1 Ce the last isSue of Industr ial Minerals Notes in March, two Survey pub- sissSrSsrjss? ' amons others ' have interest to niinois P1 " S pm* 2? Investigations 195, "Preliminary Report on Portland Cement Mate- SSL" I ^ n 1 ? 01S ' ""audes a chart showing the succession of the various rock S*™> iSlJ 110 iS ' a Se«eralized geologic map indicating the distribution of the bedrock formations, a concise discussion of the various Illinois limestone, dolo- mite, and shale formations, and typical chemical analyses. Thus, aside from its o^f y illinois' thS reP ° rt alS ° aff ° rdS anover - a11 P icture of ««<* of the geol- ^^*|wial Series k, "A Guide for Beginning Fossil Hunters," contains draw- f S L ^ IOS ! llS f0U ? d in IUiaoi8 rocks and ascribes in nontechnical Jan- tltl, \ lt CteT t^ life habitS of the animals frou which the fossils were IZT»L l° r ?? Se v J?. ha y e been curi0lls a ^out the fossils found in the deposits they are operating, this booklet will answer many questions. „« * / s ff sle C0 ^ of either report is available for only postage charres (k Savers tfV^ 1 ^ ide and 5 cents for the cement report) to residents and ta.cpayeis of Illinois until October 1, 1956. Thereafter there will be a charge of 25 cents per copy for either report. "lux-ge CAPSULE REPORT SUBSURFACE DOLOMITE IN LAKE, MCHENRY, AND PART OF NORTHWESTERN COOK COUNTIES Meredith E. Ostrom rm'+P m ^' McHenr ?' and northwestern Cook counties contain no limestone or dolo- ZIL£ II eXGept near Garden Prairie in * ***** n o r t h western Mchenry County. iSn ^J area / om P rlsed ^ thes ^ counties is adjacent to the Chicago metropol- 2"^ and Presumably night ther efore be favorable for quarries, the Sur- -S ivoT ? 5 * l° r information regarding limestone or dolomite outcrops in JwSEIL . ?^ ata ? n th0Se areae wbfire such rocks are at shallow depths. ;"it1e^i a rj ?? ta; cMefly tbe records of vells > were sbudied * and Bignifi- u*nt results follow. ILLINOIS 'LOGICAL SURVEY LIBRARY SEP] 6 ,1956 URBANA Out crops The only known outcrops in the area occur in the vicinity of Garden Prairie. An old geological report records shallow occurrences of limestone in the NV7.. sec. 1 and the NWj sec. 31, T. kk N., R. 7 E., in the NE-J sec. 36, T. kk N., R. 10 E., in the NE cor. sec. 17, T. ^U N., R. 9 E., and in the SW part of sec. 21, T. kk N., R. 6 E., hut attempts to substantiate these reported outcrops have been unsuccess- ful. The well data for the specific areas involved suggest that outcrops of bed- rock are unlikely. Rock forma tio ns The bedrock of the Lake -McIIenry -Cook County areas is overlain by unconsoli- dated deposits of clay, silt, sand, or gravel in varying amounts. These deposits are principally of glacial origin. Their thickness varies because both the sur- face of the bedrock and the ground surface are uneven. The bedrock immediately underlying the unconsolidated deposits consists of dolomites of Niagaran and Alexandrian age, the Maquoketa shale, and the Galena - Platteville dolomite, Niagaran and Alexandrian rocks underlie all the area except small tracts in the southwestern and extreme northwestern part of McHenry County, where Maquoketa shale occurs, and a small area in extreme northwestern McIIenry County where the bedrock is Galena dolomite. This distribution of formation re- sults because the bedrock strata rise gently to the west as shown in figure 1. The Niagaran dolomite and some of the Alexandrian dolomite formations are extensively quarried as sources of crushed or broken stone for a variety of com- mercial purposes in northeastern Illinois in the Chicago, Joliet, and Kankakee areas. The quarry at Garden Prairie is producing stone from Alexandrian dolomite. The Galena-Platteville dolomite is quarried commercially at many places in north- ern, central, and northwestern Illinois. The Maquoketa formation contains rela- tively thin limestone and/or dolomite beds but these hove been used commercially only in a very small way. The maximum thickness of Niagaran rocks penetrated in the area being con- sidered is about 33? feet, the Alexandrian dolomites about 100 feet, the Maquo- keta shale roughly 210 feet and the Galena-Platteville dolomite about 308 feet . The Maquoketa formation, although principally shale, contains one or more limestone or dolomite beds which reach a maximum thickness of about 50 feet but usually range between 10 and 20 feet thick. Ar eas of Shallow Bedrock Figures 2, 3, and k show the location of wells which encounter bedrock at depths of 0-50, 50-100, or 100-150 feet. The bedrock encountered is dolomite ex- cept in those wells indicated on the maps as entering the Maquoketa formation where the depth figure indicates the depth to the first limestone or dolomite found in the Maquoketa formation. Mostly the data regarding depths and the char- acter of the bedrock encountered have been provided by the drillers of the wells; a few well records result from studies of samples collected during the drilling of the wells and subsequently studied by Survey geologists. In Lake County (fig. 2), the shallowest bedrock occurs along and adjacent to DesPlaines River and Lake Michigan, with the shallowest areas north of Half L Banister, H. M., Gcol. Survey of 111., vol. k, p. 131-132, I.87O. S.li&XS'E "saflS th ° beto ><* i- "^aran dolomite. The ^ thick . and has boon quarried for some years EisMc^f?, ™ C V S Alcxon ™*<* encountered at depths from 61 to 78 foot 1 ttr, presen *- Niagoran dolomite was east part of T. 4 3 H., B. 8 E. a]ot Eok Elver l^ZJ?. /a 3°na.uin In the south- frorn^e river hoeause of the greatcr^S " &%£ ^t^TtT^ eastern^^^lre^'^e^U ^^! ^ 00 * ^ <"* »' — *> «. 50 feet below tho surface. ?L hedroc, i? 0? «?° S 0iic0U!rtci - ed **»<* less than ness penetrated is 275 feet hut thi- ? . ™£ , f- agai '°" ^ ™d the greatest thick- Wiagaran dolomite. lo 1S 1*°**** not the total thickness of tho < P>4 •• :°,\K\M HI'M'hhi o 4 43 /\ ( / / !h O / N—^ ' ' / S*H ( / / / ' w ° 1 / / 1 •H £1 \ { ' . / 1 1 vl-J i / ( 1 ' / / J ! / ^ f } r H / ! / i ' ct5 / \ i i J3 / < ( \ 1 * 1 P • a ■ 1 ■ 0^ 0» \ H *i'i | / 1 i \ i ; i - (/ * \ -p ii©' / W ,/ O CD / o y 3 1 -P i 1 p, 97 ' "d | T5 ( , a | O 1 1 J % r t 1 i i O VrMM 4 j® 1 j / 1 1 i CD -p ( r\ \ j 1 o5 ! 5 / ' / £ I rH / A/ . G ! c5 1/ / ( / if / -a [ p °^li ''UVN Hi * ' • - n i i M l! HV . 1 ^ Y m / / \ o5 / ' \ CO / / / \ S \ ' / ' s \ , m i «j Q « • / s s / > . \> II L I 1 , , J J_ C5$ M a o o 100-1^0 feet ^ Less than £0 feet © 50 to 100 feet M Well encountering Maquoketa limestone and dolomite • Location uncertain Figo 3. - till a? ^Henry Covnty encountering limestone or dolomite bed- lit,*L?? aS -f 15 ° feet ° r less - A11 wells encountered biluiian dolomite except those identified by an «»M« v/hich en- countered Maquoketa limestone or dolomite. NORTHWESTERN COOK CO. T e l|2N. I r R • 9E. -j — R< > j- OE 1 T R ol o u > • T _ j » ? r»' i .1 1 © "~ r i 1 Q I i. 1 o o 1 O © °°l i | o o o 1 o 7 c o \-c— D 1 1 J ' ft i 1 1