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Home , Dunleith Formation, Fossiliferous limestone

LEGEND Surficial Geology of the Highlandville () 7.5' Quadrangle CENOZOIC 91°45'0"W 91°42'30"W 91°40'0"W 91°37'30"W SYSTEM

Os DOo Os Os ! 43°30'0"N HUDSON EPISODE D D Osp D Os Qpsr Qal Qpsr 43°30'0"N Os Os Qpsr Os ! Qal - Alluvium (De Forest Formation-Undifferentiated) One to four meters (3 to 13 feet) of massive to weakly stratified, grayish brown to D D Qal brown loam, silt loam, clay loam, or loamy sand overlying less than three meters of poorly to moderately well sorted, massive to moderately D Os Osp Osp Os well stratified, coarse to fine feldspathic quartz sand, pebbly sand, and gravel and more than three meters of pre-Wisconsin or late Wisconsin Os Os Qpsr Os D Odpg Noah Creek Formation sand and gravel. Also includes colluvium derived from adjacent map units in stream valleys, on hillslopes, and in closed Qpsr Qpsr Qpsr D Osp depressions. Seasonal high water table occurs in this map unit. Os Os Os Odpg Qal Odpg Osp Qpsr D Qpsr DD Os D WISCONSIN EPISODE Os Os Os Os Qpsr ! Osp Qpsr Qps - Loess (Peoria Formation— silt facies) Generally 2 to 6 meters (6 to 19 feet) of yellowish to grayish brown, massive, jointed Odpg Os Qps Os Oo noncalcareous grading downward to calcareous silt loam to silty clay loam. Overlies massive, fractured, loamy glacial till of the Pre -Illinoian Os D Odpg ! D ! D Wolf Creek or Alburnett formations with or without intervening clayey Farmdale/Sangamon Geosol. In most areas the Pre-Illinoian till is 1 to D D Os 5 m (3 to 16 ft) thick, but may be up to 8 m (27 ft) thick locally. This mapping unit encompasses upland divides, ridge-tops and convex-side D Os D D Os Os D Os slopes. Well to somewhat poorly drained landscape. Oo Qal Os Osp D ! D Qpsr - Loess over bedrock (Peoria Formation— silt facies) Generally 2 to 6 m (6 to 19 ft) of yellowish to grayish brown, massive, jointed Osp Os Odpg Osp Qpsr Qpsr noncalcareous grading downward to calcareous silt loam to silty clay loam. Overlies bedrock units or colluvium. This mapping Osp Oo Os unit encompasses upland divides, ridge-tops and convex side-slopes. Well to somewhat poorly drained landscape. Os

! Oo Os Osp ! Os D Osp Odpg Os PALEOZOIC Osp Qps Qpsr Qpsr Os Osp Osp Os Os ! D ORDOVICIAN SYSTEM Os Osp D Osp Os Qpsr Qpsr D Os Os D Os Osp D D ! Os D D D Od - (Dunleith Formation) A prominent ledge and cliff-forming unit of up to 42 m (137 ft) of limestone with minor thin Osp Os Os Od interbedded shale. This is the lower of two successive major cavern and karst-forming bedrock map units of the . The formation Osp Qpsr Os Os ! consists of fossiliferous limestone and argillaceous limestone with common nodules; it is commonly quarried for aggregate. Major ! Os Os Qpsr Os D Oo ! Os springs occur near the base and sinkholes and karst features are common. Along valley wall positions it is frequently mantled by 0 to 2 m (0 to Os Os Osp Qpsr Osp Osp 6 ft) of loess-derived and weathered bedrock-derived colluvium. Oo Osp Qpsr Osp D Osp Os Odpg - Shale, Limestone, and Dolomite (Decorah, and underlying Platteville, and Glenwood formations) A nonresistant slope-forming unit ! Osp Oo Os Os D Os of green-grey shales, dense , argillaceous limestones, and dolostone with average thickness of 26 to 27 m (85 to 90 ft). Along steep Os Os Os Odpg Qpsr D D Os Os valley wall slopes large detached slump-blocks of overlying Dunleith Formation limestone often rest on the upper surface of this unit. Forms a Osp D D Os regional confining unit that serves as the basal boundary of the karst system in the overlying Dunleith, Wise Lake and Dubuque formations of Os D Oo Oo Os Osp Osp Os the Galena Group. The upper division, the Decorah Formation, consists of 12 to 14 m (39 to 46 ft) of interbedded fossiliferous green -grey Oo Odpg Oo Oo Os 43°27'30"N shale and limestone. The middle division, the Platteville Formation, consists of 7.5 m (25 ft) of limestone, argillaceous limestone, and Osp Os Os D Os Osp ! ! Os DD Osp D D dolostone; it serves as a source of quarried aggregate. The lower division, the , consists of 2 to 3 m (7 to 9 ft) of green- 43°27'30"N Qpsr Os ! grey shale with minor siltstone to fine sandstone. This map unit, especially the Decorah and Glenwood subdivisions, is rarely exposed and is D! Os Os Qpsr D Os ! commonly mantled by 0 to 2 m (0 to 6 ft) of loess-derived and weathered bedrock-derived colluvium. Os Os OsD Odpg Os Osp - Sandstone (St. Peter Sandstone Formation) A moderately resistant unit forming distinctive elongate ridges in upland landscape ! Oo Osp Osp positions, especially where capped by Platteville Formation limestone of map unit Odpg. It generally ranges from 18 t o 23 m (60 to 75 ft) in Osp Osp !D Odpg Osp Osp Os thickness, but may attain thicker sections where it overlies paleotopographic low areas on the high -relief surface of unconformity with Os Os underlying units. A white to tan, and occasionally red to orange-stained, pure quartz sandstone, it ranges from hard cemented at the top to D Os Odpg Qpsr Os Qal friable. Grey shale and conglomerate occurs locally in the lower part, particularly in thicker sections. Locally serves as a source of fill sand. Os Oo Oo Oo ! Forms a local bedrock aquifer where confined by overlying bedrock. Commonly mantled by 0 to 2 m (0 to 6 ft) of loess-derived and weathered D Os Os Oo Oo D bedrock-derived colluvium. Os Oo Os Os Qal Osp D Oo ! Os Os Os - Dolomite and Sandstone (Shakopee Formation) A variably resistant slope to ledge-forming unit ranging in thickness from 0 to 30 m (0 Osp Osp Os Os Osp Os B Os to 100 ft). Composed of interbedded dolomite, sandy dolomite and sandstone with a prominent 8 to 10 m (26 to 33 ft) thick horizontally Osp D D Os ! ! D stratified sandstone (New Richmond Sandstone Member) occupying its lower part. Contains some chert nodules, and has distinctive oo litic Osp ! D D Oo ! Os ! and stromatolitic facies. May locally be thin or absent where truncated beneath the unconformity at the base of the overlying St. Peter D Odpg Formation. Small springs locally occur near its base and it may host karst caverns. Mostly mantled by 0 to 2 m (0 to 6 ft) of loess-derived and Osp ! Odpg Qal weathered bedrock-derived colluvium. ! Oo D Qal Os Qpsr Os Osp Oo - Dolomite (Oneota Formation) A highly resistant ledge and cliff-forming unit of up to 60 m (200 ft) of dolomite that has chert nodules, Os Oo Os D D D D small crystal filled cavities, and stromatolite facies. May host limited karstic cavities, caverns, and springs. Forms a bedrock aquifer Odpg D Os D D throughout much of the map area. May be mantled by 0 to 2 m (0 to 6 ft) of loess-derived and weathered bedrock-derived colluvium. Osp Os Qal Os Odpg D D Os Oo Osp D Oo Osp ! D D Od Odpg Os Os Os Osp Osp Os Os Osp Oo Os Well Points Osp Osp Odpg Odpg Qpsr D Od Os Osp Osp Os Osp Osp Osp DD Od Osp Osp D Od Qpsr Os Osp Outcrops Qpsr D Osp Os ! D Odpg Osp Osp Odpg ! Osp Adjacent 7.5' Quadrangles Osp Odpg Odpg ! ! Qal D D D D Os D D Qpsr D D Qpsr D D Od D Od Quadrangle Location Odpg MABEL SPRING_GROVE WILMINGTON Os D LYON OSCEOLA DICKINSON EMMET WINNEBAGO WORTH D Osp 43°25'0"N MITCHELL HOWARD Od Od ! Osp ! WINNESHIEK ALLAMAKEE Osp D KOSSUTH SIOUX OBRIEN PALO CERRO CLAY HANCOCK Odpg D ALTO GORDO FLOYD CHICKASAW 43°25'0"N Os Od D Osp Od D ! FAYETTE CLAYTON Od PLYMOUTH CHEROKEE BUENA HUMBOLDT BREMER D D VISTA POCAHONTAS WRIGHT FRANKLIN BUTLER ! Osp D BLACK ! HAWK BUCHANAN DELAWARE DUBUQUE Osp WOODBURY IDA SAC WEBSTER Odpg Odpg Osp CALHOUN HAMILTON HARDIN GRUNDY ! Os D ! JACKSON Osp Osp JONES Osp MONONA Od Oo BURR_OAK CRAWFORD TAMA BENTON LINN D HIGHLANDVILLE DORCHESTER CARROLL GREENE BOONE STORY MARSHALL Osp Odpg D Qpsr Osp Osp Osp D CLINTON Osp CEDAR Qpsr HARRISON Osp SHELBY AUDUBON GUTHRIE DALLAS IOWA Qpsr Od Osp POLK JASPER POWESHIEK JOHNSON SCOTT D D MUSCATINE Od Osp Osp POTTAWATTAMIE CASS Od Osp ADAIR MADISON WARREN MARION MAHASKA KEOKUK WASHINGTON Odpg DD LOUISA ! Oo Osp D MILLS A Odpg MONTGOMERY ADAMS MONROE WAPELLO JEFFERSON Qpsr UNION CLARKE LUCAS Oo HENRY ! DES D MOINES Os FREMONT PAGE TAYLOR VAN Odpg D RINGGOLD DECATUR WAYNE APPANOOSE DAVIS BUREN Osp ! LEE Od Odpg Os Osp Osp Os HANOVER Od Od Qpsr D Oo DECORAH FREEPORT Od Qal Osp Osp D Os ! Osp Od Od Odpg Os Qal ! D Odpg DD D Od Os ! D ! Odpg ! Odpg ! Osp Od Qpsr Qpsr Osp Oo Os Os ! Base map from USGS Highlandville 7.5' Digital Raster Graphic (IGS GIS file DRGB41.TIF) which was Osp D scanned from the Freeport 7.5' Topographic Quadrangle map, published by US Geological Survey in 1981 Odpg Odpg D Qpsr ! Odpg ! Topographic contours and land features based on 1975 aerial photography, field checked in 1977 Od Odpg Osp D D ! Osp Osp Land elevation contours (20' interval) based on NGVD 1929. Osp Os Osp ! Osp Od Osp Osp Osp ! D Os Od D ! Iowa Geological Survey digital cartographic file Highlandvillequad07.mxd, version 7/30/07 (ArcGIS 9.1) Odpg Odpg DD Map projection and coordinate system based on Universal Transverse Mercator (UTM) Zone 15, datum NAD83. Qal Odpg Osp Osp Osp ! ! Qpsr Osp The map and cross section are based on interpretations of the best available information at the time of Os Qpsr D Os Od Qpsr Odpg mapping. Map interpretations are not a substitute for detailed site specific studies. Os Osp Osp Qpsr ! Osp Osp Qpsr Od Qpsr Osp Od Qpsr Qpsr Od Osp Os Os ! Osp Osp Os D D Osp D D Osp D Os Qpsr Odpg Qpsr D Osp D Osp Osp Oo Osp Os Osp ! Os Os Odpg Odpg D Os Od Odpg Od Qpsr ! Odpg Osp ! ! Osp Od ! Os ! Odpg Osp Qal Os GEOLOGIC MAPPING OF Osp Os Os Qpsr Oo Osp D Odpg Oo THE UPPER IOWA RIVER WATERSHED: Qal D ! Oo Osp Osp Oo DQal Os Qpsr Os Odpg Oo Qal Qps Os Os D D Osp Qal Osp Qpsr Oo 43°22'30"N PHASE 3: Highlandville 7.5’ Quadrangle D ! Qpsr ! Qpsr Qpsr Qpsr Qpsr Qal Oo Oo Odpg Os 43°22'30"N Osp Osp Osp ! Qal Osp Os Osp Osp Iowa Geological Survey Open File Map OFM-07-2 July 2007 91°45'0"W 91°42'30"W 91°40'0"W 91°37'30"W prepared by

Robert M. McKay1, Huaibao Liu1, Jean Young2, and Stephanie Tassier-Surine1

± 1 1:24,000 Iowa Geological Survey, Iowa City, Iowa 2 0 0.5 1 2 3 4 Luther College, Decorah, Iowa Miles 0 0.5 1 2 3 4 Kilometers ) l e

v e l Iowa Department of Natural Resources, Richard A. Leopold, Director a

e Iowa Geological Survey, Robert D. Libra, State Geologist s

e v o

b a

A GEOLOGIC CROSS-SECTION A-B B t Supported in part by the U.S. Geological Survey 1300 1300 e Cooperative Agreement Number 06HQAG0031 e f

Locust Upland (

Qpsr National Cooperative Geologic Mapping Program (STATEMAP)

Qpsr n o i Qpsr t a

Od Od v e l 1200 1200 E Odpg ACKNOWLEDGMENTS Odpg Qpsr We thank Lora Friest of the Northeast Iowa RC & D for her effort in helping to initiate this mapping project and for supporting our work in the Upper Iowa River Osp Qpsr Osp watershed. New subsurface geologic data was generated by the University of Iowa students Amber Koch and Gregory Stark who produced descriptive logs of water well drill samples. Luther College in Decorah actively participated in the project through subcontract 06-7368-01 for field mapping support. Luther College students 1100 1100 Gabriel Demuth and Carl Haakenstad were participants in field and office work in support of the mapping effort. Birgitta Meade of Luther College was instrumental in Qpsr Qpsr Os accurately locating and elevating water wells in the map area.. Drilling in selected sites was provided under contract by Aquadrill, Inc. of Swisher, Iowa. Deborah Os Quade, Iowa Geological Survey (IGS) lent support with Quaternary field and office expertise; Brian Witzke (IGS) provided valued information concerning the Os South Bear Os Ordovician stratigraphy of the area; and Andy Asell and Chris Kahle (IGS) provided GIS mapping technical help. Digital cartography provided by Jim Giglierano (IGS). Special thanks to the following landowners who graciously allowed access to their land for drilling: Elton Thorson, Jim & Shirley Casterton, Harold Jammes, Creek and James Craw. 1000 1000

E Oo Oo

l Special Acknowledgment and Map Dedication e v

a t i o Qal Oo We note with great sadness that during the final preparation of this map, our co-author, Jean Young passed away on June 28, 2007 after a brief illness following n

surgery. Jean was the curator of the geologic and paleontologic collections at Luther College, the author of and Rocks of Eastern Iowa, a longtime student and (

f 900 900

e investigator of the geology of northeast Iowa, and a talented artist. Additionally, in 2004, she participated in the discovery of a new Ordovician Lagerstätte site in e

t Winneshiek County, and in 2006 co-authored a Geological Society of America scientific paper with H. Liu and R. McKay about that new and rare fossil fauna. Jean

a Vertical Exaggeration = 20 X resided along Echo Valley Road near the center of the Highlandville Quad for 25+ years, and had intimate knowledge of the geology of the quadrangle and the b

o surrounding area. Despite her deteriorating health and mobility Jean participated in field work for this map at every opportunity; her knowledge of key outcrops, wells v

e and landowners were invaluable. This map is dedicated to Jean and the memories of Iowa geology and fieldwork that we and other Survey geologists have shared with

s Jean over our careers. Jean’s spirit, goodwill, knowledge and enthusiasm will be missed by us and many others. e a

l e v e l )