Surficial Geology of the Burr Oak (Iowa) 7.5' Quadrangle Quaternary System

LEGEND

Cenozoic Surficial Geology of the Burr Oak (Iowa) 7.5' Quadrangle Quaternary System

91°52'30"W 91°50'0"W 91°47'30"W 91°45'0"W D HUDSON EPISODE

Qal - Alluvium (De Forest Formation-Undifferentiated) One to four meters (3 – 13 ft) of massive to weakly stratified, grayish brown to brown Qal loam, silt loam, clay loam, or loamy sand overlying less than three meters of poorly to moderately well sorted, massive to moderately well Osp 43°30'0"N Osp Osp Osp Osp QpsDr stratified, coarse to fine feldspathic quartz sand, pebbly sand, and gravel and more than three meters of pre-Wisconsin or late Wisconsin Noah Osp Qpsr D Odpg 43°30'0"N ! Odpg Qpsr Qpsr Creek Formation sand and gravel. Also includes colluvium derived from adjacent map units in stream valleys, on hillslopes, and in closed D Qal Qpsr Od Odpg D Osp depressions. Seasonal high water table occurs in this map unit. Qal Qal Qpsr D Qpsr D Odpg Osp Od D ! Od D Qpsr ! Od Odpg ! D D D Qpsr Odpg Qpsr Osp Qallt - Upper Iowa River Valley - Low Terrace/Modern Channel Belt (DeForest Formation-Camp Creek Member and Roberts Creek Od Qallt Osp Od Member) Variable thickness of less than 1 m to 5 m (3 – 16 ft) of very dark gray to brown, noncalcareous, stratified silty clay loam, loam, or Odpg Qpsr Qpsr Od clay loam, associated with the modern channel belt of the Upper Iowa River valley. Ox-bow lakes and meander scars are common features Od D Qal Qal ! Osp associated with this terrace level. Post-settlement alluvium thickness varies from 0.5 m (1.5 ft) in higher areas to 2 m (6.5 ft) along the river Od Od Odpg ! Qpsr Qpsr Qpsr D Odpg course and in lower lying areas. Seasonal high water table and frequent flooding potential. Od Qpsr Osp Od D Osp Od Osp Od Odpg Qalit - Upper Iowa River Valley - Intermediate Terrace (DeForest Formation-Camp Creek Member, Roberts Member and Gunder Member) Od ! Od Osp ! Qalit Od Od Variable thickness of less than 1 m to 5 m (3 – 16 ft) of very dark gray to brown, noncalcareous, stratified silty clay loam to loam that overlies ! ! Qpsr D !! calcareous, medium- to coarse-grained sand and gravel of Wisconsinan (Noah Creek Formation) and/or pre-Wisconsinan age. Occupies low ! ! Qps ! ! ! D D ! ! terrace position. Seasonal high water table and frequent flooding potential ! ! ! ! ! ! ! Od !

Osp Osp ! Od D ! Qpsr Osp WISCONSIN EPISODE Qpsr Qpsr Od Qpsr Qpsr Odpg Qpt - High Terrace - either Late Phase or Early Phase (Peoria Formation – silt and/or sand facies) Two to seven meters of yellowish brown to Qpsr Qpsr Qpt Osp gray, massive, jointed, calcareous or noncalcareous, silt loam and intercalated fine to medium, well sorted sand. May grade downward to Qpsr D Qal poorly to moderately well sorted, moderately to well stratified, coarse to fine feldspathic quartz sand, pebbly sand, loam, or silt loam alluvium D Osp (Late Phase) or may overlie a Farmdale Geosol developed in Roxanna Silt which in turn overlies a well-expressed Sangamon Geosol developed Od Odpg D in poorly to moderately well sorted, moderately to well stratified, coarse to fine sand, loam, or silt loam alluvium (Early Phase). Od D Qpsr D !D Od Od D Qpsr ! D ! D D Qps - Loess (Peoria Formation— silt facies) Generally 2 m to 8 m (6 – 27 ft) of yellowish to grayish brown, massive, jointed noncalcareous ! ! ! D Od Od ! Qps Qpsr Qpsr grading downward to calcareous silt loam to silty clay loam. Overlies massive, fractured, loamy glacial till of the Pre-Illinoian Wolf Creek or Odpg Od Alburnett formations with or without intervening clayey Farmdale/Sangamon Geosol. In most areas the Pre-Illinoian till is 1 m to 5 m (3 – 16 Qal Qpsr Odpg ft) thick, but may be up to 8 m (27 ft) thick locally. This mapping unit encompasses upland divides, ridge-tops and convex-side slopes. Well Odpg ! Odpg Qpsr Qpsr to somewhat poorly drained landscape. ! Od Qpsr Od Od Osp Qpsr Qpsr - Loess over bedrock (Peoria Formation— silt facies) Generally 2 to 8 m (6 – 27 ft) of yellowish to grayish brown, massive, jointed Od Odpg Qpsr Owd Odpg Qal noncalcareous grading downward to calcareous silt loam to silty clay loam. Overlies Ordovician bedrock units or colluvium. This mapping Qpsr ! ! Odpg Qpsr unit encompasses upland divides, ridge-tops and convex side-slopes. Well to somewhat poorly drained landscape. !Od ! ! ! Qps Od Od Od Od ! Odpg Odpg ! Odpg ! Od PLEISTOCENE UNDIFFERENTIATED Owd ! D Od ! Odpg 43°27'30"N Odpg ! Qal ODwd ! ! Qrc - Rock Core Meanders/Structural Benches Includes rock core meanders associated with Pre-Wisconsin river development and terrace 43°27'30"N Od D D ODdpg Od ! Od ! Qrc ! ! ! Od deposits overlying bedrock benches. Some areas occupy positions as much as 10m (33 ft) above the modern floodplain. Consists of Owd ! Od Od Odpg Qpsr Owd undifferentiated alluvial and colluvial fill of unknown age and thickness. May be mantled by 1 to 3 m (3-10 ft) of Peoria Formation- silt facies ! ! Owd ! Od (loess). Q! al ! Od Owd !Od Od ! Od Od

! Od Paleozoic Qpsr Od Odpg Ordovician System Odpg DOd Od Od Odpg ! Qpsr D Odpg D Odpg Qal Od Owd - Limestone and minor Shale (Wise Lake Formation and overlying Dubuque Formation) A prominent ledge and cliff-forming unit of Qpsr Owd Qal ! D up to 31 m (102 ft) of limestone with notable thin interbedded shale in the upper 6 m. This map unit is the upper of two successive major Owd Osp Qpsr Osp ! Qpsr Od D cavern and karst-forming bedrock units in the area. The Wise Lake Formation consists of 21 m (67 ft) of medium to thick-bedded relatively Owd Osp Osp ! ! Qpsr Osp chert-free limestone, portions of which exhibit a distinctive bioturbated fabric; serves as a quarried aggregate source The Dubuque Formation Owd ! Odpg Qpsr consists of 10 m (34 ft) of crinoidal limestones and thin interbedded shale. Sinkholes are common to abundant within this map unit. Often Qpsr Qpsr Odpg Osp Qpsr mantled by 0 m to 2 m (0 –6 ft) of loess-derived and weathered bedrock-derived colluvium. Od Od Od Od Od ! Od Owd Od Owd Qpsr Od - Limestone (Dunleith Formation) A prominent ledge and cliff-forming unit of up to 42 m (137 ft) of limestone with minor thin Od D Od ! Qpsr D interbedded shale. This is the lower of two successive major cavern and karst-forming bedrock units in the area. The formation consists of Od Od ! Owd Od Odpg fossiliferous limestone and argillaceous limestone with common chert nodules; it is commonly quarried for aggregate. Major springs occur ! Od Od D near the base and sinkholes and karst features are common. Frequently mantled by 0 m to 2 m (0 – 6 ft)of loess-derived and weathered Owd D D Odpg Qpsr bedrock-derived colluvium. Qpsr ! Odpg Owd Odpg Odpg Odpg Od D Qp!sr Owd Qal Odpg Od Od Odpg - Shale, Limestone, and Dolomite (Decorah, and underlying Platteville, and Glenwood formations) A nonresistant slope-forming unit Qpsr Odpg Owd Qpsr of green-grey shales, dense limestones, argillaceous limestones, and dolostone with average thickness of 26 m to 27 m (85 –90 ft). Along steep ! Odpg Odpg Osp Qal ! Odpg Odpg valley wall slopes large detached slump-blocks of overlying Dunleith Formation limestone often rest on the upper surface of this unit. Forms a Owd ! D Owd Qpsr regional confining unit that serves as the basal boundary of the karst system in the overlying Dunleith, Wise Lake and Dubuque formations. Owd Od Od Osp Od Od ! The upper division, the Decorah Formation, consists of 12 m to 14 m (39 – 46 ft) of interbedded fossiliferous green-grey shale and limestone. D D! ! Qpsr Qpsr Osp The middle division, the Platteville Formation, consists of 7.5 m (25 ft) of limestone, argillaceous limestone, and dolostone; it serves as a Od Odpg Qpsr B source of quarried aggregate. The lower division, the Glenwood Formation, consists of 2 m to 3 m (7 – 9 ft) of green-grey shale with minor Od Od Od D Odpg siltstone to fine sandstone. This map unit, especially the Decorah and Glenwood subdivisions, is rarely exposed and is commonly mantled by Os Owd Odpg 0 m to 2 m (0 – 6 ft) of loess-derived and weathered bedrock-derived colluvium. Owd Owd Osp Qpsr Osp D Odpg Qpsr D DD ! D Osp - Sandstone (St. Peter Sandstone Formation) A moderately resistant unit forming distinctive elongate ridges in upland landscape Owd Od Od D Os D Osp Od ODdpg positions, especially where capped by Platteville Formation limestone of map unit Odpg. It generally ranges from 18 m to 23 m (60 – 75 ft) in ! D Od Od Osp ! Owd ! ! thickness, but may attain thicker sections where it overlies paleotopographic low areas on the high-relief surface of unconformity with D Owd Od Od D underlying units. A white to tan, and occasionally red to orange-stained, quartz-rich sandstone, it ranges from hard cemented at the top to Od Odpg Owd Od Odpg Od Odpg Osp 43°25'0"N friable. Grey shale and conglomerate occurs locally in the lower part, particularly in thicker sections. Forms a local bedrock aquifer where Qpsr D Od Od Odpg confined by overlying bedrock. Commonly mantled by 0 m to 2 m (0 – 6 ft) of loess-derived and weathered bedrock-derived colluvium. 43°25'0"N Od Os

Od ! Od Osp Os - Dolomite and Sandstone (Shakopee Formation) A variably resistant slope to ledge-forming unit ranging in thickness from 0 m – 30 m (0 ! Od Qal Qpsr ODd Os ! Qpsr Od Qpsr Odpg – 100 ft). Composed of interbedded dolomite, sandy dolomite and sandstone with a prominent 8 m – 10 m sandstone (New Richmond Qpsr ! Osp Osp Od Os Sandstone Member) occupying its lower part. Contains some chert nodules, and has distinctive oolitic and stromatolitic facies. May locally be ! D Odpg Odpg Osp thin or absent where truncated beneath the unconformity at the base of the overlying St. Peter Formation. Small springs locally occur near its ! D Od Qpsr Qpsr Odpg DD Owd D Osp ! Osp base and it may host karst caverns. Mostly mantled by 0 m to 2 m (0 – 6 ft) of loess-derived and weathered bedrock-derived colluvium. D Osp Od D D D Odpg Qpsr Qpsr D Os Odpg Od Od Owd ! Qpsr Qpsr ! Odpg Od ! Osp ! Qpt Qpsr D Water Features Odpg Qps Osp Qpsr D ! Qpsr Od Qalit Owd Od D Qps Qpsr Qpsr ! Drill Holes Odpg Qpsr D Odpg Od Adjacent 7.5' Quadrangles Owd Owd Od Osp ! OdD Qpt Odpg Osp D Od Od Outcrops Od Qpsr Odpg ! Odpg ! Od Od ! Od Od Quadrangle Location ! Qpsr Od ! Odpg Od CANTON_MN MABEL SPRING GROVE Qal Qpsr D Odpg Qpsr LYON D Odpg OSCEOLA DICKINSON EMMET Owd Qpsr WINNEBAGO WORTH MITCHELL HOWARD Qpsr WINNESHIEK ALLAMAKEE Odpg KOSSUTH Qpt SIOUX OBRIEN Od CLAY PALO ALTO HANCOCKCERRO GORDO D Qrc ! Osp D FLOYD CHICKASAW Qrc Qpsr ! Odpg D D FAYETTE CLAYTON Qpsr D PLYMOUTH CHEROKEE BUENA VISTA HUMBOLDT BREMER D POCAHONTAS WRIGHT FRANKLIN BUTLER Od Od D Od Od D Qpsr BLACK HAWKBUCHANAN DELAWARE DUBUQUE Odpg WOODBURY WEBSTER ! IDA SAC CALHOUN HAMILTON HARDIN GRUNDY Qpt Odpg JACKSON Odpg JONES ! Qpsr BLUFFTON BURR_OAK HIGHLANDVILLE MONONA TAMA BENTON LINN CRAWFORD CARROLL GREENE BOONE STORY MARSHALL Owd ! Od CLINTON Odpg Od ! Qpsr D Odpg CEDAR HARRISON SHELBY AUDUBON GUTHRIE Qpsr D D DALLAS POLK JASPER POWESHIEK IOWA JOHNSON SCOTT Od D Od D Qpsr Osp MUSCATINE Od Od Osp ! Owd POTTAWATTAMIE Od ! D ! CASS ADAIR MADISON WARREN MARION MAHASKA KEOKUK WASHINGTON LOUISA D ! Od Osp Od Od MILLS MONTGOMERY ADAMS UNION CLARKE LUCAS MONROE WAPELLO JEFFERSON Odpg HENRY D Qpsr Odpg DES MOINES Od FREMONT Owd PAGE TAYLOR RINGGOLD DECATUR WAYNE DAVIS VAN BUREN Qpt Qalit Qallt ! Osp APPANOOSE LEE Odpg Osp RIDGEWAY DECORAH FREEPORT D ! Odpg Odpg Qpsr ! ! ! Qpt D ! Od Od D D Odpg Odpg Qpsr Od D Owd Od Qpsr Od Odpg Od D D Odpg ! Owd Od Qalit D Qal Osp D Od D Qpsr ! Odpg ! Base map from USGS Burr Oak 7.5' Digital Raster Graphic (IGS GIS file DRGB40.TIF) which was D Od D ! Qpsr ! Qal scanned from the Burr Oak 7.5' Topographic Quadrangle map, published by US Geological Survey in 1981 Owd ! Osp ! Od Qallt Topographic contours and land features based on 1975 aerial photography, field checked in 1977 Qpsr QDpsr Osp D Qpsr Os ! Land elevation contours (20' interval) based on NGVD 1929. Od Qpsr Qps ! Osp D Qal Qps ! Qpsr Os Qpsr Owd D Qrc Qal Odpg 43°22'30"N A Od Qps ! Iowa Geological Survey digital cartographic file BurrOakquad07.mxd, version 7/30/07 (ArcGIS 9.1) Qpsr Qalit Qpsr Od Qpsr 43°22'30"N ! Map projection and coordinate system based on Universal Transverse Mercator (UTM) Zone 15, datum NAD83. Qpsr Odpg Qrc Odpg ! ! D The map and cross section are based on interpretations of the best available information at the time of mapping. Map interpretations are not a substitute for detailed site specific studies. ! D D 91°52'30"W 91°50'0"W 91°47'30"W 91°45'0"W

GEOLOGIC MAPPING OF THE UPPER IOWA RIVER WATERSHED: PHASE 3: Burr Oak 7.5’ Quadrangle 1:24,000 0 0.5 1 2 3 4 Miles Iowa Geological Survey 0 0.5 1 2 3 4 Open File Map OFM-07-1 Kilometers ± July 2007

prepared by

Huaibao Liu1, Robert McKay1, Jean Young2, and Stephanie Tassier-Surine1 ) l

e v 1 e GEOLOGIC CROSS-SECTION A-B l Iowa Geological Survey, Iowa City, Iowa 2 a Luther College, Decorah, Iowa e s

A B

e v o

1300 1300 b a

Qps North t Upper Iowa Qps Canoe Qpsr Qpsr e e

Qpsr Canoe f Qpsr Qpsr Qpsr ( River Valley Qps Qpsr Qpsr Qpsr Creek Qal n o Qpsr Creek i Qal t

Qal Qal a 1200 Qal Qal 1200 v e

Qal E Owd Iowa Department of Natural Resources, Richard A. Leopold, Director Qpsr Qpsr Iowa Geological Survey, Robert D. Libra, State Geologist Qal 1100 Qal 1100 Supported in part by the U.S. Geological Survey Qpsr Cooperative Agreement Number 06HQAG0031 Od National Cooperative Geologic Mapping Program (STATEMAP) Qalit & Qallt ACKNOWLEDGMENTS 1000 Qpt 1000 We thank staff of the Northeast Iowa RC & D for their efforts in helping to initiate this mapping project and for supporting our work in the Upper Iowa River Odpgg watershed. New subsurface geologic data was generated by the University of Iowa students Amber Koch and Gregory Stark who produced descriptive logs of water

E well drill samples. Luther College in Decorah actively participated in the project through subcontract 06-7368-01 for field mapping support. Luther College students l

e 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 v

a 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 t

i 900 900 o Quade, Iowa Geological Survey (IGS) lent support with Quaternary field and office expertise; Brian Witzke (IGS) provided valued information concerning the

n Osp

Ordovician stratigraphy of the area; and Andy Asell and Chris Kahle (IGS) provided GIS mapping technical help. Digital cartography provided by Jim Giglierano

( f

e (IGS). Assistance obtaining drilling records and geologic information was provided by Dave Stanley at Bear Creek Archeology. Special thanks to the following e

t Vertical Exaggeration = 20 X landowners who graciously allowed access to their land for drilling: Anne Dykstra, John Schnitzler, Jim and Carrie Horihan, and Don Sacquitne.

a Os b o Special Acknowledgment v 800 800

e 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

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

e and investigator of the geology of northeast Iowa. Her spirit, goodwill, knowledge and enthusiasm will be missed by us and many others.

l )