Prepared and Published with the Support of COUNTY ATLAS SERIES THE CASS COUNTY BOARD OF COMMISSIONERS, ATLAS C-43, PART A MINNESOTA GEOLOGICAL SURVEY Cass County Harvey Thorleifson, Director THE MINNESOTA DEPARTMENT OF NATURAL RESOURCES, the Minnesota Environment and Natural Resources Trust Fund Plate 4—Quaternary Stratigraphy as recommended by the Legislative-CitiZen Commission on Minnesota Resources, AND the Minnesota Legacy Amendment'S Clean Water Fund A CSS-5 (276617) A' 1,400 bdt2 Pike Bay Middle Sucker Lake Foot Lake U.S. Highway 2 Lake Winnibigoshish Mississippi River sc sc 1,300 bds1 hti2 hta1 hsa2 hsa3 bds1 hsa2 bdt2 hta2 hta2 hsa4 hti2 1,200 hsa3 hta3 hsi2 brt1 sct sfs1 sft1 sft1 sct mlt1 mlt2 ebt1 ebt2 mlt2 QUATERNARY STRATIGRAPHY 1,100 mlt3 sft2 ebt2 ebl3 ebt2 ups1 et2 1,000 mt ml mt Amv mi By 900 ups1 Amv ups1 800 Elevation in feet above mean sea level Abd Barbara A. Lusardi, Maurice K. Nguyen, and Amie E. Staley 700 LOCATION DIAGRAM B B' 2018 1,400 Crooked Lake Sucker Bay Leech Lake CSS-6 (276618) Leech Lake River Leech Lake River Mud Lake Mississippi River bds1 sc pgs hti1 sc sc bds1 pgs sc 1,300 hti1 bds1 bdt2 bds1 bdt1 sft1 mlt1 bdl2 hti2 hsa1 hta1 hsa1 hti2 hti2 mlt2 1,200 brt1 brs1 hsa2 hta2 hsa2 mlt3 sct hsa3 sft2 sft3 hsa3 hta3 et1 1,100 mls3 mlt3 es2 ebt2 uns1 ebs2 ebs2 ups1 et2 ups1 1,000 uns2 ups1 mt Amv Agr uns2 ups2 Amv Aif 900 Amv Aif Aif Borehole name: CSS-1; unique number: 276613 Borehole name: CSS-2; unique number: 276614 800 Avs Amv Location: T. 140 N., R. 27 W., sec. 13; DDBC Location: T. 54 N., R. 27 W., sec. 9; DCDA Elevation in feet above mean sea level CASS COUNTY (sands associated with Elevation in feet above mean sea level: 1,360 Elevation in feet above mean sea level: 1,433 700 underlying till unit) Depth Matrix texture Lithology Coarse-grained sand lithology Depth Matrix texture Lithology Coarse-grained sand lithology (feet) (feet) sc pgs 0 Approximate age before present) !Cass Lake Marine Isotope Geologic age (calibrated years East 0 Speculated West C C' Stage (MIS) age bdo, bdl hti0 ( bdg ist0 iss1 1,600 1 (( ( " ( ( hl al, eolian -10 A ( A' bds hio Blackduck Formation hti1 -10 !Bena 13,650 CSS-5 bdt hsi Hewitt Formation, ist1 -20 ou hti2 -20 1,500 Long Lake Walker Bay Leech Lake Town Line Lake Lake Lomish Boy River Little Swift Lake bdl2 hti iso, isl Itasca phase bds, bdt Blackduck Formation ist2 iss1 iss isg Independence Formation, hta1 -30 ist1 -30 hsi1 hti1 hsi1 hsi1 hig ist3 ou bdt1 ist South Long Lake Member 1,400 hti1 hsi1 bds1 hta2 -40 sc ou, tel, teu ist4 -40 hsi2 ou isl2 hti2 hti2 bds1 hti1 sc hsa Hewitt Formation, hta3 hsi2 bds1 sc hti1 hti1 iss1 ist1 iss1 (( ((( ((( ((( ( (((( -50 -50 hta1 hsa1 sc hsi2 hsi2 iss1 ( ( ( (((!((( "( (( hta Alexandria phase ist5 1,300 hta1 ist3 2 B B' hsa2 hti2 iss3 hsi, hti Hewitt Formation, Itasca phase Federal Dam hta4 iss2 -60 hta2 ist4 ist4 CSS-6 EXPLANATION ist6 -60 hsa2 bds1 hsa2 iss4 brl Red rock brt1 hsa3 sft3 mlt3 mlt1 iss, ist 1,200 hsa3 hta3 Amv sft2 Late Wisconsinan Browerville fragments -70 ebs2 sfs3 mls3 mlt3 sft1 brs -70 Sand iss1 hsa4 hsa4 ebt2 ebt2 sft3 Post-glacial silt and clay Formation Silt Clay mlt3 ebs2 Independence Formation brt ist2 ebt2 es2 Agr ebt2 " -80 -80 1,100 sct Ag Amv Amv et2 et2 ups1 aq hsa, hta Hewitt Formation, Alexandria phase iss3 et2 es2 et2 av et2 CSS-2 -90 Agm Agr Post-glacial sand and/or gravel unnamed -90 Aif Amv ups1 27,300 uts formation ist3 1,000 mt ups1 -100 -100 Asg av Sand and/or gravel Amv >200,000 !Walker ups1 Browerville Formation (undifferentiated as to formation) scs Lake Henry Formation, -110 -110 Red rock 900 ( ( ((((((( ( (( (((((((((((((((( ( (((( ( ( ( ( (((((( ((( ( fragments C ((((((( (((((((( (((((((((( (((( ( ( ( (( ( (( ( C' sct Sauk Centre Member Elevation in feet above mean sea level brs, brt ! mlt1 -120 -120 Remer Silt and clay Lake Henry Formation, mls Lake Henry Formation, sft1 800 Sauk Centre Member -130 iss4 -130 Riding Mountain-provenance mlt Meyer Lake Member mlt2 scs, sct ist4 -140 ist1ist1 diamicton sft2 -140 700 !Longville sfs St. Francis -150 sft Formation (lower) mlt3 -150 iss5 Winnipeg-provenance diamicton isl2 mls sft3 ist5 -160 isl2 ( (( ( (( ((((( (((((((((((((((((((((((((( (((( ((((( ( ((((((((((( ((( ( (( ( (((((((( ( ( ( -160 D D' mlt Lake Henry Formation, Meyer Lake Member ( ( (( ((!(((((((( ( ( ( ( ((((((( (((( (((( (( (((((( "( ((((( (( ebl iss6 D D' Rainy-provenance diamicton Eagle Bend -170 CSS-1 ebs -170 1,500 sc Hackensack Formation Birch Lake Boss Lake Trillium Lake Pick Lake Bungey Bay Woman Lake Heffron Lake Little Boy Lake McCarthey Lake CSS-1 (276613) Thunder Lake 8 or #" ebt -180 sft2 -180 iss1 greater sfs, sft St. Francis Formation (lower) CASS-1 Superior-provenance diamicton mlt1 sc ist1 sfs3 1,400 hsi1 hti1 sc sks Shooks -190 Crystalline -190 Carbonate ist1 ist1 ou through skt Formation sft3 Sand Silt Clay hti2 hsi2 hti1 sc ist1 ebs hsa1 hti2 hti1 hti1 ist2 iss2 Eagle Bend Formation Unknown provenance -200 Carbonate -200 hta1 ist1 ist1 ou ist2 18 ebt Crystalline 1,300 hsa1 iss1 iss3 ist3 sft1 hsa2 hta2 hsa2 iss3 ou iss2 iss2 ist2 usw unnamed ist2 iss3 ist3 mls1 unnamed formation -210 -210 hsa3 hsa2 iss4 iss5 ist4 iss4 skt, sks Figure 3. Stratigraphic position of sand and gravel utw formation ebt2 hta3 hsa3 sfs2 iss4 ist4 iss5 iss4 usw, utw mlt2 brt1 sft2 mlt1 Pre- Late Wisconsinan 1,200 sct sft3 sft2 -220 -220 mlt3 sfs3 ebs2 ebt2 sft1 Shooks Formation bodies depicted in the cross sections and figures. By scs sks sfs3 mlt3 ebs2 sft3 mlt3 es es Elmdale -230 et2 Acg skt et2 Elmdale Formation convention, the name designations of sand and gravel et Formation -230 sft2 es2 sft3 es2 ebt2 et Figure 2. Location of the 135 cross 1,100 sft3 ( ( ((( (( (((( ((((((( es2 Asg (( ( ( (( (((((((((( (((!(((((( ( bodies are associated with their underlying till (unless -240 Acg Acg et2 E E' sections, constructed at regular 0.6-mile -240 et2 ac Pine River ml et2 (1-kilometer) intervals, used to create a otherwise interpreted from rotary-sonic core data). On Mulligan -250 mlt3 1,000 ups1 ups1 ms -250 av av ms, mt the cross sections, tills and associated sands of several Formation three-dimensional model of the Quaternary mt Shale -260 Acd Mulligan Formation -260 sft3 900 ups1 deposits of Cass County. Cross sections formations are subdivided into multiple layers. Units that are complex and subdivided into three or more uns undifferentiated -270 -270 uns, ups A–A' through F–F' appear on this plate. ups Pleistocene sediment 0 20 40 60 80 100 0 20 40 60 80 100 Elevation in feet above mean sea level Older tills -280 800 Squares denote the locations where rotary- layers are broken down and depicted here. These layers cumulative percent cumulative percent are identified by ascending numbers from the surface -290 20 CSS-4 sonic cores were collected. Open circles bedrock Figure 4. Cass County rotary-sonic core CSS-1. Independence 700 and " denote the location of water wells within down. Some units are divided into only two layers -300 greater ( (( ( ( ( (( (( ( Formation till has been subdivided into multiple units on the cross (((((( ( (( ( ( ( (((( ((( ( (((((((((( for processing purposes, but are depicted as one layer F F' 0.3 mile (0.5 kilometer) of the published -310 EXPLANATION " sections based on sand lenses within the core. This sequence can be E E' cross sections. here, including units bdt, brt, ebt, et, and ups. Colors 1,500 Goose Lake Clam Lake Norway Lake CSS-3 interpreted in two ways: these sands represent former water flow in -320 Riding Mountain-provenance Rainy-provenance represent provenance from which the sediments were 0 20 40 60 80 100 0 20 40 60 80 100 deposits small tunnels within the ice (such as a single event leaving behind iss1 ou deposits derived. Multiple formations from the same provenance cumulative percent cumulative percent 1,400 iss1 ist1 Winnipeg-provenance Superior-provenance till and isolated sand bodies); or the sands represent a shift in the ou CROSS-SECTION SYMBOLS deposits are distinguished by shades of the base color. Gray text hta1 hsa1 ist3 pgs sc deposits ice-margin position, which allowed meltwater to flow in front of Figure 5. Cass County rotary-sonic core CSS-2. This core was hsa2 hta2 brs1 ist4 Period of sediment erosion Deposits of unknown indicates units found in the regional stratigraphy but not 1,300 iss3 ou ist1 Geologic contact—Approximate. No-line boundaries occur where data are insufficient to the ice, depositing sand and gravel outwash. This was followed drilled just outside of the county to the east in what is interpreted brt1 sft2 iss4 ist3 iss3 iss1 and/or deposition of provenance encountered in drill holes in Cass County. Associated sfs2 sfs2 reliably extend units. nonglacial sediment by a readvance of ice from the same provenance that deposited to be an ice-marginal moraine consisting of a complex mixture ist5 sft1 1,200 sct mlt3 sft3 iss5 surficial map unit labels are shown, where appropriate, of glacial till and sand and gravel (see Plate 3, unit ). For the sfs3 Bedrock contact—Contact point shown at the base of the Quaternary deposits with the Figure 1. Diagram showing relative age, location (from west to another layer of similar till on top of the sand and the process isg sfs3 beneath the stratigraphic unit boxes and labels. et2 mlt3 Amv repeated as the ice margin shifted (multiple events leaving behind purpose of modelling, however, mixed unit isg is combined with 1,100 et2 associated bedrock map unit label from Plate 2, Bedrock Geology.