Prepared and Published with the Support of COUNTY ATLAS SERIES THE REDWOOD COUNTY BOARD OF COMMISSIONERS, ATLAS C-36, PART A MINNESOTA GEOLOGICAL SURVEY the Minnesota Environment and Natural Resources Trust Fund Redwood County Harvey Thorleifson, Director as recommended by the Legislative-Citizen Commission on Minnesota Resources, Plate 4—Quaternary Stratigraphy AND the Minnesota Legacy Amendment's Clean Water Fund A 273769 Belview Delhi Minnesota River A' 1,100
1,050 Qth A ) A' Qa Qsw RWR-9 1,000 Qtm Qs3 Qg3 Qs3 Qs3 Qs4 QUATERNARY STRATIGRAPHY 950 Qsu Qg4 ! Qws RWR-10 Qws Qws Qw Qws LOCATION DIAGRAM ) Redwood Falls Qsu B' Qu ¤71 Qw ! B )19 900 Amt Qsw ) )19 Qu Amn RWR-2 Qsu Qu Qa Vesta By 850 Amg ! ¤71 Aqm )67 800 Seaforth RWR-8 ) C' Angela S. Gowan (273762) Minnesota Highway 19 Ramsey Creek 273770 Redwood River Redwood Falls Minnesota River C B B' 1,100 Qs Milroy) RWR-3 RWR-4 Morgan D' Qs Qs Qs Qa Qs ) Qs Qs Qa Lucan Wabasso 2016 Qth D ) )68 1,050 Qth Qa Qs Qsw ) RWR-5 Figure 1. Location of 57 cross sections, constructed at Qsd Qtd Qth Qs 68 Qtd Qa Qth Qsw 0.6-mile (1-kilometer) intervals, used to create a three- Qtu ! Qu Qsm ! 1,000 ! Amg Qsm Amg Ku Qtm dimensional model of the Quaternary deposits of Redwood ! Qtd Qsm Qs3 RWR-7 ! ! Qg3 Qs3 Qs4 Qs3 Qg3 ! ! ) County. The locations of cross sections A–A' through 950 Qs4 E' Qu Ku Qg4 Ku Qs3 Qg4 Qs4 Qg4 Qs4 Amt ! Qg4 E F–F' are shown here, and are also shown on Plate 3, Wanda ¤71 900 Ku Qsu Qw Surficial Geology. Black squares depict the locations of Amt Ku ! Qsu ! Amg Qtu Qsu ten Minnesota Geological Survey (RWR-1 to RWR-10) Qsu Ku Qu 850 ! ! rotary-sonic core sites. Qu Amt 800 Qa RWR-6 Amt ) Amg Walnut Grove Revere 750 Lamberton ¤14 F' 700 F )RWR-1 Approximate age present) Marine Isotope Geologic age (years before Speculated Stage (MIS) age West East C C' 1,150 14,000 Heiberg Member Qth U.S. Highway 71 273768 Minnesota Highway 67 Qtn Qs Villard Member Qtv Qtn 1,100 Winnipeg Qtv Qs Qs Provenance Dovray Member Qtd Qtn Qsv Qw Qwt Qth 16,000 1,050 2-4 Qth New Ulm Formation Figure 3. Diagram showing relative age, location (across Qu Qg1 Qs5 Qtv Ku ! ! Qtn Rainy 1,000 Riding Redwood County from west to east), provenance (Fig. 2), and Qg5 Qtu Provenance Amt Mountain Late Wisconsinan Ivanhoe Member Qti Moland Member related unit labels from the cross sections for late Wisconsinan and Agr Qtn Qtm Qtd Qsd Qsu ! Qg1 Provenance Qtm 950 ! Qg3 Qs2 Qs1 pre-late Wisconsinan glacial deposits (Table 1). The age column Amt Qs2 Qg2 Verdi Qs3 Member Qtr ! Qs3 and deposit drawings are not to scale. Marine Isotope Stage (MIS) Ku Qs3 Qs3 29,000 900 Qs3 Qg3 New Ulm Formation correlations were estimated using figures in Jennings and others Amg Qs3 Superior Qs3 ! Rainy lobe (2006). The age shown for the end of deposition for till of the !! Provenance >200,000 850 Qtu ! ! Amt !! Qtu Heiberg Member of the New Ulm Formation is the calendar year p Amg Amg Wadena Mesabi Iron Range gd Qsu Browerville Formation? p ! lobe conversion of a radiocarbon date (12,260 ± 90 yr BP) from wood 800 Qsu Amg ! at the contact between the till and overlying lake sediment from a Amt Brainerd site to the southeast in Blue Earth County (Jennings and others, 750 lobe Good Thunder formation 1 Qg1 Amg 2012). The Browerville Formation has not been recognized in the Superior lobe Good Thunder formation 2 700 Qg2 subsurface in Redwood County and its presence here is used as Good Thunder formation 3 Qg3 a time marker. Studies in Sibley (Lusardi and others, 2012) and Nicollet (Meyer and others, 2012b) Counties placed it between Des Moines lobe Grantsburg D D' sublobe Good Thunder formation 4 1,150 (273763) 273764 (273765) U.S. Highway 71 Minnesota Highway 67 Morgan REDWOOD 6 Qg4 the New Ulm and Good Thunder formations. Two calcite samples COUNTY through from interglacial marl deposits above Browerville Formation Qs Pre-Wisconsinan 18 Good Thunder formation 5 1,100 Qsh Qsh Qs Qg5 till in Todd County in central Minnesota had a uranium series Qtv Qtn Qs Qth minimum age of 200,000 yr BP (Knaeble and Meyer, 2007). All Qw 1,050 Qws Qsv Qtv Qsv Qsn core samples from the area that have undergone detrital remanent Qs1 Qs5 Qg1 Qs5 Qtv Qsu Qtn Qth Elmdale Formation Qte magnetization analysis at the Institute for Rock Magnetism at the ! ! !! Qu 1,000 Qwt Qtu Amt Qg5 University of Minnesota have yielded normal polarity, indicating Ku gd Ku Qg1 Amt Qtu Qtd Qtn Figure 2. Location of major provenances (source regions) and the Pre-Late Wisconsinan they were likely deposited after the Bruhnes normal-Matuyama 950 ! Qs2 Qtm Qsu ! Qg2 distribution of ice-lobe materials at the land surface. Glacial sediments reversed polarity boundary, dated at 780,000 yr BP, and therefore Amt Qg3 deposited in Redwood County derive their distinct material content Qs3 "W" Qw no older than MIS 18 (Lisiecki and Raymo, 2005). Position of 900 Qg3 Amg ! from bedrock and sediment found in the region of these provenances. "V" sequence units as older than 780,000 yr BP is speculative. Amt Qu During the last glaciation, the late Wisconsinan, ice carrying debris of 850 ! predominantly Rainy provenance (brown) covered portions of northeast "W" Qwt >780,000? 800 (Rainy lobe) and central (Wadena and Brainerd lobes) Minnesota and the debris is discontinuously present in the subsurface as far south and 19 or EXPLANATION Amg greater "V" Qv 750 west as the Minnesota River. After Wadena-lobe ice melted, Redwood Riding Mountain provenance Winnipeg provenance County was completely covered by deposits of at least five advances deposits deposits 700 Rainy provenance Period of sediment erosion of the northwestern-source Des Moines lobe (green). "V" Qvt deposits and/or deposition of nonglacial sediment E E' 1,200 Qs Cottonwood River Sleepy Eye Creek U.S. Highway 71 Sleepy Eye Creek 273767 1,150 Qtv Qa Qa Borehole name: RWR-1; unique number: 273761 Borehole name: RWR-2; unique number: 273762 Borehole name: RWR-3; unique number: 273763 Borehole name: RWR-4; unique number: 273764 Qw Qtv Location: T. 108 N., R. 40 W., sec. 1; ABAAB Location: T. 112 N., R. 39 W., sec. 7; DBBCDD Location: T. 111 N., R. 39 W., sec. 16; CCACCA Location: T. 111 N., R. 38 W., sec. 22; BBDBBB 1,100 Qtd Qtv Qa Qa Qs Elevation in feet above mean sea level: 1,451 Elevation in feet above mean sea level: 1,093 Elevation in feet above mean sea level: 1,104 Elevation in feet above mean sea level: 1,086 Qs Qsd Qth Qtd Qth Qs Qs Qs Depth Description Depth Description Depth Unit Description Depth Description 1,050 Qsu Qw Unit Unit Unit Ku Qa (feet) (feet) (feet) (feet) Qtu Qsu Qth 0 0 0 0 Qsu Qsh Olive-brown to black loam till, low amount of gray shale, sandy and pebbly zones Olive-brown to light olive-brown variable sand and silt, esker deposit; Fill 1,000 Qws Qtv Olive-brown becoming very dark grayish-brown loam till, low amount of around 20'; Ivanhoe Member, New Ulm Formation. Heiberg Member, New Ulm Formation. gray shale; Villard Member, New Ulm Formation. Light olive-brown becoming olive-brown loam till, high amount of Qtu Qsu Qw Qtm Qtd Qtn Qsm gray shale; Heiberg Member, New Ulm Formation. ! Qsu 5 Qth 950 Qu Qsu 20 Olive-brown to light olive-brown variable sand and silt with several small till 5 Ku Qsu Qsu layers and inclusions, esker deposit; Heiberg Member, New Ulm Formation. Agr Qtu Qsh 10 ! ! Qsu 900 ! Qu ! Qu Qti 10 ! ! 10 Very dark grayish-brown loam till, low amount of gray shale, a Ku Ku Agr Agr Agr ! 40 few sandy and/or silty seams; Villard Member, New Ulm Qtv Amt Formation. 850 15 15 GIS compilation by J.D. Hamilton Olive-brown loam till, thin sand layer at 20', high amount of gray shale; 20 Edited by Lori Robinson 60 Heiberg Member, New Ulm Formation. Qtv F 20 Qth F' Qsi Black variable sand and gravel with some till layers, outwash; Ivanhoe Member, 1,500 273761 20 Qti New Ulm Formation. Qsh Olive-brown silt/very fine- to medium-grained sand/silt sequence, outwash; Black loam till, low amount of gray shale; Ivanhoe Member, New Ulm Formation. 30 80 25 Qth Heiberg Member, New Ulm Formation. 1,450 Very dark grayish-brown, very fine- to fine-grained sand and silt, local silt and/or Qsh Olive-brown loam till, high amount of gray shale; Heiberg Member, New Ulm 25 Qsv Very dark grayish-brown clayey silt, lacustrine deposits; Villard Member, clay laminations or layers, outwash; Ivanhoe Member, New Ulm Formation. Qsi Formation. Qtv New Ulm Formation. 1,400 30 Olive-brown very fine-grained sand, some silty areas; Heiberg Member, New Very dark grayish-brown loam till, low amount of gray shale; Villard Dark grayish-brown sand, sand with some gravel, and sand and 100 Qth gravel, very fine- to fine-grained sand with silt in bottom 1', Ulm Formation. 30 Qsn Member, New Ulm Formation. Qsi CROSS SECTION SYMBOLS 40 outwash; Villard Member, New Ulm Formation. Qli Dark olive-brown loam till, high amount of gray shale; Heiberg Member, New Very dark grayish-brown clayey silt with some sand, sandier downward, 1,350 Olive-gray silt with some fine-grained sand, laminated light and dark grains, 35 Ulm Formation. lacustrine deposits; unnamed member, New Ulm Formation. Geologic contact—Approximate. No-line boundaries occur where data are insufficient Qli Qsd Qti Qa Plum Creek Pell Creek Dutch Charley Creek Highwater Creek lacustrine deposits; Ivanhoe Member, New Ulm Formation. Olive-brown sand, and sand and silt, outwash; Dovray Member, New Ulm Very dark grayish-brown loam till, high amount of gray shale; unnamed Qsi 120 35 Qtn Qsv 1,300 to reliably extend units. Qsi Black silt, massive, lacustrine deposits; Ivanhoe Member, New Ulm Formation. Formation. member, New Ulm Formation. Black sand, very fine- to medium-grained, with coarser-grained carbonate grains 40 Very dark grayish-brown loam till, moderate amount gray shale; Dovray Qtr Qa Dark grayish-brown to very dark grayish-brown silt and very fine-grained 50 Qte Scientific drill hole—Cored rotary-sonic drill holes with their associated unique numbers. (1') over olive sand and gravel, common carbonate clasts, outwash; Ivanhoe Member, New Ulm Formation. sand, faintly laminated at top, becomes light and dark laminated in 1,250 Qti Member, New Ulm Formation. 40 Qa Unique numbers in parentheses denote borings on adjacent cross section lines 140 bottom third, outwash; pre-Wisconsinan "W" sequence, Riding Mountain Qss Qvs Qwt Dark olive-gray loam till, common carbonate clasts; Ivanhoe Member, New Ulm 45 Qvt Qa Qws source. Qv used for reference (FIg. 1). Formation. 1,200 Qsu Sanborn U.S. Highway 71 Olive-brown sand and gravel grading to sand with depth, outwash; pre- Qtv Dark grayish-brown loam till, low amount of gray shale with 6" Qtu Drill hole—Includes water-well drillers' sites. The top of the drill-hole symbol may Dark olive-gray loam till, abundant carbonate clasts; Verdi Member, New Ulm Qtd 45 sand layer; Villard Member, New Ulm Formation. Qs Qtr Formation. Wisconsinan "W" sequence, Riding Mountain source. 60 Qti Qa 160 50 Qs1 Dark olive-gray sand and gravel, sand, and sand and fine- 1,150 Qa Cottonwood River not coincide with the cross section surface elevation line because the point is Olive-brown to dark and very dark olive-brown loam till, hard; Elmdale Formation. grained gravel, outwash; Good Thunder formation 1. Qw Very dark grayish-brown loam till; pre-Wisconsinan "W" sequence, Qg1 Qws Qtd located near (commonly within 0.3 mile [0.5 kilometer]) but not on the cross 50 Riding Mountain source. Dark olive-gray loam till; Good Thunder formation 1. 55 Qs5 1,100 section line and therefore may have a slightly different surface elevation. Very dark gray to black variable sand and silt with numerous very thin Yellow-brown, blue-green, and brown clay loam diamicton; Good Ku Qws Qs 180 Qte Qti Qa till layers, outwash; pre-Wisconsinan "W" sequence, Riding Mountain 70 Thunder formation 5. Qtd ! Bedrock contact—Point representing the contact between bedrock units at the 1,050 Qws Qw 60 55 source. Qg5 Very dark grayish-brown loam till; Good Thunder formation 5. Qs Qti bedrock surface. Unit labels are shown between the contact points and match Qu Qu Qw Olive-brown till, averages 50% sand and no gray shale; pre-Wisconsinan "W" Very dark grayish-brown sand with some gravel, abundant lignite, some those on Plate 2, Bedrock Geology. 200 Qwt Qsu carbonate and gray shale, less gravel with depth, outwash; Quaternary, Qws Dark gray silt with some clay, non-calcareous, some shell 1,000 sequence, Rainy source. 60 65 undifferentiated. fragments; Cretaceous bedrock, undifferentiated. Light olive-brown sand, very fine- to medium-grained, with a few larger clasts and Qtu 80 Qvs Black clay, fissile, non-calcareous; Cretaceous bedrock, till blobs, outwash; pre-Wisconsinan "V" sequence, Riding Mountain source. Very dark grayish-brown clay loam till, very high amount of gray shale; 950 Quaternary, undifferentiated. undifferentiated. Vertical exaggeration = 50x 220 Black till, common Cretaceous clasts; pre-Wisconsinan "V" sequence, Riding 70 Light olive-brown sand, very fine- to very coarse-grained with quartz and pink 65 Mountain source. feldspar granules, some silty finer-grained layers, non-calcareous; Qv Qwt Cretaceous bedrock, undifferentiated. 90 75 70 Black till; pre-Wisconsinan "W" sequence, Rainy source. 240 Dark greenish-gray sand with clay or silt, non-calcareous; Cretaceous Qws Loam till (new unit)—Recognized in rotary-sonic drill hole RWR-1 bedrock, undifferentiated. Very dark grayish-brown sand, outwash; pre-Wisconsinan "W" INTRODUCTION grained sand fraction (Table 1; Plate 3, Fig. 4). May include thin of each Good Thunder formation unit is locally oxidized to yellow- Qvt Borehole name: RWR-5; unique number: 273765 sequence, Rainy source. 80 Black, medium gray to light gray, clayey sand, common black organics, lake sediment (unit Qhl), debris flows, and inclusions of sand and brown or oxidized/reduced to green or green-blue, suggesting that (Fig. 4). Locally includes materials from older glacial deposits, Location: T. 111 N., R. 37 W., sec. 23; CDBBBC Qss non-calcareous; Cretaceous bedrock, undifferentiated. 75 Boulder The Quaternary Stratigraphy plate shows the unconsolidated materials expected gravel, particularly near the land surface. a significant period of exposure and weathering took place between and bedrock. Elevation in feet above mean sea level: 1,082 260 Dark gray sand with some silt and organics, becomes pinkish-white very Very dark gray clay, fissile, calcareous, with shell remnants and calcite 100 Qvt Black sand and gravel, outwash; pre-Wisconsinan "V" sequence, Winnipeg source. seams; Cretaceous bedrock, undifferentiated. to be encountered between the land and bedrock surfaces in Redwood County. Depth Unit Description 85 coarse-grained sand (quartz) with some finer grains, non-calcareous; depositional events. Some of these units probably correlate with Undifferentiated deposits Black till; pre-Wisconsinan "V" sequence, Winnipeg source. Villard Member—Found at the surface in rotary sonic boring RWR-3 (feet) Cretaceous bedrock, undifferentiated. 80 Cross sections A–A' through F–F' are representative of 57 cross sections (Fig. Olive-brown sand and gravel, outwash, Quaternary, undifferentiated. and also within RWR-4, RWR-5, RWR-7, and RWR-8. See Figures the Lake Henry and Eagle Bend Formations of central Minnesota 0 Qsu Whitish-green becoming medium green after 1', saprolith (weathered 1) that were constructed to create a three-dimensional model of the Quaternary Qsu Undifferentiated sand and gravel (new unit)—Commonly composed 280 Dark gray sand, almost pure quartz with some lignite, and sandy (Johnson and others, 2016). Although all five Good Thunder Fill 90 serpentinized peridotite) with darker green veining; pre-Cambrian, 3, 6, 7, 8, 10, and 11; Table 1; Plate 3, Figure 4. 110 silt interbedded with lignite, non-calcareous; Cretaceous bedrock, deposits of Redwood County. The major sand bodies from this model are depicted of stream sediment from the underlying till unit; may include Qtu Dark olive-brown till and rocks, non-calcareous, very hard; Quaternary, undifferentiated. 85 formation till units are similar in texture and grain content, subtle Black silt with organics, some clay, trace sand; organic deposits. undifferentiated. Qsv Sand, gravelly sand, and sandy gravel—glacial-stream sediment materials from units Qtu and Qu and reworked bedrock. May Qo undifferentiated. on Plate 5, Sand-Distribution Model; the full model and all the cross sections used Black clayey silt, non-calcareous; Cretaceous bedrock, distinctions can be made, as shown in Table 1 and noted in the 4 Medium gray clay, fissile, non-calcareous; Cretaceous bedrock, undifferentiated. 95 to develop it can be accessed through the digital files of the Minnesota Geological (new unit)—Sediment deposited by glacial meltwater chiefly include till in places. Qhl Olive-brown silt with some clay and sand; modern lake sediments. undifferentiated. unit descriptions. All units contain pods, lenses, and thin layers Figure 5. Descriptive log of rotary-sonic core RWR-2, drilled by Traut 90 associated with the Villard Member of the New Ulm Formation Olive-brown silt, sand and some gravel toward the bottom, coarsens Figure 4. Descriptive log of rotary-sonic core RWR-1, drilled by Traut Survey. The Quaternary geologic units shown on the cross sections were defined Qtu Undifferentiated till (new unit)—May contain older New Ulm Formation Figure 7. Descriptive log of rotary-sonic core RWR-4, drilled (Johnson and others, 2016), but may include proglacial meltwater of outwash sand and gravel and sand. In other previously mapped Qsh downward, outwash; Heiberg Member, New Ulm Formation. Companies for this study. Drill site location is shown on Figure 1 from interpretation of new data collected for this study and from existing data from deposits (in the northwest corner of the county, as in Fig. 5) but Companies for this study. Drill site location is shown on Figure 1 and Plate by Traut Companies for this study. Drill site location is shown deposits of the overlying Heiberg Member. counties (Renville and Sibley), thin, red, glacial sediments of 8 and Plate 1. Unit symbols and colors match those shown on the cross 95 previous investigations. These include (in order of importance): rotary-sonic drill typically contains one or more pre-late Wisconsinan deposits (Fig. Olive-brown loam till, high amount of gray shale; Heiberg Member, 1, Data-Base Map. Unit symbols and colors match those shown on the cross on Figure 1 and Plate 1. Unit symbols and colors match those Superior provenance (Fig. 2) have been observed between Good Qth New Ulm Formation. sections. See Table 1 for matrix texture and composition averages of Figure 6. Descriptive log of rotary-sonic core RWR-3, drilled by core from ten drill holes completed by the Minnesota Geological Survey; outcrops Loam till deposits with patchy areas of thin glacial-lake sediment 3): the Good Thunder or Elmdale formation, "W" or "V" sequence, sections. See Table 1 for matrix texture and composition averages of till Qtv Thunder formation units; however, these were not encountered in Olive-brown sand, mostly very fine- to coarse-grained, low amount of till units. Traut Companies for this study. Drill site location is shown on shown on the cross sections. See Table 1 for matrix texture along the Redwood River (Patterson and others, 1999); outcrops along Ramsey (modified unit)—Map units Qwv and Qtv from Plate 3. Also found or older deposits. Although some water wells extend below this coarser-grained sand and fine-grained gravel, outwash; Heiberg units. and composition averages of till units. Redwood County. 12 Qsh Figure 1 and Plate 1. Unit symbols and colors match those shown on and Highwater Creeks; rotary-sonic drill core in adjacent Renville (Knaeble, 2013) in the subsurface beneath Heiberg Member deposits, but in places boundary, the data are too few to make meaningful correlations. Member, New Ulm Formation. the cross sections. See Table 1 for matrix texture and composition beneath thin lake sediment, debris flows, and locally sorted and Qs1 Sand and gravel (new unit)—Chiefly composed of stream sediment and Brown (Knaeble, in press) Counties; 54 shallow auger borings completed by Qsb Undifferentiated sand and gravel (new unit)—Stream sediment that Dark grayish-brown, becoming very dark grayish-brown, loam till, derived from unit Qg1, but may also include materials from averages of till units. the Minnesota Geological Survey for Plate 3, Surficial Geology; shallow auger redeposited materials. Till of this unit commonly contains clasts occurs below unit ; may include materials from units and rusty areas above 25', high amount of gray shale; Heiberg Member, overlying units. Qtu Qtu 16 borings completed by the Minnesota Geological Survey for Patterson (1997), of gray, siliceous shale, typically composing 15 to 25 percent of New Ulm Formation. Qu and reworked bedrock. May include till in places. Not shown Borehole name: RWR-6; unique number: 273766 Borehole name: RWR-7; unique number: 273767 Borehole name: RWR-8; unique number: 273768 the very coarse-grained sand fraction (Table 1). May include thin Qg1 Loam till (new unit)—Contains slightly more gray shale and other Patterson and others (1999), and Jennings (2010); drill cutting descriptions from on the printed cross sections, but included in the digital files Location: T. 109 N., R. 37 W., sec. 17; DCADDD Location: T. 110 N., R. 34 W., sec. 8; CADCDA Location: T. 112 N., R. 35 W., sec. 36; DBAACB Cretaceous rock fragments than Good Thunder formation units the Minnesota Geological Survey cuttings library; U.S. Geological Survey borings lake sediment (unit Qhl) and debris flows at the surface. accompanying this atlas. Elevation in feet above mean sea level: 1,140 Elevation in feet above mean sea level: 1,042 Elevation in feet above mean sea level: 1,042 , , and (Table 1). 20 (Broussard and others, 1973); water-well drillers' logs; and Minnesota Department Unnamed member—A thin (4 to 9 feet [1 to 3 meters]) unit found Qg2 Qg4 Qg5 Undifferentiated sediment (new unit)—Includes till, sand, gravel, and Depth Unit Description Depth Unit Description Depth Unit Description Sand and gravel (new unit)—Commonly composed of stream Qu Qth (feet) (feet) (feet) of Transportation bridge boring logs (Minnesota Department of Transportation, beneath the Villard Member in rotary-sonic borings RWR-3, Qs2 fine-grained lake sediments. Shown in areas where control data 0 0 0 Yellow-brown loam till, moderate amount of gray shale; Dovray Mixed sand and till, drainage ditch spoils. Olive-brown loam till, high amount of gray shale; Heiberg Member, New Ulm Formation. 2014). Where there are more data along the cross section lines, all units tend RWR-5, RWR-7, and RWR-8. May correlate with the "Lower sediment from unit Qg2, but may include some materials derived 24 Qth are scarce or absent. Member, New Ulm Formation. to be discontinuous and variable in thickness and elevation over relatively short from overlying units , , and . Heiberg Member till" from Blue Earth County (Meyer and others, Qg1 Qti Qtm 5 Qsh Olive-brown sand with some silt, granules at base, outwash; Heiberg Member, New Ulm Formation. 4 Qth Mixed orgainics and silty till; Heiberg Member, New Ulm Formation. distances—which reflects more accurately the actual complexity of glacial deposits, 2012a). See Figures 6, 8, 10, and 11; Table 1. Qg2 Loam till (new unit)—Locally oxidized, contains trace amounts of ACKNOWLEDGEMENTS Qth Dark olive-brown loam till, high amount of gray shale, gravelly upper 1'; Heiberg Member, New Ulm especially as older, deeper, and thus potentially more eroded and dissected units gray shale and other Cretaceous rock fragments, similar to unit Sand, esker deposit; Heiberg Member, New Ulm Formation. 20 Formation. Qsn Sand, gravelly sand, and sandy gravel—glacial-stream sediment 28 10 Dark olive-brown silty sand, outwash; Heiberg Member, New Ulm Formation. Jon Mitchell, director of the Redwood County Environmental Office, assisted Qsh Sand and gravel, esker deposit; Heiberg Member, New Ulm Formation. Qsh are examined. Where the above data are scarce along the cross section lines, units (new unit)—Sediment deposited by glacial meltwater; associated Qg4, but also contains an average of 3 percent red clasts (Table Very dark grayish-brown loam till, low amount of gray shale; Villard Very dark grayish-brown loam till, high amount of gray shale; Heiberg Member, New Ulm in siting rotary-sonic drilling locations on county properties. William Rabenberg 8 Qth composed of till are generally portrayed (modeled) as continuous, with relatively 1). Locally can include material derived from units and , Member, New Ulm Formation. Formation. with the melting of the ice that deposited the underlying till (unit Qg1 Qg3 permitted us to drill at the Redwood County Highway Department yards in Wabasso, 15 uniform thicknesses and minimal elevation change, and the less common, thinner, and fine-grained lake sediment. 32 Very dark grayish-brown loam till with thin silt and sand layers in top 1', high 40 Very dark grayish-brown loam till, low amount of gray shale, 6" sand layer at 43.5'; Villard Member, Qtn), but may include proglacial meltwater deposits of the overlying Milroy, and Lucan. Karl Ramey helped site the Gilfillan Farm boring. Pauline Qtv lacustrine, sand and gravel units are portrayed as discontinuous. Glacial till is 12 amount of gray shale; Heiberg Member, New Ulm Formation. New Ulm Formation. Villard Member. Qs3 Sand and gravel (new unit)—Commonly composed of stream sediment Nickel and Jodi Getting allowed access to the University of Minnesota Southwest Qtv 20 portrayed as more widespread and continuous because the source ice typically Very dark gray loam till, high amount of gray shale; unnamed member, New Ulm Formation. Qtn Loam till deposits (new unit)—Primarily loamy till, which contains derived from unit Qg3; may include some materials derived from Research and Outreach Center. Minnesota Geological Survey staff members Bruce Qtn No recovery carried abundant fine-grained sediment and spread it over broad areas. By contrast, overlying units and . 36 Qth abundant clasts of gray, siliceous shale, composing 28 to 49 percent Qg1 Qg2 Bloomgren, Alan Knaeble, Alex Gjorvad and Matt Matko provided support during 16 Qtd 25 60 Very dark gray loam till, moderate amount of gray shale; Dovray Member, New Ulm Formation. sand and gravel units are depicted as more discontinuous because they formed by Qtd of the very coarse-grained sand fraction (Table 1). Loam till (new unit)—Contains approximately 10 percent gray shale Qg3 rotary-sonic drilling. Valerie Stanley processed and V.W. Chandler interpreted Dark grayish-brown very fine-grained sand and silt, outwash; streams flowing along isolated depressions on, beneath, and in front of glaciers. Qsn Qtd Qsd Dark gray variable sand with silt, outwash; Dovray Member, New Ulm Formation. Dovray Member—Discontinuous deposits attributed to the Altamont and other Cretaceous rock fragments (Table 1), which makes the paleomagnetic measurements for samples of rotary-sonic core from RWR-8. unnamed member, New Ulm Formation. 30 40 Qtm Very dark gray loam till, moderate amount of gray shale; Dovray Member, New Ulm Formation. These factors should be kept in mind when viewing the cross sections. Very dark grayish-brown loam till, 6" silty sand at 45', high amount of 20 Gray loam till, a few thin sand layers toward the base; Dovray Qs1 phase of the Des Moines lobe (Johnson and others, 2016). Exposed this unit easy to confuse with Des Moines-lobe till deposits in Vania Stefanova analyzed and interpreted pollen samples in rotary-sonic core from Very dark grayish-brown loam till, low amount of gray shale; Moland Member, New Ulm Formation. Cross section locations are shown on Figure 1 and on Plate 3, Surficial gray shale; unnamed member, New Ulm Formation. Member, New Ulm Formation. Very dark grayish-brown loam till, low amount of gray shale; Villard Member, New 80 Qg1 at the surface (boring RWR-6) generally south of the Cottonwood outcrops along the Minnesota River valley bluffs. Locally can RWR-6 and RWR-8. Thanks are extended to all landowners who allowed rotary- 35 Ulm Formation. Qs1 Grayish-brown sand, some silt, outwash; Good Thunder formation 1. Geology. Some cross section units match those on Plate 3, some new units Qg1 Very dark grayish-brown loam till; Good Thunder formation 1. River, otherwise found in the subsurface in most of the county include material from units Qg2 and Qg4, and fine-grained lake sonic drilling on their property, and to all gravel pit operators and landowners Qtv appear only on the cross sections because they are present only in the subsurface 44 Qtn 24 Grayish-brown to dark grayish-brown sand, some silt, 3 thin till layers included, outwash; Good (borings RWR-2, RWR-7, RWR-8, and RWR-10). See Figures 3, sediment. who gave permission to examine exposures on their property. 40 Qs2 Thunder formation 1. or because the area of exposure on the surficial map is too small to be mapped Layers: silt, loam till, sand; Dovray Member, New Ulm Formation. Very dark grayish-brown loam till; Good Thunder formation 1. 5, 9, 10, 11, and 13; Table 1; Plate 3, Figure 4. Sand and gravel (new unit)—Commonly composed of stream sediment Very dark grayish-brown loam till, high amount of gray shale; unnamed member, 100 Qg2 Qs4 Gray to brownish-gray sand with silt, mixing zone at base, outwash; Good Thunder formation 2. (stream cut exposures), and other units are a combination of multiple units from REFERENCES 28 New Ulm Formation. Sand, gravelly sand, and sandy gravel—glacial-stream sediment from unit Qg4; may include some materials derived from overlying 48 45 Qg3 Dark grayish-brown to very dark grayish-brown loam till; Good Thunder formation 2. Qsd Very dark grayish-brown sand and silt, dominantly quartz grains, Plate 3. Organic deposits (unit Qo from Plate 3), alluvial fan sediment (unit Qf Qtn Qs3 (new unit)—Sediment deposited by glacial meltwater. May include units Qg2 and Qg3. Broussard, W.L., Anderson, H.W., and Farrell, D.F., 1973, Water resources of rusty, coarser-grained zone at base. Very dark grayish-brown loam till, includes 8" sand layer in middle; Good Thunder formation 3. from Plate 3), modern lake sediment (unit Qhl from Plate 3), and colluvium (unit Gray loam till; Dovray Member, New Ulm Formation. Qg3 Grayish-brown to dark grayish-brown sand, with granules and fine-grained gravel, coarsens proglacial meltwater deposits of the overlying Villard and Heiberg Qg4 Loam till (new unit)—Contains trace amounts of gray shale and other the Cottonwood River watershed, southwestern Minnesota: U.S. Geological 32 50 120 downward, outwash; Good Thunder formation 3. Qc from Plate 3) are too thin to show on the cross sections, but may appear on the Qsu Qs3 52 Gray loam till; pre-Wisconsinan "W" sequence, Riding Mountain Members (units Qtv and Qth, respectively). Cretaceous rock fragments, similar to unit Qg2 (Table 1). Locally Survey Hydrologic Atlas 466, 3 pls. Bluish/greenish mixed zone: sand and silt, silt, minor clay, with rusty Qsd Dark grayish-brown very fine- to fine-grained sand with silt, outwash; Dovray Very dark grayish-brown loam till, includes sand layer 114'-116'; Good Thunder formation 3. rotary-sonic logs (Figs. 4 through 13). Unit modifications were made in order to source. Qg3 Qtd Member, New Ulm Formation. Mixed zone: sand, silt, till layers; Good Thunder formation 3. Qtd Loam till deposits with patchy areas of thin glacial-lake sediment can include material from unit Qg5, older undifferentiated units, Hobbs, H.C., 1998, Use of 1-2 millimeter sand-grain composition in Minnesota areas and joints. Qw 55 produce subsurface models showing the interfaces between sand and till layers 36 Very dark grayish-brown loam till, moderate amount of gray shale; Dovray Very dark grayish-brown loam till, includes numerous thin sand, silt, and gravelly layers; Good (modified unit)—Map units and from Plate 3. Till tends and fine-grained lake sediment. Green to greenish-blue (reduced) Qs3 that could be processed to create the sand-distribution models on Plate 5. A few Qtd Qwd Quaternary studies, in Patterson, C.J., and Wright, H.E., Jr., eds., Contributions Green saprolite, quartz-rich; pre-Cambrian, undifferentiated. Member, New Ulm Formation. 140 Qg3 Thunder formation 3. sediment is present in places and forms the upper contact of this 56 Qs3 Dark grayish-brown very fine-grained sand with silt and local drop stones, outwash; Good Thunder key stratigraphic control points (rotary-sonic drill holes) are shown on the cross to contain less matrix sand and an intermediate amount of gray, to Quaternary studies in Minnesota: Minnesota Geological Survey Report 60 Very dark grayish-brown loam till, common sandy seams and partings above 71', unit. Dark gray sand and silt layers, outwash; pre-Wisconsinan, low amount of gray shale; Moland Member, New Ulm Formation. Qg3 formation 3. sections with an associated unique number. Some rotary-sonic drill core from siliceous shale clasts than the overlying Villard and Heiberg Member of Investigations 49, p. 193-208. 40 undifferentiated. Very dark grayish-brown loam till; Good Thunder formation 3. Qs3 Renville (Knaeble, 2013) and Brown (Knaeble, in press) Counties were used for deposits. Typically, shale content ranges from 20 to 35 percent Qs5 Sand and gravel (new unit)—Commonly composed of stream sediment Jennings, C.E., 2010, Sediment source apportionment to the Lake Pepin TMDL— Granite or gneiss, slightly weathered; pre-Cambrian, undifferentiated. 65 Grayish-brown to dark grayish-brown sand and sand and gravel, outwash; Good Thunder formation 60 160 3. interpretation because they were near the county border and provided significant of the very coarse-grained sand fraction (Table 1). May include from unit Qg5; may include some materials from overlying units Source characterization middle Minnesota watershed: Minnesota Geological Figure 8. Descriptive log of rotary-sonic core RWR-5, drilled 44 Very dark grayish-brown loam till, includes sand layer 148'-149'; Good Thunder formation 3. thin lake sediment (unit ) and debris flows at the surface. and , and older undifferentiated units. 70 Qtm detail. These drill sites are not shown on the cross sections, but their unique Qhl Qg3 Qg4 Survey Open-File Report 10-1, scale 1:100,000. by Traut Companies for this study. Drill site location is shown Qg3 Dark grayish-brown sand, till layer 153'-155', outwash; Good Thunder formation 3. Very dark grayish-brown loam till, iron-rich cobble at 167'; Good Thunder formation 3. well numbers are included in the digital data file. Drill holes, represented by the Moland Member—Discontinuous deposits of an earlier phase of the Qg5 Loam till (new unit)—Contains trace amounts of gray shale and Jennings, C.E., Aber, J.S., Balco, G., Barendregt, R., Bierman, P.R., Rovey, C.W., on Figure 1 and Plate 1. Unit symbols and colors match those vertical lines, may start above or below the land surface elevation because the Des Moines lobe (Johnson and others, 2016). Exposed in places other Cretaceous rock fragments (Table 1). Its moderate carbonate 48 Dark gray silt with some sand and clay, large wood fragments, 75 180 II, Roy, M., Thorleifson, L.H., and Mason, J.A., 2006, Mid-Quaternary in shown on the cross sections. See Table 1 for matrix texture and Grayish-brown to dark grayish-brown silt, laminated, lake sediment; pre-Wisconsinan, Qsu lacustrine; pre-Wisconsinan, undifferentiated. data are projected onto the cross section from a distance of up to 0.3 mile (0.5 along the Cottonwood and Redwood Rivers, but otherwise found content distinguishes it from other Good Thunder formation units. North America, in Elias, S.A., ed., Encyclopedia of Quaternary science: composition averages of till units. undifferentiated. kilometer) from the line of section. Bedrock units taken from Plate 2, Bedrock only in the subsurface near the Minnesota River (borings RWR-7, Locally can include material from unit Qg4, older undifferentiated Oxford, England, Elsevier, p. 1044-1050. 80 Light olive-brown sand, generally very fine- to coarse-grained, locally contains silt or gravel, 52 outwash; pre-Wisconsinan, undifferentiated. Geology, are shown at the base of the Quaternary deposits between associated RWR-8, RWR-9, and 10). See Figures 3, 10, 11, 12, and 13; Table units, and fine-grained lake sediment. In places an organic soil Jennings, C.E., Lusardi, B.A., and Gowan, A.S., 2012, Surficial geology, pl. 3 Qw Very dark grayish-brown loam to sandy loam till; pre-Wisconsinan "W" sequence, 200 black dots (unit contact lines). 1; Plate 3, Figure 4. horizon has developed, commonly in lake sediment, forming the 85 Riding Mountain source. of Lusardi, B.A., project manager, Geologic atlas of Blue Earth County, Qsu upper contact of this unit. Some wood fragments are present. Sand, very fine- to coarse-grained, some coarser-grained, a few pebbles, Figure 2 is a map showing the general up-ice location of major provenances Qsm Sand, gravelly sand, and sandy gravel—glacial-stream sediment Minnesota: Minnesota Geological Survey County Atlas C-26, 6 pls., scale 56 Dark gray sand with some silt and organics and wood layers; pre- Qsu Wisconsinan, undifferentiated. outwash; pre-Wisconsinan, undifferentiated. Borehole name: RWR-9; unique number: 273769 90 (source regions) for tills in Minnesota and the extent of the material, divided as to (new unit)—Sediment deposited by glacial meltwater. May include Elmdale Formation—Yellow-brown to dark gray bedded sediment and 1:100,000. Silt with some clay, faintly laminated, lacustrine; pre-Wisconsinan, undifferentiated. Location: T. 113 N., R. 37 W., sec. 17; BADACD 220 depositional ice lobe, currently at the surface. A schematic illustration showing proglacial meltwater deposits of the overlying New Ulm Formation dense loam to clay loam till of Winnipeg provenance (Figs. 2, Sand, very fine- to fine-grained, 99% quartz grains, outwash; pre-Wisconsinan, Johnson, M.D., Adams, R.S., Gowan, A.S., Harris, K.L., Hobbs, H.C., Jennings, Elevation in feet above mean sea level: 1,059 the relationships between age, provenance, stratigraphic position, and location of members. 3) associated with the "W" sequence units of central and north- 60 95 undifferentiated. C.E., Knaeble, A.R., Lusardi, B.A., and Meyer, G.N., 2016, Quaternary Depth Unit Description Lignite; Cretaceous, undifferentiated. Dark gray, plastic, fissile, clay, non-calcareous; Cretaceous bedrock, the sediments deposited in Redwood County by major glacial episodes is shown central Minnesota (Meyer, 1997). The till contains small to (feet) Qtm Loam till deposits (new unit)—Till tends to be denser and contains lithostratigraphic units of Minnesota: Minnesota Geological Survey Report undifferentiated. Saprolith; pre-Cambrian, undifferentiated. 0 Light olive-brown sand, generally very fine- to coarse-grained with some gravel, contains clay in Figure 3. Logs of the ten rotary-sonic cores, recovered during drilling for the moderate amounts of carbonate, some gray shale, and 2 percent Qo Organic deposits. 100 240 more matrix sand than the Ivanhoe Member and fewer clasts of of Investigations RI-68. 64 laminations at 240.5' and 242', outwash; pre-Wisconsinan, undifferentiated. Minnesota Geological Survey by Traut Companies, are shown in Figures 4 to 13. gray, siliceous shale than the Dovray, Villard, and Heiberg Member red clasts (Table 1). Commonly thin and patchy. Locally contains Light olive-brown silt and very fine- to fine-grained sand, coarsens Figure 10. Descriptive log of rotary-sonic core RWR-7, drilled by Traut Knaeble, A.R., 2013, Quaternary stratigraphy, pl. 4 of Setterholm, D.R., project downward; modern lake sediments. Figure 9. Descriptive log of rotary-sonic core RWR-6, drilled Analyses of the texture and clast composition of the Quaternary sediments were deposits. Typically, shale content ranges from 5 to 18 percent of significant amounts of incorporated saprolite (weathered bedrock) 5 Qhl Companies for this study. Drill site location is shown on Figure 1 and Plate Figure 11. Descriptive log of rotary-sonic core RWR-8, drilled by Traut Companies for manager, Geologic atlas of Renville County, Minnesota: Minnesota Geological by Traut Companies for this study. Drill site location is shown completed for selected geologic units, and are listed in Table 1. the very coarse-grained sand fraction (Table 1). and bedrock. 1. Unit symbols and colors match those shown on the cross sections. See this study. Drill site location is shown on Figure 1 and Plate 1. Unit symbols and colors Survey County Atlas C-28, 5 pls., scale 1:100,000. on Figure 1 and Plate 1. Unit symbols and colors match those Ivanhoe Member—Discontinuous deposits attributed to the Bemis Qte Loam till (new unit)—Recognized in rotary-sonic drill hole RWR-1 Table 1 for matrix texture and composition averages of till units. match those shown on the cross sections. See Table 1 for matrix texture and composition ———in press, Quaternary stratigraphy, pl. 4 of Boerboom, T.J., project manager, 10 Dark olive-brown to very dark grayish-brown loam till, high amount of gray shown on the cross sections. See Table 1 for matrix texture and DESCRIPTION OF CROSS SECTION UNITS phase of the Des Moines lobe (Johnson and others, 2016). Exposed (Fig. 4). Locally includes materials from the underlying units Qw, shale; Heiberg Member, New Ulm Formation. averages of till units. Samples at approximately 182' from silt beneath Good Thunder Geologic atlas of Brown County, Minnesota: Minnesota Geological Survey composition averages of till units. only in the southwest corner of the county and only observed in Qwt, Qv, and Qvt. formation 3 exhibited normal polarity remanent magnetism (Chandler, unpub. data). Each unit on the cross sections is designated by a letter code, which is County Atlas C-37, 5 pls., scale 1:100,000. Borehole name: RWR-10; unique number: 273770 15 Qth rotary-sonic boring RWR-1. See Figures 3 and 4; Table 1; Plate Other "W" sequence units—Brown to very dark gray or grayish-brown Location: T. 113 N., R. 36 W., sec. 36; CCBDAB described below and placed in one of three categories that designates the origin Knaeble, A.R., and Meyer, G.N., 2007, Quaternary stratigraphy, pl. 4 of Setterholm, of the code, as indicated in parentheses after the description: 1. Surficial Geology 3, Figure 4. to black bedded sediment and dense loam and clay loam tills of Elevation in feet above mean sea level: 1,027 D.R., project manager, Geologic atlas of Todd County, Minnesota: Minnesota Depth Unit Description Sand, gravelly sand, and sandy gravel—glacial-stream sediment Winnipeg and Rainy provenance (Figs. 2, 3) associated with the 20 unit—units having an identical description, label, and color as on Plate 3, Surficial Qsi Geological Survey County Atlas C-18, 6 pls, scale 1:100,000. (feet) Geology; see Plate 3 for the detailed descriptions; 2. New unit—units that appear (new unit)—Sediment deposited by glacial meltwater. May include "W" sequence units of central and north-central Minnesota (Meyer, 0 Lisiecki, L.E., and Raymo, M.E., 2005, A Pliocene-Pleistocene stack of 57 globally Qsm Dark gray to dark grayish-brown silty sand, gravelly sand, silt, and sand Olive-gray silt and very fine-grained sand; glacial River Warren fluvial deposits. only on the cross section and have a unique label and color; and 3. Modified proglacial meltwater deposits of the overlying New Ulm Formation 1997). These tills contain small amounts of carbonate, zero to layers, outwash; Moland Member, New Ulm Formation. distributed benthic 18O records: Paleoceanography, v. 20, 17 p. 25 Qsw members. trace percent of gray shale clasts, and average 2 percent red clasts δ Very dark grayish-brown loam till, low amount of gray shale; Moland unit—multiple units from Plate 3 that are combined into one unit on the cross Qth (Table 1). Commonly thin and patchy, and where present appears Lusardi, B.A., Meyer, G.N., Knaeble, A.R., Gowan, A.S., and Jennings, C.E., 2012, Member, New Ulm Formation. 4 Table 1. Average values for the matrix texture and sand composition of tills recognized in Redwood County. Matrix texture (the less sections (for example units Qa and Qrk are combined into unit Qa). Contact lines Qli Silt with some very fine-grained sand (new unit)—Only encountered Mixed zone Moland Member till and numerous sand and silty sand layers. to be the basal glacial unit above bedrock. Locally contains Quatenary stratigraphy, pl. 4, of Meyer, G.N., project manager, Geologic atlas Olive-gray loam till, high amount of gray shale; Heiberg Member, New Ulm than 2 millimeter grain-size fraction of the sample) is expressed as relative proportions of sand, silt, and clay in percent. The lithologic that intersect the land surface on cross sections do not match all contact lines in rotary-sonic boring RWR-1. Approximately 9 feet (3 meters) of 30 Qsd Formation. composition of the very coarse-grained sand fraction (1-2 millimeters) is expressed in percent as relative proportions of crystalline rocks, significant amounts of incorporated saprolite (weathered bedrock) of Sibley County, Minnesota: Minnesota Geological Survey County Atlas 8 Dark olive-brown sand, outwash; Dovray Member, New Ulm Formation. shown on the surficial map because some units shown on Plate 3 are too small or finely laminated black and light gray lacustrine sediment becomes Very dark grayish-brown loam till, low amount of gray shale; Moland C-24, 6 pls., scale 1:100,000. Olive-brown loam till, moderate amount of gray shale; Dovray Member, New Ulm carbonate rocks, and gray shale modified from the classification system of Hobbs (1998). Also shown is the percentage of Cretaceous thin to be shown on the cross sections. It should also be noted that all of the till massive (not laminated) in the lower 3 feet (1 meter). and bedrock. Member, New Ulm Formation. 35 Formation. grains, which helps to classify samples. The Precambrian crystalline 1-2 millimeter fraction is further differentiated by crystalline rock Sand and gravel (new unit)—Commonly composed of stream sediment Meyer, G.N., 1997, Pre-late Wisconsinan till stratigraphy of north-central Minnesota: units described below may include pods, lenses, and thin layers of outwash sand Clay loam till deposits (modified unit)—Map units and Qws 12 Qti Qti Qwi Minnesota Geological Survey Report of Investigations 48, 67 p. Qtd type into light grains (granite and gneiss), dark grains (mafic-igneous and other metamorphic rocks), and red grains (iron-formation, and gravel, and sand, as well as lacustrine sand, silt, and clay. from Plate 3. Till tends to be denser and contains more matrix from unit Qw; locally includes materials from overlying units and Qtm 40 rhyolite, agate, and sandstone). Clear quartz is a further differentiation of the Precambrian crystalline light 1-2 millimeter grain-size clay than other members, along with containing fewer clasts of reworked bedrock. Meyer, G.N., Knaeble, A.R., Lusardi, B.A., Jennings, C.E., and Gowan, A.S., HOLOCENE 16 fraction. gray, siliceous shale than all but the Moland Member deposits. Qw Loam till (new unit)—Recognized in three rotary-sonic drill holes 2012a, Quaternary stratigraphy, pl. 4, of Meyer, G.N., project manager, MATRIX TEXTURE CLAST TYPE Qsm Light olive-brown, silty, fine- to very fine-grained sand, outwash; Moland Member, Sand, gravely sand, silt and clay—alluvium (modified unit)—Map Geologic atlas of Blue Earth County, Minnesota: Minnesota Geological Percentage of total grains Qa Typically, shale content ranges from 10 to 23 percent of the very (RWR-3, RWR-6, and RWR- 7; Figs. 6, 9, and 10, respectively). 45 New Ulm Formation. counted of the 1-2 units Qa and Qrk from Plate 3. May be thin (less than 18 inches Locally includes materials from the underlying units , , and Survey County Atlas C-26, 6 pls., scale 1:100,000. 20 Olive-brown loam till, low amount of gray shale; Moland Member, New Ulm Percentage of total crystalline coarse-grained sand fraction (Table 1). Qwt Qv millimeter fraction Qtm Formation. Percentage of the less [48 centimeters]) over bedrock or include bedrock in some areas Qvt, older glacial deposits, and bedrock. Meyer, G.N., Lusardi, B.A., Knaeble, A.R., Jennings, C.E., and Gowan, A.S., grains counted Verdi Member—Discontinuous deposits attributed to the earliest 50 than 2 millimeter sand where associated with unit Qrk. 2012b, Quaternary stratigraphy, pl. 4, of Meyer, G.N., project manager, advance of the Des Moines lobe (Johnson and others, 2016) that Qwt Loam till (new unit)—Recognized in two rotary-sonic drill holes 24 fraction HOLOCENE AND PLEISTOCENE extend beyond the Bemis moraine. Not exposed at the surface in (RWR-1 and RWR-3; Figs. 4 and 6, respectively). Locally includes Geologic atlas of Nicollet County, Minnesota: Minnesota Geological Survey Light olive-brown very fine-grained sand, outwash; Moland Member, New Ulm 55 Qsm Formation. materials from the underlying "V" sequence units, older glacial County Atlas C-25, 6 pls., scale 1:100,000. Very dark gray, hard, loam till, very low amount of gray shale; Good Clear quartz
Redwood County and only observed in rotary-sonic boring RWR-1. Shale Total number Total of samples Gravel (percentage of total sample weight) Sand Silt Clay Crystalline Carbonate Light Dark Red Cretaceous Light olive-brown silt and very fine-grained sand, outwash; Moland Member, number Total of samples Sand and gravelly sand—glacial River Warren fluvial deposits Thunder formation 3. 28 Qsw See Figures 3 and 4; Table 1; Plate 3, Figure 4. deposits, and bedrock. Minnesota Department of Transportation, 2014, Office of materials and road New Ulm Formation. Late Wisconsinan (Surficial Geology unit). research web site: St. Paul, Minn.,