(The stratigraphic nomenclature used in this report is that of the State Geological Survey of Kansas and differs in some respects from that of the United States Geological Survey)
Unconsolidated deposits of Pleistocene age form the surficial material in most of Jefferson County (pl. 1). In the upland areas, the unconsolidated material is glacial drift mantled almost everywhere by eolian deposits. Alluvial deposits underlie the flood plains in the valleys and colluvium generally mantles the valley slopes. Bedrock of Pennsylvanian age crops out in sharp ridges and along bluffs and steep valley walls, especially in the western part of the county bordering the Delaware River valley and in the southern part of the county bordering the Kansas River valley. The Pennsylvanian rocks generally dip gently west-northwestward at about 15 feet per mile.
The Lawrence Formation of the Douglas Group is the oldest formation exposed; it crops out in the southeastern part of Jefferson County near the Kansas River valley. Rocks of the Shawnee Group overlie the Douglas Group (table 1) and are exposed in the southern, central, and eastern parts of the county. Rocks of the Wabaunsee Group overlie the rocks of the Shawnee Group and crop out in the central and western parts of the county. The Willard Shale of the Wabaunsee Group is the youngest formation of Pennsylvanian age that crops out in the county; it underlies glacial drift in the uplands in the northwestern part of the area. The stratigraphic relationship of the bedrock units is shown on the geologic section (pl. 1).
Table 1--Generalized columnar section and water-bearing characteristics.
|System||Series||Stage||Group||Formation or rock unit||Member||Thickness, in feet (1)||Lithology||Water-bearing characteristics (2)|
|Quaternary||Pleistocene||Recent and Wisconsinan||Alluvium and terrace deposits||0-90||Coarse sand and gravel containing some silt and clay beneath the flood plain and Newman terrace in the Kansas River valley. In smaller valleys, the alluvium contains a large percentage of fine-grained material.||Large quantities of water are available to wells in the Kansas River valley. Moderate to large quantities of water are available locally to wells in the Delaware River valley. Only small quantities of water are available to wells in smaller tributary vall|
|Wisconsinan and Illinoisan||Loess||0-20||Wind-blown deposits of silt containing clay and fine sand. Generally mantles the upland area.||Small quantities of water are available locally to wells.|
|Wisconsinan, Illinoisan, and Kansan||Terrace deposits||0-50||Sandy gravel and clay locally beneath terraces bordering bluffs in the Kansas and Delaware River valleys.||Small quantities of water are available locally to wells.|
|Kansan and Nebraskan||Lacustrine clay||0-70||Silty clay with a few pebbles. Contains a few beds of silty sand in the north-central part of the county.||Yields no water to wells in the area.|
|Glacial drift||0-100||Glacial till (unsorted mixture of clay, silt, sand, gravel, and boulders) and associated glaciofluvial material. Remnants of these deposits generally mantle the bedrock surface in the upland areas. Drift generally is thinly mantled by loess, except in the||Moderate quantities of water are available locally to wells in coarse-grained glaciofluvial materials incorporated in till, especially in the northeastern part of the county. Elsewhere, only small quantities of water are available.|
|Pennsylvanian||Upper Pennsylvanian||Virgilian||Wabaunsee||Willard Shale||20-30||Dark-bluish-gray and brown silty shale and locally fine-grained sandstone.||Small quantities of water are available locally to wells in the upper weathered zone.|
|Emporia Limestone||Elmont Limestone||20-30||Limestone members are dense, hard, and bluish gray weathering light bluish gray to light brown. Shale member is bluish gray to brown and sandy to clayey.||Small quantities of water are available locally to wells in the upper part of the limestones, where weathered.|
|Auburn Shale||20-30||Gray to brown sandy shale locally containing silty sandstone.||Small quantities of water are available locally to wells.|
|Bern Limestone||Wakarusa Limestone||20-30||Upper limestone is thick bedded and dark bluish gray weathering to light brown. Shale is bluish gray and sandy to clayey. Lower limestone is thick bedded and grayish brown weathering to brown; contains shale partings between beds.||Small quantities of water are available locally to wells in the upper part of the limestones, where weathered.|
|Soldier Creek Shale|
|Scranton Shale||Silver Lake Shale||75-120||Upper shale is bluish gray to yellowish brown and sandy to clayey; contains thin platy limestone beds. Upper limestone is bluish gray weathering to gray or brown. Middle shale is bluish gray to yellowish brown and sandy to clayey; contains the Elmo coal b||Small quantities of water are available locally to wells.|
|Cedar Vale Shale|
|Happy Hollow Limestone|
|White Cloud Shale|
|Howard Limestone||Utopia Limestone||10-20||Upper limestone is thin to medium bedded and brownish gray to gray weathering to bight brown. Shale is clayey and gray to reddish brown. Lower limestone is bluish gray weathering to light gray or yellow brown.||Small quantities of water are available locally to wells.|
|Severy Shale||30-70||Brown to gray fissile sandy to clayey shale. Nodaway coal bed and carbonaceous shale in upper part. Locally contains a silty fine-grained sandstone.||Small quantities of water are available locally to wells.|
|Shawnee||Topeka Limestone||Coal Creek Limestone||20-30||Limestone members generally are medium to thick bedded and gray to grayish brown weathering to yellowish brown. Upper shale is a platy dark-gray carbonaceous shale. Two middle shales are silty to clayey and calcareous. Lower shale is sandy to clayey and b||Small quantities of water are available locally to wells in the upper part of the limestones, where weathered.|
|Du Bois Limestone|
|Turner Creek Shale|
|Jones Point Shale|
|Iowa Point Shale|
|Calhoun Shale||20-45||Gray to brown silty to sandy shale, locally containing silty fine-grained sandstone.||Small quantities of water are available locally to wells.|
|Deer Creek Limestone||Ervine Creek Limestone||30-40||Upper limestone is thick bedded with wavy partings and gray weathering to yellowish brown. Upper shale unit grades upwards from black fissile shale to light-gray silty and sandy shale. Middle limestone is gray to brown weathering to yellowish brown. Lower||Small quantities of water are available locally to wells in the upper part of the thicker limestones, where weathered.|
|Undifferentiated Burroak and Larsh Shale|
|Rock Bluff Limestone|
|Tecumseh Shale||60-85||Bluish-gray to olive-gray silty to sandy shale locally containing silty fine-grained sandstone beds.||Small quantities of water are available locally to wells.|
|Lecompton Limestone||Avoca Limestone||30-45||Upper limestone is dark gray weathering to light yellowish brown and is interbedded with gray silty shale. Upper shale is clayey and olive gray weathering to gray. Second limestone is thin to medium bedded, bluish gray weathering to light tan, and very fo||Small quantities of water are available locally to wells in the upper part of the thicker limestones, where weathered.|
|King Hill Shale|
|Queen Hill Shale|
|Big Springs Limestone|
|Spring Branch Limestone|
|Kanwaka Shale||Stull Shale||60-90||Upper shale is dark gray and silty to sandy; locally contains a silty fine-grained sandstone. Limestone is thin, dense, and bluish gray weathering to light grayish brown. Lower shale is silty to sandy and bluish gray; locally contains a silty fine-grained||Small quantities of water are available locally to wells.|
|Clay Creek Limestone|
|Jackson Park Shale|
|Oread Limestone||Kereford Limestone||35-60||Upper limestone is very fossiliferous, even to wavy bedded, and light gray weathering to yellowish brown. Upper shale is silty to clayey and light gray to reddish gray. Second limestone is wavy bedded and gray weathering to light grayish brown; contains c||Small quantities of water are available locally to wells in the upper part of the thicker limestones, where weathered.|
|Douglas||Lawrence Formation||60||Reddish-gray and bluish-gray to olive-gray sandy to clayey shale and locally silty fine-grained sandstone.||Small quantities of water are available locally to wells.|
(1) Outcrop thickness given for rocks of Pennsylvanian age.
(2) In this report, small supplies refers to yields generally less than 10 gpm, moderate supplies to 10 to 100 gpm, and large supplies to greater than 100 gpm.
The present configuration of the bedrock surface has resulted from subaerial erosion before Pleistocene time, erosion caused by the advance of continental glaciers into northeastern Kansas during Nebraskan and Kansan time, and development of Pleistocene interstadial and present drainage systems. The present drainage system generally has developed along courses coincident with those of a previous drainage system or systems. Present streams generally flow on the bedrock or on unconsolidated deposits just above the bedrock. Except in the upland area in the northeastern part of the county, the unconsolidated deposits generally are less than 50 feet thick.
Continental ice sheets advanced into northeastern Kansas during the Nebraskan and Kansan Stages of the Pleistocene Epoch. Nebraskan till has not been recognized in surface exposures in the county. However, a dense pebble-bearing clay overlying the bedrock that was penetrated by deep test holes in the vicinity of Nortonville may be Nebraskan till. The clay was either directly on the bedrock or above thin intervening glaciofluvial deposits of sand and gravel.
Kansan till overlies bedrock, or the till of possible Nebraskan age, everywhere in the upland part of the county. The Kansan till contains glacial erratics composed of principally pink quartzite, but pebbles and cobbles of igneous rock are common. Two or more zones of pebble-bearing clay interbedded with fine to medium glaciofluvial material were penetrated by test holes in the vicinity of Nortonville; these clays are also believed to be Kansan till. In areas where the till is thin and the topography reflects the bedrock surface, the bedrock formations are shown on the geologic map (pl. 1).
In the upland area in the north-central part of the county, the Kansan till is overlain by the "Nortonville clay." Frye and Leonard (1952, p. 81) suggest that this silty clay may have been "... deposited in slight initial depressions on the surface of the newly formed Kansan till plain as the Kansan ice front retreated..."
Loess underlies most of the upland areas in Jefferson County. It is principally of Wisconsinan age, but studies by James Thorp and others (unpublished material in the files of the State Geological Survey of Kansas) indicate that some of the loess is of Illinoisan age. The loess may be as much as 20 feet thick in the northern part of the county, but thins and becomes discontinuous southward. Where soils have developed on loess, the surface is virtually free of pebbles.
Terrace deposits are found principally in the Kansas and Delaware River valleys. The Newman terrace of late Wisconsinan age (Davis and Carlson, 1952) is a major topographic feature in the Kansas River valley. The material beneath the Newman terrace generally grades from clay and silt at the surface to coarse sand and gravel overlying the bedrock. These deposits generally increase in grain size and thickness with increasing distance from the valley wall. Dissected and weathered remnants of terrace deposits of Kansan, Illinoisan, and Wisconsinan age locally border the bluffs along the Kansas and Delaware River valleys.
Alluvium of Recent age is found in all the valleys. In the Kansas and Delaware River valleys, the material grades from clay and silt at the surface to coarse sand and gravel overlying the bedrock. In some areas, the material in abandoned meanders is clay. Alluvium in the smaller valleys generally is finer grained than in the two principal valleys.
Kansas Geological Survey, Jefferson County Geohydrology
Web version July 2002. Original publication date Dec. 1972.
Comments to email@example.com
The URL for this page is http://www.kgs.ku.edu/General/Geology/Jefferson/03_geol.html