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Geologic Formations and Their Water-bearing Properties
Cretaceous System
Gulfian Series--Colorado Group
Dakota Formation
The Dakota formation does not crop out in Wichita or Greeley County and it yields no water to wells in the area. However, the Dakota formation contains water and is an important aquifer in the Syracuse upland to the south, in Hamilton and Kearny counties (McLaughlin, 1943, pp. 124-125). Two known attempts to obtain water from the Dakota formation have been made in Greeley County. In 1901 the Missouri Pacific Railway Company drilled a well at Horace to obtain water for use by the railroad. The Dakota is reported to have been reached at 1,050 feet and penetrated to a depth of 1,350 feet, where the Permian redbeds were encountered (Parker, 1911, pp. 101-102). The water in the Dakota rose to about 800 feet below the surface. The well was never used extensively. In 1948 another experimental well was drilled in the NW cor. sec. 36. T. 17 S., R. 42 W., in an area where shallow water supplies are scarce, to see if there was enough water in the Dakota formation of proper quality for irrigation. Analysis of a bailer sample of water from the well indicated that the water contained too much sodium to be used for irrigation. The well is not used. During the course of an investigation of the geology and ground-water resources of Hamilton and Kearny counties (McLaughlin, 1943, p. 154 the record of a well drilled in the SE cor. sec. 8, T. 21 S., R. 41 W., 2 miles south of the Greeley County line, was obtained. It was reported that this well entered the Dakota fromation at 800 feet and that water rose to within 350 feet of the surface. At the time of the investigation the well was used for domestic and stock purposes.
Details concerning the character and the thickness of the Dakota formation in Wichita and Greeley counties are lacking. Sandstone and variegated shale and clay are the predominant materials in the Dakota, but the percentages of the constituents in the two counties are not known.
The Dakota formation is characteristically lenticular, and consequently it varies considerably in thickness. According to Parker (1911, pp. 101-102) the Dakota was 300 feet thick in the deep well drilled at Horace. However, rocks belonging to the Kiowa shale and the Cheyenne sandstone, which underlie the Dakota, may be included in this thickness. The probable range in thickness of the Dakota is from 200 to 300 feet. The entire area is underlain by the Dakota formation.
Graneros, Greenhorn, and Carlile Formations
Above the Dakota formation, and below the Niobrara formation are 300 to 450 feet of deposits which consist mainly of shale and limestone. Included in this thickness are the Graneros shale, Greenhorn limestone, and Carlile shale, in ascending order. These formations do not crop out in Wichita and Greeley counties. As they are generally very poor aquifers and yield no water to wells in these counties, they will not be discussed.
Niobrara Formation
The uppermost Cretaceous beds in Wichita and Greeley counties consist of chalk and chalky shale of the Smoky Hill member of the Niobrara formation. This member crops out along White Woman Creek on the western border of Greeley County. The lower member of the Niobrara formation, the Fort Hays limestone member, does not crop out in the area.
Fort Hays limestone member--The Fort Hays limestone member consists of thick massive beds of chalky limestone and chalk separated by very thin beds of chalky shale and bentonite. The limestone and chalk beds commonly range in thickness from less than a foot to a few feet, and where unweathered they are light to dark gray. Weathered exposures of Fort Hays limestone in near-by areas are white, tan, buff, or cream. None of the test holes drilled in Wichita and Greeley counties penetrated the Fort Hays limestone, but test hole 23, drilled in the SE SW sec. 32, T. 20 S., R. 34 W., in southwestern Scott County, penetrated 65 feet of Fort Hays chalk and chalky shale (Waite, 1947, p. 187). This limestone probably underlies the entire area, but its range in thickness is not known. It yields no water to wells in Wichita and Greeley counties.
Smoky Hill chalk member--The Smoky Hill chalk member, which overlies the Fort Hays limestone member, consists of chalk and chalky shale. The beds contain numerous limonitic concretions and shells of Inoceramus grandis and Ostrea congesta. Where unweathered these beds are light to dark gray, but exposures in Greeley County are weathered to yellow, orange, or tan. Although the thickness of the Smoky Hill member in these counties is not known in detail, in southeastern Wichita County it is judged to be less than 100 feet (Waite, 1947, p. 187, log 23) and it probably reaches a maximum thickness of 550 to 600 feet in the northern part of Greeley County. The Smoky Hill chalk and chalky shale underlies all of Wichita and Greeley counties and serves as an impervious floor beneath the overlying water-bearing sediments. It prevents the downward percolation of water in much the same manner as the floor of a tank. No wells in the area are known to obtain water from the Smoky Hill chalk, but it may locally contain very small amounts of water along bedding planes or fractures.
Tertiary System
Pliocene Series
Ogallala Formation
Character--The Ogallala formation in Wichita and Greeley counties consists of sand, gravel, silt, and clay and lesser amounts of sandy limestone and opal. To the north in Wallace County (Elias, 1931) beds of volcanic ash, diatomaceous marl, bentonitic clay, and silicified beds (Frye and Swineford, 1946) are found. The character of the Ogallala is indicated by the logs of test holes included in this report.
Most of the materials composing the formation are poorly sorted, and gradations from one lithologic type to another take place within short distances. Individual beds are characteristically lenticular and, with the exception of the "Algal limestone" at the top, cannot be traced very far.
Sand is the most common constituent of the Ogallala formation, occurring at all horizons. The sand ranges in size from very fine to very coarse and is composed predominantly of quartz with lesser amounts of feldspar and other minerals. Beds of uniform well-sorted sand are found in some places, but most of the sand is mixed with silt, clay, or gravel. Beds of gravel are encountered in test drilling, but usually they contain sand or silt. Sand and gravel beds in the Ogallala may be well cemented to form hard beds of sandstone or conglomerate. In many places the materials have been so firmly cemented with calcium carbonate as to produce a series of hard ledges, interbedded with only slightly cemented beds. These hard beds of sandstone usually form rough, weathered benches and cliffs, and they have been called "mortar beds" because of their resemblance to old mortar. Calcium carbonate is the most common cementing material in the Ogallala formation, but in places sand and gravel deposits are cemented with ferruginous or siliceous cement. Some sand and gravel beds in the Ogallala, particularly those that supply water to irrigation wells in Wichita and Greeley counties, contain little or no cementing material. Structurally, the sand and gravel deposits may be even-bedded, irregularly cross-bedded, or may have no apparent bedding.
Beds of sandy silt are very common in the Ogallala. The color of the silt is gray, red, brown, tan, buff, or white where it contains a large amount of calcium carbonate. Some of the silt deposits are bedded, but many are structureless, and have a superficial resemblance to wind-blown silt or loess. Silt layers commonly contain stringers, nodules, or pipettes of calcium carbonate.
In addition to occurring as cementing material, nodules, or stringers, calcium carbonate also occurs in beds of caliche or limestone. The term caliche as used here refers to deposits of soft calcium carbonate that are thought either to have been deposited a short distance beneath the land surface from surface water that contained calcium bicarbonate or to have been precipitated from ground water by the loss of carbon dioxide at times when the water table was near the surface. However, the "Algal limestone" which caps the Ogallala formation in many areas is thought to have been deposited in shallow lakes, as explained previously. It has a maximum thickness of about 4 feet in the Wichita-Greeley area. In typical outcrops it is hard and weathers to a reddish knobby, irregular surface. The "Algal limestone" has been recognized in test holes drilled in the area (as in test hole 20-38-29ddd), and it also crops out on several hills (for example, NW sec. 23, T. 18 S., R. 38 W.).
Distribution and thickness--The Ogallala formation underlies all of Wichita and Greeley counties except an area in western Greeley County along White Woman Creek. There a bedrock high exists and the Ogallala, which was originally very thin, has been removed, exposing the underlying Smoky Hill chalk member. The Ogallala is covered by the Sanborn formation, slope deposits, or alluvium throughout much of the Wichita-Greeley area, but it crops out in several places, principally along Ladder, White Woman, and Sand Creeks (Pl. 7). The thickness of the Ogallala formation encountered in test drilling ranged from 194 feet in test hole 20-38-29ddd to 15 feet in test hole 19-36-16dad in Wichita County and from 243 feet in test hole 16-41-15ccc to 8 feet in test hole 20-42-29bbb in Greeley County. The thickness of the formation in various areas is indicated in the cross sections (Figs. 6 and 7) and in the logs of test holes given in this report.
Plate 7--Outcrops of the Ogallala formation. A, View of rough, weathered beds of the Ogallala formation in sec. 28, T. 17 S., R. 42 W., Greeley County. B, Bluff formed by beds of the Ogallala formation. View is in NW sec. 18, T. 17 S., R. 36 W., Wichita County, looking east across valley of Ladder Creek.
Age and correlation--In 1899 Darton (pp. 732, 734) applied the name Ogallala formation to deposits formerly called "Tertiary grit" and considered by Hay (1895, p. 570) to be of Miocene age. Darton named the formation for a locality in southwestern Nebraska and considered the formation to be of late Tertiary or Pliocene(?) age. In 1920 (p. 6) he designated the type locality as being near Ogallala Station in western Nebraska. Since the work of Darton, the most important studies of the stratigraphy of the Ogallala in western Kansas have been made by Elias (1931), Smith (1940), and Frye and Leonard (1949). In 1943 McLaughlin described the Ogallala formation in Hamilton and Kearny Counties, and in 1947 Waite described the Ogallala in Scott County.
The Ogallala formation ranges in age from early Pliocene or possibly late Miocene to late Pliocene. The Ogallala has been subdivided into three members, which are in ascending order the Valentine, Ash Hollow, and Kimball. No attempt was made to differentiate the members in Wichita and Greeley counties, but all the members may be present. As Elias (1931) described the "Algal limestone" bed in Wallace County to the north as defining the top of the formation, it seems certain that the Kimball member and Ash Hollow member at least are present in these counties.
Water supply--In Wichita and Greeley counties, as in much of the High Plains, the Ogallala formation is the principal water-bearing formation. A few wells of small capacity obtain water from alluvial deposits and it is possible that a small amount of water may be obtained from cracks or bedding planes in the Niobrara formation, but all irrigation wells, all public-supply wells, and most of the domestic and stock wells derive their water from the Ogallala. The Ogallala supplies water also to small springs along Ladder Creek. The yields of wells tapping the Ogallala formation in Wichita and Greeley counties range from a few gallons a minute for domestic and stock wells of small capacity to 1,800 gallons a minute from irrigation wells of large capacity (well 18-35-34abb, Table 8). The largest yields from the Ogallala are obtained from the coarser materials, which generally are in the lower part of the formation. Figure 12 indicates that water-bearing deposits reach a maximum thickness of about 170 feet in the area. Logs of test holes show that much of the water-bearing material is composed of sand and gravel; therefore the amount of water in storage is large.
Water samples were collected from 28 wells that derive their water from the Ogallala formation. Analyses of the samples are given in Tables 10 and 11, graphical analyses of a few samples are given in Figure 13, and a summary of some of the chemical characteristics of the water given in Table 12. Analyses indicate that the water is slightly hard but of good quality both for domestic use and for irrigation. The hardness ranges from 146 to 386 parts per million, 24 samples had less than 300 parts per million hardness, and 4 had between 300 and 400 parts. Water from the Ogallala formation in some places contains enough fluoride to cause mottling of children's teeth, the amount ranging from 0.1 to 2.6 parts per million. Thirteen samples contained 1.5 parts per million or less; 15 samples contained more than 1.5 parts per million.
Quaternary System
Pleistocene Series
Sanborn Formation
The term Sanborn formation was first used in 1931 by Elias (pp. 163-181) for deposits consisting mainly of silt. The type locality was in northwestern Cheyenne County, Kansas, and the deposits were named for the town of Sanborn, Nebraska, located just north of the type locality. Sanborn formation was used to replace such terms as "Plains marl" and "Tertiary marl" used by Hay (1895) and other early workers in the central Great Plains region for deposits later recognized as consisting mainly of loess. Several more recent reports further describe, subdivide, and correlate the Sanborn formation in the western Kansas area. Some of the more noteworthy of these reports are by Frye and Fent (1947), Frye, Swineford and Leonard (1948), Frye and A. R. Leonard (1949), Frye and A. B. Leonard (1951), Swineford and Frye (1951), A. B. Leonard (1951), and Frye and A. B. Leonard (1952). This report uses the classification and correlation of the Sanborn formation as described by Frye and A. B. Leonard (1952).
Character--The Sanborn formation in Wichita and Greeley counties is divided into three silt members, the Loveland, Peoria, and Bignell, and a sand and gravel member, the Crete.
The Crete sand and gravel member is the oldest member of the Sanborn formation. It is composed predominantly of pebbles of quartz, quartzite, basalt, flint, and jasper. The Loveland silt member, which is the next oldest, consists of massive reddish-brown silt. At the top is a weathered zone, oxidized to a dark reddish brown, that contains a concentration of lime in the form of nodules and stringers of caliche in the lower part. This upper weathered part of the Loveland is classed as the Sangamon soil. The Peoria silt member, which consists of tan to light-brown silt, lies above the Sangamon soil. The Peoria is capped in a few localities in Wichita and Greeley counties by a dark soil, the Brady soil, which is somewhat thicker than the modern topsoil. The Bignell silt member which overlies the Brady soil lithologically resembles the Peoria member but nowhere in the area exceeds a thickness of 4 or 5 feet.
Distribution and thickness--As shown on Plate 1, the Sanborn formation underlies the surface of a large part of Wichita and Greeley counties and was penetrated by most of the test holes drilled in the area. The Peoria silt member is the thickest and most widespread unit of the Sanborn; its thickness ranges from a featheredge to 27 feet in the test holes. The extent of the Loveland is not known; it was recognized in only a few of the test holes and its outcrops are scarce. However, the Sangamon soil can be seen in some plowed fields on hillsides, where it occurs as a dark band on the slope below the crest of the hill. The maximum thickness of the Loveland silt in Wichita and Greeley counties is not known, but in test hole 20-37-21aaa in Wichita County 8 feet of reddish-brown silt was thought to represent the Loveland. The occurrence of the Bignell loess in the area is sporadic. The only recorded outcrop of the Bignell is in the NW sec. 9, T. 16 S., R. 40 W., Greeley County.
Age and correlation--The Sanborn formation ranges in age from Illinoian to Mankatoan. The Loveland, Peoria, and Bignell silt members of the Sanborn have been traced from southern Kansas northward to Nebraska, where they are called the Loveland, Peorian, and Bignell loess, respectively. They have been traced farther across Nebraska to western Iowa and to southeastern South Dakota. In Nebraska the Peorian loess has been found above Iowa till and has been established as post-Iowan in age. The Loveland loess underlies the Iowa till in places and thus is of pre-Iowan age (Condra, Reed, and Gordon, 1947, p. 48).
Fossil snails are listed by Frye and A. B. Leonard (1951, Fig. 4) from the Sanborn formation in Wichita and Greeley counties.
| Fossil snails from the Peoria silt member of the Sanborn formation in Wichita and Greeley counties (identified by A. Byron Leonard). |
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|---|---|
| Discus shimeki Helicodiscus singleyanus Helicodiscus parallelus Hawaiia minuscula |
Pupilla muscorum Vallonia gracilicosta Succinea avara |
Water supply--In the uplands of Wichita and Greeley counties the Sanborn formation lies above the water table and yields no water to wells. In a few isolated areas where the water table is close to the surface of the ground, it is possible that meager amounts of water can be obtained from the Sanborn formation or from slope deposits, which are virtually indistinguishable from the Sanborn.
Dune Sand
A thin deposit of dune sand mantles a small area in Greeley County, in sec. 1, T. 17 S., R. 41 W. The fine to medium sand that comprises this deposit probably has been blown by the wind from some near-by outcrop of the Ogallala formation. The thickness of the dune sand probably does not exceed 10 feet. The dune sand is above the water table and yields no water to wells.
Alluvium
General features--Alluvial deposits occur along the bottoms of White Woman and Ladder creeks and along the eastern extremity of Sand Creek. A few scattered remnants of terrace deposits occur in places along these creeks but the deposits are not materially different from alluvium and will be considered with it. The alluvium of White Woman Creek is composed principally of silt, sand, and gravel that were derived from the Ogallala formation, and to a lesser degree of silt and clay derived from the Sanborn formation and slope deposits. The alluvium of White Woman Creek is difficult to distinguish from the Ogallala formation in drill cuttings, but the maximum thickness of the alluvium in the area is thought to be about 30 feet. The alluvium of Ladder Creek is also composed of sand, gravel, and silt, but in general it is finer than the alluvium of the White Woman and contains a higher percentage of material derived from the Sanborn formation and slope wash. The alluvium in test hole 17-35-7add, which was drilled in the valley of Ladder Creek, was composed mainly of silt and clay. One of the layers was a 10-foot bed of dark-blue mucky clay, which was high in organic material. No test holes were drilled along Sand Creek and the thickness and character of the alluvium there are not known.
Water Supply--Only one sample of water was obtained from a well tapping alluvial deposits. The analysis of this sample is given in Table 11 and is shown graphically in Figure 11. The sample contained 391 parts per million of dissolved solids, 294 parts per million of total hardness, and 0.5 part per million of fluoride. In general, the quality of the water is similar to that from the Ogallala formation.
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Kansas Geological Survey, Geology
Placed on web Jan. 11, 2008; originally published April, 1954.
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