Geology and its Relation to Ground Water, continued
Unconsolidated deposits composed of clay, silt, sand, and gravel of Pleistocene age overlie the eroded surface of Cretaceous and Permian rocks in all of Stafford County, much of the southern half of Barton County, in the vicinity of Galatia, and in the Cow Creek drainage basin in east-central Barton County. These materials comprise undifferentiated early Pleistocene sediments, the Meade formation, and the Sanborn formation.
Undifferentiated Pleistocene Deposits
Unconsolidated clay, silt, sand, and gravel unconformably overlie the Carlile shale and form the surface rock of the upland in the vicinity of Galatia in northwestern Barton County (Pl. 1). The area underlain by these deposits is roughly elongate, is 1 to 4 miles wide and about 7 miles long, and trends northwest-southeast. Nine test holes (16-15-9cc, 16-15-11cc, 16-15-21aa, 16-15-22dd, 16-15-23aa, 16-15-25cc, 16-15-33aad, 17-14-6bb, and 17-15-1dd) were put down to determine the character, thickness, and distribution of these sediments. Geologic cross sections based on these test holes are shown in Figure 10. Although similar in lithology to the Ogallala formation these sediments occupy a lower topographic position and are believed to represent deposits laid down by an early Pleistocene stream that crossed this area. Because of their local extent and the doubt as to their exact age, no formation name is assigned to them in this report.
In the Galatia area these deposits range from a featheredge to about 40 feet in thickness. They consist chiefly of light-colored silt, sandy silt, and clay containing caliche and, locally, thin lenses of fine to coarse sand. Six of the nine test holes penetrated from less than 1 foot to 14 feet of poorly sorted granitic sand and gravel at the base. Some of the gravel is coarse, but it is mostly fine to medium in texture. Test hole 16-15-25cc penetrated about 6 inches of white, very hard lime-cemented gravel just above the Carlile shale and below 8 feet of loose sand and gravel.
A few domestic and stock wells in the immediate vicinity of Galatia obtain water from these early Pleistocene sands and gravels. A sample of water from well 16-15-15dc2, which taps these deposits, was analyzed and found to be a relatively soft sodium chloride water.
The character of the Meade formation is well shown by the logs of test holes that penetrated these deposits in Barton and Stafford Counties, and its distribution and relation to older and younger deposits are shown by cross sections in Plate 3.
The Meade formation consists chiefly of sand, gravel, and silt, the proportions of which differ greatly from place to place. The materials making up the formation generally are poorly sorted, and gradations from one lithologic type to another take place within short distances, both laterally and vertically. The sands, gravels, and silts form lenses that overlap one another irregularly. Some of the beds have been loosely cemented by calcium carbonate.
The finer materials of the Meade formation are composed mostly of silt and in general include only small amounts of clay. Test hole 21-11-36dd in northeastern Stafford County penetrated 21 feet of blue-gray clay between depths of 126 and 147 feet, but this seems to be an exceptional occurrence. Lenses of sandy silt ranging in thickness from a few inches to more than 50 feet are common and are likely to be encountered in any part of the formation. The color of the silt is tan to brown, buff, yellow, and various shades of gray. Some of the lenses are very calcareous and are white to gray.
Interbedded with the silt and sandy silt are thick lenses of granitic sand and gravel. Beds composed entirely of sand or gravel are uncommon, but beds composed of a mixture of sand and gravel in different proportions make up more than half the formation. Silt is also a common constituent intermixed with the sand and gravel. The sand ranges in texture from fine to coarse, and the gravel ranges from fine to very coarse. Pebbles from 1 to 4 inches in diameter occur with the coarser gravel. Lenses of cross-bedded sand and gravel ranging in thickness from a few inches to more than 100 feet may be encountered in any part of the formation. Most of the material has been derived from crystalline igneous and metamorphic rocks, although pebbles of Cretaceous sandstone and "ironstone" are common in gravel pits in Stafford County and were found in the gravels near the base of the formation in a few test holes. (See logs 21-11-24cc, 22-11-28bc, and 24-11-5aa.)
Caliche in the form of nodular calcium carbonate is common in the silt, sand, and gravel throughout the Meade formation. Volcanic ash, although not common, also occurs in the Meade formation. A 2-foot bed of ash was penetrated between depths of 135 and 137 feet in test hole 19-10-18bb in sec. 18, T. 19 S., R. 10 W., Rice County. Ash is poorly exposed in the NW 1/4 SE 1/4 sec. 28, T. 25 S., R. 11 W., in southeastern Stafford County. Most of the deposit there is covered by dune sand.
The Meade formation is exposed in two areas in Stafford County--the one lies west and southwest of St. John and the other lies south and southeast of Stafford (Pl. 1). Excellent exposures of the sands and gravels are found in commercial gravel pits in these two areas. This formation occurs in the subsurface beneath dune sand or alluvium over all Stafford County and the southern part of Barton County. It was difficult to differentiate the Meade formation from the alluvium of the Arkansas Valley; therefore, a dashed line has been drawn separating the two in the cross sections. The Meade formation also occurs beneath the Sanborn formation in the lower part of the deep channel north and northeast of Ellinwood. (See logs 18-11-36aa, 19-11-12aa, and 19-10-18bb; and section L-L', Pl. 3.)
The thickness of the Meade formation in this area ranges from a featheredge to more than 200 feet. Its thickness is controlled largely by the uneven surface on which these sediments were deposited (Fig. 10). It is thinnest in the northwestern part of T. 22 S., R. 11 W., and the central and north-central parts of T. 21 S., R. 13 W., where it overlies buried Cretaceous highs (Pl. 3, E-E', G-G', and J-J'). It is thickest in the buried lowland areas of Stafford County. The greatest thickness penetrated was 210 feet in test hole 25-15-33dd in sec. 33, T. 25 S., R. 15 W., near the southwest corner of Stafford County. An oil test in sec. 17, T. 22 S., R. 14 W., in west-central Stafford County, penetrated 205 feet of the Meade (log 22-14-17baa), and test hole 21-11-36dd at the southeast corner of T. 21 S., R. 11 W., encountered 203.5 feet of material that has been assigned to this formation. In the buried channel north and northeast of Ellinwood in Barton County, the thickness of the Meade formation ranges from a featheredge to about 60 feet.
The sand and gravel lenses of the Meade formation are the most important sources of ground water in Stafford County and southern Barton County. Most of the domestic and stock wells and all the irrigation and public-supply wells south of Arkansas Valley derive water from these deposits, and many of the domestic, stock, irrigation, and industrial wells in Arkansas Valley and the city-supply wells at Great Bend derive all or a part of their water from the Meade formation.
The beds of sand and gravel in the Meade formation, particularly those composed dominantly of gravel, are very good water bearers and generally yield abundant supplies of water. The yields of wells tapping these deposits range from a few gallons a minute for small domestic and stock wells to several hundred gallons a minute for the larger irrigation, industrial, and public-supply wells. Some irrigation wells in Stafford County yield 700 to 900 gallons a minute, and a few irrigation wells in the Arkansas Valley that penetrate both the Meade formation and alluvium have yields greater than 1,000 gallons a minute.
Waters in the Meade formation, although moderately hard, are in most places of good quality and suitable for most ordinary uses. In the vicinity of Big and Little Marshes in the northeastern part of Stafford County, waters in the Meade formation locally are highly mineralized and contain excessive concentrations of chloride. In some places the waters from the middle and upper parts of the formation are of good quality, whereas waters from the basal part of the formation are highly mineralized. The chemical character of the waters in the Meade formation are discussed in more detail on pages 132-134.
The term Sanborn formation was first used in 1931 by M. K. Elms (p. 163) to describe Pleistocene deposits in northwestern Cheyenne County, Kansas, that were composed chiefly of loess. Courtier (1934, p. 34) used the term Sanborn formation in a similar sense in south-central Kansas, including Stafford County. Since that time, the term has been used in central Kansas to include not only loess but also Pleistocene sand and gravel deposits younger than the Meade formation (Frye and Fent, 1947, p. 42). This latter usage has been accepted by the State Survey and will be followed in this paper.
Silt and associated sediments of the Sanborn formation underlie the surface in the following areas in Barton County: (1) the divide between Cheyenne Bottoms and Arkansas Valley; (2) terraces along Dry Walnut Valley and the upland divide between Dry Walnut and Arkansas Valleys; (3) the terrace along the north side of Walnut Creek; and (4) the Cow Creek drainage basin. The areal distribution of the Sanborn formation in these areas is shown on Plate 1, and each area is described in the following paragraphs.
Cheyenne Bottoms-Arkansas Valley divide--The divide area between Cheyenne Bottoms and Arkansas Valley is from 1 to 3 miles wide and extends roughly from U.S. Highway 281, north of Great Bend, to a point northwest of Ellinwood. Unconformably overlying the Dakota formation in this narrow area is loess or loess-like silt of the Sanborn formation. The silt is tan, yellow tan, buff, brown, light to dark gray, or white and contains some fine sand, clay, and caliche nodules. (See logs 18-13-34cc and 19-12-21bb.) Fragments of "Algal limestone," Cretaceous sandstone, and "ironstone" are common at the base of the formation. The thickness of the Sanborn formation in this area ranges from a featheredge to more than 50 feet (Pl. 3, E-E' and F-F'). The materials making up the Sanborn here are relatively impervious and would yield little or no water to wells. As far as is known, no wells in this area derive water from the Sanborn formation.
Terraces along Dry Walnut Valley and Pawnee Rock upland area--The low terraces bordering Dry Walnut Valley and part of the upland area that separates Dry Walnut Valley from Arkansas Valley, here called the Pawnee Rock upland area, are underlain by silt, sandy silt, and clayey silt of the Sanborn formation. (See logs of test holes 19-14-17bb, 19-15-Sdda, 19-15-11aa, 19-15-12da, 20-15-2dd, 20-15-4cd, 20-15-5aa, 20-15-22cc, 20-15-28cbb, and 20-15-31aa; and Pl. 3, C-C' and D-D'.) The silts are tan, buff, brown, and light to dark gray and contain caliche nodules. Fragments and pebbles of sandstone, "ironstone," and limestone are commonly found at the base of the formation. Test hole 20-15-2dd in sec. 2, T. 20 S., R. 15 NW., encountered 6 feet of fine sand, clay, and sandstone fragments at the base of the formation. The deposits of the Sanborn formation in this area overlie the dissected surface of the Dakota formation, Graneros shale, or Greenhorn limestone and range in thickness from a featheredge to about 60 feet.
In part of the Pawnee Rock upland area the Sanborn formation lies above the water table and, therefore, could not yield water to wells. In the lower terrace areas along Dry Walnut Valley, however, the lower part of the formation is saturated and would yield small supplies of water to wells where the materials making up the lower part of the formation are sufficiently permeable. Locally, sand or the zone of sandstone and "ironstone" pebbles and fragments at the base of the formation will yield water to wells. Well 19-15-32db, in sec. 32, T. 19 S., R. 15 NW., is the only recorded well known to tap the Sanborn formation in this area. It is a drilled stock well, 6 inches in diameter and 37 feet deep, in which the measured water level was 30.2 feet below the ground surface on July 24, 1944.
Walnut Valley terrace area--A terrace ranging from about 0.5 mile to nearly 4 miles in width borders the north side of Walnut Creek Valley (Pl. 1). Also included in this area is the small terrace remnant south of Walnut Creek and northwest of Great Bend. The sediments underlying this terrace are in the Sanborn formation and consist of silt, sandy silt, and clayey silt that contain lenses of sand and gravel. The character of these deposits is shown by logs 18-13-31aa, 18-14-14bec, 18-14-15bb, 18-14-17add, 18-14-23add, 18-14-24dd, 18-14-29aa, 18-14-32aab, 18-15-4cc, 18-15-21bb, and 19-13-6db, and their relation to other deposits is shown by cross sections C-C' and D-D' on Plate 3.
Silt, commonly containing fine sand or clay, is the dominant constituent of the Sanborn formation in the Walnut Valley terrace area. Many of the silt beds contain caliche in nodular form or as a cementing material. Beds containing much caliche are gray white, whereas those silt beds containing little or no caliche are light to dark gray, brown, buff, or yellow. Fragments of Cretaceous sandstone and "ironstone" were encountered in the silts in many of the test holes. Such fragments are most common at the base of the formation but are also found higher up in the formation. The lower 6 feet of silt at test hole 18-15-4cc, near the north edge of the terrace, contained granules and pebbles of limestone and much sand.
Lenses of loose sand and fine to coarse gravel ranging from a few inches to more than 50 feet thick occur interbedded with the silt. Most of the test holes drilled near the northern edge of the terrace failed to penetrate any sand and gravel. Most of the holes drilled within a mile or so of the south edge of the terrace encountered a single lens of sand and gravel at the base of the formation. Test hole 18-14-32aab, near the south edge of the terrace north of Heizer, encountered three distinct lenses of gravel and sand, 3, 9, and 24 feet in thickness, separated by lenses of silt. According to the driller's log, well 19-13-6db at the edge of the terrace in sec. 6, T. 19 S., R. 13 W., penetrated 60 feet of sand and fine to very coarse gravel between 55 and 115 feet. Well 19-13-18db, located on the terrace remnant south of Walnut Creek, is reported to have penetrated 25 feet of sand and gravel between 55 and 80 feet. The sand and gravel encountered near the northern edge of the Walnut Valley terrace is locally derived and composed of Cretaceous sandstone and "ironstone" grains and granules, whereas the sand and gravel found elsewhere is chiefly granitic and has been derived from crystalline igneous and metamorphic rocks. Locally, the sands and gravels have been tightly cemented by calcium carbonate (logs 18-14-15bb, 18-14-23add, and 19-13-6db).
The Sanborn formation in the Walnut Valley terrace area is more than 100 feet thick near the south edge and thins to a featheredge against the Cretaceous bluffs along the northern edge. The greatest thickness encountered was 134.5 feet in test hole 18-14-29aa, drilled about 1 1/4 miles north of the south edge of the terrace north of Heizer. Throughout most of the area the Sanborn formation unconformably overlies the Dakota formation, but it overlaps the Graneros shale and Greenhorn limestone at the north.
Most of the domestic and stock wells in the Walnut Valley terrace area derive water from sand and gravel of the Sanborn formation. Irrigation wells 19-13-6db and 19-13-18db, each having a reported yield of more than 1,000 gallons a minute, also tap these deposits. Analyses of samples of water from wells 18-14-25cb and 18-14-30cb indicate that waters in the Sanborn formation in this area are hard and contain excessive iron, but otherwise are of suitable chemical quality for most uses.
Cow Creek drainage basin--The Sanborn formation covers an area of about 85 square miles in the Cow Creek drainage basin in Barton County, east and northeast of Cheyenne Bottoms (Pl. 1), and extends to the east and southeast into Rice County. The material composing the Sanborn formation in this area consists of silt, clayey silt, sandy silt, and very fine to medium sand (logs 17-11-17cc, 17-11-32cc, 18-11-2dd, 18-11-13dd, 18-11-15cc, 18-11-19aa, 18-11-20dd, 18-11-24bb, 18-11-31cc, 18-11-36aa, 19-11-7aa, 19-11-12aa, 18-10-31cc). The silts are tan to brown, light to dark gray, and white, and contain caliche nodules. Gravel composed of Cretaceous-derived sandstone and "ironstone" pebbles is commonly found at the base of the formation. The gravel generally contains much sand and silt and in most places is less than 10 feet thick. The greatest thickness of sand and gravel, 20.5 feet, was encountered in test hole 18-11-15cc at the SW cor, sec. 15, T. 18 S., R. 11 NW. Six of the test holes drilled in this area failed to encounter any coarse material in the Sanborn formation other than scattered sandstone or "ironstone" pebbles in silt near the base of the formation. Surface exposures of the formation consist entirely of silt (Pl. 10B).
The thickness of the Sanborn formation in the Cow Creek drainage basin ranges from a featheredge to a known maximum of 138 feet (Pl. 3, secs. G-G', H-H', and L-L'). In most parts of the area it overlies the eroded surface of the Dakota formation.
Small to moderate supplies of water for domestic and stock use are available from the Sanborn formation in the Cow Creek drainage basin. All the recorded domestic and stock wells in this area are thought to derive water from these deposits. The quality of the water from the Sanborn formation is indicated by the analysis of samples of water collected from wells 17-11-31dc, 17-11-36cc, 18-11-15bc, 19-11-6dd, and 19-12-15ad, given in Table 8. The content of dissolved solids in these samples ranged from 320 to 1,502 parts per million and their hardness ranged from 270 to 606 parts.
Pleistocene and Recent Series
Dune sand ranging in age from Pleistocene to Recent covers most of the area in Barton and Stafford Counties south of the Arkansas Valley and smaller areas north of the Arkansas Valley in eastern Barton County (Pl. 1). The dune sand is composed predominantly of fine- to medium-grained quartz sand and contains minor amounts of clay, silt, and coarse sand. The sand has been accumulated by the wind to form low mounds and small hills, some of which are 50 feet or more high (Pl. 5A and 7B).
The dune sand in the Barton-Stafford County area probably is of at least two ages (Smith, 1937, p. 290). A large part of the area south of Arkansas Valley is covered by older dune sand which is semi-consolidated and contains a larger percentage of clay and silt than does the younger sand. Areas underlain by the older dune sand have a low, hummocky topography and have a sufficiently well-developed soil to support vegetation. Such areas are in farms and are cultivated. The younger dune sand is clean and loose and locally does not have a protective covering of vegetation. The largest areas of bare, unprotected sand occur in the northeastern, central, and southwestern parts of Stafford County. Such areas are subject to wind erosion.
As far as is known, no wells obtain water from dune sand in Barton and Stafford Counties. Because the sand is loose and highly permeable, the sand dunes favor groundwater recharge from local precipitation.
Marsh and Beach Deposits
Unconsolidated marsh deposits consisting of clay, silt, sand, and fine to medium gravel that were derived mostly from dune sand, but in part from the Meade formation and the Kiowa shale, underlie the flat areas of Big and Little Marshes in northeastern Stafford County. The maximum thickness of these deposits is not known, but it probably does not exceed 10 or 15 feet. The upper 1 to 2 feet consists of fossiliferous sandy silt and clay, below which are layers of poorly sorted silty and clayey fine to coarse sand containing only minor amounts of fine to medium gravel.
A ridge of beach sand having a maximum thickness of about 15 feet occurs along the east and southeast sides of the intermittent lake that occupies the central part of Big Marsh (Pl. 1). The beach sands are composed chiefly of fine to medium sand and are lithologically similar to the dune sand from which they were derived.
They are not as well sorted as the dune sand and contain a larger percent of silt, clay, and coarse sand. Some medium to fine gravel is also found locally in the beach sands. The beach sands are gray to gray tan and have a dirty appearance caused by the silt and clay in them. Fragments of shells occur sparingly in these deposits.
No wells obtain water from the beach sands, but a few shallow wells are known to obtain water of very poor quality from the marsh deposits beneath Big Marsh. Well 21-11-22cb is the only recorded well denying water from marsh deposits.
Alluvium of late Quaternary age occurs in Arkansas Valley, Walnut Valley, Dry Walnut Valley, Blood Creek Valley, Cheyenne Bottoms, Cow Creek Valley, Rattlesnake Valley, and North Fork Ninnescah Valley (Pl. 1), and in the valleys of many of the smaller streams. The alluvium in Cow Creek Valley, North Fork Ninnescah Valley, the upper part of Rattlesnake Valley, and the valleys of smaller streams is thin and occurs only as narrow bands along the present channels; therefore, it is not shown on the geologic map. The alluvium consists of stream-laid deposits that range in texture from clay and silt to sand and very coarse gravel.
Arkansas Valley--The area mapped as alluvium in the Arkansas Valley includes those materials underlying the low terrace on the north side of the river. The edge of this terrace is shown by a dashed line on the geologic map where it was possible to identify it. The sediments immediately underlying this terrace deposit are lithologically similar to the alluvium but are somewhat older, probably of late Sanborn age.
The upper 2 to 20 feet of the alluvium in the Arkansas Valley consists of silt and fine to coarse sand. Beneath these finer surficial deposits are thick beds of coarse granitic sand and gravel that are lithologically similar to the sands and gravels of the Meade formation. Because of this similarity, it was not possible to differentiate the alluvium in the Arkansas Valley from the underlying Meade formation.
The alluvial sands and gravels in the Arkansas Valley are excellent sources of ground water, and wells that tap them yield large quantities of water. The alluvium is the source of supply for many domestic, stock, and irrigation wells, and for a few industrial wells. Records were obtained of 27 wells that tap the alluvium in the Arkansas Valley in Barton County. These include nine domestic wells (nos. 19-11-33bb, 19-12-26aa, 19-12-28cc, 19-12-31ab, 20-11-2ba, 20-11-18ba, 20-12-10ab, 20-14-20bc, and 20-15-33db), four stock wells (nos. 19-12-28da, 20-11-2aa, 20-11-3dd, and 20-14-18dd), one domestic and stock well (no. 19-11-20bb), seven irrigation wells (nos. 19-11-31bc, 19-12-19bc, 19-13-29cc, 19-14-22ac, 19-14-32ac, 20-15-33ad, and 20-15-35bc), two industrial wells (nos. 19-13-33bd1 and 19-13-33bd2), and four wells (nos. 19-11-15cd, 19-11-24bb, 20-11-16ab, and 20-14-29cc) that were formerly used to supply water for oil-well drilling operations. Five additional wells, including four irrigation wells (nos. 19-14-23bb, 19-14-26eb, 19-14-32db, and 19-14-36bb) and one industrial well (no. 19-13-33db), derive water from both the alluvium and the underlying Meade formation. The yields of the wells tapping the alluvium in the Arkansas Valley range from a few gallons a minute to about 1,200 gallons a minute.
The quality of the ground waters in the Arkansas Valley alluvium is indicated by the analyses (nos. 19-12-28cc, 20-11-2ba, 20-11-18ba, 20-14-20bc, and 20-15-33db) of five samples of water taken from wells that tap the alluvium. The ground water in the alluvium is hard but otherwise it is suitable for most ordinary uses. The five samples analyzed contained between 508 and 898 parts per million of dissolved solids and had between 242 and 450 parts of hardness. Three of the samples contained less than 0.1 part per million of iron, and two samples (19-12-28cc and 20-15-33db) contained 0.16 and 0.72 part of iron. The fluoride content of the samples was low. The chloride content ranged from 24 to 260 parts per million.
Walnut Valley--In Walnut Valley, the upper 20 to 30 feet of alluvium consists of silt, clay, and sandy silt, beneath which are thick beds of coarse granitic sand and gravel. Thin lenses of silt occur locally in the beds of sand and gravel. The thickness of the alluvial deposits beneath Walnut Valley, as revealed by test drilling, ranges from about 40 feet to nearly 100 feet. The alluvium grades into terrace deposits of the Sanborn formation that border Walnut Valley on the north. The lower part of the valley fill in some places probably is of late Pleistocene age and represents the basal part of a cut-and-fill terrace deposit.
The alluvial sands and gravels in Walnut Valley are highly permeable and wells that tap them yield large quantities of water. The alluvium is the source of supply for many domestic and stock Wells, several irrigation wells, and two industrial wells. The yields of wells tapping alluvium in Walnut Valley range from a few gallons a minute to about 1,000 gallons a minute. The water is hard but otherwise of good chemical quality.
Dry Walnut Valley--Test holes drilled in Dry Walnut Valley penetrated 50 to 125 feet of unconsolidated deposits above the Cretaceous bedrock. (See logs 19-14-19ad, 19-15-16cc, 19-15-21cc, and 19-15-33bb.) Most of this material consists of clay, silt, and sandy silt containing only minor amounts of poorly sorted silty sand and gravel. The beds of sand and gravel are generally found at the base of the alluvial deposits and are thickest where the valley was cut deepest. Test hole 19-15-33bb on section C-C' (Pl. 3) penetrated 50 feet of silt and sandy silt but no course material, and test hole 19-15-16cc penetrated 84 feet of alluvial material, the lower 5 feet of which consisted of poorly sorted lime-cemented silt, sand, and gravel. Test hole 19-15-21cc on the same line encountered 106 feet of clay, silt, and sandy silt above 19 feet of poorly sorted silty sand and fine to coarse gravel.
Many domestic and stock wells derive water from the alluvium in Dry Walnut Valley. Most of these wells are shallow and have small yields. Larger yields probably could be obtained locally from deeper wells tapping the basal gravels in the alluvium.
Blood Creek Valley--Test holes 17-14-35dd and 18-13-6dd were drilled in Blood Creek Valley to ascertain the character and thickness of the alluvium in that valley. Both test holes were located near the middle of the valley. Test hole 18-13-6dd, which was drilled 0.5 mile southwest of Hoisington, penetrated 88 feet of alluvial deposits. Test hole 17-14-35dd was drilled about 2 miles above Hoisington and penetrated 78 feet of alluvium. The alluvium is undoubtedly much thinner upstream and along the margins of the valley. The alluvium consists of clay, silt, and sandy silt containing lenses of sand and gravel that range from a few inches to 15 or 20 feet in thickness. The sand and gravel generally is poorly sorted and contains silt.
The alluvium in Blood Creek Valley supplies water to numerous domestic and stock wells.
Cheyenne Bottoms--The Cheyenne Bottoms is underlain by unconsolidated clay, silt, sand, and, locally, gravel that range in age from Pleistocene to Recent. The thickness of these deposits ranges from less than 20 feet near the margins of the Bottoms to more than 100 feet in the deepest part of the old buried channel that trends northwest-southeast through the central part of the Bottoms in line with Blood Creek Valley. (See sections E-E' and F-F' in Plate 3).
Fine-grained sediments, including clay, silt, and sandy silt, make up the greatest part of the fill in Cheyenne Bottoms. Beds of silty very fine to medium sand ranging in thickness from 2 feet to 22 feet were encountered in three (test holes 18-11-19bb, 18-13-9aa, and 19-12-5aa) of the eight test holes drilled in this area. Test hole 18-12-21cc, which penetrated the greatest known thickness of alluvium in the Bottoms, encountered 11 feet of fine gravel containing much sand and silt at the base of the alluvium between depths of 101 and 112 feet. The gravel is composed chiefly of sandstone and "ironstone" fragments that were derived from the Dakota formation.
The alluvium in Cheyenne Bottoms supplies water to numerous stock and domestic wells, most of which are shallow wells that tap fine to medium sand and sandy silt and have low yields. The quality of the water in the alluvium in most places is poor. The analyses of four samples of water collected from wells that tap the alluvium in Cheyenne Bottoms are given in Table 8 (nos. 17-12-31dc1, 18-11-19bb, 18-13-15da, and 19-12-6bc). They contained 449 to 2,728 part per million of dissolved solids and had 310 to 904 parts of hardness.
Rattlesnake Valley--The alluvium in Rattlesnake Valley is relatively thin, probably being less than 20 feet thick everywhere. It is composed chiefly of poorly sorted sand and gravel that was derived from the Meade formation. The alluvium is everywhere underlain by thick deposits of the Meade formation.
Records were obtained of five wells (nos. 21-11-26ad, 22-11-3cd, 23-11-1bc, 23-12-2cd, and 24-14-1aa) that derive water from the alluvial deposits in Rattlesnake Valley. They are shallow wells less than 15 feet deep that yield small supplies of water for domestic and stock use.
Kansas Geological Survey, Barton and Stafford Geohydrology
Web version Dec. 2001. Original publication date Dec. 1950.
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