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Stanton County Geohydrology

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Summary of Stratigraphy

[Note: The classification and nomenclature of the rocks described in this report have been adopted by the State Geological Survey of Kansas. They differ somewhat from the classification and nomenclature given in formal reports of the Federal Geological Survey.]

The rocks that crop out in Stanton county are all of sedimentary origin and range in age from early Upper Cretaceous to Recent. Outcrops of the formations are shown on plate 1. The oldest rocks exposed at the surface are shale and sandstone that have previously been called Dakota sandstone. For reasons given later this sandstone of early Upper Cretaceous age is named Cockrum sandstone in this report. This formation crops out in narrow belts along Bear creek and Sand arroyo in the southwestern part of the county. Calcareous sands, gravels, and silts of the Ogallala formation of Tertiary (Pliocene) age unconformably overlie the Dakota sandstone and lie at or near the surface over most of the county, except where they are covered by undifferentiated Pleistocene deposits. It is not possible to differentiate between the Pliocene and Pleistocene deposits so they are described in this report under the name Ogallala formation. Minor amounts of Quaternary loess, dune sand, or alluvium cover a large part of the surface.

Knowledge of the unexposed rocks that lie beneath Stanton county is at the best very general. The Kiowa shale and Cheyenne sandstone, both of early Cretaceous age, underlie the Cockrum sandstone in most or all of the county. The Morrison formation (Jurassic) may underlie the Cheyenne sandstone in the extreme western part of the county, but no direct evidence of this is available. Red shales and light-colored sandstones of Triassic age probably underlie the Cheyenne sandstone throughout most of the county. Beneath the Triassic (?) beds are thick deposits of red shale, hard blue shale, limestone, anhydrite, and gypsum belonging to the Permian system.

A generalized section of the geologic formations of Stanton county is given in Table 1.

Table 1—General section of the geologic formations of Stanton county.

System Subdivision Thickness
Character Water supply
Quaternary Alluvium (?) Thin mantle of sand, gravel, and silt; covers the valleys of the larger streams. Alluvium nearly everywhere lies above the water table. Supplies water to only a few shallow wells in the county. Serves as important catchment area for recharge of the underground reservoir.
unconformable on older formations
Dune sand (?) Composed principally of quartz sand, but contains some silt and clay. Covers large areas south of Bear creek. Does not yield water to any wells in the county, Dunes serve as important catchment areas for recharge from local precipitation.
unconformable on older formations
Loess 0-10 (?) Unstratified, tan to buff clay and silt. Thin mantle covering interstream areas. Relatively impermeable. Yields little or no water to wells and tends to resist the downward percolation of rainfall.
unconformable on older formations
Pliocene (including the Ogallala formation) and Pleistocene undifferentiated. 0-450+ Calcareous clay, silt, sand, and gravel, mainly unconsolidated. Hard conglomerate occurs at base in some places. By far the most important water-bearing deposits in the county. Supplies water to stock, domestic, municipal, and irrigation wells. Water table at depths ranging from less than 50 to more than 200 feet below the surface.
unconformable on older formations
Cretaceous Dakota
0-125+ Light tan to reddish brown. Massive to thin-bedded, fine-grained ferruginous sandstone and varicolored shale and clay shales. Sandstones yield adequate supplies of water to stock and domestic wells at most places in the western part of the county. Water level at depths ranging from 50 to 250 feet below the surface. Water is under slight artesian pressure, but the pressure is not great enough to produce flows at the surface.
25-115+ Blue-gray to black, soft to hard clay-shale and shale. Not exposed in Stanton county. Not known to yield water to wells.
45-100+ Loose to cemented, fine to coarse, light-colored sand and some calcareous shaly silt. Yields water to few wells in western part of county where the Cockrum supply is inadequate or entirely lacking.
disconformity (?)
Morrison (?) formation (?) Thought to be present in western Stanton county, but no evidence is available to substantiate this. Crops out about 25 miles west of this county and is found in drill holes in adjacent areas. No data obtained
disconformity (?)
Undifferentiated redbeds 213+ Pink and buff calcareous sandstone and light-gray to red-brown clay. Unimportant in Stanton county. Reported to yield artesian water in southwestern Morton county, some of which is highly mineralized.
Permian Undifferentiated shale, limestone, anhydrite, and gypsum (?) Red shale, hard blue shale, limestone, and some beds of sandstone, anhydrite, and gypsum. Encountered in gas test well south of Johnson. Unimportant in Stanton county. Yields water to flowing wells at Richfield in central Morton county. Water is highly mineralized and unfit for ordinary uses.

Geologic History

The geologic history of Stanton county is the same in a general way as that of a large area of the central Great Plains. The rocks underlying the county comprise sediments of several types, including limestone, shale, sandstone, clay, sand, and gravel. The composition, appearance, and relations of these rocks indicate to the geologist the condition under which they were deposited.

Paleozoic Era

Very little is known of the conditions existing in the southwestern part of the state during the Paleozoic era. An oil test well drilled to a depth of 5,488 feet in southern Hamilton county penetrated thick beds of Mississippian and Pennsylvanian shales and limestones overlain by about 2,000 feet of Permian red shale and sandy shale containing beds of salt, anhydrite, gypsum, and limestone. A well drilled for gas about 1 mile south of Johnson penetrated Permian red shale and sandstone, limestone, gypsum, and anhydrite between depths of 880 feet and 3,005 feet below the surface. The limestones encountered in the two wells were deposited under marine conditions. The area probably was covered by great seas during most of the Paleozoic era except possibly during the Silurian and Devonian periods (Darton, 1906, pp. 45-46). Thick deposits of limestone, such as are found in the two deep wells mentioned, were deposited in these seas. It is not to be inferred that the land was covered continuously by a body of water, but rather that there were long periods of submergence separated by comparatively short intervals of emergence.

Permian period

During the early part of the Permian period there was alternating submergence and emergence of the. land, and during the latter part there was a widespread emergence that produced shallow basins and low plains. It was on this type of topography that the great mass of red clay and sand that forms the upper part of the Permian system in this region was laid down. Streams deposited the materials of the coarser beds; and the materials of the finer beds were laid down in shallow local basins or bayous and on wide mud flats. The climate seems to have been prevailing arid during the time these sediments were being deposited. The deposition of sand and clay was interrupted at different times by the chemical precipitation of almost pure gypsum, which is a product of evaporation in shallow bodies of water. Its relative purity indicates that the waters in which it was precipitated were probably very quiet, for if there had been much movement of the water the gypsum would probably contain a large amount of sand and clay. This summary of Permian history as applied to southwestern Kansas is largely based on a report by Darton (1907, p. 7).

Mesozoic Era

Triassic period

The conditions that existed in late Permian time probably continued with little change into the Triassic period, for the sediments that were deposited in the central western states during the two periods are very similar. Most of the Triassic (?) sediments of southwestern Kansas are red shales and light-colored sandstones predominantly of continental origin. The sediments of the two periods differ in the amounts of gypsum they contain; the Permian contains a large amount of gypsum, but the Triassic has only a very small amount.

The entire Triassic period is not represented by rocks in Stanton county, indicating either that strata equivalent in age to all rocks known to comprise this system elsewhere were not deposited in this part of Kansas, or that some of the deposits were subsequently eroded after an uplift of the sea bottom in late Triassic (?) time.

Jurassic period

Rocks representing the Jurassic system are not known to occur in Stanton county, but 160 feet of sediment (Morrison) crops out in southern Prowers county, Colorado, about 25 miles west of Stanton county (Saunders, 1934, p. 870), and a test hole drilled northwest of Richfield in Morton county (T. G. McLaughlin, personal communication) penetrated about 40 feet of blue-green marl, which is probably a part of the Morrison formation. If sediments of Jurassic age were deposited in Stanton county they seem to have been removed later by erosion except perhaps in the western part.

Cretaceous period

The Cretaceous period began with the deposition of quartz .sand forming the Cheyenne sandstone. The Cheyenne sandstone represents either shallow-water marine or stream deposition (Twenhofel, 1924, p. 19). After the deposition of the Cheyenne sands the land was submerged and covered by a moderately deep sea in which was deposited the dark clay forming the Kiowa shale. Next came a recurrence of conditions similar to those of Cheyenne time and nearly pure quartz sand was deposited, forming the Cockrum sandstone. The deposition of the Cockrum sand marks the beginning of late Cretaceous time. A thick series of younger Upper Cretaceous sediments was probably deposited over all or at least a part of Stanton county, but was entirely eroded prior to the deposition of the Ogallala (Pliocene) sediments.

Cenozoic Era

Tertiary period

Early in the Tertiary period the land was uplifted and a long time of erosion began. All the late Cretaceous beds down to and in places including part of the Cockrum sandstone were stripped off, leaving an irregular topography. Sometime prior to the beginning of Pliocene time the strata in southern Hamilton county were arched or gently folded, resulting in what is now known as the Syracuse anticline (Bass, 1926, p. 77). The flank of this anticline dips southward to form a broad basin or trough in the northern part of Stanton county. The trough was probably very shallow at first, but was deepened by erosion before the beginning of Ogallala time. The present shape of the pre-Tertiary trough in cross section is shown by section AA' on plate 4, and the areal shape is indicated in figure 4 by contour lines drawn on the pre-Tertiary surface. The axis of the trough is a short distance north of Johnson and trends roughly from northwest to southeast.

Figure 4—Map of Stanton county showing the shape and slope of the pre-Tertiary surface by means of contours (dashed lines), location of test holes (numbered circles), and location of cross sections, shown on plate 4.

Map of Stanton county showing the shape and slope of the pre-Tertiary surface by means of contours.

Plate 4—Geologic profiles through Stanton county, along lines AA' and BB' in figure 4. [A larger Acrobat PDF version of this figure is available.]

Geologic profiles through Stanton county, along lines AA' and BB' in figure 4.

Late in Tertiary time, during the Pliocene epoch, there was a reversal of conditions, from stream erosion to stream deposition. Rock debris from the mountains to the west was deposited over the entire High Plains surface by widely shifting streams. These deposits, consisting of sand, gravel, clay, and silt, make up the Ogallala formation and the Pleistocene undifferentiated beds. The trough in Stanton county and the Syracuse anticline were both buried beneath a thick mantle of these sediments, leaving a flat and featureless surface.

Quaternary period

Owing to a general uplift or to a change in climate in the Quaternary period, the streams again began to erode, resulting in the widespread denudation of the Tertiary and Pleistocene deposits. This period of erosion has continued to the present time and has progressed so far as to lay bare the rocks underlying the Tertiary beds in the southwest part of the county and at a few localities in adjacent areas.

During Quaternary time there was some additional folding and faulting of the Ogallala deposits and underlying Cretaceous strata on the south flank of the Syracuse anticline. Smith (1941, pp. 136, 137) first suggested the presence of a fault on the south flank of the Syracuse anticline, basing his conclusions principally on physiographic evidence. During the course of the present investigation the Cockrum sandstone was encountered at an altitude of 3,039 feet in a test hole drilled on the Hamilton-Stanton county line. About 1 1/8 miles north of this test well the Cockrum sandstone is exposed at an altitude of about 3,350 feet, more than 300 feet higher than in the test hole. It seems unlikely that this much difference in altitude can be attributed to folding and erosion alone; rather, the evidence indicates a normal fault that trends roughly northwest, and dips to the southwest. The Cretaceous strata seem to have been displaced vertically 250 to 300 feet, the downthrown side being the south side. North Branch of Bear creek follows in general the fault-line scarp. The combined faulting and crustal movement has produced the prominent ridge just north of the Stanton county line in southern Hamilton county, which ends within a short distance eastward in northwestern Grant county and southwestern Kearny county.

The streams in the southwestern part of the county are in a youthful stage of development, for down cutting is dominant and the valleys have relatively steep sides. In the eastern part of the county, however, the same streams have wide open valleys that have exceedingly gentle slopes, and they seem to be approaching base level, for they are aggrading their valleys instead of eroding them.

Within Quaternary time wind-blown sand has accumulated to form the dunes or sand hills south of Bear creek. At about the same time or perhaps before the formation of the sand hills a thin mantle of loess, mostly silt and clay, was deposited on the crests and slopes of the upland areas in the county. At the present time some areas of loess and sand dunes are sufficiently covered by vegetation so that the material is more or less permanently fixed, but in other large areas, where there is no protective vegetation, the fine surficial materials are being continually shifted and transported by the wind.

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Kansas Geological Survey, Geology
Placed on web Oct. 5, 2018; originally published November 1941.
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