Appendix D--Surface Sinkholes and Other Solution Features
From Merriam and Mann, 1957.
Ashland Basin (Ashland-Englewood Basin)--The Ashland Basin in southern Clark County, southwestern Kansas, forms a large topographic depression. It is a coalescing sinkhole (Frye, 1942). The depression probably was caused by solution of Permian salt and gypsum, which occur less than 1,000 feet below the surface (Frye, 1950; Jewett, 1951; Smith, 1940).
This large sinkhole is as much as 12 miles wide and 500 feet below the general level of the High Plains (Schoewe, 1949). The walls are Permian redbeds capped by Ogallala (Pliocene). The basin is dissected and drained by Cimarron River. As much as 100 feet of late Pleistocene fill has been deposited in the depression. Frye (1950) dated its subsidence as mid-Pleistocene to late Pleistocene and believed that solution is directly related to faults that formed in Pleistocene time in the area.
Big Basin and Little Basin--Two sinkholes in western Clark County are well known; the larger, Big Basin (Pl. 26A), is located just west of the smaller, Little Basin, which contains within its boundaries a picturesque and smaller sinkhole known as St. Jacob's Well (Pl. 26B).
Big Basin is situated in sec. 24 and 25, T. 32 S., R. 25 W. The sinkhole is subcircular and approximately one mile in diameter. The floor is relatively flat and 125 to 150 feet below the rim. Small depressions or sags, often retaining water, occur on the floor of the basin. The wall of the sinkhole is still essentially vertical although slightly dissected. Permian, Cretaceous, and Tertiary rocks crop out in the wall of the basin. Its formation probably occurred from several hundred to a few thousand years ago (Smith, 1940).
Little Basin is about one-third mile east of Big Basin. The floor is 35 feet below the rim level. Although Little Basin is shallower than Big Basin, the two sinkholes are believed to be the same age. St. Jacob's Well, a relatively recent sinkhole, is on the floor of Little Basin. The water which is retained in this smaller sinkhole forms an "oasis" in the semiarid country.
Both Big and Little Basins are believed to be due to solution of the underlying soluble Permian beds.
Cherokee County Sinkholes--Sinkholes are observable where rocks of Mississippian age crop out in some areas of southeastern Kansas. All known sinkholes in Cherokee County are attributed to solution of the thick Mississippian limestone in post-Cherokee time, as well as recently. Howe (1956) reported that Pennsylvanian strata are commonly faulted in older sinkholes because the collapse of caverns in the Mississippian limestone occurred after consolidation of overlying sediments. Some faults have a throw of as much as 6 feet. Pyrite and marcasite are common along fault planes.
Nine recent sinkholes were described by Pierce and Courtier (1937). Old sinkholes dated as post-lower Cherokee are exposed in four of the recent sinkholes.
Two of the recent sinkholes subsided about 1905. One is located in the SW sec. 34, T. 32 S., R. 25 E.; the other is in the NW sec. 28, T. 33 S., R. 25 E. Both sinkholes are elliptical, 75 to 125 feet across, and 30 or more feet deep. Their walls are nearly vertical.
Two more sinkholes are in the W2 sec. 34, T. 32 S., R. 25 E. The earlier sinkhole was formed in 1911. A few years prior to 1911 a sag, about 14 feet in diameter, appeared in a corn field, but no water was retained in the depression. In 1911 a larger hole suddenly appeared in the area of the former sag. The wall was vertical and extended down 72 feet; water was present in the bottom. In 1933 the north rim sank approximately 20 feet. The second sinkhole in sec. 34 formed in 1922 and was a shallow depression about 10 feet in diameter.
Two other shallow sinkholes, about 10 feet in diameter, are located in the NE sec. 9, T. 32 S., R. 25 E.; one formed about 1921 and the other in 1929. Another sinkhole in the NE sec. 34, T. 32 S., R. 25 E., was reported to have formed in 1911 or 1912; it was filled prior to 1937, and no further data on it are available. In 1924 cracks appeared in the soil in the E2 sec. 9, T. 32 S., R. 25 E. The area of soil cracks subsided in 1929 to form a vertical-walled, elliptical sinkhole, 75 to 125 feet across and 30 feet deep.
Coolidge Sink--On December 18, 1926, a hole suddenly appeared in the ground 15 miles south of Coolidge, Hamilton County (NE sec. 22, T. 25 S., R. 43 W.). On July 1, 1930, the sinkhole was reported to be about 60 feet in diameter and 40 feet deep (Bass, 1931). It was circular with a steep and undercut wall; the floor sloped at a low angle toward the center of the depression. Three sets of crevices encircled the structure.
By August 8, 1930, the sinkhole had enlarged to a diameter of 104 feet and increased in depth to 68 feet (Bass, 1931). The material in which the sinkhole was formed was homogeneous silt; no stratified rock could be seen in the hole. Smith reported that in 1940 water filled the hole to within 10 feet of the surface and that the wall had slumped so that no overhang was visible. The depression had increased in size to 150 by 200 feet in 1941 and had elongated from its original circular shape, engulfing a nearby country road. It also had filled with water to within 15 feet of the rim (McLaughlin, 1943).
Bass attributed the sinkhole to solution and formation of a cavern with subsequent collapse of the roof. He reported that bedrock dips at 5' toward the sinkhole, indicating that the entire area of recent subsidence may be part of a larger and older sinkhole. Landes (1931) studied the area and determined that Graneros Shale was exposed below the rim. From this, Landes decided that the original cavern must have been formed in either salt or gypsum in the Permian section. Smith found that this sinkhole is but one of a linear series and suggested that they occur along a post-Ogallala fault.
Meade Salt Sink--Sudden sinking of a circular area 150 to 200 feet across took place sometime between the 3rd and 18th of March 1879, in Meade County, 1 1/2 miles southeast of Meade. The sinkhole is on the east side of Crooked Creek, just east of the Crooked Creek Fault. The Great Salt Well, as it was called at the time of formation, engulfed a portion of the "Jones and Plummer Trail," an often-used wagon road and cattle trail (Cragin, 1884). Mudge (1879) stated that by the 18th of March It was 60 feet deep and had a circumference of 610 feet; It was nearly circular with a perpendicular wall. Saline water filled the hole to within 17 feet of the land surface. The depth of the water ranged from 15 to 27 feet at the edge to 42 feet at the center. Water finally rose to within 14 feet of the ground surface.
Sod cracks formed on the rim around the sinkhole. They were 5 to 15 feet deep and 1 to 10 inches wide. The more distant cracks were 126 feet from the hole.
Mudge (1879) stated that 1 bushel of salt was recovered for every 43 gallons of water, about a 7 percent concentration. At one time salt was produced commercially from the well.
Presently the sinkhole is filling with sediment. In the last few years the sinkhole has been completely dry (W. H. Schoewe, personal communication).
Mudge (1879) thought that a cavern had been formed in the Dakota Formation, softer material having been washed out by subterranean water, causing subsequent caving. Johnson (1901), Smith (1940), and Frye (1942) suggested that the cavern formed in underlying Permian salt beds and that overlying rocks collapsed. Frye (1942) pointed out that the shallowest soluble rock is in Permian redbeds several hundred feet below the present water table. He believed that Pliocene faulting provided the necessary openings for water to have access to soluble beds in the Permian and the faulting therefore controlled development of solution caverns; the period of sinkhole formation thus has been limited to post-Pliocene time.
Mitchell County Sink--An unusual type of sinkhole developed in Mitchell County in 1927. Subsidence in the form of a trench in loess, 200 feet long, 75 feet wide, and 18 feet deep, necessitated moving a farm house. Landes (1932) reported that flat discoidal pebbles of the Fort Hays Limestone, derived from nearby outcrops, are found in loess at the level of the trench floor. He believed that solution of limestone pebbles formed a small cave in the loess, that erosion by circulating ground water enlarged the cave, and that the result was collapse of the overlying loess and formation of a sinkhole. A second collapsed cave 40 feet long was formed in 1931 at right angles to the main trench.
Jones Ranch Sink--The Jones Ranch Sink, 8 miles southeast of Meade, forms a large topographic depression in Meade County (T. 32 and 33 S., R. 27 W.). The sinkhole is subcircular, 3 miles in diameter, and controls a centripetal drainage pattern. It is dissected and partly filled with sediment. Exposed bedrock dips slightly into the sinkhole. Its origin is attributed to solution and collapse (Smith, 1940; Frye, 1942; Jewett, 1951). From the molluscan fauna which it contains, Frye and Leonard (1952) dated the fill as early Wisconsinan. They pointed out that isolated features such as this are dated either by fossils or by intersection of lines of dissection.
Old Maid's Pool--This sinkhole is northwest of Sharon Springs in Wallace County (sec. 30, T. 12 S., R. 40 W.). Moore (1926b) described it as 80 feet in maximum depth and three-eighths of a mile in diameter. It holds a small lake 300 feet wide, although in 1962 it was dry. The hole is circular, and the wall is moderately dissected. Pierre Shale is exposed on the south side of the basin (Elias, 1931).
Potwin Sink--A sinkhole which occurred suddenly near Potwin has been described by Gordon (1938). The hole, located in the SE sec. 24, T. 24 S., R. 3 E., Butler County, was formed on the afternoon of September 22, 1937. It was 90 feet by 150 feet, elongated in an east-west direction, and about 45 feet deep. Water filled the hole to within 15 feet of the rim. The unstratified loam of the wall of the sinkhole was perpendicular. It was estimated that approximately 500,000 cubic feet of material was involved in the subsidence. The rim was estimated to be about 35 feet below base of the Herington Limestone. Gordon believed that solution had taken place in the Fort Riley Limestone about 75 feet below base of the sinkhole and that sudden collapse of the cavern roof resulted in the sinkhole.
Two older partly filled sinkholes are found in the vicinity of the Potwin Sink.
Smoky Basin Cave-in--A sudden subsidence which took place near Smoky Hill River about 5 miles east of Sharon Springs on March 9, 1926, attracted nationwide attention. The sinkhole (sec. 33 and 34, T. 13 S., R. 39 W., Wallace County) had a diameter of about 50 feet. By March 11 it had increased in size to about 125 by 250 feet, giving it an irregular elliptical shape (Moore, 1926b). By April 13 its dimensions had increased to 150 by 290 feet, and still later to about 250 feet north-south by 350 feet cast-west. The wall was vertical down to the water level, 165 to 170 feet below the lip. Water was 50 feet deep in the center of the hole. Moore (1926a) estimated the total depth of the sinkhole to be 300 to 350 feet and the amount of material involved to be approximately 1 1/2 million cubic feet. Pierre Shale is exposed in the wall of the sinkhole, and the Niobrara Formation is exposed a short distance east of the area.
Moore (1926a) suggested that because of its size and the large amount of material involved, the sinkhole was due to roof collapse into a cavity of considerable size in chalk in the upper part of the Niobrara. Chalk was dissolved by eastward-moving ground water, which entered the formation at the outcrop farther west.
Russell (1929) discarded Moore's idea of solution of the Niobrara and postulated instead that the sinkhole was the indirect result of structural deformation. He thought there was too much shale in the Niobrara to be dissolved for cavern formation, and he found no evidence that the formation carried water. The clue to the origin of the sinkhole, he believed, lies in the structure of the region, because in nearby counties there are many faults which were formed during pre-Ogallala and post-Ogallala deformation. He believed that cavities, strong enough to resist pressures for a long time, occurred along faults, ultimately collapsing as did the Smoky Basin Cave-in. Many previously formed sinkholes probably have been obliterated by erosion and deposition so that only recent ones are evident. Russell reported a fault having a throw of 50 feet in the north wall of the cave-in.
Elias (1930) was of the opinion that the theory of collapse or subsidence along fault voids is unsound. He suggested that the fault may have aided indirectly in the cave-in by permitting surface water to descend underground and gain access to underlying chalk, causing subsequent solution in the Niobrara Formation.
Flint Hills Sinkholes--Hay (1896) described numerous sinkholes on upland areas of the Flint Hills in the Fort Riley Military Reservation, Riley County. Although not large, deep, nor spectacular, they are described here because they are representative of the common upland type in Kansas.
These sinkholes range in diameter from 30 to 50 feet and. in depth from 8 to 10 feet. All are roughly circular or oval in shape. Hay counted as many as 42 individual sinkholes in 1 square mile. Most individual sinkholes do not retain water. One of the larger sinkholes in the area contains five smaller ones in its floor. Upland sinkholes on the Fort Riley Reservation have been formed by solution and subsidence of the Fort Riley Limestone, which lies near the surface in the region. The Fort Riley is readily soluble and exhibits well-defined jointing.
Similar sinkholes have been reported in Wabaunsee County by Savage (1881) and in Morris County by W. R. Atkinson (personal communication), Hay (1896), and Schoewe (1949). Small, circular, shallow sinkholes due to solution of the Fort Riley Limestone also occur in Cowley County (Bass, 1929) and Butler County (Fath, 1921).
Other Solution Features--Commonly associated with sinkhole development in Kansas are caves, natural bridges, underground drainage, and soil cracks. These related features are prominent mainly in the western part of the state. For the most part they are small and do not form a major part of the physiography.
Lee and Payne (1944) described an interesting occurrence of cave deposits in Mississippian rocks found in the subsurface of the McLouth gas and oil field, in Jefferson and Leavenworth counties. Pennsylvanian deposits occur in the caves, which were found at depths of as much as 150 feet below the top of the Mississippian.
Davis (1955) described in detail three small caves in the Stanton Limestone (Pennsylvanian) in Wilson and Montgomery counties.
Caves, presumably In the Fort Riley Limestone (Permian), have been mentioned by Savage (1881) as occurring in Wabaunsee County. Stalactites and stalagmites occur in the caves. W. R. Atkinson (personal communication) reported the occurrence of caves in the Fort Riley Limestone in southwestern Morris County. Caves in this part of the geologic section are usually low and narrow but long.
Solution of gypsum in the Blaine Formation (Permian) has resulted in many small sinks, caves, and natural bridges in Barber and Comanche counties. Caves in this area and adjoining portion of Oklahoma are commonly called "The Bat Caves." These caverns have been described in detail by Twente (1955). Grimsley and Bailey (1899) described a gypsum cave on Cave Creek, 4 miles west of Evansville, known as Big Gypsum cave. A stream entered from the west of the 100-foot cave and left by an east opening.
The largest and best known natural bridge in Kansas spanned Bear Creek at a point 7 miles south of Sun City in Barber County (Pl. 26C). The bridge, 12 feet high, 55 feet long, and 35 feet wide, collapsed late in 1961 (D. J. Malone, personal communication). Many other small natural bridges occur in this part of the state, but they are not as well known as the Sun City Natural Bridge. Such bridges have also formed by solution of Permian gypsum.
The absence of surface drainage courses may indicate subterranean water courses In soluble rocks. In the Bird City area in Cheyenne County, there is an absence of drainage channels. In western Kansas, White Woman Creek offers an excellent example of subsurface water drainage. The stream enters the state in Greeley County and flows east across Wichita County into western Scott County, where the surface water course disappears. No re-entry to the surface is known. The point at which the stream disappears is a short distance west of the Modoc Basin.
McLaughlin (1946) mentioned the area of the Bear Creek depression, where Bear Creek crosses the northwestern corner of Grant County. In places, drainage consists of a series of sinkholes and short intermittent streams, indicating underground water channels. In southern Kearny County, surface expression of the Bear Creek drainage ends abruptly. Many other small streams, especially in Wichita, Scott, Kearny, Finney, Grant, and Haskell counties, flow for short distances on the surface and then disappear underground.
Kansas Geological Survey, Geologic History of Kansas
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Web version April 2006. Original publication date Dec. 1963.