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Stratigraphy: Buried Rocks
Seven deep wells have been drilled in Ness and Hodgeman counties. They range in depth from 2,910 feet to 5,120 feet. and penetrate rocks of Cambrian, Ordovician, Mississippian, Pennsylvanian, Permian, Lower and Upper Cretaceous and Tertiary ages (Plate VI). The rocks of Upper Cretaceous and Tertiary ages have already been described from surface exposures in the area. Following are descriptions of the older rocks, which are not exposed in the area, but which have been traced by means of logs and well cuttings from areas where they crop out.
Cretaceous System
Upper Cretaceous
Dakota Formation
The Dakota formation has already been discussed, but as only the upper part is exposed in Ness and Hodgeman counties it is included here also. The Dakota consists of gray and variegated shales and gray sandstone. The sand is usually fine and angular and frequently contains pyrite concretions. The sands do not seem to form continuous beds, but some of them carry water and it is necessary to run a string of casing to prevent caving if standard tools are used. A string of 15-inch casing is usually run in the Dakota and underreamed to the top of the Permian red beds. The Dakota formation is always recognizable by its lithology, water content, and position below the calcareous beds of the Greenhorn limestone.
Lower Cretaceous
Kiowa Shale
In the Phillips-Hausman well, in sec. 30, T. 22 S., R. 22 W., a bluish-gray shale containing fragments of fossils was penetrated at a depth of 515 feet. No fossils could be identified, but the lithology and position of the shale, together with the occurrence of fossils, suggests correlation with the Kiowa shale of southern Kansas. The sandstone between this shale and the top of the Permian red beds may be equivalent to the Cheyenne sandstone, but is more probably also of Kiowa age, as are similar sandstones in McPherson County (Twenhofel, 1924). The Lower Cretaceous rocks become progressively younger to the north, due to overlap.
A definite correlation of the beds in the Phillips-Hausman well cannot be made without a detailed paleontologic study of cores. The correlation of the Kiowa shale in the other wells in Ness and Hodgeman counties is only tentative, as no samples from the other wells were available from that horizon.
Permian System
Next below the Cretaceous beds lie about 2,300 feet of continental and marine Permian strata. The upper part, which is chiefly of nonmarine origin, is composed of red beds, anhydrite, and gypsum and is called the Cimarron group. The lower, or Big Blue group, is composed of rock salt, anhydrite, gray and red shales, limestone and dolomite. Some of the limestones are cherty.
The regional dip of the Permian strata in this area is to the southwest. Consequently older beds underlie the unconformity at the base of the Cretaceous to the northeast. Pre-Cretaceous erosion completely removed the Cimarron group in Dickinson County, so that the Dakota sandstone rests on beds of the Big Blue group. The Cimarron group becomes considerably thicker to the south and is over 3,000 feet thick in the Anadarko Basin in the northern part of the Texas Panhandle.
Cimarron Series
The beds of the Cimarron series are red and maroon sandy shales containing beds of red and gray sandstone, anhydrite, and gypsum. The thickness of the group ranges from 1,150 to 1,320 feet. The anhydrite and gypsum beds are usually hogged as "lime" by the drillers.
Two of the anhydrite beds are persistent over the area. The upper one, which lies 130 to 300 feet below the top of the Cimarron group, is 15 to 50 feet thick and is tentatively correlated with the Medicine Lodge gypsum. This bed is not present to the north and east, as it was removed by pre-Cretaceous erosion. The lower anhydrite bed is about 600 feet below the Medicine Lodge. It is 20 to 60 feet thick and, inmost places, consists of a single bed of laminated anhydrite, but locally it also contains gypsum and dolomite. This bed is tentatively correlated with the gypsum beds of the Cedar Hills formation. It has been traced over about fifteen counties in central-western Kansas and makes an excellent subsurface marker and casing seat.
The lower limit of the Cimarron series is the base of the red beds. In Ness and Hodgeman counties this is 150 to 350 feet below the Cedar Hills anhydrite. The irregularity of the base of the Cimarron series is probably due to an unconformity. An unconformity at this position has been noted in Sumner County, Kansas, by Baker (1929, p. 19).
Big Blue Series
This series may be considered as a transition from the typical marine sediments of the Upper Pennsylvanian of this area to tile dominantly nonmarine beds of the Cimarron series. The wells in Ness and Hodgeman counties show the Big Blue series to be 1,000 to 1,125 feet thick. The upper 125 to 200 feet is bluish-gray shale containing thin beds of anhydrite. Below this is 250 to 350 feet of rock salt containing thin beds of anhydrite and gray shale. These upper two members comprise the Wellington group.
Below the Wellington group is a series of gray anhydrite and gray and red-shale beds having a thickness of about 200 feet that is correlated with the Marion group. Next below these anhydrite beds is about 150 feet of cherty limestone, gray shale, and dolomite that is correlated with the Chase group, the cherty beds probably corresponding to the Florence flint and Wreford limestone. The remaining 300 feet of the Big Blue series is made up of limestones and gray and red shales. This lower division contains fusulinids, such as Pseudofusulina and Triticites and is correlated with the Council Grove group, including the Eskridge shale, Neva limestone, Elmdale shale and the Americus (Foraker) limestone which were formerly included in the underlying Wabaunsee group.
Pennsylvanian System
Strata belonging to the Pennsylvanian system in Ness and Hodgeman counties comprise a series of marine beds 1,350 to 1,650 feet thick. These strata are predominantly limestone, with interbedded gray, black and red shales. The Pennsylvanian system has recently been reclassified by Moore (1931, 1932). This classification places the top of the Pennsylvanian lower in the stratigraphic section than it was formerly. The Pennsylvanian rocks underlying Ness and Hodgeman counties include strata correlated with the Virgil, Missouri and Des Moines series. A more detailed correlation is not attempted, as these rocks crop out 200 to 250 miles to the east, and the lithology is considerably different here than it is at the outcrop.
The Pennsylvanian in this area contains no sand except in the conglomerate that is usually present at the base of the system. Oil and gas production from the Pennsylvanian in the counties to the northeast comes from porous limestones in the Missouri and Des Moines series or in the basal conglomerate.
Virgil Series
This series is 800 to 1,000 feet thick and is composed of limestone and shale. The upper part is composed chiefly of limestone, the middle part chiefly of shale, and the lower 300 to 400 feet almost entirely of limestone. The limestones are gray to cream-colored, and some contain light-colored chert. Some of the beds are porous and carry water. The shales are usually light-gray, but some are nearly black. The middle shaly portion of the Virgil series is usually difficult to drill with standard tools, as the shales tend to cave and frequently must be cemented.
Microfossils, such as ostracodes, bryozoans and fusulinids, can usually be picked from the drill cuttings. Of the fusulinids Triticites ventricosus was found in the upper part, and T. beedei, T. cullomensis and T. secalicus in the lower part.
The base of the Virgil series is marked by an unconformity and the lower 25 feet usually contains thin beds of maroon and green shale.
Missouri and Des Moines Series
The lower part of the Pennsylvanian section in this area is correlated with the lower part of the Missouri series and the upper part of the Des Moines series. These rocks have a thickness of 550 to 640 feet in Ness and Hodgeman counties and are chiefly composed of limestone. The upper part is locally known as the "Oswald lime" and the lower 20 to 80 feet as the "Gorham sand," or basal conglomerate. The "Oswald lime" is composed of cream to gray colored limestone containing some beds of gray shale. One or two thin, red shales occur in most places about 300 feet below the top of the formation. The limestones contain cherty and oolitic beds that in general are porous. These porous beds carry oil at Fairport, Gorham and elsewhere, but in this area only water and a small amount of gas have been found.
The basal conglomerate varies both in thickness and composition. It is usually thin in the areas which are structurally high. It characteristically consists of beds of weathered chert pebbles, derived from the underlying rocks, and of variegated shales and sandstone, but in the Continental-Aldrich well, in sec. 7, T. 18 S., R. 25 W., it was represented by only a few feet of sand.
Microfossils are found in several zones. No identifiable fossils were found in the upper 100 feet of the "Oswald lime" in this area, but Triticities was found at the same horizon in cuttings of wells in Russell and Rush counties. In the Continental-Aldrich well Fusulina was found at depths of 4,155, 4,185 and 4,230 feet, and Chaetetes milleporaceous was found at a depth of 4,185 feet.
The upper part of the Missouri series is not present in this area. It either was not deposited or was eroded away before the deposition of the Virgil series. This unconformity has been demonstrated by correlation of closely spaced wells, from Russell County to the central eastern part of the state, by Roy Hall (Kansas Geol. Soc. Meeting, Lawrence, Kan., April, 1931). The great porosity of the "Oswald lime" at some places may be due to subaerial erosion. No conglomerate has been found at this horizon, to the writer's knowledge, except in the eastern part of the state. However, if such a conglomerate was present in the Ness-Hodgeman area, it would probably be composed of limestone pebbles and would, therefore, be difficult to determine from drill-bit cuttings.
Since Triticites has been found in the upper 30 to 50 feet of the "Oswald lime" in Russell and Rush counties and that genus has not been reported lower than the Missouri series, the upper part of the "Oswald lime" is correlated with the lower part of the Missouri beds,
The lower part of the "Oswald lime" and the basal conglomerate are correlated with the upper part of the Des Moines Series and belong to the Marmaton and, possibly, Cherokee groups (Roth, 1930, p. 1258). The lowermost beds of the Pennsylvanian probably vary in age from place to place, as the surface upon which the early Pennsylvanian sediments were deposited was not a smooth, level one. Therefore, the basal conglomerate of different areas was not deposited at the same time and so is only lithologically equivalent.
Pre-Pennsylvanian Rocks
The rocks in Ness and Hodgeman counties lying below the Pennsylvanian are chiefly cherty limestones and dolomites with some sand and greenish shale. Correlation of some of these strata is rather difficult because of their lithologic similarities.
These rocks are important oil and gas producers. Some of the members of the Simpson formation are the most prolific oil and gas producers in the Midcontinent area, and any of the limestones or dolomites lying immediately below the unconformity at the base of the Pennsylvanian are potential oil and gas reservoirs.
Four wells in this area have penetrated rocks older than Pennsylvanian age. These are the Continental-Aldrich and Gypsy-Coleman wells on the Beeler anticline, and the Phillips-Hausman and Barnsdall-Lank wells on the Bazine anticline.
Mississippian System
The Mississippian rocks underlying Ness and Hodgeman counties are gray to white, cherty and dolomitic limestones which contain thin beds of greenish-gray shale. The Phillips-Hausman well, in sec. 30, T. 22 S., R. 22 W., penetrated 270 feet of cherty dolomitic limestone, between depths of 4,620 and 4,890 feet., which is probably of Mississippian age. Mississippian cherty and dolomitic limestone is also present in the Gypsy-Coleman well, sec. 25, T. 17 5., R. 25 W., between depths of 4,384 and 4,493 feet (Charles Ryniker, Letter of April 24, 1931). In the Barnsdall-Lank well, in sec. 35, T. 18 S., R. 21 W., Mississippian strata are present between depths of 4,320 and 4,390 feet (McClellan, 1930, p. 33). The producing horizon of the Continental-Aldrich well, in sec. 7, T. 18 S., R. 25 W., is probably in the porous, weathered surface of the same limestone.
To the south and east the Mississippian strata are of considerable thickness. In Clark County, Kansas, McClellan (1930, p. 108) has reported 1,600 feet of Mississippian strata. These strata are entirely lacking to the northeast. on the Barton Arch, where they were probably removed by pre-Pennsylvanian erosion.
Ordovician System
Urschel (Viola) Limestone
In the Phillips-Hausman and Gypsy-Coleman wells a gray, cherty, dolomitic limestone was penetrated below the Mississippian. This limestone is correlated with the Urschel (Viola) limestone. The Urschel limestone is not present in the Barnsdall-Lank well, where it was probably removed by pre-Mississippian erosion (McClellan, 1930, p. 33).
Simpson Group
The Simpson group is composed of green shale and white quartz sand and, where present, is 20 to 50 feet thick. In the Barnsdall-Lank well it was found immediately below the Mississippian limestone, and in the Phillips-Hausman well it was found below the Urschel limestone. It carried only water in those two places. It was not present in the Gypsy-Coleman well. The Simpson beds lie between two unconformities and are consequently quite irregular.
Cambro-Ordovician
Arbuckle Limestone ("Siliceous lime")
The Arbuckle limestone is composed of sandy cherty dolomite. It lies unconformably below later rocks and may be overlapped by any of them. It has not been drilled through in any of the wells in this area. The Phillips-Hausman well entered it 75 feet and the Gypsy-Coleman well 140 feet. it is probably over 300 feet thick over most of the area of Ness and Hodgeman counties but may be thin or entirely missing in places, as it is in the Fairport and Gorham oil fields and the Bison gas field.
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Kansas Geological Survey, Ness and Hodgeman Geology
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Web version May 2004. Original publication date Dec. 1, 1932.
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