Kansas Geological Survey, Bulletin 194, pt. 1, originally published in 1969
Originally published in 1969 as part of "Short Papers on Research in 1968," Kansas Geological Survey Bulletin 194, part 1, p. 29-33. This is, in general, the original text as published. The information has not been updated.
The lowest part of the Greenhorn Limestone received a geographic name more than a quarter of a century before the remaining part of the unit was formally subdivided. First referred to as the "Lincoln Marble" (Logan, 1897), the unit was later renamed "Lincoln Limestone Member" by Rubey and Bass (1925). Because no type section for the Lincoln Limestone Member was designated by early workers, the author has designated as a reference section the exposure in SE SE sec. 31, T. 12 S., R. 10 W., Lincoln County, Kansas. The stratigraphic section is described and illustrated.
(Note: The writer expresses his thanks to Norman King, geology graduate student at Indiana University, for his assistance in measuring and describing the reference section. Thanks are extended also to the following staff members of the Department of Geology, Indiana University, for assistance in manuscript preparation: James Tolen--drafting, Thea Brown--typing.)
The Lincoln Limestone Member (Cenomanian) of the Greenhorn Limestone (Upper Cretaceous) is the oldest formally named member of the formation. Originally known as the "Lincoln Marble" (Logan, 1897), the member has been known in more recent years as the "Lincoln Limestone Member" (Rubey and Bass, 1925, p. 27). The Member is recognized across the entire outcrop of central and western Kansas and enjoys formal status also in New Mexico and Colorado. The member extends also into Cimarron County, Oklahoma, where it is poorly exposed in an outlier of the Colorado Group near the former town of Mineral (Kauffman, Powell, Hattin, manuscript). Logan did not designate a type section for the Lincoln and he failed to indicate whether the name is derived from the city of Lincoln or from Lincoln County. The base of the member is poorly exposed on the east side of Kansas Highway 14 about 1 mile north of Lincoln, but I know of no completely exposed section in the vicinity of that city. Parts of the member are well exposed in cuts on Highway 14 in northern Lincoln County and also north of Sylvan Grove, Lincoln County, on Kansas Highway 18. Partial sections of the Lincoln are exposed at a number of additional localities in Lincoln County, in road cuts and gullies, and I have measured a complete, but poorly exposed, section on Interstate Highway 70 in S/2 sec. 36, T. 13 S., R. 7 W., Lincoln County. However, the only complete, extensively exposed, fresh exposure in Lincoln County known to me is in a road cut on an east-west county road, approximately 1.5 miles east of the Wilson Dam and located in SE SE sec. 31, T. 12 S., R. 10 W. and in NE NE sec. 6, T. 13 S., R. 10 W. The cut was made when road improvements were undertaken during construction of Wilson Dam. The cut is approximately 100 yards long and the faces are relatively steep. It is likely that the Lincoln will remain well exposed here for many years, and probable that the cut will be regraded from time to time because of the heavy flow of reservoir-bound traffic. Because of the general desirability of having a reference section for any stratigraphic unit, and especially one where the unit is well exposed, of characteristic lithologic development, and of typical thickness, I am designating the exposure on the north side of this cut as the reference section for the Lincoln Limestone Member of the Greenhorn Limestone. Description of this section is presented herein because this material will not be included in a forthcoming publication on the Greenhorn Limestone (Hattin, in preparation).
In the Kansas outcrop the Lincoln Limestone Member ranges in thickness from 16.2 feet (western Kearny County) to 32.4 feet (southeastern Mitchell County), averaging 23.1 feet for 11 measurements including two that are composites. At the reference section the thickness is 24.1 feet. Through much of central Kansas the base of the member lies at a widespread disconformity (Hattin, 1968) that separates mostly noncalcareous or only weakly calcareous shales in the upper part of the Graneros Shale from basal Greenhorn skeletal limestones that are overlain by shaly chalk or chalky shale and other carbonate rocks. In westernmost Kansas and in the northern part of central Kansas the contact is gradational and, in a section that grades upward from noncalcareous shales to calcareous strata, is placed at the base of the first bed or zone of abundant lenses of skeletal limestones, or bed of chalky limestone, above which the section consists predominantly of shaly chalk and skeletal limestone. The upper contact is located at the top of the uppermost bed, group of beds, or zone of abundant lenses of skeletal limestones above which the section is largely devoid of such rock. In most of central Kansas this contact lies from 0.91 to 11.68 feet below a prominent, widespread marker bed that contains the Sciponoceras gracile assemblage of invertebrate fossils and that characteristically shatters readily upon weathering. In general, the interval increases in thickness from northeast to southwest. In the southwestern part of the central Kansas outcrop and along the Arkansas River (in Kearny and Hamilton counties) the contact is located much lower in the section, owing to the lateral gradation of the upper part of the Lincoln into a predominantly shaly chalk section having characteristics typical of the Hartland Shale Member.
As thus defined the Lincoln Limestone Member consists principally of shaly chalk through which are scattered abundant lenses and mostly irregular thin beds of calcite-cemented skeletal limestones, including rare calcilutites, calcarenites, and calcirudites, as well as numerous seams of bentonite and a few thin, commonly discontinuous, beds of chalky limestone. In the northern part of central Kansas the lower part of the Lincoln contains some calcareous shale and chalky shale, especially in Mitchell, Cloud, and Washington counties. Molds of ammonites, especially including species of Calycoceras, Dunveganoceras?, Borissiakoceras, and Stomohamites, have been collected at many Lincoln localities, but the most abundant and characteristic fossil is an early form (fide E. G. Kauffman) of Inoceramus pictus J. de C. Sowerby. Ostrea beloiti Logan and Exogyra columbella Meek occur locally in the basal part of the member. An undescribed species of Exogyra is abundant in the lower part of the Lincoln at most central Kansas localities, and this species occurs in the middle and/or upper parts of the member in Hodgeman, Ford, and Kearny counties.
At the newly designated reference section, lithologic and stratigraphic character of the Lincoln is typical for the member as developed in Lincoln County, as well as for nearby counties to the south and west (i.e., Russell, Ellsworth, and Ellis counties), with the exception that the lowermost few feet contains some calcareous and chalky shale. North and northeast of Lincoln County, such rocks are common in the lower part of the Lincoln. The upper and lower contacts are typical of sections exposed in or directly adjacent to Lincoln County. Although the reference section contains few ammonites, the rest of the fauna is typical of the Lincoln of central Kansas. The reference section is illustrated in Figure 1 and described in detail below.
Figure 1--Graphic representation of reference section of the Lincoln Limestone Member of the Greenhorn Limestone.
In the description colors are based on the National Research Council Color Chart (Goddard, 1948) and code designations are given only for those names having more than one color or that are not actually included in the chart. Skeletal limestones are wholly cemented by sparry calcite unless otherwise noted. Although many units are measured to the nearest hundredth of a foot, the thickness totals are rounded to the nearest one-tenth foot.
|Hartland Shale Member||Thickness,
|42.||Chalky limestone, relatively hard, shatters upon exposure, burrow-mottled. This is the lowest widespread chalky limestone marker bed in the Greenhorn of Kansas||0.6|
|41.||Shaly chalk, olive-gray (5Y 4/1) to dark-olive-gray (5Y 3/1), thinly laminated, calcareous, silty, speckled, weathers chippy; 0.02-foot-thick lensing layer of foraminiferal and Inoceramus-fragment skeletal limestone, grayish-orange, hard, brittle, petroliferous, lies 0.52 foot above base; 0.15-foot thick bed of soft, crumbly, burrow-mottled chalk lies 0.55 foot below top||3.5|
|40.||Bentonite, yellowish-gray (5Y 8/1), much stained by limonite, sparsely speckled by minute dark-colored mineral grains, very slightly silty||0.21|
|39.||Shaly chalk, dark olive-gray (5Y 3/1), thinly laminated, calcareous, silty, speckled, weathers chippy; bentonite, yellowish-gray (5Y 8/1), 0.01-foot thick, lies 0.32 foot above base. FOSSILS: Inoceramus fragments, fish scales||0.89|
|Thickness of measured part of Hartland Shale Member.||5.2|
|Lincoln Limestone Member||Thickness,
|38.||Shaly chalk and skeletal limestone; shaly chalk as in unit 39; skeletal limestone, light olive-gray (5Y 6/1) to very pale orange, hard to very hard, mostly brittle, mainly foraminiferal, harder lenses also contain Inoceramus fragments and sparse fish scales and bones, lenses very small in lower 0.5 foot, larger and more abundant in upper 0.15 foot. FOSSILS: Inoceramus pictus, Inoceramus fragments, fish scales, and bones||0.71|
|37.||Bentonite, very pale orange to nearly white, locally olive-gray (5Y 4/1), much stained by limonite||0.25|
|36.||Shaly chalk, olive-gray (5Y 3/2), as in unit 39, with much powdery gypsum along joints and bedding fractures; unit contains moderately abundant very thin to extremely thin lenses of hard, brittle, skeletal limestone, light olive-gray (5Y 5/2) to pale grayish-orange (10YR 8/4), mainly foraminiferal, some with Inoceramus fragments. FOSSILS: Inoceramus pictus, Inoceramus fragments||1.25|
|35.||Shaly chalk and skeletal limestone; shaly chalk dark olive-gray (5Y 3/1), as in unit 39, weathers flaky, many fine-grained crystals of selenite along joints and bedding fractures; skeletal limestone, light olive-gray (5Y 6/1, 5Y 5/2), dark yellowish-brown, or pale grayish-orange (10YR 8/4), somewhat chalky, to wholly spar-cemented, ranges from very thin streaks consisting mainly of foraminifera to small irregular lenses consisting mainly of foraminifera and/or Inoceramus prisms and fragments; large lens 0.35 foot above base is 0.24-foot thick and 1.5 feet wide and consists of very hard Inoceramus-prism limestone that contains abundant bone fragments and scattered Inoceramus fragments; many limestone lenses have burrow and fecal casts on soles, largest lens is load casted; most of limestone has petroliferous odor. FOSSILS: Inoceramus pictus, Inoceramus fragments, fish scales and bones, coprolites||3.6|
|34.||Chalky limestone, medium olive-gray (5Y 4/2), very fine-grained, in part crystalline, soft, somewhat crumbly, weakly resistant; FOSSILS: Inoceramus pictus, Inoceramus fragments||0.16|
|33.||Bentonite, light-olive-gray (5Y 5/2), silty, biotitic, stained by limonite||0.03|
|32.||Shaly chalk, dark-olive-gray (5Y 2/2, 5Y 3/1), as in unit 39, contains widely scattered very thin, small, mostly irregular lenses of hard, brittle, petroliferous skeletal limestone that is grayish-orange to pale grayish-orange (10YR 8/4) and consists chiefly of Inoceramus prisms. FOSSILS: Inoceramus pictus, Inoceramus fragments, fish bones||2.6|
|31.||Bentonitc, pinkish-gray to very light gray,very slightly silty, very sparsely speckled by minute dark-coloredl mineral grains, much stained by limonite, locally wedges out beneath lens of soft, very fine grained, granular chalk that is very light gray||0.06|
|30.||Shaly chalk, dark-olive-gray (5Y 3/1), as in unit 39, only slightly calcareous silty||0.12|
|29.||Bentonite, very pale orange, very slightly silty, very sparsely speckled by minute dark-colored mineral grains, contains small selenite crystals in parts that are much stained by limonite||0.05|
|28.||Shaly chalk and skeletal limestone; shaly chalk, dark-olive-gray (5Y 3/1) as in unit 39, much powdery gypsum along bedding fractures of partly weathered rock; skeletal limestone, pale-grayish-orange, hard, brittle, as numerous very thin and mostly very small lenses, consists of foraminiferal and/or Inoceramus prisms and fragments; lenses most abundant in lower 0.9 foot. FOSSILS: Inoceramus pictus, Inoceramus fragments, fish scales, and bones||1.3|
|27.||Bentonite, nearly white, slightly silty, very sparsely speckled by minute clark-colored mineral grains, stained by limonoite and jarosite.||0.23|
|26.||Shaly chalk, dark-olive-gray (5Y 3/1), thinly laminated, speckled, slightly calcareous silty, with much fine granular gypsum along bedding fractures. FOSSILS: Inoceramus pictus, Inoceramus fragments, fish scales and bones||0.27|
|25.||Bentonite, nearly white, sparsely speckled by minute dark-colored mineral grains, much stained by limonite, many slender selenite crystals in limonitic part||0.04|
|24.||Shaly chalk and skeletal limestone; shaly chalk, olive-black, as in unit 26, with much powdery gypsum along bedding fractures; skeletal limestone, consisting largely of shell fragments, pale-grayish-orange, very thin beds and irregular very thin lenses, petroliferous odor; unit also contains very thin, small even lenses of pale-yellowish-brown calcisiltite; all limestone is hard, brittle. FOSSILS: Inoceramus pictus, Inoceramus fragments, coprolites||1.65|
|23.||Chalky limestone, discontinuous bed, olive-gray (5Y 3/2), very fine-grained, gritty, speckled, contains very thin lenses of olive-gray (5Y 4/1) foraminiferal limestone and local, irregular-shaped, flattened nodules of marcasite.||0.0-0.17|
|22.||Shaly chalk, dark olive-gray (5Y 3/1) to olive-black, as in unit 39, contains scattered fragments of Inoceramus and very thin lenses of skeletal limestone consisting of imbricated Inoceramus fragments and very thin lenses of pale-yellowish-brown bone-fragment-bearing Inoceramus-prism limestone that contains sparse foraminifers||1.5|
|21.||Bentonite, nearly white, very slightly silty, limonite stained, contains sparse, minute, dark-colored mineral grains||0.02|
|20.||Shaly chalk, dark-olive-gray (5Y 3/1), as in unit 39, contains scattered very thin, small lenses of partially spar-cemented olive-gray (5Y 4/1), chalky limestone and pale-grayish-orange skeletal limestone consisting of Inoceramus prisms and fragments and fish-bone fragments. FOSSILS: Inoceramus pictus, Inoceramus fragments, fish scales and bones.||1.65|
|19.||Bentonite, yellowish-gray (5Y 7/2), silty, biotitic, much stained by limonite||0.25|
|18.||Shaly chalk, dark-olive-gray (5Y 3/1), as in unit 39, slightly calcareous, silty. FOSSILS: Inoceramus pictus, Inoceramus fragments, fish scales||1.70|
|17.||Bentonite, discontinuous bed, nearly white, silty, sparse minute dark-colored mineral grains and selenite crystals, much stained by limonite||0.0-0.35|
|16.||Chalky limestone, medium-gray, medium-dark-gray, and light-olive-gray (5Y 6/1), very fine-grained, speckled, tough, weakly resistant, gritty||0.24|
|15.||Shaly chalk, chalky limestone, and skeletal limestone, dark-olive-gray (5Y 3/1), very slightly calcareous, silty, with abundant Inoceramus both whole and as fragments; skeletal limestone, pale-grayish-orange to very pale orange, abundant lenses in upper half of unit consisting of Inoceramus prisms and fragments with fish bone fragments in some lenses; lower half of unit contains some skeletal limestone lenses and many very thin lensing beds and small lenses of relatively hard, olive-gray (5Y 4/1) to light olive-gray (5Y 5/2) chalky limestone that contains Inoceramus shell fragments and fish bones. FOSSILS: Inoceramus pictus, Inoceramus fragments, fish bones, and scales||1.75|
|14.||Skeletal limestone, olive-gray (5Y 4/1), hard, brittle, resistant, thin to very thin irregularly bedded, composed chiefly of Inoceramus prisms with locally abundant fish bones, all spar-cemented, unit thins laterally where it is split by shaly chalk partings. FOSSILS: Inoceramus pictus, Inoceramus fragments, ammonite mold fragment, fish scales and bones.||0.65-0.7|
|13.||Bentonitic shaly chalk, olive-black, calcareous, silty.||0.05|
|12.||Bentonite, light-bluish-gray, slightly silty, biotitic, jarosite- and limonite-stained||0.15|
|11.||Skeletal limestone, olive-gray (5Y 4/1), thin to very thin irregularly bedded, with very thin shaly chalk partings, consisting mainly of Inoceramus prisms with some Inoceramus fragments, fish bones, coprolites, small white fecal? pellets, clay galls, and clay-gall molds, and bentonite pebbles. FOSSILS: Inoceramus pictus, mold fragment of large acanthoceratid ammonite, sharks' teeth, fish bones and scales, coprolites||0.2|
|10.||Chalky shale, olive-black, thinly laminated, speckled, weathers flaky, with much finely crystalline selenite on bedding fractures; basal 0.12 foot contains very thin lensing beds of skeletal limestone consisting mostly of Inoceramus prisms and small bone fragments||0.75|
|9.||Calcareous sand, olive-gray (5Y 4/1) weathering grayish-orange to dark-yellowish-orange, unconsolidated, consisting of foraminifera and Inoceramus prisms||0.18|
|8.||Shaly chalk and chalky shale, olive-black, thinly laminated, calcareous, silty, speckled, weathers flaky, with much finely crystalline gypsum along bedding fractures||0.15|
|7.||Skeletal limestone, olive-gray (5Y 4/1), thin- to very thin bedded, upper part thinly laminated to gently cross laminated, lower part consists of one or two irregular, lensing beds that are separated from upper part by 0.04 foot of olive-black shaly chalk. FOSSILS: Fish scales and bone fragments, coprolites||0.25|
|6.||Chalky shale and calcareous shale, dark-olive-gray, thinly laminated, slightly speckled, weathers flaky, with very thin even lenses of pale yellowish-brown skeletal limestone consisting of foraminifers and Inoceramus prisms lying 0.6 foot below top||0.9|
|5.||Limestone, discontinuous, very light olive gray (5Y 7/1), weathers to nearly white spheroidal masses, very fine-grained, crystalline, breaks blocky, apparently a concretion. FOSSILS: Borissiakoceras? sp.||0.0-0.35|
|4.||Bentonite, bluish-gray weathering yellowish-gray (5Y 8/1), slightly silty, limonite- and jarosite-stained along joints, especially in upper part||0.25|
|3.||Skeletal limestone, olive-gray (5Y 4/1) weathers pale-yellowish-brown, one bed that locally splits into three beds, irregularly jointed, hard, brittle, consists chiefly of Inoceramus prisms and shell fragments and fish scales and bone fragments, sparsely glauconitic, basal part consists of oyster biostrome. FOSSILS: Ostrea beloiti, Inoceramus sp., Inoceramus fragments, fish scales and bones||0.23-0.28|
|Total thickness of Lincoln Limestone Member||24.06|
|2.||Shale, dark-olive-gray (5Y 3/1), thinly laminated, weathers flaky, weakly calcareous to non-calcareous, moderately silty, very small selenite crystals throughout; unit contains very thin lens of dark-yellowish-brown (10YR 4/2) skeletal limestone lying 0.45 foot below top consisting of Inoceramus and Ostrea fragments. FOSSILS: Ostrea beloiti, Inoceramus fragments||1.0|
|1.||Bentonite, very light olive gray (5Y 7/1) to pale-greenish-yellow, biotitic, stained with jarosite and limonite, tastes of melanterite; this unit is the bentonite marker bed ("X" bentonite of authors) that lies near the top of the Graneros Shale throughout most of central Kansas||1.2|
|Measured thickness of Graneros Shale||2.2|
|Total thickness of measured section||31.5|
Goddard, E. N., and others, 1948, Rock-color chart: Natl. Res. Council, Washington, D.C., 6 p.
Hattin, D. E., 1968, Plesiacanthoceras wyomingense (Reagan) from Graneros Shale and Greenhorn Limestone (Upper Cretaceous) of central Kansas: Jour. Paleontology, v. 42, p. 1,084-1,090.
Logan, W. N., 1897, The Upper Cretaceous of Kansas: The University Geol. Survey of Kansas, v. 2 [Haworth, Erasmus, ed.], p. 195-234.
Rubey, W. W., and Bass., N. W., 1925, The geology of Russell County, Kansas: Kansas Geol. Survey, Bull. 10, pt. 1, p. 1-86.
Kansas Geological Survey, Short Papers on Research in 1968
Placed on web July 26, 2011; originally published in Feb. 1969.
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