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Longford Member, Kiowa Formation

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Appendix A

Work Methods and Terminology

Field work pertinent to this report was done as a part of a larger study of Kiowa and Dakota rocks (Franks, 1966, 1975) in 1962, 1963, and 1965. Additional field work was done in 1975 and 1976. Reconnaissance mapping of the Permian-Cretaceous boundary and formational contacts shown in Plate 1 was done in the field using vertical aerial photographs. The upper contact of the Longford Member is based partly on field mapping, but it also was inferred from field notes, aerial photographs, and topographic maps. Accordingly, that contact is approximate at best, but it is judged to be reasonably accurate at the scale of the map. Surficial deposits shown in Plate 1 were mapped only locally, and their boundaries are adapted mainly from the work of Walters and Bayne (1959). The bedrock-surficial deposit contacts are intended to indicate those areas where abundant Quaternary cover generally masks bedrock.

Clay-rock samples taken for X-ray diffraction studies were dispersed in distilled water, and Stokes-law settling was used to obtain the fraction finer than two microns. Smear mounts on glass petrographic slides were prepared using the method of Gibbs (1965). X-ray diffraction traces were made using a proportional counting diffractometer and nickel-filtered copper radiation at a scan rate of 1°2Θ per minute. One-degree and one-half degree slit systems generally were employed, and the instrument was operated at 35 KV and 18 ma. The terms "illite" and "kaolinite" are used here as generally accepted. Any 14-Angstrom component that expanded on treatment with glycerol to give a diffraction of 18 A, and collapsed to about 10 A on heating to 450° C, was classed as smectite. The name "chlorite" refers to any 14-Angstrom component whose basal spacing did not expand on glyceration and did not collapse below 13.8 A on heating at 575° C for one-half hour. The name "vermiculite" refers to 14-Angstrom components that showed variable expansion toward 18 A on glyceration and variable collapse below 13.8 A on heat treatment. Randomly interstratified mixed-layer clays whose diffraction maxima showed as skew shoulders on the low-angle side of the illite 001 diffraction, or as bumps between that diffraction and 14 A, generally had illite assigned as one component. Depending on the degree of expansion and collapse, other components, such as smectite, chlorite, or vermiculite, were assigned to the mixed-layer structures.

Size analyses of sandstone samples were made after disaggregating the samples using a ceramic mortar and a rubber-tipped pestle. One-hundred gram samples were sieved for a total of 30 minutes on a Ro-Tap, using standard screens sized at 1/4-Phi intervals.

Appendix B

Descriptions of Measured Sections

1. Type section for Longford Member, Kiowa Formation, measured from creek bottom about 0.25 mile south cen. W line sec. 9, T. 10 S., R. 1 E. (about 200 ft south of bridge) to top of roadcut about 0.15 mile north SW cor. sec. 9, T. 10 S., R. 1 E., Clay County, Kansas. Measured by Paul C. Franks. Thickness
(feet) (meters
Longford Member, Kiowa Formation:
Top of hill.
19. Siltstone, very light brownish-gray; weathers pinkish gray to pale yellowish orange. Thin wavy laminae and even laminae weathering to sets 0.1 to 0.5 ft thick. Contains sparse mica flakes; sparse limonitic stain; sparse pyrite nodules. Abundant concretionary masses of calcite cement as much as 5 ft thick and 10 ft long near top; concretions stand out in relief and hold abundant disseminated pyrite. Abundant carbon as flecks and films. Grades sharply into next below. Exposed, 8.8 2.67
18. Siltstone, light-gray to light brownish-gray; weathers very pale orange to grayish orange. Indistinct thin wavy and thin even laminae; abundant carbon flecks, films, and fragments on bedding surfaces; sparse mica flakes; carbonized wood commonly replaced by pyrite; argillaceous. Grades into next below 3.7 1.13
17. Siltstone, pale grayish-orange. Bedding largely masked by limonitic stain; chalky texture, but hard and weathers to form prominent ledge. Irregularly distributed calcite cement; basal bed 0.1 to 0.2 ft thick and cemented by calcite stands out in relief 4.5 1.37
16. Siltstone, very light gray; sparse grayish-orange "limonite" stain along bedding surfaces; weathers yellowish gray to very pale orange. Thin indistinct wavy laminae; weathers to beds 0.1 to 1. ft thick. Hard, but does not stand out in relief. Sparse interstitial clay. Scour-fill contact with next below 3.1 0.95
15. Shale, medium-gray to medium light-gray; sparse limonitic stain; weathers very light gray to yellowish gray. Kaolinitic but contains some smectite. Thin-laminated to laminated; poor fissility; silty. Thickens southward into carbonaceous Silty mudstone. Grades sharply into next below 0.7 0.21
14. Siltstone, light-gray; weathers yellowish gray. Bedding indistinct; abundant interstitial clay, sparse mica flakes. Exposed, 2.9 0.88
Covered interval 7.9 2.40
13. Siltstone, light-gray to very light gray; weathers very light gray to yellowish orange and yellowish gray. Thin-laminated and ripple laminated; bedding inclined 5 or 6' north. Variable amounts of interstitial clay; where interstitial clay is abundant, contains contorted pods of less argillaceous siltstone measuring 1 cm thick and up to 3 cm long. Carbon as leaf and stem imprints on bedding planes locally abundant; local calcareous cement forms discoidal concretions as much as 0.2 ft thick; concretions contain scattered pyrite nodules 14.5 4.40
12. Sandstone and siltstone, light-gray to very light gray; abundant yellowish-orange limonitic stain. Very fine grained to silt-sized; friable; sparse interstitial clay; sparse grains of pink quartzite and flakes of mica. No obvious bedding. Grades sharply into next below 1.3 0.40
11. Sandstone, very light gray; mainly weathered dark yellowish orange to light brown and dusky brown; abundant limonitic and manganese-oxide stain. Fine- to coarse-grained; mainly medium-grained; thin-bedded to wavy laminated; contains sparse medium gray mudstone seams and pellets; sparse interstitial clay; abundant pyrite nodules; friable. Scour-fill contact with next below 4.0 1.22
10. Mudstone, light-gray with brownish overtones grading down to light brownish-gray. Dominantly kaolinitic but contains some smectite and sparse chloritic or vermiculitic mixed-layer clay. Abundant limonitic stain on fracture surfaces in siltiest parts; conchoidal fracture in upper parts; blocky fracture in lower parts. Sparse light-gray siltstone laminae near base. Bedding mainly indistinct. Grades into next below 4.6 1.40
9. Mudstone, very light gray to light yellowish-gray; abundant purplish-red to moderate reddish-brown mottles. Dominantly kaolinitic but contains sparse illite, smectite, and chloritic or vermiculitic mixed-layer clay. Plastic; blocky fracture. Grades sharply into next below 4.8 1.46
8. Siltstone, light-gray to very light gray with brown over-tones. Bedding not obvious; locally calcareous; carbon fragments towards base; abundant limonitic stain. Grades into next below 1.7 0.52
7. Mudstone, light-gray with brown overtones and moderate reddish-brown to reddish-brown mottles. Largely kaolinitic but contains smectite and perhaps mixed-layer vermiculite-smectite. Less silty toward base; abundant carbon fragments in basal 1 to 2 ft. Grades sharply into next below 11.1 3.36
6. Lignitic shale, pale brown. Thin wavy laminae; abundant carbon as flecks, films, and carbonized wood fragments; abundant jarosite stain. Grades laterally into mudstone containing isolated fragments of carbonized wood. Grades sharply into next below 0.5 0.15
5. Siltstone grading down to mudstone. Light-gray grading down to light-gray with reddish-brown mottles. Clay fraction composed mainly of smectite and illite. Abundant grayish-yellow to yellowish-orange limonitic stain in upper 1 ft. Blocky to conchoidal fracture 12.2 3.71
4. Mudstone, light-gray grading down to light brownish-gray. Clay fraction composed mainly of illite and smectite but contains sparse kaolinite and perhaps chlorite or vermiculite. Very silty towards base; bedding indistinct; blocky fracture; abundant carbon in basal 3 ft as flecks, films, fragments, and imprints of stems and leaves; abundant jarosite stain on randomly oriented fractures 8.8 2.67
3. Mudstone, medium-gray with brown over- tones and sparse moderate-red mottles; abundant "limonite" and jarosite stain along fracture surfaces. Clay fraction composed almost completely of smectite but contains sparse illite and vermiculite or chlorite. Nonplastic, blocky fracture; sparse carbon flecks, films, and imprints of plant debris. Base Longford Member, Kiowa Formation 3.0 0.91
Total thickness Longford Member, Kiowa Formation, measured 98.1 29.91
Unconformity.
Wellington Formation:
2. Mudstone, reddish-brown. Thin-laminated to laminated but poor fissility; blocky fracture. Clay fraction composed mainly of illite but contains appreciable smectite and chlorite. Scattered laminae bleached yellowish-gray in top 0.5 ft. Abundant limonitic or hematitic cement in top 0.5 ft. Grades sharply into next below 3.4 1.03
1. Mudstone, light-gray to moderate greenish- gray; weathers dusky yellow. Thin-laminated but poor fissility; blocky fracture. Clay fraction composed mainly of illite but contains appreciable smectite and chlorite. Base covered. Exposed, 1.5 0.46
Total thickness Wellington Formation measured 4.9 1.49
Note: The Permian-Cretaceous contact and the base of the Longford Member, Kiowa Formation, also are exposed in a gully near cen. W2 NW sec. 16, T. 10 S., R. 1 E. where the Permian-Cretaceous contact is about 18 ft higher than in the section described above. The contact corresponds approximately to the middle of unit 5. The topmost Permian mudstone is intensely weathered and variegated. It contains abundant kaolinite, illite, and smectite as well as minor amounts of chloritic or vermiculitic mixed-layer clay, and is overlain by a carbonaceous mudstone and lignitic sequence as well as by gray mudstone showing abundant red mottles similar to material described under unit 7 above. Sparse chert and quartzite pebbles weather out of the basal carbonaceous Longford mudstone.

2. Section measured from Longford Member, Kiowa Formation, into overlying Kiowa rocks near cen. W2 sec. 32, T.9S., R. 1 E., Clay County, Kansas. Section complements type section of Longford Member in sec. 9, T. 10 S., R. 1 E., Clay County, Kansas. Measured by Paul C. Franks. Thickness
(feet) (meters
Kiowa Formation:
Covered.
4. Shale, light-gray to light olive-gray; weathers light gray to moderate olive brown. Composed mainly of smectite but contains abundant illite and kaolinite. Thin-laminated, plastic. Sparse jarosite stain; sparse layers of discoidal concretions of impure siderite. Grades sharply into next below. Top covered. Exposed, 4.0 1.21
3. Shale, very light gray. Dominantly kaolinitic but contains abundant illite and smectite. Silty, plastic; laminated to thin-laminated, poor fissility; sparse limonitic stain along lamination. Grades sharply and irregularly into next below 1.1 0.34
Total thickness upper part Kiowa Formation measured 5.1 1.55
Longford Member, Kiowa Formation:
2. Siltstone, very light gray with brown overtones; weathers yellowish gray to white. Sparse "limonite" stain; hard; ripple and even thin laminae; micro-cross-lamination in sets as much as 0.2 ft thick. Local calcite cement forms concretions as much as 3 ft in diameter; abundant limonitic cement in top 0.1 ft. Symmetric transverse ripple marks with wave lengths as great as 0.2 ft common on bedding surfaces. Grades irregularly into next below 5.2 1.58
1. Siltstone, very light brownish-gray with brownish-gray carbonaceous thin laminae; weathers light grayish orange. Laminated to thin-laminated; ripple and wavy laminae. Sparse "limonite" stain; argillaceous. Exposed, 2.0 0.61
Total thickness Longford Member, Kiowa Formation, measured 7.2 2.19
Total thickness Kiowa Formation, measured 12.3 3.74

3. Section of Longford Member, Kiowa Formation, measured along gully near cen. SE sec. 23, T. 16 S., R. 1 E., Dickinson County, Kansas. Measured by Paul C. Franks. Thickness
(feet) (meters
Kiowa Formation:
Covered.
10. Shale, light olive-gray to dusky-yellow. Highly weathered. Clay fraction composed largely of smectite and illite, but containing abundant kaolinite. Plastic; thin-laminated; scattered concretions of impure siderite less than 0.2 ft thick strung out along bedding. Exposed, 2.3 0.70
9. Shale, very light gray; abundant reddish-brown to dark yellowish-orange stain; weathers light brownish gray. Clay fraction composed mainly of illite and "degraded" illite, but contains abundant kaolinite. Plastic; thin-laminated; weathers to puffy slope littered with abundant gypsum needles. Contains abundant radial aggregates of gypsum as much as 0.2 ft in diameter; shaly lamination contorted about gypsum aggregates; aggregates associated with abundant "limonite" stain. Grades into next below 1.8 0.55
8. Shale, light-gray to yellowish-gray; weathers very light gray. Composed largely of illite and smectite, but contains abundant kaolinite. Plastic; thin-laminated; sparse silty laminae; weathers to puffy slope. Pyritic nodules associated with abundant "limonite" stain and partly altered to fine-grained soft aggregates of gypsum. Grades into next below 4.7 1.44
7. Shale, medium dark-gray; weathers medium light gray. Dominantly kaolinitic, but contains appreciable illite, smectite, and a vermiculite component. Plastic; laminated; blocky fracture; silty in basal 0.2 ft. Grades into next below 1.0 0.30
Total thickness upper part Kiowa Formation measured 9.8 2.99
Kiowa Formation, Longford Member:
6. Siltstone, pinkish-gray to dark pinkish-gray; weathers grayish orange. Thin-laminated to thin-bedded; hard; forms resistant ledge. Bedding surfaces show abundant symmetric and asymmetric transverse ripple marks with wavelengths from 0.1 to 0.3 ft and striking mainly E-W; micro-cross-stratification; sparse interference and linguoid current ripple marks; ripple marks mainly in upper 1 ft. Sparse nearly vertical burrows as much as 2 cm in diameter and 14 cm long. Micaceous; sparse black opaque grains; abundant iron-oxide cement in top 0.5 ft. Grades unevenly into next below; thickness measured 4.7 1.43
5. Siltstone and mudstone, light brownish-gray grading down to medium-gray; weathers dark pinkish gray to yellowish orange. Clay fraction composed largely of kaolinite, but contains abundant illite and smectite. Thin-bedded grading down to thin-laminated. Abundant "limonite" stain; sparse carbon as flecks and fragments 5.2 1.59
4. Claystone, medium dark-gray to dark-gray with brown overtones grading down to medium-gray to medium light-gray containing patches of dark-gray. Composed largely of kaolinite, but contains abundant smectitic and chloritic to vermiculitic mixed-layer clay. Plastic, nonfissile; weathers to puffy medium-gray slope. Upper foot very nearly lignitic, largely kaolinitic. Sparse pyrite or marcasite nodules; abundant hematite stain near top. Grades into next below 9.4 2.86
3. Claystone and mudstone, light-gray to medium light-gray and brownish-gray; dark-reddish-brown to dusky-red mottles; mottling most prominent near base. Composed largely of smectite and chlorite or vermiculite and interstratified smectite-chlorite mixed-layer clay, but contains appreciable kaolinite; basal parts composed almost exclusively of mixed-layer clay containing kaolinite and smectite. Plastic; no obvious lamination; weathers to puffy light-gray slope with reddish-brown stain. Near base locally contains contorted pods and fragments reworked from variegated claystone at top of Permian. Base Longford Member, Kiowa Formation 5.4 1.65
Total thickness Longford Member, Kiowa Formation, measured 24.7 7.53
Total thickness Kiowa Formation measured 34.5 10.52
Unconformity.
Wellington Formation:
2. Claystone, variegated, mainly grayish-red but streaked, stained, and mottled moderate yellowish-brown, greenish-yellow, dusky-red, white, grayish-purple, and pale yellowish- gray. Top 0.2 ft (6 cm) generally stained dusky red by iron oxide. Composed almost completely of kaolinite; contains white nodules composed of kaolinite and halloysite. Weathers to puffy reddish-purple slope with abundant white blotches; silty near base; waxy conchoidal fractures in upper parts where nonsilty. Paleosol at top of Permian. Grades irregularly into next below. Thickness variable but approximates 3.0 0.91
1. Mudstone, greenish-gray to grayish-yellow; abundant dark yellowish-orange to light olive-brown stain. Composed largely of illite and smectite, but contains appreciable chlorite and kaolinite. Silty near base where laminated and intercalated with limestone next below; blocky fracture. Thickness variable but approximates 1.5 0.46
Carlton (?) Limestone Member, Wellington Formation. Platy, dolomitic limestone. Not measured.
Total thickness Wellington Formation measured 4.5 1.37

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Kansas Geological Survey, Geology
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