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Kansas Geological Survey, Open-file Rept. 94-23, page 2 of 4
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Descriptions of Stratigraphic Section

Following are the detailed bed-by-bed descriptions of the stratigraphic interval from the base of the Johnson Shale through the Burr Limestone Member of the Grenola Limestone. The focus of these field descriptions was the characterization of discontinuity surfaces, particularly flooding surfaces and subaerial exposure surfaces. For paleosol profiles, every horizon distinguishable in the field by color or pedogenic structure was described separately.

Paleosol morphology and microfabric are little altered by later diagenesis and are therefore the most reliable environmental indicators. In the field description of paleosols, particular attention was given to the following morphological features:

Well-developed clay cutans (argillic horizons) are convincing indicators of clay translocation and downward meteoric water movement in the soil profile. Carbonate precipitation within the profile, by contrast, indicates that leaching was insufficient to remove soluble salts due to low rainfall or high evapotranspiration rates. Vertic structures such as pseudoanticlines result from the shrinking and swelling of clays under highly seasonal wet/dry environments.

Units described in section text Tuttle Creek Reservoir Spillway
Stratigraphic Section TS1
Unit 7 Wackestone
Abundant, large, skeletal debris-filled burrows
Pyramidellid gastropods and Permorphus bivalves
Large gypsum crystal molds
Oscillation ripples at top
Unit 6 Shale (Grayish black N2 to dark gray N3)
Scattered mytiloid bivalves
Unit 5 Wackestone (Yellowish gray 5Y8/1 to light gray N7)
Scattered fine phosphatic debris (bone?) in lower bed
Upper bed intensely burrowed and more argillaceous
Some large (4 cm diam) mud-filled burrows
Algal-coated grains abundant with pyramidellid gastropods and small crinoid ossicles
Fossil concentration at top: Productid brachiopods, myalinid bivalves
Unit 4 Calcareous mudstone (Medium light gray N6)
Lower ~8 cm massive and more resistant--graded skeletal lag at base and some horizontal lamination evident
Coarse subangwar blocky structure above--probably not pedogenic
Abundant skeletal-filled burrows extend down from upper surface filled with crinoid ossicles, pyramidellid gastropods, ostracods, algal-coated grains
Unit 3 Phosphatic /skeletal lag
Angular shell fragments (2-3 mm), bone debris
Phosphatic granules and small pebbles--inverse graded and concentrated near the top
Large micrite lenses up to 23 cm long and 4 cm thick--some bored
Unit 2 Shale (Medium gray N5)
Fissile shale with fine chondrities-like burrows (light greenish gray)
Desiccation cracks extend up to 50cm or more down from top
Polygons ~40 cm across with cracks up to 4 cm wide at top
Micritic fill (very light gray N8) with clay "mottles" (medium light gray N6)--slickensides on margins of cracks fillings
Columnar ped horizon locally preserved immediately overlying desiccation cracks (up to 18 cm thick with columns ~5 cm diam)
Very light gray (N8) with medium light gray (N5) clay between peds and in dendritic mottles
Unit 1 Wackestone (Medium light gray N6)
Lenticular layer (up to 4 cm thick) of granule and small pebble-size clasts (including reworked caliche nodules) and bone fragments
Highly burrowed--clay-filled burrows and large (2-3 cm diam) granule-filled burrows
Fossils include bone, crinoid ossicles, bryozoan fragments, productid brachiopods, pyramidellid gastropods, algal-coated and abraded/corroded bivalves
Thin lag of ostracodes and Permorphus bivalves at top

Units described in section text Tuttle Creek Reservoir Spillway
Stratigraphic Section TS2
Unit 19 Variegated mudstone (Greenish gray 5G6/1)
Fine angular blocky peds with clay cutans
Abundant large carbonate nodules (some >10 cm diam.)--stacked, platy nodules
Granule-size carbonate grains abundant
Abundant sheet cracks give bedded appearance
Carbonate lenses locally present at top
Unit 18 Variegated mudstone (Greenish gray 5G6/1)
Medium subangular blocky ped structure with fine clay-coated root traces abundant
Abundant inclined fracture surfaces forming wedge-shaped peds
Pseudoanticlines--wavy upper surface (gilgai relief)
Large carbonate nodules (up to 4 cm diam.) isolated and stacked--closely spaced at top giving columnar appearance
Unit 17 Variegated mudstone (Greenish gray 5G6/1)
Fine angular blocky ped structure with clay cutans
Abundant stacked nodules giving columnar-like appearance--nodules pinkish gray (5YR8/1)
Unit pinches and swells over underlying topography
Unit 16 Calcareous mudstone
Undulatory horizon 30 to 65 cm thick--gilgai relief
Extremely well-developed pseudoanticlines with pedogenic slickensides
Lower ~25 cm greenish gray (SCY6/1)
Medium to coarse subangular blocky peds
Abundant greenish gray clay-filled root traces
Upper part yellowish gray (5Y8/1)
Greenish gray root traces and clay-coated slickensides
Top locally capped by breccia with silty mudstone and carbonate clasts. Some breccia layers also present along gilgai surfaces within unit
Unit 15 Variegated mud stone (Greenish gray 5G6/1)
Fine subangular blocky peds
Greenish gray clay-filled root traces
Carbonate nodules and rhizocretions up to 5 cm diam.
Widely scattered high-angle carbonate-filled cracks extend from top
Unit 14 Variegated mudstone
Vertically elongated mottles--Medium gray (N5) to greenish gray (5G5/1) and grayinsh red (10R4/2)
Fine to very fine subangular blocky peds with clay cutans
Carbonate nodules and large rhizocretions (yellowish gray to pinkish gray)--rhizocretions abundant but with patchy distribution
Grayish red root traces in mudstone, greenish gray root traces in carbonate nodules
Diffuse but abrupt upper contact
Unit 13 Variegated mudstone Vertically elongated mottles--Medium gray (N5) to greenish gray (5G5/1) and grayish red (10R4/2)
Increase in red coloration upward--upper part appears less clay-rich and siltier
Fine subangular blocky peds with well-developed clay cutans
Abundant scattered and stacked carbonate nodules (< 1.5 cm diam.)
Rhizocretions and large stacked nodules (2-5 cm diam.) patchy
Greenish gray (5GY6/1) clay root traces assoc. with nodules
Inclined pedogenic slickensided surfaces present
Units described in section text Unit 12 Micrite/Calcrete (Very pale orange 10YR8/2
Highly irregular--thickness varies from 10 to 45cm
Greenish gray clay-filled root traces and fracture coatings increase upward--increasingly brecciated upward
Sheet cracks and inclined surfaces with pedogenic slickensides
Fenestral fabric and spar-replaced skeletal debris in lower part
Unit 11 Shaley mudstone (Yellowish gray 5Y8/1)
Highly rooted--greenish gray (5GY6/1) root traces
Unit 10 Variegated mudstone
Medium gray (N5) at base to greenish gray (5GY6/1)
Medium to coarse subangular blocky peds
Clay-coated dendritic traces in upper green part with a few scattered carbonate nodules
Ostracods present in green part
Evaporite crystal molds in lower gray interval
Sharp upper contact
Unit 9 Siltstone
Mottled--reddish brown (10R4/4) and yellowish gray (5Y8/1)
Abundant gray fine dendritic mottles and large tubular mottles up to 2 cm diam.--clay-filled root traces
Sheet cracks
Scattered carbonate nodules (~2 cm diam.) increase in abundance upward--locally form nearly continuous layer at top
Sharp irregular upper surface
Unit 8 Variegated mudstone
Upward change from light olive gray (5Y6/1) to light brownish gray (5YR6/1) to pale reddish brown (10R5/4)
Abundant gray dendritic mottles in upper reddish brown horizon
Coarse subangular blocky peds
Some scattered carbonate granules
Unit 7 Variegated mudstone (Olive gray 5Y4/1)
Coarse subangular blocky peds--fine dendritic mottling
Abundant carbonate granules increase toward base
Scattered small shell fragments
Very gradational upper boundary
Unit 6 Wackestone (Pale yellowish brown 10YR6/2)
Lower ~6 cm carbonate beds (1-1.5 cm thick) and shale interbeds
Upper 17 cm wackestone with fenestral fabric and spar-filled voids
Fine skeletal debris: crinoid ossicles, ostracods, small gastropods, unident. brachiopod and bivalve shell fragments
Unit 5 Silty calcareous mudstone
Lower ~23 cm pale reddish brown (10R5/4)
Fine horizontal lamination
Finely mottled upper contact with fine pale olive dendritic mottles
Upper part pale olive (10Y6/2)
Poorly fissile mudstone with platy peds
Thin (<5 mm) botryoidal carbonate layers
Desiccation cracks (7-15 cm diam.) on upper surface extend down ~10 cm and may be incipient columnar peds
Unit 4 Silty calcareous mudstone
Lower ~9 cm unlaminated (Medium dark gray N4)
Medium subangular blocky structure (no cutans apparent)
Middle ~6 cm laminated (Dark greenish gray 5GY4/1 and N4)
Upper part finely laminated (Pale olive 10Y7/2)
Upper few cms gradational in color with overlyijng unit
Unit 3 Silty calcareous mudstone (light greenish gray 5GY7/1)
Fine horizontal lamination
Abundant desiccation cracks throughout--polygons 18-25 cm diam. with upturned edges
Unit 2 Variegated mudstone (Grayish olive 10Y5/2)
Relict bedding--brecciated
Coarse angular blocky peds--pedogenic shckensides on ped surfaces and clay cutans
Unit 1 Grainstone
Algal-coated ostracods and pyramidellid gastropods
Stromatolites on upper surface extend ~15 cm into overlying unit

Units described in section text Tuttle Creek Reservoir Spillway
Stratigraphic Section TS3
Unit 21 Grainstone
Algal-coated ostracods and pyramidellid gastropods
Stromatolites on upper surface extend ~15 cm into overlying unit--digitate tops with cavities filled with coated grains
Unit 20 Wackestone/Packstone
Fusulinids especially abundant near bottom
Algal-coated grains, ostracods, crinoid ossicles, echinoid spines, and productid brachiopod (?) debris increase in abundance upward
Unit 19 Wackestone (Yellowish gray 5Y8/1)
Fusulinids in upper part
Productid brachiopods, fenestrate and ramose bryozoans
Large skeletal-debris-filled burrows
Unit 18 Shale (Olive black 5Y2/1)
Fossil poor except for abundant orbiculid brachiopods
Calcified shark cartilage found in this unit
Upper ~15 cm has abundant Chondrities burrows
Thallasinoides burrows filled with skeletal debris
Increasing skeletal debris upward--fish teeth and bone, small crinoid ossicles, productid brachiopods (spines)
Unit 17 Wackestone/Packstone (Medium light gray N6)
Bottom ~2.5 cm is micrite with brecciated fabric
Sharp, irregular upper surface
Intraclastic limestone
Angular to rounded micrite clasts throughout bed--become smaller and more rounded upward
Increase in skeletal component upward--fusulinids, coated grains, small gastropods, and unident. brachiopod and bivalve debris
Pyrite disseminated and as pyritized burrow fills esp near base
Black mud-filled burrows at top of bed--Diplocraterion type
Unit 16 Shale/Mudstone (Medium gray N5 to Light greenish gray 5GY7/1)
Bioturbated with destruction of lamination
Upper ~15 cm finely brecciated and massive
Unit 15 Silty shale (Light greenish gray 5GY7/1)
Highly bioturbated with fine Chondrites-like burrows
Graded silt laminae
Gradational upper contact
Unit 14 Shale (Medium dark gray N4)
Graded silt layer at base
Abundant Chondrites-like burrows (Light greenish gray 5GY7/1)
Unit 13 Shale (Dark gray N3 with Light olive gray 5Y6/1 silt laminae)
Graded laminae and starved ripples of silt--some bundling of laminae
Decrease in silt content upward--laterally continuous graded layers decrease upward in thickness and frequency
Very little silt in upper ~17 cm
Mostly thin discontinuous graded laminae
Fine Chondrites-like burrows locally present at top
Unit 12 Micrite (Light olive gray 5Y6/1)
Lower ~6 cm shaley and horizontally laminated
Horizontally bedded unit
Some scattered skeletal debris on some bedding planes (crinoid ossicles, unidentified shell debris)
Upper ~6 cm gradational with overlying shale
Units described in section text Unit 11 Mudstone breccia (Very pale orange 10YR8/2)
Clasts of calcareous mudstone in mudstone matrix
Unit 10 Calcareous mudstone
Lower ~20 cm very pale orange (10YR8/2)
Wedge-shaped peds and pedogenic slickensides
Undulatory carbonate layers up to 7 cm thick--A few large concertina root traces present within
Silty mudstone above (Greenish gray SCY7/2 to yellowish gray)
Coarse subangular blocky peds and curved fracture surfaces
More laminated toward top--organic (charcoal?) layers common
5 cm thick massive silty cap at top
Unit 9 Calcareous mudstone
Undulatory interval varies from ~10 to 25 cm thick
Mudstone locally present at base (pale yellowish brown 10YR7/2) to yellowish gray SY7/2) with platy to fine subangular blocky peds, and root traces
Columnar horizon (yellowish gray 5Y8/1)
Well-developed columnar ped structure with 4-5 cm diam. columns
Abundant root molds and concertina root traces
Unit 8 Variegated mudstone
Undulatory carbonate horizons at top and bottom of interval
Yellowish gray (5Y8/2)--abundant concertina root traces
Incipient columnar structure locally developed
Mudstone (Pale greenish yellow 10Y7/2)
Fine subangular blocky peds with clay cutans
Manganese coatings on high angle fractures and ped surfaces
Unit 7 Variegated mudstone
Yellowish gray (5Y7/2) changing upward to pale olive (10Y6/2)
Well-developed clay cutans and clay-filled root traces
Manganese coatings on joint surfaces and along high-angle fractures, also dusky yellow (SY6/4) staining
Unit 6 Silty micrite (Yellowish gray 5Y8/1)
Manganese coatings along joint planes and curved fractures--also manganese-coated slickensided surfaces
Apparant mud-fiued solution cavities--boxwork developed within some large cavities
Upper part is conclomerate with rounded micrite clasts up to 13 cm in diam. (pale yellowish brown)
Unit 5 Silty micrite (Light brownish gray 5YR7/1 to yellowish gray 5Y8/1)
Horizontally bedded (2-5 cm) and laminated
Manganese coatings on bedding planes and vertical fractures
Unit 4 Calcareous mudstone
Lower ~18 cm soft silty shale (yellowish gray SY7/2)
Shale truncated by irregular, rubbly carbonate layer with abundant celestite throughout (Yellowish gray 5Y8/1)--Overlain by collapse breccia with silty carbonate clasts in chalky matrix
Very sharp planar upper contact
Unit 3 Calcareous silty mudstone (Yellowish gray 5Y7/2)
Lower part with coarse angular blocky structure
Hard cap of varying thickness--wavy upper surface
Closely-spaced lamina of fibrous celestite (?)--botryoidal surfaces and inclined surfaces with fibrous coatings
Some overlapping crusts (tepee-like strudures)
Unit 2 Very calcareous silty mudstone
Lower ~10 cm greenish gray (SGY6/1) mudstone
Coarse subangular clocky structure and light dendritic mottles
Upper part yellowish gray (5Y7/2)
Closely-spaced thin botryoidal layers of celestite (?) and abundant small nodular masses
Unit 1 Vuggy limestone
Pale yellowish brown (10YR7/2) to dark yellowish orange (10YR6/6)
Celestite-filled vugs abundant--merge into nearly continuous mass in middle part of interval
Horizontal to wavy bedding at top and bottom--oscillation ripples locally well displayed in upper ~10 cm

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Kansas Geological Survey, Geology
Placed on web Feb. 6, 2007.
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