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Kansas Geological Survey, Open-file Rept. 94-36
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Stratigraphic Section of Exposed Rocks below Flood Gates at Tuttle Creek Reservoir Spillway

by Spillway Expeditionary Force

Locality:Tuttle Creek Dam Spillway
Area exposed when sillway was opened July and August, 1995
Location: E/2 Sec. 18 and 19, T. 9 S., R. 8 E.
Measured by: Spillway Expeditionary Force a.k.a. Tuttle Creek Reservoir Dogs

measured section described in text Bed 7C--54 cm; Hughes Creek shale; yellowish gray (5 Y 7/2) massive, blocky limestone; gradational lower contact; fossils include large productids, fusulinids (more common near top), ramose and fenestrate bryozoans, Composita, and pockets of other skeletal debris.
Bed 7B--10 cm; Hughes Creek shale; dusky yellow (5 Y 6/4), calcareous shale with fossil fragments; gradational lower contact.
Bed 7A--27 cm; Hughes Creek shale; yellowish gray (5 Y 7/2), massive limestone; sharp lower contact; fossils include mostly fusulinids, Composita, chonetids, spiriferids, ramose bryozoans, crinoid stems, Crurithyris, and a trilobite pygidium.
Bed 6--51 cm; Hughes Creek shale; olive black (5 Y 2/1), fissile shale; sharp lower contact; lower half (26 cm) less fissile; fossils include: Crurithyris, Orbiculoidea, productids, lingulids, chonetid (?); pyrite.
Bed 5--37.5 cm; Hughes Creek shale; yellowish gray (5 Y 7/2) to pale olive (10 Y 6/2), bioclastic wackestone-packstone; sharp lower contact; lower third platy and argillaceous; fossils include Composita, planispiral gastropods, brachiopods, rugose coral, fusulinids, crinoids, spiriferids, and fenestrate and ramose bryozoans; large Thalassinoides (?) burrows (100 cm long, 15-20 cm wide) filled with shale at upper contact.
Bed 4--8 cm; Hughes Creek shale; moderate yellow brown (10 YR 5/4) mudrock with limestone filled Thalassinoides burrows; sharp lower contact with burrow network; fossils include: ramose and fenestrate bryozoans, ostracodes, pelecypods, brachiopods, and crinoid fragments.
Bed 3--4 cm; Hughes Creek shale; light olive gray (5 Y 6/1), argillaceous mudstone; sharp lower contact; unfossiliferous except for two types of trace fossils; 3 mm diameter tubes filled with mudrock and Thalassinoides from overlying layer.
Bed 2--155 cm; Hughes Creek shale; sharp lower contact; 8 sub-beds; mudrock/shale with slightly differing colors and textures:
H--83 cm; gray (N 6) fissile, laminated, well-indurated shale; gradational lower contact; gypsum or phosphate crystals; one shell fragment; spirorbids at top of bed
G--22 cm; lighter gray (N 5) fissile, indurated shale; sharp lower contact; fossils include ostracodes, fish scales, Aviculopecten, and myalinids
F--6 cm; medium gray (N 5); mudrock; gradational lower contact
E--15 cm; dark gray (N 3), crumbly, mudrock; slightly fissile; mica or gypsum crystals; gradational lower contact
D--4 cm; light gray (N 5), indurated mudrock; gradational lower contact
C--9 cm; light gray (N 5); mudrock fossils include productid fragments
B--1.5 cm; very light gray (N 8) packstone-grainstone? in mudrock matrix; fossils include myalinid fragments, fenestrate bryozoans, Aviculopinna, productids, pelecypods, and crinoid columnals; some pyritization
A--9 cm; light gray (N 5); mudrock; sharp lower contact: fossils include productid fragments.
Bed 1-->22 cm; Hughes Creek limestone; medium gray (N 5), argillaceous wackestone; abundantly fossiliferous; productids, crinoids, chonetids (geodiferous), two types of fenestrate bryozoans, gastropod, Hustedia, spiriferids, ramose bryozoans, pelecypods, Composita, and Crurithyris; trace fossils include horizontal branching burrows 1 cm diameter and vertical burrows 0.5 cm diameter, top 2 cm capped by argillaceous packstone.
measured section described in text Bed 15--60 cm; Long Creek limestone; dusky yellow (5 Y 6/4) limestone; lowest 10-15 cm with vuggy porosity; upper third with discontinuous, calcareous crusts (calcretes?) similar to vertical joint fills; pyrite nodules; no burrows or molluscs observed on upper surface; laminar near top when associated with horizontal crusts; a bedding plane surface 21 cm from top has polygonal, dessication cracks.
Bed 14--Long Creek limestone; dusky yellow (5 Y 6/4) limestone; dense, not vuggy or spongy in texture; more porous in lower 10 cm; sparse bored pelecypod shells; capped by 1 cm thick pervasively fractured crust.
Bed 13--Long Creek limestone; dusky yellow (5 Y 6/4) porous mudstone; crusts in upper half; upper surface is irregular and burrowed; pelecypod (bored?), gastropod, and cephalopod molds on upper surface; calcite-celestite nodules.
Bed 12--23 cm; Long Creek limestone; dusky yellow (5 Y 6/4) porous mudstone (spongy appearance); possible pelecypod molds; burrows on upper surface; dense vertical tubes 0.5 cm diameter; quartz-chert nodules ~1-2 cm across (evaporite replacement?); upper surface has thin calcrete crust.
Bed 11--28 cm; Long Creek limestone; olive gray (5 Y 3/2), slightly silty mudrock; miniscule gypsum crystals; Aviculopecten molds rare; rare, poorly preserved burrows (?); upper 19 cm more indurated and brittle; phosphatic fish fragments in upper part; color grades upward from dark gray (N 3) to light olive gray (5 Y 6/2) to very pale orange (10 YR 8/2) when dry.
Bed 10--19 cm; Long Creek limestone; light gray (N 7) to medium light gray (N 6) argillaceous mudstone; very sharp lower contact; overlain by thin bioclastic lag; unit laminated with prominent, discontinuous, crinkly lamination every 0.5 to 2 cm; laminations fine upward from silt to mud sized particles.
Bed 9--113 cm; Hughes Creek shale; lower part; light gray (N 7), bioclastic, argillaceous wackestone; sharp lower contact with lag of Composita, productid, other brachiopod, and pelecypod valves, encrusting, ramose, and fenestrate bryozoans, planispiral gastropods, and crinoid colunmals; upper part with fusulinids starts ~30 cm above base; gradational lower contact; dense fusulinid packstone 45 cm from base to top; upper part contains a few large brachiopod valves and large fenestrate bryozoan fragments; top 17 cm, fusulinids decrease and rock becomes a mudstone with a few brachiopod valves and crinoid fragments; upper 17 cm also contains 10-15 cm by 1-2 cm pockets of shell hash which contain chonetids, fenestrate and ramose bryozoans, and crinoid columnals; large (5 cm diameter) burrows sparse in fusulinid beds.
Bed 8--72 cm; Hughes Creek shale; grayish black (N 2), blocky mudrock; sharp lower contact; pervasive, large slickensided surfaces oriented every which way; well preserved whole fossils as well as fragments include fusulinids, crinoid plates and columnals, Composita, productids, fenestrate bryozoans, pelecypods, Lingula (?), Crurithyris, and Aviculopinna; 10-15 cm fossil interval near base which is calcareous, non-calcareous in more massive parts with needle diameter burrows; fossils in thin horizons in blocky parts; burrows pyritized.
measured section described in text Bed 24--10 cm; Johnson Shale; yellowish gray (5 Y 7/2) mudrock; appearance of plum pudding; laminated (defined by fine-coarse layers); mudcracked; tabular laminations in lower part are broken by soft-sediment deformation of underlying bed; slickensides in upper part; darker, micritic, cobble-sized, rounded, bored (after deposition ?) intraclasts; mudcracked tabular layer is probably source of intraclasts; also on upper surface are "potholes" (paleokarst??) with coarse crystalline spar lining.
Bed 23--10-43 cm; Johnson Shale; light gray (N 7), carbonate tabulae (up to 10 cm long) floating in grayish olive (10 Y 4/2) mudrock; tabulae are from subjacent and superjacent beds; ribbons of disturbed carbonate tabulae in the middle.
Bed 22--12-15 cm; Johnson Shale; light gray (N 7) breccia; pebble to boulder-sized clasts; inter-particle porosity; grain supported; celestite; sharp lower and upper contacts.
Bed 21--10 cm; Johnson Shale; light olive gray (5 Y 5/2) carbonate breccia; lower 20 cm grain supported, remainder mud supported; sharp lower contact; clasts range from granules to 2-3 cm pebbles; they are subrounded and irregular in shape; spar-fllled porosity; disseminated celestite; upper part is less well indurated and has larger tabular clasts (10-12 cm); 5-8 cm moderate yellowish brown (10 YR 5/4), wet, sticky, mudrock; very clean; sharp lower contact.
Red 20--80 cm; Johnson Shale; olive gray (5 Y 4/1) mudrock with a few dark yellowish brown (10 YR 4/2) smudges; calcareous; only 22 cm thick on west side of spillway; sharp lower contact; 39-47 cm above base is a crust; weathered face looks irregular but this just reflects spotty induration.
Note--Beds 16 through 19 are poorly exposed and the relationships are not clear. They appear to be originally discontinuous and are replaced by overlying shale beds at the same elevation on the opposite side of the spillway exposure.
Bed 19--12 cm; Long Creek limestone; moderate yellow gray (5 Y 7/4) packstone-grainstone of comminuted bioclastic debris; well sorted, medium sand sized; indistinguishable from bed 17 where bed 18 is absent; contains lenticular pockets of spar as well as irregular, subspherical geodes.
Bed 18--0-20 cm; Long Creek limestone; moderate yellowish brown (10 YR 5/4) packstone-grainstone; coarse grained sand sized; pervasively recrystallized; dispersed bivalve fragments; sharp lower contact; pinches out near maximum thickness on east side of spillway.
Bed 17--6-10 cm; Long Creek limestone; dark yellowish orange (10 YR 6/6) argillaceous packstone; sharp lower contact; faintly laminated; upper surface has asymmetric current ripples (5 cm wavelength, 1-1.5 cm height, flow from 25 degree azimuth); ripples capped by calcareous crust (up to 2 cm thick) with chickenwire pattern on surface; these features are only exposed on the west side of the spillway; an additional uppermost crust is present in patches (~2 cm thick); made up of coarse crystalline calcite spar in botryoidal pockets; celestite in spar.
Bed 16--72 cm; Long Creek limestone; dusky yellow (5 Y 6/4) mudstone; discontinuous layers of calcite nodules with celestite (these layers are discontinuous in the middle of the bed but more pervasive near the top); crusts within bed also present--some continuous, some not--occur every 5-10 cm; irregular, exposed bedding plane surface at top; bedding plane under a major sparry layer is an accumulation of pelecypods; concave up and down, molds, nuculids(?), disarticulated.
measured section described in text Bed 31--145 cm; Johnson Shale; dark gray (N 3) shale; gradational lower contact; calcareous; gypsum crystals on surfaces; 40 cm above base is a less fissile layer that continues to the top; plant fossils 5-8 cm above base.
Bed 30--62 cm; Johnson Shale; medium light gray (N 6) mudrock; sharp lower contact; laminated; massive; well jointed; contains few small chert nodules.
Bed 29--20 cm; Johnson Shale; dusky yellow (5 Y 6/4) calcareous siltstone; 0-2 cm thick semi-continuous limestone flags (more continuous near top of bed); abundant, small calcite nodules.
Bed 28--3-8 cm; Johnson Shale; olive gray (5 Y 4/1), argillaceous limestone; gradational lower contact; continuous and undulose bed.
Bed 27--80 cm; Johnson Shale; yellowish gray (5 Y 8/1) mudrock: gradational lower contact; organ pipe structure (columnar peds ~5 cm diameter); calcareous; columnar ped zones within the bed pinch in and out laterally.
Bed 26--5 cm; Johnson Shale; yellowish gray (5 Y 7/1) mudrock; irregular, sharp lower contact; abundant root traces; irregular, discontinuous layers of crumbly, angular, granular peds.
Bed 25--31-44 cm; Johnson Shale; greenish gray (5 GY 6/1) mudrock; irregular, gradational lower contact; contains angular, blocky peds; crumbly basal portion has slickensides; root traces near top; caliche nodules (?); other nodules, which do react to acid; mudrock is not calcareous.
measured section described in text Bed 38--142 cm; Roca Shale; laminated mudrock; pale olive (10 Y 6/2) at base to moderate brown (5 YR 3/4) at top; water escape structures and microfaults present; laminations are siltier and can be up to 1 cm thick (they can be discontinuous or cross-laminated).
Bed 37--7-16 cm; Howe limestone moderate brown (5 YR 4/4) packstone-grainstone; coarse grained, well sorted sand sized particles; fossils include ostracodes, gastropods, and brachiopod fragments; chickenwire texture on upper surface; protruding upward 12-13 cm from this layer are stromatolites; stromatolite heads are hemispherical and possibly current oriented; up to 1 m diameter, often grow into larger mounds; some coated with crust, areas free of crust have egg-shaped and sized holes along the top; crust has some secondary quartz crystals.
Bed 36--44-45 cm; Howe limestone; light olive gray (5 Y 5/2) packstone-grainstone; grains are well sorted and coarse sand sized; gradational lower contact; fossils include echinoid spines, brachiopod fragments, crinoid debris, fusulinids (2-3 mm long), gastropods, coiled and straight cephalopods, Aviculopinna, and other pelecypods; poorly preserved burrows.
Bed 35--8 cm; Howe limestone yellowish gray (5 Y 8/1), argillaceous, fusulinid packstone; sharp lower contact; fossils include echinoid spines (in collapsed orientation hinting that they are undisturbed), brachiopods with brachidia, fenestrate and ramose bryozoans, crinoid debris and fusulinids (5-6 mm long); Thalassinoides with faint meniscae.
Bed 34--57 cm; Howe limestone yellowish gray (5 Y 8/1) wackestone-packstone; sharp lower contact; fossils include fusulinids (starting 40 cm from base), pelecypod fragments, productids, fenestrate and ramose bryozoans, and Composita (?); burrows.
Bed 33--115 cm; Bennett Shale; olive black (5 Y 2/1), fissile shale; sharp lower contact; calcite vein fill; top 14 cm contains mud clasts, fossil fragments, and burrows (Thalassinoides and Chondrites); Orbiculoidea in fossiliferous layers; part of upper jaw, with teeth, and left palatoquadrate of Bobbodus schaefferi.
Bed 32--68 cm; Glenrock limestone; medium light gray (N 6), massive limestone; sharp lower contact; fossils include gastropods, brachiopods, crinoids, fusulinids (especially in top 23 cm), pelecypods, productids, chonetids, bryozoans(?), and Aviculopinna; black, shale filled borings/burrows on upper surface; rounded intraclasts 2-10 mm in diameter.
measured section described in text Bed 49--1-3 cm; Roca Shale; multicolored, granular mudrock; sharp lower contact; well sorted gravel of mud intraclasts; few larger pebbles and cobbles; both on hummocks and in swales of underlying bed; in small pockets in slickensides of underlying bed.
Bed 48--70 cm; Roca Shale; mudrock; light olive gray with a touch of green (5 Y 6/1) near top and dark greenish gray (5 GY 4/1) in lower part; lower part--22 cm thick--lower contact undulating and gradational; no "fizz"; rounded granule to pebble sized peds; upper part slightly calcareous; peds grade out upward; top surface has hummocky relief; broad clay slickensides (some with green clay lining from below); very gradational lower contact; irregular, subhorizontal planes cutting the hummocks; some poorly developed vertical soil joints; some clay filled cracks (but not from dessication).
Bed 47--22 cm; Roca Shale; speckled, grayish green (10 G 4/2) mudrock; gradational lower contact (color change rather than lithologic); root traces and rhizocretions; granular to pebble sized peds; upper surface undulates with 10-15 cm relief; some rhizocretions red stained; upper few cm have sparse, coarse sand-sized, subangular grains of mudrock floating in green matrix.
Bed 46--10 cm; Roca Shale; variegated, greenish gray (5 GY 4/1) to greenish brown (5 YR 3/2) mudrock; spattered appearance due to dense, calcareous rhizocretions (greenish gray, 5 GY 7/1).
Bed 45--31 cm; Roca Shale; yellowish gray (5 Y 8/1) mudrock; sharp lower contact: root trace abundance increases upward; slickensides.
Bed 44--15 cm; Roca Shale; mudrock; dusky yellowish brown (10 YR 2/2) at base grading up to grayish green (5 GY 5/2) at top; pedogenic; crumbly; iron oxide stains.
Bed 43--42 cm; Roca Shale; mottled, argillaceous limestone; sharp lower contact; color at base moderate brown (5 YR 3/4); abundant root traces.
Bed 42--25 cm; Roca Shale; mudrock; grayish green (5 G 4/2) at base to moderate brown (5 YR 3/4) at top; crumbly, granular peds; faint, variegated root traces near top.
Bed 41--19 cm; Roca Shale; irregularly layered mudstone with root truces and sharp lower contact; crumbly and pedogenic; all internal contacts are irregular and flaggy; color varies from grayish brown (5 YR 3/2) to greenish gray (5 G 5/1) to pale yellowish brown (10 YR 6/2).
Bed 40--11 cm; Roca Shale; light olive gray (5 Y 6/1) mudstone; sharp lower contact.
Bed 39--33-35 cm; Roca Shale; variegated mudrock (from 5 YR 3/4 moderate brown to grayish green 8 GY 5/2); gradational lower contact: mudcracks; crumbly; peds are 6-7 cm diameter flattened ellipsoids; remnant laminations evident.
measured section described in text Bed 57--45 cm; Burr limestone; dark gray (N3) shale; sharp lower contact; silt fraction; myalinid bed 5-10 cm from top.
Bed 56C--30 cm; Burr limestone; olive gray (5 Y 4/1) mudrock; lower contact indistinct; abundant, fragmented fossil debris includes crinoid columnals and brachiopods; upper surface has crust of fossil debris; same skeletal debris as below, but better preserved and including Aviculopinna.
Bed 56B--26 cm; Burr limestone; coarser and more fossiliferous layer of underlying bed (5 G 6/1); fossils include brachiopod spines, crinoid columnals, fenestrate bryozoans, Aviculopecten, high-spired gastropods, productids, and large Orbiculoidea; micritic intraclasts: bioturbated.
Bed 56A--5 cm; Burr limestone; greenish gray (5 G 6/1) "biosparite" with mud partings in the lowermost 5 cm; fossils include gastropods and fish remains(?) at top; trace fossils include Thalassinoides and Chondrites.
Bed 55--34 cm; Legion Shale; medium gray (N5), crumbly, calcareous mudrock; sharp lower contact; no silt; paleosol peds; top 10 cm has Thalassinoides burrow network filled with meniscate, brown, fossil packstone (up to 4 cm across); patches of ostracodes on the top surface.
Bed 54--16 cm; Legion Shale; medium dark gray (N4), argillaceous packstone; sharp lower contact: lower part of fragmented fossil debris and small (<l cm), lighter colored intraclasts: upper part has grunular, lighter colored intraclasts and larger, horizontally oriented, tabular intraclasts; topmost 23 cm a packstone shell lag with horizontal burrows at top.
Bed 53--78 cm; Legion Shale; olive gray (5 Y 3/2), crumbly mudrock; sharp lower contact; root traces throughout: lower 46 cm has large (25-30 cm deep) dessication cracks filled with lighter, slightly calcareous, gray mudrock; 2 cm diameter peds in lower 48 cm grades into upper 30 cm with columnar peds with well developed, dark argillans around a lighter core.
Bed 52--5 cm; Sallyards limestone; medium light brownish gray (N6 to 5 YR 6/1), calcareous shale crust with bivalve lag on top; sharp lower contact; fossils in shale include: algally coated bioclasts and fragments of Aviculopinna ; crust on top is calcareous cemented and has lag of well-sorted, oriented, elongate pelecypod shells but includes other fossils like algally coated shells, Aviculopinna and Aviculopecten.
Bed 51--30 cm; Sallyards limestone; very light gray (N8) to grayish yellow green (5 GY 7/2), dense, argillaceous, wackestone-packstone of comminuted debris; sharp lower contact; gray-green, tabular intraclasts throughout; other clasts include: brachiopod valves, algally coated shells, crinoid debris; pervasively bioturbated (Chondrites ?); top surface is a shell lag which includes Aviculopecten, fenestrate bryozoans, brachiopod (?) spines, crinoid debris, Aviculopinna (exhumed and in place), other ribbed and spined pelcypods, and bored algally coated shells; about 1/3 way below top is an argillaceous layer with Thalassinoides burrow network.
Bed 50--10 cm; Roca Shale; variegated dark greenish gray (5 GY 4/1) (but variable in color) mudrock; sharp lower contact; lower 45 cm; contains lenses of granular intraclasts (up to 15 cm thick and several meters long); few small slickensided surfaces; upper part same color; gradational lower contact; large (5 cm diameter) rhizocretions; hairline root traces, and hard, brown, calcareous, angular granules floating in upper 35 cm; at upper surface olive black (5 Y 2/1) sub-vertical, well-defined structures (possibly burrows); bluish-green to olive green variegation near top; top capped by dark brown mud incorporating yellow gray granules (as a lag) and includes a single crinoid columnal and shell fragment.
measured section described in text Bed 58--120 cm; Burr limestone; dark yellowish orange (10 YR 6/6) to medium gray (N5) packstone; sharp lower contact; phosphatic fish debris; asymmetrical ripple marks on top surface; 12 cm above lower contact irregular lag deposit with intraclasts; 10 cm shale break 20 cm above lower contact with burrows filled with skeletal debris; Chondrites and Thalassinoides; evaporite molds (blades and rosettes); fossils include brachiopods and high-spired gastropods.

Pedogenic features

Other features

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Kansas Geological Survey, Geology
Placed on web Feb. 26, 2007.
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