Lithological Description of Strata in Core from Kennecott Crooked River Kimberlite SK-168-93-1 Drill Hole, East-central

C.F. Gilboy

Gilboy, C.F. ( 1997): Lithological description of Cretaceous strata in core from Kennecott Crooked River Kimherlite SK-l 6B-93- l drill hole, cast-central Saskatchewan; in Summary of Investigations 1997, Saskatchewan Geological Survey, Sask. Energy Mines, Misc. Rep. 97-4.

1. Introduction O. .'i to 1.5 rnrn in diameter. are present in some places (they arc possible Chmulrite.1· burrow infills) as arc very rare sand-filled Chondrites and/or sand-lined Terebel/i11a Several exploration companies, actively searching for burrows up to 3 mm wide. Small ovoid to irregularly diamonds in Saskatchewan, have donated cores of shaped pyrite concentrations, generally surrounded by strata to the provincial government for brown staining, may he replacements of fowl 1na11er. storage in the Subsurface Geological Laboratory in White, tubular to conical siliceous microfossils up to Regina. These cores arc most useful in improving the about 6 mm long and I mm in diameter, most with a shallow median groove, arc moderately common. Black understanding of the geology of Saskatchewan's specks in the mudstone are probably carboni/.ed plant sedimentary section as, firstly, most are from drill holes remains. Rare honey-coloured fish scales and spines are located in areas that have been sparsely drilled by the also prescnl. Between 43.6 and81.7 mare about 12 pale hydrocarbon industry and, secondly, they arc to moderate brown sideritic layers 4 to IO cm thick. At 81.7 mis an internal cast of a small ( I cm wide) partly essentially continuous. open hinged pelecypod with very line concentric striae; no calcareous shell material is pr,:sc rvcd At 114 m is the The Kennecott core described here is of particular highest hentonite layer, whitish-gr,:y, J cm thick, with interest in that it provides a high-quality, almost biotitc crystals up to 0.2 mm across concentrated at the base. Six more hentonite beds, ranging in thickness from complete lithological profile through Colorado Group I mm to 4 crn, are present above the base of the Millwood rocks at a location (01-04-45-1 OW2) some 110 km Member; several arc burrowed, especially close to their southwest from where they crop out at the north end of top. the Pasquia Hills and 50 km south of the Carrot River outcrops (Figure I). The latter are well known for mid­ late Cenomanian and Turonian vertebrate fossil assemblages which include an almost complete 7 m long skeleton of Teleorhinus sp., a marine crocodile (Cumbaa and Tokaryk, 1993), and the oldest diverse bird fauna known from (Tokaryk et al., 1997). In summer l 997, several outcrops of the Belle Fourche, Second White Specks, and Carlile Formation (following the stratigraphic nomenclature in part proposed by Bloch et al., 1993; sec also McNeil and Caldwell, 1981,andGilboy, 1996)onthcCarrotand Etomami rivers and at the north end of the Pasquia Hills were studied in detail by Dale Leckie (Geological Survey of ), Claudia Schroder-Adams (Carleton University), Stephen Cumbaa (Canadian Museum of Nature), John Bloch (geological consultant), and others with a view to establishing detailed micropaleontological control of the exposed strata and further expanding knowledge of their fish and bird faunas. Greg Ludvigson, Brian Witzke, and Tim White (Iowa State Geological Survey) are also researching Mannvillc and Colorado Group rocks in western and eastern Saskatchewan lo gain deeper insight into the evolution of the central reaches of the Cretaceous Interior Seaway. K:lorr.c trc s 50 0 50 100 1--~ __ ] 2. Core Description Figure 1 -Location of Kennecott Crooked River Kimber/ite Pierre Shale Formation: Millwood Member SK-16B-93-l and SK-69-93-1 drill holes in east central Saskatchewan and of Colorado Group outcrops sampled 39.9 to 116.3 m Uniform, pale grey mudstones, slightly silty in during 1997 for micropaleontological and vertebratefaunal places. Subhorizontal pyritized black tubular markings, studie.~.

188 Summary of Investigations 1997 Pierre Shale Formation: Pembina Member cement locally well developed. This very fine-grained muddy sandstone, about 30 cm thick. grades down into biotite-rich muddy siltstoncs which are weakly calcareous l 16.3 to 129.5 rn Moderate to dark grey shales containing in places near their top but arc mostly noncalcareous. abundant fi sh remains, pkntiful biotite flakes up to From about 149 to 150.7 m, intense bioturbation 0.5 mm across. subhedral, dear gypsum crystals several (Chondri1es and Terebellina) is evident, and is moderate millimetres across, and white spotting from non­ to very slight to 15 l. 9 m. Fish remains arc plentiful. calcareous foramimfera tests. Actween 116.3 and l 24.8 rn Aiotite makes up several percent of the rock. This interval are 2'\ well-developed bcntonite seams and four possible of the member is also notable for the 22 bentonitc scams se:uns in poorly recovered core; they range in thickness it contains, eight of which are between 5 and 10 cm thick; from I mm to 15 cm. Bentonites arc absent until 20 cm only the uppermost one at 148. l m (about l mm thick) is above the base of the member where a l mm thick !aver is so poorly preserved that its existence is questionable: the followed by a possible I cm thick seam resting on top of lowest (5 nun thick) is at 152.4 m. A biotite-rich the underlying member. The shales are non-bioturbatcd bentoni te seam at l 51 .9 rn overlies a 5 mm thick bone from 116.5 to l 20.8 m. below which burrowing activity is bed in very fine-grained muddy sandstones. At l 52.2 m very slight, made up essentially of subhoriwntal simple arc poorly sorted, fine-grained sandstones rich in fish branching, commonly pyritized Chondrites. Below bo_nes and with rounded bentonitic clasts of possible fecal 125.8 rn to the base of the memher at l 29.5 m, fish ongm. remains and foraminitcra appear to become rarer whereas recognizable carbonized plant debris is slightly more l 52.6 to 153.6 m :-o cm thick transition wne: very fine-grained conunon. sandstones interbedded with white speckled calcareous siltstones and shales at the top overlie calcareous white speckled shales. A single 5 mm thick bentonitc layer lies Pierre Shale Formation: Gammon Ferruginous at 153.5 m. Member l 29.5 to l 37 .0 m Moderate to dark grey shales. typically with Second White Specks Formation, Keld Member several percent biotite flakes; intervals almost devoid of fish remains and foraminifcra alternate with intervals l 53.6 to 157.6 m Top of the Keld Member is defined by a containing low to moderate abundances. Upper coniact of marked increase in abundance of inoccramid shell member is marked hy 6.5 cm thick siderite layer with fragments, many of which are large and subparallel to small pebbles nr concretions of siderite in underlying bedding, in dark grey slightly silty shales. Between l 54 l mashed up cure. Between the base of this layer and and 156.5 m arc seven pale grey, thin-bedded, impure l JI .J rn arc eight bemonite beds ranging in thickness limestone layers which range in thickness from about 4 to from 0.2 mm 10 4 cm; no further bentonites are present in 1R cm. The limestones arc rich in fish remains and this member. Very slightly bioturbated (subhorizontal O. l mm diameter calcisphcres; they also contain pyritizcd Chondrites and, possibly, Planolite.1 burrows) inoceramid shell fragments; intcrbeddcd with dark grey from 129.5 to about I 32 m, below which shales are biotite-rich calcareous white speckled shales which also nonbioturbatcd. contain abundant fish remains but only rare inocerarnid fragments; in places, 5 to 10 mm thick shale beds show grading from speckle-free bases to speckle-rich tops. Niobrara Formation (First White Speckled Shales) Between 154 5 and 156.7 mare three bentonite scams ranging in thickness from 2 to 14 cm. Below the lowest of l 37.0 to 144.6 m Moderate to dark grey, nonbio1urbated these scams arc two inoceramid-rich speckled shale beds, calcareous shales containing sparse 10 moderate 62 and l'.l cm 1hick, separated by a l7 cm thick abundance of biolite !lakes, fish remains. and inoccramid-poor speckled shale hed. The interval is foraminifrra; calcareous white specks first observed at essentially nonbioturbated. 137 .3 m. Only two bcntonitc scams present in this formation, at I J7.5 m (0.5 cm thick) and l 38 m ( 1 cm l 57 .6 to l 6J. l m Dark grey calcareous speckled shales with rare thick. bluish, biotite-ric h). lnoceramid shell fragments fish remains and inoceramid fragments: pyrite present. present, but rare, with occurrences of haculitid and Two bentonite seams are present, the upper at l 59.6 mis ostrcid shells even rarer. 15 mm thick, the lower at l 60.6 mis J mm thick; both arc bluish grey. The interval is essentially nonbioturbated. Carlile Formation (Morden Shale) Belle Fourche Formation 144.6 to 146.0 m At 144.6 rn is an abrupt transition from cakareou s to noncalcarcous dark grey. biot i tc~ rich shales; 16~. l to 168.8 m Contact between calcareous speckled and fish remains abundant: probable foraminifcra tests mostly noncalcareous shales is sharp and apparently rare hut locally common. Bentonite layers are absent. conformable. Shales in this interval are black and arc interbcdded with one grain thick siltstones which are sparse (make up less than l pcrccnl of the interval), are Second White Specks Formation, Assiniboine relatively (compared with the shales) rich in fish remains, Member especially scales, contain carbonized plant remains, and are micaceous, with both white mica and biotite 146.0 10 148.0 rn Abrupt transition back into moderate to dark represented. Rare inoccramid fragments are present: in grey calcareous speckled shales in which biotile flakes places siltstones display concentrations of inoceramid and fish remains arc generally more abundant than in 1he prisms with subparallel alignment. suggesting current speckled shales of the Niobrara Formation. At 147.8 m, is activity during deposition. A few one layer thick a 20 cm thick bed of dark grey noncalcareous shales. coccolithic blooms are developed, some a-sociated with biotile-rich, and containing moderate abundance of fish very abundant fish remains. Be1ween 166.1 and 166. 9 rn rcmams. are five bentonite seams. The upper four arc a few millimetres thick. The lowest, 50 cm thick and blue-grey, is the thickest bcntonitc in the core. It is overlain by a 148.0 to 152.6 m Sharp. hut apparently conformable, contact with highly calcareous rock full of fish debris (20 to 25 5 cm thick pale grey bedded limestone rich in fish percent) and containing subangular to rounded quartz remains especially at its ba\e. It is underlain by a poorly consolidated 13 cm thick, impure white chalky limestone grains up 10 125 µ across as wdl as sparse soft-centred. calcitc-rirnrncd clasts (possibly of fecal origin) up to in which very fine quartz grains are present along with about 1 cm maximum diameter: intcrgranular pyrite abundant fish remains; calcispheres were not recognized. Transitional contact into dark to moderate grey

Saskalchewan Geological Survey 189 noncalcareous shales with one grain 1hick siltstone fish remains and modcra1cly abundant disseminated laminae containing angular to subangular quartz particles pyrite. and common white mica. Fish remains are less abundant than above the thick bcntonitc. Bioturhation (Cho11drites) is very weakly developed in a few places but the interval Viking Formation is essentially nonbioturbated. At 168.7 mis a 3.5 cm thick blue-grey bentonite. 196.8 to 197.4 m Weakly consolidated, poorly sorted, very coarse-grained sandstones; contain subroundcd to rounded clear quart7, grains up to 2 mm across supported Fish Scales Formation in a matrix of very fine- to fine-grained quartz; interbcddcd with shaly beds up to about 2 cm rhick, also 168.8 to 172.5 m Gradational upper boundary; this formation is containing large rounded quartz grains. At l 96.9 m. a characterized by moderate grey shales with substantially I cm thick very poorly sorted conglomerate bed is increased abundance and thickness of interbeddcd present, with about 5 percent subangular to well-rounded siltstones and very line-grained, well-soned sandstones quartz grains up to 3 mm across, mostly clear, but some (layers up to 8 mm thick) which have richer content of grey to dark grey chert, supported in a matrix of very fine fish remains; white mica is common. Below about quartz and clay minerals. Abundant white mica, 171.4 m, 30 cm of core is missing, followed by 40 cm of moderately abundant interstitial pyrite, rare fish remains poorly recovered core made up of very fine-grained and Terebellirw burrowing are present. sandstones. locally calcite cemented and fish debris rich, and shales in approximately 50:50 ratio. At l 72.3 m. split 197 .4 to 199.4 m About 50 percent core recovery in this core reveals several 5 mm thick beds with thin siltstone interval, made up of poorly cemented, essentially base (where fish debris is concentrated) grading upwards nonbioturbated. well-sorted, very fine-grained laminated into moderate grey shale. The formation is sandstones containing some interstitial pyrite. nonbioturbated. !Is base is taken at the bottom of a I cm thick bluish bentonite 199.4 to 202.4 m 75 cm core recovered, mostly formed of poorly cemented, well-soned, very line- to fine-grained ( 125 to 177 µ) laminated sandstones; grains (some dark) are Westgate Formation subangular to rounded, white mica is present along with rare bio1i1e; carbonized plant remains are rare In places, 172.5 to 187.8 m Very slightly bioturbated moderate grey shales I to 3 mm thick laminae show an increase in clay content containing disseminated pyrite and spotted by probable from base upwards. foraminifera tests; bioturbation represented by subhorizontal pyritizcd Clwndrites and by rare, but 202.4 to 205.4 m About 40 cm core recovered. cakitc- robust, Terebellina and very rare Teic:hich11us. At cemented, well-sorted, fine-grained sandstones, 174.4 m. a few fish remains-rich, very fine-grained moderately bioturbated (P/anoliles, Skolithos) al the top. sandstone laminae are present, followed at J 74.6 m by the where up to lO percent interstitial pyrite is present. Grains first of six pale grey bentonite seams, all concentrated in a are subangular to angular, with about 5 percent being 15 cm thick intersection: the top five range in thickness black (possibly bone material and/or an iron oxide such from 2 to 5 mm, the lowest is 4 cm thick. Below the as hematite). bentonites, 5 to 15 mm thick graded beds have siltstones at their ha~es, dark grey shales at their tops: fish remains 205.4 to c 207.0 m About 50 percent core recovery comprising are moderately abundant. At 175.3 m, the sand and silt friable, slightly bioturbatcd, fine-grained sandstones component is lost. leaving non- to slightly bioturhated (grains rounded to subangular, about 5 percent being of (Chondrires, Terebelli11a) moderate grey shales with very an unidentified black material), laminated in places; up to few small fish remains and rare foraminifera tests as the about 5 percent interstitial pyrite locally present. dominant rock type. About 45 cm rubbly poorly recovered core between 181.4 and 181 .9 m: bcntonitc and c. 207.0 lo 214.5 m Very fine-grained muddy sandstones and very fine-grained sandstone possibly present. Below arc laminated silty shales, 60:40 ratio, mostly inlenscly very slightly bioturbated (pyritized Cho11dr11es and rare bioturbated (sand-filled Chmulrite.1, Terebel/i1111 and Terebellina) moderate grey shales with foraminifera tests, Teid1ic:h11ul); common white mica, rare b1otitc. pyrite disseminated pyrite, small white mica and biotite flakes, and gypsum are present, mainly in sandy layers; sanu rare carbonized plant debris, very rare fish scales, and grains rounded to subangular. Carbonate cement locally other remains. Contact with underlying interval is developed. Some sandstone beds arc well sorted. gradational. Carbonized plant remains are increasingly rare upwards through the interval. At the base of the formation is a 187.8 to 189.9 m Slightly bioturbated (pyritizcd C/wndrires, 5 cm thick, poorly sorted conglomerate containing dark Terebellina. and probable Helminthopsis) muddy greyish black rounded pebbles, mostly phosphatic, up to siltstone to sihy rnudstonc; fish remains moderatdy 4 mm across (apart from one with dimpled surface which abundant in top 10 cm: pyrite, white mica common, exceeds 3.5 cm in diameter); some clear, well-rounded 10 biotite rare. Contact with underlying interval is angular quarv grains up ro I mm in diameter arc also gradational. present along with a few grains of possible chert. Very fine sand particles and clay minerals; fish scales and 189.9 to 196.6 m Very slightly bioturbatcd (pyritizcd bones are abundant and a little carbonized plant debris. Chondrires, Terebelli,w) moderate grey shales and mudstoncs containing rare foraminifera tests, fish scales, and fish bones; white mica present, along wi1h rare Joli Fou Formation biotite. At l 95.1 mis the top of a 30 cm thick zone of very slightly bioturbatcd moderate grey shales 214.5 to 226.2 m Moderate grey shales, very slightly to slightly interbedded with white mica- and fish remains-bearing bioturbated in places (c. 216.6 to 217.5 m. 222.0 to siltstone laminae up to about 0.2 mm thick. These arc in 224.5 m, sand-filled Ch,mdrires, rare Terebel/i1111). gradational contact with underlying siltstone-free shales essentially nonbio1urbaled in 01hcrs (214.5 to 216.6 m, similar to those higher in the interval but appar.:ntly 217.5 to 222.0 m. 224.5 to 226.2 m); up to abou1 5 almost non-foraminifcrous and a little more bioturbatcd. percent, but generally less than I pcrccnl. silrstoncs and very fine-grained sandstones prcsen1, generally at ba,c of 196.6 to 196.8 m Very fine-grained sandstones with subrounded 5 to lO mm thick graded beds. Disseminated pyrite in to subangular quartz grains are present in predominant shales, interstitial pyrite concentrations locally developed shales and mudstones, mainly as burrow infills in sandy layers; which also contain white mica and (Chondrites, Terebellina, possible Planoliles); scattered biotite. Fish scales and bones are very rare. Shell fragments from pelecypods and other molluscs occur in

190 Summa')' of Investigations /997 the upper half of the interval, where two small (about carbonized plant remains and coaly fragments about 5 mm long) complete delicate pelecypod valves were 3 mm across; white mica flakes up to about I mm rernrded (216.3 and 217. 9 m). diameter. A probable rootlet zone is present.

226 2 10 227 .8 m Very fine- 10 fine-grained, laminated, c. 245.0 lo 251.0 m Poor core recovery at top (about 60 cm moderate grey to appk green, glauconitic sandstones, between 245.0 and 248.1 rn, made up ofsiltstones with I carbonate cemented in lop 20 cm and in basal 60 cm: to 5 mm thick layers enriched in carbonized plant carbonate also concentrated in subhorizontal veins up to fragments, one of which is more than 4 cm long and is I cm thick in which it develops a fibrous habit. About I partially pyritized).Three fining upward units 2.2 to 0.6 m percent biotile and white mica flakes up to 0.) mm thick arc present, grading from very fine-grained muddy across. Low-angle and hummocky cross-bedding and sandstones at the base to muddy siltstones at the top. subhorizontal parallel laminalions. In places moderately Sandstones contain rounded to subrounded grains up to bio1urbated (Astermoma, Chondrites, Terehellina), but 177 µ across, but mostly 62 to 125 µ; sand:mud ratio is moslly nonbioturbatcd. Minor faulting of laminae with about 65:35. Siltstoncs feature sandy lenses and a few 2 offsets of a few millimetres Pyrite concentrations to 3 mm diameter sand-filled burrows (Chondrire.1). crosscut bedding, e.g. I 10 5 mm thick along fault zones. White mica flakes are common, mostly about O I mm In fault contact (45°) with underlying mudstoncs at hase. across but up to 2 mm, as are carbonized and locally pyritized plant remains which form up to about 3 percent 227.8 to 229.9 m Moderate grey muds tones and shales with, in of the rock and are up to 2 cm long with most less than places, silt-based graded beds 5 to IO mm thick; 2 mm. Primary laminae arc poorly preserved. moderately bioturbated (sandstone-infilled subhorizonlal Ch,mdrites burrows); biotite present in shales and sandstones, white mica in sandstones; rare fish bones and 251 15 m End of core. scales: pyrite concentrations locally developed.

229 9 to 231.5 m Three upward-coarsening beds, each about 55 cm thick, with, at top, moderate green glauconitic very 3. Summary fine-grained (66 to 88 µ) laminated sandstones showing low-angle current cross-bedding . These overlie planar The Kennecott Crooked River Kimherlite SK-168-93-1 laminated siltstones and mudstoncs (laminae lt:ss than drill hole intersected Cretaceous rocks representing, I mm thick). Sandstones are locally carbonate cemented; quartz grains arc subrounded to subangular. Rare small n from oldest to youngest, the upper Mannville Group to to 4 mm maximum width) complete disarticulated the Millwood Member of the Pierre Group over an pclccypod valves and fish remains. Pyrite concentrations almost completely recovered cored interval of present. 21 1.25 m. Although geophysical logs were not run in

231.5 to 23 3. l 111 Modcra1e grey shales, weak Iy bioturbated this hole, the core provides an unparalleled standard for (sand-filled Clwndrires, Plmwlites) ro nonbioturbated, correlating strata with geophysical logs from the few with several percent very fine-grained sandstones exploratory oil wells drilled in the region. It also containing traces of while mica, biotitc, and pyrite. provides an excellent resource for micropaleontological 233. I to 234.4 m Modera1e green, very fine-grained, muddy studies aimed at improving our understanding of: a) the glauconitic sandstones interbeddcd with shales (65:35 detailed age relationships of Colorado Group rocks of ratio). Sandstone beds, I to 10 cm thick, are not graded eastern Saskatchewan, and b) the stratigraphic and and locally show fine parallel wavy laminations sedimentological relationship between the Niobrara highlighted by calcite cement in the coarser layers; calcite cement most common in basal 15 cm of the interval. (First White Speckled Shales) and Second White above which it is patchy Sandstones arc generally well Specks formations. Such studies are likely to benefit sorted with subroundcd to subangular grains up to 125 µ substantially from material collected from another long in diameter, hut very rare, well-rounded grains up to core (40.5 to 239.0 m) from Kennecott Crooked River I mm across also present. as are pyrite nodules up 10 2.5 cm across. Shales have rare fish remains, sand-filled Kimherlite SK-69-93-1 (located at \0-\6-44-IOW2, see Clwndrires burrows, about I percent white mica, and Figure I) which has yet to be lithologically logged. traces of fresh biotite. This interval sharply overlies the shales. 234.4 to c. 238.2 m Moderate grey shales with rare laminae of very 4. References fine-grained sandstone in which fish remains arc concentrated, though also rare. Very slightly bioturbatcd Bloch, J., Schroder-Adams, C., Leckie, D.A., Mcintyre, D.J., (pyritizcd Chondrires) to nonbiolurbated. Rare large Craig, J., an

Saskatchewan Geological Survey 191 McNeil, D.H. and Caldwell . W .G.E. (1981): Cretaceous rocks and thei r Foramini fcra in the Manitoba Escarpment, Geol. Assoc. Can., Spec. Pap. 21. 439p.

Tokaryk, T.T.. Cumbaa. S.L., and Storer, J.E. ( 1997): Early Late Cretaceous birds from Saskatchewan, Canada: The oldest diverse avifauna known from North America: J. Vert. Palco .. vl 7, no!, pl72-176.

192 Summary of !nve.1·11xatio 11s I 997