Field Trip # 1 Marine Cretaceous Reservoirs in Central and Northern Montana: Road Log for Day 1 Published in association with the Annual Meeting of the Rocky Mountain Section, American Association of Petroleum Geologists Billings, MT, June 2006 Karen W. Porter Montana Bureau of Mines and Geology, Butte, MT 59701 Jennie Ridgley U.S. Geological Survey, Denver, CO 80225 Montana Bureau of Mines and Geology Open File Report 534 2006 This report has not been reviewed for conformity with technical and editorial standards of the Montana Bureau of Mines and Geology, 1300 West Park St., Butte MT 59701, 406.496.4180, www.mbmg.mtech.edu. C A N A D A 37 4 46 Day 2 Port of M Port of Port of Port of Sweet Grass il Wild Horse SWEET GRASS HILLS S k Turner Morgan age 232 15 LIBERTY HILL 191 C r R TOOLE e i BLAINE e ve 241 Cut Bank k Fresno r PHILLIPS Reservoir Chinook 409 2 Havre Harlem Shelby 2 Mil Chester k Rocky Boy's Mari Tiber Rive as Reservoir Indian r 2 Reservation 66 Ri Fort ver Cleveland Belknap Malta PONDERA 1 Indian 2 Reservation Big Sandy Conrad 223 191 CHOUTEAU BEARS PAW MTNS LITTLE ROCKY MTNS Teton R 3 iver M 236 Choteau is s o Rive TETON Fort Benton u r ri 87 McClelland r Ferry Charles M. Russell Fort e 80 Peck iv National Wildlife Refuge R Lake r Winifred e Great Falls v i R FERGUS h t i i r HIGHWOOD d 236 u MTNS u N so 81 J 3 191 is CASCADE 200 JUDITH M MOCCASIN MTNS 87 MTNS 19 15 PETROLEUM Stanford Lewistown JUDITH 200 87 Winnett Mosby BASIN 200 LITTLE Grassrange 2 k C BIG SNOWY LITTLE SNOWY BELT MTNS MTNS MTNS F latwillow W 87 Ck BIG BELT MTNS White il low Judith Gap low N. Wil Sulphur C Springs k Stops, Day 1 191 ver 12 GOLDEN 1 Ri MEAGHER Roundup 12 Harlowton VALLEY MUSSELSHELL Area, Day 2 ll he Ryegate Mussels Stops, Day 3 WHEATLAND Planned route YELLOWSTONE Chinook Field trip lodging 191 94 PARK 87 SWEETGRASS Big Timber Y el low STILLWATER st 90 Livingston one r Billings ve Hardin 90 Columbus Ri 25 0 25 Miles Figure 1. Location map for area of central Montana showing field trip route and field stops for three-day trip. i Figure 2. Portion of Structure Contour Map of the Montana Plains showing geologic structures of central Montana (reduced from original scale), Sweet and route traveled during field trip. Grass Hills Field trip route Bears Paw Mountains Little Rocky Mtns Judith Moccasin Mtns Mtns C E N T R A L M O N T A N A U Big Snowy P L I Mtns F T Devils Basin A. Modified from: Dobbin, C.E., Erdmann, C.E., 1955, Structure contour map of the Montana Plains: United States Geological Survey Oil and Gas Map 178B, 1:1,000,000. ii SOUTHERN ALBERTA NORTHWEST MONTANA CENTRAL MONTANA NORTHEASTERN WILLISTON BASIN STAGE Fort Union EPOCH Willow Creek Willow Creek Fort Union PERIOD Formation Formation Hell Creek Fm. Hell Creek Fm. Maestrichtian Cretaceous Marine Reservoirs St. Mary River Fm. St. Mary River Fm. Lance Fm. Fox Hills Ss. Fox Hills Ss. Sh. Horsethief Ss. Blood Reserve Ss. Gas production or shows Rye Grass Ss. Odanah Fm Bearpaw Sh. Kip Ss. Bearpaw Shale Bearpaw Shale Magrath Ss. DeGray M. Oldman Sh. Oil production or shows Judith River Fm. Gregory M. Two Medicine Fm. Campanian Pierce Shale Foremost Fm. Clagget Shale Pembino M. Brackish water beds Gas and oil production or shows Belly River Fm. Eagle Ss. Gamman Sh. Leo Park Sh. Telegraph Creek Fm. Santonian Upper Unit 1st white specks Niobrara Fm. Middle Unit Wapiabi Sh. Niobrara Fm. Coniacian McGowan Cgl. beds Middle Unit Kevin Sh. Lower Unit Cordium Fm. Upper Cretaceous Upper Unit Middle Unit Carlile Shale Carlile Shale Lower Unit Ferdig Sh. 2nd white specks Turonian iii Alberta Marias River Shale Cone Calcareous Mbr. Greenhorn Colorado Shale Greenhorn Fm. Blackstone Shale Mosby Ss. Mbr. Colorado Group Floweree Mbr Belle Fourche Shale Cenomanian Colorado Shale Belle Fourche Shale Cretaceous Fish-Scale Zone Big Elk Ss. Mbr. Crowsnest Mowry Sh. Volcanics Bootlegger Mbr. Mowry Sh. Shell Creek Sh. Shell Creek Sh. Vaughn Shell Creek Sh. Viking Muddy Ss. Bow Island Ss. Bentonite Mbr. Bow Island Ss. Dakota Albian Muddy Ss. Sandy Mbr Ss. Newcastle Joli Fou Sh. Taft Hill Mbr. Blackleaf Fm. Dakota Ss. Dakota Shale Skull Creek Sh. Skull Creek Sh. Thermopolis Fall River Ss. Bst. Colo. Ss. Flood Mbr. First Cat Creek Ss. Glauconitic Ss. Upper Blairmore Upper Manville Ostracode Zone Kootenai Fm. Second Cat Creek Ss. Fuson Shale Aptian Third Cat Creek Ss. Lakota Ss. Lower Cretaceous Sunburst Ss. Figure 3. Comparative stratigraphic columns for Cretaceous marine Cut Bank Neocomian Lower Manville reservoirs of central Montana and Lower Blairmore Kootenai Formation Sunburst-Moulton Zone adjacent areas. Adapted from Cutbank Ss. McGookey (1972) Field Trip # 1 Marine Cretaceous Reservoirs in Central and Northern Montana Karen W. Porter Montana Bureau of Mines and Geology, Butte, MT 59701 Jennie Ridgley U.S. Geological Survey, Denver, CO 80225 With assistance from Duncan McBane, Jack Warne, Don French, and Denis Foley ROAD LOG FOR DAY 1: Billings to Chinook via Roundup, Winnett, Lewistown, Winifred, and Cleveland INTRODUCTION The following road log is in five separate legs over a travel distance of 317 miles, and covers Day 1 of the three-day field trip. It begins in Billings, MT and covers the traverse north across the Bull Mountains Basin onto the Central Montana Uplift, then west to Lewistown, north to Winifred, north across the Missouri River into the Bears Paw Mountains to Cleveland, and north to Chinook on the Montana Highline. Exposed strata will be principally Tertiary and Upper Cretaceous in age; Lower Cretaceous, Upper Jurassic, and Paleozoic strata will dominate the section in the Lewistown area. Figure 1 shows the route traveled in this road log for Day 1 and also for the other two days of the field trip. Figure 2, modified from Dobbin and Erdmann (1955) shows the structural features of central Montana. Figure 3 provides comparative stratigraphic columns for the region. Road logs for Days 2 and 3 of this Field Trip are provided in Montana Bureau of Mines and Geology Special Publication 113 (Porter, 1998), provided separately. LEG 1: Billings to Roundup, a distance of 45.2 mi (72.3 km). Traverses rocks of Upper Cretaceous and Tertiary age across the Lake Basin Fault Zone and the Bull Mountains Basin. One rolling stop, south of Klein. LEG 2: Roundup to Winnett, a distance of 55.5 mi (88.8 km). Traverses the north flank of the Bull Mountains Basin, then onto the Central Montana Uplift across Tertiary and Cretaceous beds exposed in the Devils Basin Anticline and northward. STOPS 1 and 2. LEG 3: Winnett to Lewistown, a distance of 52.4 mi (83.8 km). Approximately parallels northwest- southeast trend of Central Montana Uplift, crossing Upper and Lower Cretaceous strata exposed in northwest-striking, low rolling folds subparallel to the uplift. Jurassic and Paleozoic beds exposed in domes in Lewistown area. No field stops. Lunch stop in Lewistown. 1 LEG 4: Lewistown to junction of State Highway 81, plus a round-trip loop on Hwy. 81, a distance of 51 mi (81.6 km). Traverses Upper Cretaceous beds and extensive gravel deposits exposed on flanks of Judith and South and North Moccasin Mountains. STOP 3. LEG 5: State Highway 81 junction north to Winifred and Chinook, a distance of 113 mi (180.8 km) via McClelland Ferry and Cleveland. Traverses Upper Cretaceous rocks in gravity-slide folds and faults south of Bears Paw Mountains. In mountains, Tertiary volcanic rocks flank a Cretaceous sediment-filled graben. Alternate route in wet weather is Winifred to Big Sandy via County Road 236 across Missouri River at Judith Landing (PN) Bridge, then north to Havre, east to Chinook. No field stops, either route. LEG I: BILLINGS TO ROUNDUP Nye-Bowler fault zone and Cat Creek Anticline. (45.2 mi/72.3 km; one rolling stop) via Highway 87 These NW-trending features, and associated NE- trending en echelon faults, are thought to be Log begins at intersection of 1st Avenue North and U.S. related to left-lateral displacement along major Highway 87, on the east side of Billings. During the basement faults at depth. Bull Mountains ahead on cross-town drive from the motel area to the starting skyline occupy center of Bull Mountains syncline. point, the Eagle Sandstone is seen forming the “rimrock” 0.8 to the north and east, dipping 4° to 6° east. It is 4.5 Hill crest. Judith River beds form low ridge at transitionally underlain by silty mudstone, siltstone, and 3:00. Valley ahead is developed on Bearpaw shaly sandstone of the Upper Cretaceous Telegraph Shale with overlying Fox Hills Sandstone Creek Formation, forming the lower cliff faces. To the (probable) and Hell Creek Formation forming north, lower stratigraphic section is largely obscured by buttes, knobs and ridges both sides of road extensive terraces. To the south, however, the highly (surface mapping of Fox Hills to east by E.M. dissected dark shales down to the valley floor are Upper Wilde (pers. comm.), suggests Fox Hills is present Cretaceous units earlier assigned to the Colorado Shale, in this area). Gentle north dip continues to reflect now assigned to the Mowry Shale and Belle Fourche south flank of Bull Mountains Basin Shale west of Blue Creek (at Blue Creek Road Exit off I- 2.6 90), and to the Carlile Shale and Niobrara Formation 6.9 Shepherd-Acton crossroad.