WYOMING STATE GEOLOGICAL SURVEY OPEN FILE REPORT 15-3 Thomas A. Drean, Director and State Geologist Laramie, Wyoming Interpreting the past, providing for the future Introduction regressive and coarsening-up sandstone, visible on both gamma termed the Horse Butte coal bed. Approximately 250–350 ft (76–110 Cross Sections Study Area Location Map and SP geophysical logs, and below the first coal of the Lance m) above this coal is the main Cherokee coal zone consisting of the Cross Sections Uppermost Cretaceous and Paleocene strata characterize Laramide Formation. Sandstones of the Fox Hills interfinger with the under- Lower Cherokee, Cherokee, and Upper Cherokee coal beds. These basin development throughout much of Wyoming and the Rocky lying marine Lewis Shale and remain undifferentiated for this study. coals, while regionally correlative, contain many thick coals that are Tie Well Mountain region. These strata are of economic importance because Tie Well sometimes laterally discontinuous. Cherokee coals are of lower quality Lost Valley (F-F’) they can host thick and shallow coal deposits, as well as productive oil than China Butte coals and are lignitic to subbituminous C in rank. (C-C’) Tie Well Location map showing key features in the Great Divide Basin region, a sub-basin of the Lance Formation D Block-A 5 D’ Tie Well Stewart Creek and natural gas reservoirs. The Upper Cretaceous Lance and Paleocene Lost Valley 49-037-21923 (E-E’) Chain Lakes Sooner Greater Green River Basin. Inset map of Wyoming (left) highlights the Greater Green Bravo Federal 1 Unit 1 (D-D’) 11-5-23-93 Unit 2 Fort Union Formations in the Greater Green River Basin (GGRB) of The Maastrichtian Lance Formation contains thin sandstones, shales, South Unit 4 T26N R98W S30 North C Red Desert Reservoir 2 C’ River Basin (light green), the Precambrian outcrops or mountain ranges (purple), and the Wasatch and Battle Spring Formations, Undifferentiated 49-037-20064 49-037-21329 Encana Federal Molitor Seaver 49-037-25952 49-037-21025 southwestern Wyoming are no exception. The purpose of this study T24N R99W S22 MD Bravo Red Lake W-20355 1-5 49-037-21633 and coals that record the last of the Cretaceous Interior Seaway coast- 49-037-23513 T25N R98W S17 GR(ft) Res 21-31 Federal 1 Unit 1 T23N R93W S5 T23N R91W S5 Great Divide Basin study area (red box). Detailed map (below) shows outcrops of the Fort T23N R99W S4 West Unit 4 1-3 49-037-21186 T24N R92W S34 East WYOMING is to clarify the stratigraphy of the Lance and Fort Union Formations al- and delta-plain transitioning into terrestrial deposits (Flemings and The Wasatch and Battle Spring Formations represent the last phases MD GR(ft) Res MD 49-037-26691 49-037-25987 49-037-25498 MD Union Formation (brown), modified from the 1:500,000 scale geologic map of Wyoming Federal-I GR(ft) Res Wasatch & 49-037-23513 49-037-24914 T23N R94W S5 MD MD in the Great Divide Basin (GDB), a sub-basin of the northeastern MD 4.2 mi T23N R95W S9 GR(ft) Res SP (ft) Res. Nelson, 1991; Gillespie and Fox, 1991). Overall thickness of the Lance of basin filling in the Greater Green River Basin. The Battle Spring GR(ft) Res 3.8 mi 7.0 mi T24N R96W S31 T23N R96W S2 GR(ft) Res Ruddy 1 2500 Battle Spring T23N R99W S4 T23N R98W S1 MD (Love and Christiansen, 1985). Cross section locations are displayed as red lines, and MD GR Res F 1 GGRB, to help guide future hydrocarbon and coal exploration and aid Formation varies from 950–5,200 ft (290–1600 m). The lower boundary Formation is a thick succession of boulder conglomerate and sandstone Formations MD MD GR Res (ft) 5.6 mi 8.3 mi 4.1 mi 49-037-21011 MD MD GR(ft) Res GR(ft) Res (ft) wells used in the cross sections are named by their 10-digit API number and highlighted (part) GR(ft) Res GR(ft) Res 49-037-05934 in constraining the timing of local Laramide tectonic events. Formation is conformable and transitional with the underlying Fox Hills Sandstone, that records the uplift of the Granite Mountains (Pipiringos and Denson, T23N R99W S22 4.7 mi 1500 Tie Well Well Big Dune 8.5 mi 7.1 mi 4.2 mi 4.6 mi 9.9 mi T24N R90W S14 as large black dots. All other wells used in this study are denoted as small gray dots. 2.8 mi 1000 2000 tops, member tops, and coals were correlated throughout the GDB generally denoted below the first coal in the section. The Lance For- 1970). The distal part of the Battle Spring Formation interfingers with the MD 2500 SP(ft) Res 3000 3 Unit 2 1500 2000 MD Greater (B-B’) 1500 SP (ft) Res. from a Wyoming State Geological Survey database of 4,309 oil, gas, mation contains the upper Red Rim Member and the lower (unnamed) Wasatch Formation, the lateral and finer-grained equivalent. Coals are 49-037-05930 49-037-05918 5.9 mi 500 1500 Wasatch & Tie Well Black Rock Crk T23N R101W S1 T23N R100W S9 1500 and coal exploration wells (IHS, 2015; WOGCC, 2015). Stratigraphic member, which was further informally divided into an upper and lower present in the Wasatch Formation (Pipiringos, 1961; Masursky, 1962; 1000 2000 Green STUDY Upper Cherokee Battle Spring (A-A’) Unit 3 1500 500 3000 MD 2500 and coalbed nomenclature was derived from Madden (1989), Flores zone (Hettinger and others, 1991; Hettinger and Kirschbaum, 1991) Hettinger and others, 2008) but were not mapped as part of this study. Upper 500 MD Formations AREA 3500 SP(ft) Res SP(ft) Res 2000 2500 49-037-05868 2000 River 23-1 3.4 mi Lower Cherokee (part) and others (1999), Honey and Hettinger (2004), and Hettinger and and correlated through this study area. Coals are more prominent in the Arch Playa Unit T22N R99W S20 6.9 mi 1000 2000 Monell ? Cherokee Cow Butte Unit 81 3-1 49-037-20176 2000 500 others (2008). Results are presented in graphic format as a series of six lower zone of the lower member, but were neither denoted nor named in 15-22B 1500 2500 Unit 33-34 T21N R99W S23 MD Basin SP(ft) Res 2000 1000 49-037-05681 49-037-05785 3500 3000 1000 Horse Butte cross sections, three structure contour maps, and two isochore maps. this study. The lower zone of the lower member is generally comprised 49-037-26778 4000 500 2500 3000 T19N R99W S3 MD ? T20N R99W S22 2500 T19N R99W S34 SP(ft) Res 1500 2500 of thin and locally continuous sandstones interbedded with shale, coals, 500 The six cross sections of the Great Divide Basin depict Paleocene GRMD Res MD 2500 1000 MD 4.7 mi (ft) 3.7 mi SP(ft) Res 5.6 mi 6.3 mi 2000 3000 and carbonaceous shales. The upper zone of the lower member contains GR(ft) Res Fort Union Formation members and coal beds, as well as Cretaceous 2500 4000 1500 3500 References 1500 4500 1000 3000 3500 thicker sandstone beds and fewer beds of carbonaceous shale and coal. Lance Formation members. The datum for these stratigraphic cross 500 CB1200 3000 2000 103 102 101 100 99 98 97 96 95 94 93 92 91 90 89 88 85 1000 3000 28 sections is the top of the China Butte Member of the Fort Union The Red Rim Member is a prominent sandstone package named for Flemings, P.B., and Nelson, S.N., 1991, Paleogeographic evolution ? ? Member Overland 3000 1500 500 2500 3500 of the latest Cretaceous and Paleocene Wind River Basin: The basal sands Formation (described in more detail below) because it subdivides its color as it crops out south of Interstate 80 on the eastern rim of 3000 2000 4000 500 4500 CB1200 500 2000 5000 1500 3500 4000 Mountain Geologist, v. 28, p. 36–52. 500 CB700 the two members of the Fort Union Formation and highlights the two the Washakie Basin. Hettinger and others (1991) and Hettinger and 1000 3500 Nuttal? 2500 3500 27 CB700 1500 main coal zones. Cross sections A-A’, B-B’, and C-C’ are oriented Kirschbaum (1991) define the Cretaceous-Paleocene boundary at a CB700 3500 2000 Member Overland Flores, R.M., Ochs, A.M., Stricker, G.D., Ellis, M.S., Roberts, S.B., 1000 CB700 3000 4000 CB700 3500 CB700? 5000 Union Formation Fort 2500 4500 west to east. These cross sections cover the GDB from the east side conglomeratic horizon within but near the top of the Red Rim Mem- 1000 Keighin, C.W., Murphy, E.C., Cavaroc, V.V., Jr., Johnson, R.C., 1000 2500 5500 2000 CB700 4000 Middle Fort Union Lower 4500 ± Bairoil 1000 DATUM 4000 of the Rock Springs uplift (R101W) to the west side of the Rawlins ber. This boundary was defined through palynology at the outcrops 1500 ! ! and Wilde, E.M., 1999, Location, stratigraphy, and coal quality 3000 4000 Fort Union 15 2000 (!73 basal sands D' E'!(! 4903721309 26 Fort Union 14 ! uplift (R90W), a maximum distance of 84 mi (135 km). They show 2500 ! 0 6 12 18 Miles (Hettinger and others, 1991). No outcrops were examined for this Upper Deadman 1500 4000 !( ! ! for selected Tertiary coal in the northern Rocky Mountains and Fort Union 13 3500 4500 Fort Union 3 Lower Upper Big Red DATUM 4903721923 Upper Big Red 4000 Upper Deadman Deadman 5500 3000 5000 the variability in member thickness and coalbeds of the Fort Union study, and the conglomerate bed is not visible on geophysical logs.