Stratigraphic Framework, Structure, and Thermal Maturity of Cretaceous and Lower Tertiary Rocks in Relation to Hydrocarbon Potential, Crazy Mountains Basin, Montana By Ronald C. Johnson, Thomas M. Finn, David J. Taylor, and Vito F. Nuccio Chapter A Structural and Stratigraphic Framework and Hydrocarbon Potential of Cretaceous and Lower Tertiary Rocks of the Crazy Mountains Basin, Montana By Ronald C. Johnson and Thomas M. Finn Chapter B Basin Structure from Two-Dimensional Seismic Reflection Data, Crazy Mountains Basin, Montana By David J. Taylor Chapter C Thermal Maturity and Petroleum Generation History of Cretaceous and Tertiary Source Rocks, Crazy Mountains Basin, Montana By Ronald C. Johnson, Vito F. Nuccio, and Thomas M. Finn Scientific Investigations Report 2004–5091 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior Gale A. Norton, Secretary U.S. Geological Survey Charles G. Groat, Director U.S. Geological Survey, Reston, Virginia: 2005 For sale by U.S. Geological Survey, Information Services Box 25286, Denver Federal Center Denver, CO 80225 For more information about the USGS and its products: Telephone: 1-888-ASK-USGS World Wide Web: http://www.usgs.gov/ Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this report is in the public domain, it contains copyrighted materials that are noted in the text. Permission to reproduce those items must be secured from the individual copyright owners. Suggested citation: Johnson, R.C., Finn, T.M., Taylor, D.J., and Nuccio, V.F., 2005, Stratigraphic framework, structure, and thermal maturity of Cretaceous and lower Tertiary rocks in relation to hydrocarbon potential, Crazy Mountains Basin, Montana: U.S. Geological Survey Scientific Investigations Report 2004–5091, 95 p. ISBN 0-607-97158-4 Structural and Stratigraphic Framework and Hydrocarbon Potential of Cretaceous and Lower Tertiary Rocks of the Crazy Mountains Basin, Montana By Ronald C. Johnson and Thomas M. Finn Chapter A of Stratigraphic Framework, Structure, and Thermal Maturity of Cretaceous and Lower Tertiary Rocks in Relation to Hydrocarbon Potential, Crazy Mountains Basin, Montana By Ronald C. Johnson, Thomas M. Finn, David J. Taylor, and Vito F. Nuccio Scientific Investigations Report 2004–5091–A U.S. Department of the Interior U.S. Geological Survey Contents Abstract .......................................................................................................................................................... 1 Introduction ................................................................................................................................................... 1 Geology of Basin-Centered Gas Accumulations..................................................................................... 1 Regional Geologic Setting of the Crazy Mountains Basin ..................................................................... 3 Cretaceous and Lower Tertiary Strata in the Crazy Mountains Basin ....................................... 5 Kootenai Formation .................................................................................................................... 5 Fall River Sandstone................................................................................................................... 6 Thermopolis Shale...................................................................................................................... 6 Mowry Shale ............................................................................................................................... 8 Frontier Formation ...................................................................................................................... 8 Cody Shale ................................................................................................................................. 10 Telegraph Creek Formation..................................................................................................... 11 Eagle Sandstone ....................................................................................................................... 13 Claggett Shale Through Teapot Sandstone Member of the Mesaverde Formation and Its Equivalent Interval.......................................................................................... 13 Judith River Formation............................................................................................................. 15 Bearpaw Shale.......................................................................................................................... 17 Lennep Sandstone.................................................................................................................... 17 Hell Creek Formation................................................................................................................ 18 Livingston Group ....................................................................................................................... 18 Fort Union Formation or Group ............................................................................................... 19 Potential Hydrocarbon Source Rocks in the Crazy Mountains Basin ............................................... 20 Hydrocarbon Production in the Crazy Mountains Basin...................................................................... 20 Implication of Present Investigation on the Structural Development of the Crazy Mountains Basin................................................................................................................................................ 21 Defining Basin-Centered Gas Accumulations in Rocky Mountain Basins ....................................... 26 Key Deep Wells in the Crazy Mountains Basin...................................................................................... 35 Discussion.................................................................................................................................................... 36 References Cited ........................................................................................................................................ 37 Plates 1. Detailed northwest to southeast cross section of Upper Cretaceous and lower Tertiary rocks across Crazy Mountains Basin and northernmost part of Bighorn Basin, Montana, showing lithologies and depositional settings 2. Detailed west to east cross section of Upper Cretaceous and lower Tertiary rocks across Crazy Mountains Basin, Montana, showing lithologies and depositional settings 3. Detailed south to north cross section of Upper Cretaceous and lower Tertiary rocks across northern part of Crazy Mountains Basin, Montana, showing lithologies and depositional settings v 4. Detailed west to east cross section of Upper Cretaceous and lower Tertiary rocks across east-central part of Crazy Mountains Basin, Montana, showing lithologies and depositional settings 5. Detailed measured sections of selected Upper Cretaceous and Paleocene intervals, Crazy Mountains Basin, Montana Figures 1. Map showing location of Crazy Mountains Basin and surrounding uplifts....................... 2 2. Map showing generalized geology of Crazy Mountains Basin............................................ 3 3. Balanced structural cross section across southwest flank of Crazy Mountains Basin............................................................................................................... 6 4. Generalized stratigraphic chart of Cretaceous and older Tertiary rocks, Crazy Mountains and Bighorn Basins...................................................................................... 7 5–18. Maps showing: 5. Depositional settings at maximum sea level lowstand during deposition of Muddy Sandstone, central Rocky Mountain region....................................................... 9 6. Cretaceous shoreline and facies distributions during maximum extent of Mowry Shale, central Rocky Mountain region.............................................................. 10 7. Approximate extent of Boulder River Sandstone Member of Upper Cretaceous Frontier Formation, Crazy Mountains Basin................................................................... 11 8. Approximate extent of pebbly sandstone of Upper Cretaceous Frontier Formation, Crazy Mountains Basin.................................................................................. 12 9. Approximate extent of Upper Cretaceous marine Claggett Shale, Crazy Mountains Basin................................................................................................................. 15 10. General depositional settings during deposition of Upper Cretaceous Parkman Sandstone, Crazy Mountains Basin ............................................................... 16 11. Generalized depositional settings during maximum transgression of Upper Cretaceous Bearpaw Shale, Crazy Mountains Basin...................................... 17 12. Structure contours on base of Lower Cretaceous Kootenai Formation, Crazy Mountains Basin and northernmost part of Bighorn Basin ............................. 22 13. Structure contours on top of Upper Cretaceous Teapot Sandstone Member of Mesaverde Formation and Teapot equivalent, Crazy Mountains Basin and northernmost part of Bighorn Basin................................................................................ 23 14. Isopachs of interval from top of Lower Cretaceous Mowry