University of Montana ScholarWorks at University of Montana Graduate Student Theses, Dissertations, & Professional Papers Graduate School 1965 Hydrogeology of the Cascade-ulm Area Montana Richard D. Fox The University of Montana Follow this and additional works at: https://scholarworks.umt.edu/etd Let us know how access to this document benefits ou.y Recommended Citation Fox, Richard D., "Hydrogeology of the Cascade-ulm Area Montana" (1965). Graduate Student Theses, Dissertations, & Professional Papers. 9309. https://scholarworks.umt.edu/etd/9309 This Thesis is brought to you for free and open access by the Graduate School at ScholarWorks at University of Montana. It has been accepted for inclusion in Graduate Student Theses, Dissertations, & Professional Papers by an authorized administrator of ScholarWorks at University of Montana. For more information, please contact [email protected]. HYDROGEOLOGY OF THE CASCADE-ULM AREA, MONTANA by Richard D. Fox B.S. Iowa State University, 1963 Presented in partial fulfillment of the requirements for the degree of Master of Science UNIVERSITY OF MONTANA 1965 Approved by: Chairman,Board of Examinerd Dean, Graduate School vy-t, 9 0 !?S5 Date UMI Number: EP72620 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. Dissertation PoblisMng UMI EP72620 Published by ProQuest LLC (2015). Copyright in the Dissertation held by the Author. Microform Edition © ProQuest LLC. All rights reserved. This work is protected against unauthorized copying under Title 17, United States Code ProQuest ProQuest LLC. 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106- 1346 7 W f *~ ABSTRACT The Cascade-Ulm area, located approximately 30 miles southwest of Great Falls, includes 415 square miles of semi-arid plains that are bounded on the south by the Big Belt Mountains. The area is drained by the Missouri and Smith Rivers. Exposed rock units include 35 feet of Jurassic and 2300 feet of Cretaceous sedimentary strata. The lowest outcropping unit is the upper part of the Jurassic Morrison Formation consisting of carbon­ aceous siltstone. It is overlain disconformably by the Cretaceous Kootenai Formation, composed of sandstone, limestone, and red siltstone. The Colorado Group, which disconformably overlies the Kootenai includes the Blackleaf and Marias River Formations. The Blackleaf is composed mostly of bentonitic shale with many sandstone beds. The Marias River is predominantly shale. The Montana Group, the upper part of which has been removed by erosion, is made up of the Telegraph Creek and Virgelle Formations. The Telegraph Creek is composed of interbedded sandstones and shales whereas the Virgelle is characterized by massive quartz sandstone. h Surficial deposits include terrace gravel, glacial lake sedi­ ment, \alluvium-colluvium, dune sand, and alluvium. Igneous rocks of probable early Tertiary age include the Adel Mountain Volcanics and intrusive dikes and sills. Gentle westward dips in the north part of the area reflect uplift of the Sweetgrass Arch. The west-northwest structural trend in the south part of the area resulted from late Eocene diastrophism. ii There the strata have been folded and faulted into reverse and high angle faults. These structural features postdate igneous intrusion. The quality of ground water in the area is generally good. The most productive aquifers are in the Blackleaf Formation, which contains numerous sandstone units that generally yield adequate sup­ plies of water for domestic and stock use; sandstone units in the Flood Member of this formation are the best aquifers in the area. Alluvial deposits along the Missouri River yield adequate supplies of water at shallow depths. The Virgelle Formation is an excellent aquifer, but its small areal extent limits its water yielding capa­ bility. Sandstone units in the Kootenai Formation are undeveloped potential aquifers. The Morrison, Marias River, and Telegraph Creek Formations are relatively impermeable and are not considered as potential aquifers. Springs commonly issue out of the sandstone units of the Blackleaf Formation and alluvium. A few springs occur in the Kootenai, Telegraph Creek, and Virgelle. TABLE OF CONTENTS PAGE INTRODUCTION ................................. 1 Purpose and scope .......... .......... , ....... 1 Location and accessibility ........................ ....... 1 Previous work . ............. , . .......... 3 Present study ........................................... 4 Acknowledgements . ............ * , . 5 PHYSIOGRAPHY ................................................... 6 Climate ............... 6 Vegetation ................................................. 8 Topography .............................................. 8 Glaciation ................................................. 11 Drainage .................. 12 Missouri River ........................... 13 Smith River ............................................. 15 Land utilization ....... 16 Irrigation ........................................... 16 STRATIGRAPHY ............................................... 18 Geologic setting ........................................... 18 Jurassic System ............. 20 Morrison Formation .......... 20 Cretaceous System ........................................ 22 Kootenai Formation ............................ 22 Colorado Group ........................................ 26 Blackleaf Formation ....................... 26 iv PAGE Flood Member ....................... 26 Taft Hill Member ...... 31 Vaughn Member 33 Bootlegger Member ........ 36 Marias River Formation ................ 40 Floweree Member .................................. 41 Cone Member ............ 42 Ferdig Member ....................................... 43 Kevin Member . ............................... 45 Montana Group ................................ 46 Telegraph Creek Formation ............... 46 Virgelle Formation ..................................... 48 Quaternary deposits ....... 51 Terrace gravel ....................................... 52 Glacial lake deposits ........................................ 53 Dune sand ....... 55 Alluvium-colluvium........................... 56 Landslide deposits ......................... 56 A l l u v i u m ......................................... 57 IGNEOUS ROCKS ................................. 58 Adel Mountain Volcanics ............. 58 Dikes .................... 58 Sills .......................... 60 STRUCTURAL GEOLOGY ............. 64 Structural setting ................................ 64 v PAGE Folds .......... 65 Faults .............................. r...... ................ 69 Reverse faults .............. 69 High angle faults ..................... 72 Structural interpretation ............................ 74 ECONOMIC GEOLOGY ..................................... 76 Gravel ..... 76 Coal ...... 76 Other Economic deposits .................. 78 GROUND W A T E R ........... 80 Terms ............................... 80 Principal aquifers .............................. 81 Kootenai Formation ...................... 81 Flood Member .............. 82 Taft Hill-Vaughn Member .......... 83 Ferdig-Kevin Member ................... 84 Telegraph Creek Formation ..... 85 Virgelle Formation ............. 85 Alluvium . 86 Springs .................................... 87 Negro Creek springs ....... 88 Williams spring . ............................... 88 Springs in dune sand ..... 89 Springs in Cretaceous sediments ........................ 89 Quality of water ............... 92 vi PAGE REFERENCES CITED . ..................... 95 APPENDIX I .................................... .................. 98 Water wells ........... 98 APPENDIX II ............................. 103 Springs . ...................... ........ ...... ............. 103 APPENDIX III ........................................ 105 Deep wells . .............................................. 105 APPENDIX I V ............................... 107 Measured section of Kootenai Formation ................. 107 APPENDIX V . .............................. 109 Measured section of Flood Member .................... 109 APPENDIX VI ............................... 112 Measured section of Vaughan M ember .................. 112 APPENDIX VII ........................................ 114 Thin section d a t a ..... ....... .................... ........ 114 LIST OF T A B L E S TABLE PAGE 1. Weather data ......................... ............... 7 2. Historical development of Colorado Group nomenclature ........ 19 3. Subsurface stratigraphic section ............. 20 4. Chemical composition of coal from Smith River District ....... 77 5. Chemical analyses of well and spring water ...... 93 viii LIST OF ILLUSTRATIONS Geologic map and cross sections Cascade-Ulm area, Montana ...... Index map showing area of study and drainage pattern ........... 2 Big Belt Mountains with mature valley in foreground .......................... 9 Rocky Reef dike . .............. 10 Dune sand topography ......... ..... 11 Shoreline of glacial Lake Great Falls ........ 13 Smith River Valley ........ 15 Apparent disconformity between Morrison and Kootenai Formations .............. 22 Kootenai Formation cropping out along the Smith River .......... 24 Brown concretion in upper Flood sandstone .... 30 Vaughn badlands topography .................