University of North Dakota UND Scholarly Commons Theses and Dissertations Theses, Dissertations, and Senior Projects 1980 Geology and petrology of the Devils Tower, Missouri Buttes, and Barlow Canyon area, Crook County, Wyoming Don L. Halvorson University of North Dakota Follow this and additional works at: https://commons.und.edu/theses Part of the Geology Commons Recommended Citation Halvorson, Don L., "Geology and petrology of the Devils Tower, Missouri Buttes, and Barlow Canyon area, Crook County, Wyoming" (1980). Theses and Dissertations. 119. https://commons.und.edu/theses/119 This Dissertation is brought to you for free and open access by the Theses, Dissertations, and Senior Projects at UND Scholarly Commons. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of UND Scholarly Commons. For more information, please contact [email protected]. GEOLOGY AND PETROLOGY OF THE DEVILS TOWER, MISSOURI BUTTES, AND BARLOW CANYON AREA, CROOK c.OUNTY, WYOMING by Don L. Halvorson Bachelor of Science, University of Colorado, 1965 Master of Science Teaching, University of North Dakota, 1971 A Dissertation Submitted to the Graduate Faculty of the University of North Dakota in partial fulfillment of the requirements for the degree of Doctor of Philosophy Grand Forks, North Dakota May 1980 Th:ls clisserratio.1 submitted by Don L. Halvol'.'son in partial ful­ fillment of the requirements fo1· the Degree of Doctor of Philosophy from the University of North Dakota is hereby approved by the Faculty Advisory Committee under whora the work has been done. This dissertation meets the standards for appearance aud con­ forms to the style and format requirements of the Graduate School of the University of North Dakota, and is hereby approved. ii Permission GEOLOGY AND PETROLOGY .OF THE DEVILS TOWER, MISSOURI BUTTES, Title AND BARLOW CANYON AREA, CROOK COUNTY, WYOMING Degree'--~~~~~~~-D_o_c_t_o_r~o_f~P_h_i_l_o_s_o~p_h~y~~~~'--~~~~~~~~- In presenting this dissertation in partial fulfillment of the requirements for a graduate degree from the University of North Dakota, I agree that the Library of this University shall make it freely available for inspection. I further agree that permission for extensive copying for scholarly purposes may be granted by the professor who supervised my dissertation work or, in his absence, by the Chairman of the Department or the Dean of the Graduate School. It is understood that any copying or pub­ lication or other use o~ this dissertation or part thereof for financial gain shall not be allowed without my written permis­ sion. It is also understood that due recognition shall be given to me and to the University of North Dakota in any scholarly use which may be made of any material in my dissertation. Signature iii TABLE OF CONTENTS ILLUSTRATIONS • • V LIST OF TABLES • • viii ACKNOWLEDGMENTS • . X ABSTRACT • • • • • • • . xi INTRODUCTION • . • 1 ANALYTICAL METHODS AND PROCEDURES •• • . • 7 PREVIOUS WORK • • • • • . • • • 12 FIELD RELATIONSHIPS . • . ~ 15 DEVILS TOWER . • . • 30 MISSOURI BUTTES • . • 60 BARLOW CANYO~ LACCOLITH • 83 PETROCliEMISTRY • • . 95 FORMATION OF ANALCIME • . 103 MODE OF EM.PLACEMENT • 114 PETROGENETIC MODEL AND SUMMARY • . 120 APPENDICES . 129 APPENDIX I. IGNEOUS ROCK DESCRIPTIONS • • . 130 APPENDIX II. SEDIMENTARY ROCK DESCRIPTIONS • 138 APPENDIX III. X-RAY FLUORESCENCE AND MICROPROBE CHEMICAL AND NORMATIVE ANALYSES • • , • • • • • 148 APPENDIX IV. X-RAY DIFFRACTION DATA FOR ANALCIME UNIT CELL CALCULATIONS • . 156 REFERENCES CITED . .. 158 iv ILLUSTRATIONS Figure 1. Location of Study Area. .. • • • . 6 2. Structure Contour Map of the Devils Tower, Missouri Buttes, and Barlow Canyon Area . • • . • . • • 25 3. Northwest Side of Devils Tower, Showing Columnar Jointing and the Massive Base • • • • . • . • • • . 32 4. Outward-flaring Columns on the Northeast Shoulder of Devils Tower, Showing Hori:ontal Ridges and Swells (Striations) ............... , • • . 35 5. Southwest View of Devils Tower Showing Merging and Splitting columns • • • • • , • • • • • . 35 6. Hand Specimen of Devils Tower Analcime Phonolite Showing Large Anorthoclase Phenocrysts and Small Crystals of Aegirine-Augite in an Aphanitic Groundmasa • • .. • • • • • • • • • • • • • • • • 39 7. Photomicrograph of Devils Tower Analcime Phonolite, 35X, Showing a Large Anorthoclase Phenocryst and Euhedral Aegirine-Augite Crystals Zoned to Aegirine in a Trachytic Groundmass of Dark Acicular Aegirine, Albite Laths, and Analcime ••• , • 39 8. Microprobe Profile from Core to Margin of Devils Tower Anorthoclase Sample Tl04 ••••• , •• . 43 9. Ordering of Feldspars in the Devils Tower Phonolite Determined from Wright's {1968) 3-peak Method . 47 10, Microprobe Profile Across a Zoned Pyroxene Phenocryst, Showing a Decrease in Ca and Mg and an Increase in Fe from Core to Margin, Sample Tl04 • • • • • • • • 54 11. Microprobe Profile Across a Zoned Pyroxene Phenocryst, Showing a Na Increase from Core to Margin, Sample Tl04 . .. , , , . .. " . " . 56 12. View of the Missouri Buttes from the Northwest 62 V 13. Outcrop of Alloclastic Breccia 0.7 km West of the Missouri Buttes ................. • . 6S 14. Close-up View of the Alloclastic Breccia Pictured in Figure 13; Clasta of Sedimentary, Igneous, and Metamorphic Rocks in a Matrix of Glass and Crystal Fragmen_ts • • • • • • • • • • . • • . • . • .. • . 6S 15. Zoned Sanidine Phenocrysts i~ Tr.achyti'c. Groundmass, Missouri Buttes Sample MB167, Showing Analcime Replacement and Poikilitic Aegirine. .. .. .. 69 16. Glomeroporphyritic Aegirine-Augite with Poikilitic Sphene • . • • . • • • . • . • • • .. .. • . 69 17. Ordering of Feldspars in Missouri Buttes Phonolites and Trachytes Determined by Wright's (1968) 3-peak !tethod • • • . • • . • . .. • . • • • . .. 72 18. Zoned Euhedral Sanidine Phenocryst, Showing no Resolution Along Margin and Little Analcime - Replacement • . .. .. • . • • . • ,. • . 87 19. Euhedral Analcime Phenocrysts with Patterned Inclusions Set in a Groundmass of Aegirine Star Bursts, Sanidine Laths, and Interstitial Analcime, Barlow Canyon, •• . 87 20. Ordering of Feldspars .in Barlow Canyon Phonolite Determined from Wright's (1968) 3-peak Method. 90 21. Fractionation Curves in Part of the NaAlSi04-ICJIJ.Si04- Si02-H20 System at Pa2o • 1 kbar (lOOMPa) Projected onto the Anhydrous Base • • • • ~ • , • • , • • • • . • . 97 22. Plot of Devils Tower, Missouri Buttes, and Barlow Canyon Bulk Rock Composition on a Ne-Ks-Q Di.a.gram 100 23. Pyroxene Composition Trends Diagram. 102 24. Plot of Analcime Unit Cell Dimensions • . 10S 2S. Analcime Determinative Curve . • . 106 26. Temperature of Crystallization diagram for analcimes of Study Area, Based on Unit Cell Dimensions (after Liou 1971) ....................... 109 27. Differentiation Trend of Devils Tower, Miasouri Buttes, and Barlow Canyon Suite •• , , • . 122 28. Isobaric, Polythermal Liquidus Diagrams for Part of the Residua System for a Ne-Ks-Q Diagram •• , • , , •• . 123 vi Plate 1. Geologic Map of the Devila Tower, Missouri Buttes, and Barlow Canyon Area ••• (in pocket) 2. Geologic Map of the Devils Tower Area . {in pocket) 3. Geologic Map of the Missouri Buttes Area. (in pocket) 4, Geologic Map of the Barlow Canyon Area. , • , (in pocket) 5. Location Map for Sedimentary Rock Sat11ples and Geologic Map Plates , ••••••• , •• (in pocket) vii LIST OF TABLES Table 1. Instrument Parameters for X-ray Fluorescence ••• • 10 2. Modal Analyses of Devils Tower Phonolite •• 40 3. Microprobe Analyses of Devils Tower Feldspars 49 4, Microprobe Analyses of Devils Tower Pyroxenes •• 52 5. Microprobe Analyses of Missouri Buttes Feldspars 73 6. Modal Analyses of Missouri Buttes Phonolites and Trachytes • . • • . .. _. • • • • • • • . • • • 75 7. Microprobe Analyses of Missouri Buttes Py,:oxenes . 77 8. Microprobe Analyses of Missouri Buttes Analcime 80 9. Modal Analyses of Barlow Canyon Phonolite • 85 10. Microprobe Analyses of Barlow Canyon Minerals • • 91 11. Igneous Rock Description - Devils Tower Phonolite 131 12. Igneous Rock Description - Devils Tower Alloclastic Breccia • • . .. • . .. • • . .. 132 13. Igneous Rock Description - Missouri Buttes Trachyte . 133 14. Igneous Rock Description - Missouri Buttes Phonolite 134 15. Igneous Rock Description - Missouri Buttes Alloclastic Breccia •••• , , •• . 135 16, Igneous Rock Description - Barlow Canyon Altered Zone 136 17. Igneous Rock Description - Barlow Canyon Lower Unit 137 18. Sedimentary Rock Descriptions . .. 139 19. Chemical Composition and Normative Mineralogy of Devils Tower Phonolite • • • • • • • . .. 149 viii 20. Chemical Composition and Normative Mineralogy of Missouri Buttes Phonolite ••••••••• .. 151 21. Chemical Composition and Normative Mineralogy of Missouri Buttes Trachyte • • • • • , • • • • • • • • • 153 22. Chemical Composition ~d Normative Mineralogy of Barlow Canyon Phonolite • ••••••••• . 154 23. Chemical Composition and Normative Mineralogy of Barlow Canyon Contact Zone and Sedimentary Rocks • • • 155 24. X-Ray Diffraction Data for Analcime Unit Cell Calculations •••••••••••••.• . 157 ix ACKNOWLEDGMENTS I would like to express sincere appreciation to those people who have helped me in the preparation of this dissertat~on,•especial!) the members of my Faculty Advisory Committee--Dr. Frank R. Karner (chairman}, Dr. James Clark, Dr. Lee Gerhard, Dr. Fc·D. Holland, Jr., and l)r. Walter Moore--for their critical review of the manuscript, and for .valuable direction and advice. Special thanks are conveyed to Dr. Karner for microprobe