This dissertation has been microfilmed exactly as received Mic 60-4104 KRUSHENSKY, Richard Dean. GEOLOGY OF THE VOLCANIC FEATURES OF THE HURRI­ CANE MESA AREA, PARK COUNTY, WYOMING. The Ohio State University, Ph. D ., 1960 Geology University Microfilms, Inc., Ann Arbor, Michigan GEOLOGY OF THE VOLCANIC FEATURES OF THE HURRICANE MESA AREA, PARK COUNTY, WYOMING DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By RICHARD DEAN KRUSHENSKY, B.S., M.S. The Ohio State University I960 Approved by Adviser Department of Geology TABLE OF CONTENTS Page INTRODUCTION....................................... 1 Location ....................................... 1 Purpose of the w o r k ............................. 1 Field and laboratory w o r k ......... 3 Previous work . ............................ 3 Acknowledgments................................. 1* GEOGRAPH! .......................................... 5 Topography..................................... 5 D r a i n a g e .................. 6 Climate......................................... 6 Vegetation ..................................... 7 Access ......................................... 7 RELATIONS TO SURROUNDING GEOLOGIC U N ITS......... 8 Beartooth Range ................................. 8 Bighorn B a s i n ................................... 10 Owl Creek Ra n g e ........................... 11 Washakie R a n g e ................................. 11 Yellowstone Plateau .............................. 12 REGIONAL STRATIGRAPHY............................... 13 GEOLOGY OF THE ABSAROKA RA N G E ........................ 1? Division and distribution of the Absaroka volcanics . 17 Classic stratigraphic terminology ................. 17 Description of the classic units ................. 18 Faulting in the Absaroka Mountains . ........... 20 TERMINOLOGY AND CLASSIFICATION OF VOLCANIC ROCKS .... 21 GEOLOGIC AND TOPOGRAPHIC FEATURES OF THE HURRICANE MESA A R E A .................. 26 Topography..................................... 26 Glaciation.................................... 33 VOLCANIC ROCKS OF THE HURRICANE MESA A R E A ............. 1*0 Papoose volcanics ............................... 1*0 Name and general features.................... 1*0 Rocks south of Hurricane M e s a ................. 1*1 The lower un i t ...................... 1*2 The upper un i t ........................... 1*9 Volcanic p l u g ............................ 53 Rocks immediately north of Hurricane Mesa .... 56 The lower un i t ........................... 56 The upper un i t ........................... 57 ii VOLCANIC ROCKS OF THE HURRICANE MESA AREA - continued Page Papoose volcanics - continued Rocks between Onemile and Squaw C r e e k .......... 57 The lower u n i t .......................... 57 The upper unit . ...................... 57 Squaw flows ..................................... 58 Exposures on Hoodoo Creek .................... 60 Exposures east of Hurricane M e s a ............. 61 Volcanic vent .................... 62 Exposures along Tepee Creek and between Onemile Creek and Squaw Creek.. ................... 65 Closed volcanics ................................ 65 Name and general features , . ................. 65 Volcanic plugs .............................. 66 Rocks of the Closed volcanics in the eastern part of the map a r e a ......... 69 Exposures................................ 69 Lithologic character... ................... 69 Volcanic plug on the southeast flank of Hurricane Mesa .................... 72 Volcanic plug in the Hoodoo Creek area . 73 Volcanic plug in the upper Crandall Creek area 73 Exposures in the Tough Creek area ............. 7^ Exposures in the Timber Creek-Closed Creek area . Ik Rocks on the western margin of the map area . 75 Volcanic vents between Timber Creek and Closed Creek ........................ 78 Post-Closed volcanics......... 83 Hurricane Mesa v o l c a n i c s .............. 8U Name and general features . ................. 8I4. Exposures on Hurricane M e s a ................... 88 Exposures on the northern margin of the map area 93 INTENSIVE ROCKS OF THE HURRICANE MESA A R E A ........... 9k Crandall ring-dike complex ...................... 9U Ring-dike centers on the eastend of Hurricane Mesa . 97 Mietamorphism of the Madison limestone.......... 102 Linear d i k e s ......................... 102 Age . ................................... 108 Gross lithology of the andesite dikes ......... 108 Gross lithology of the basalt d i k e s ........... Ill Gross lithology of the diorite dikes ......... 113 Intrusive near the head of Closed C r e e k ........... 113 MICROSCOPIC PETROGRAPHY.............................. 115 Papoose volcanics............ ................... 115 Volcanic breccias............................ 115 Volcanic conglomerates ...................... 121 Volcanic sandstones.............. 121 T u f f s ....................................... 126 Squaw flows ............................... 127 iii MICROSCOPIC PETROGRAPHY - continued Page Closed vo l c a n i c s ............................... 13U Volcanic breccias...................... 13l* Volcanic conglomerates and sandstones......... li*0 F l o w s....................................... li*0 T u f f ....................................... U*1 Post-Closed volcanics......................... * 11*6 Hurricane Mesa v o l c a n i c s ........................ 11*9 F l o w s....................................... 1^0 Tuff-breccias ............................... 151 Volcanic p l u g s ................................. 152 A l t e ration................................. 152 Ring-dike complexes .............................. 157 N o r i t e ..................................... 157 Oligoclase andesite . ...................... 160 Hypersthene diorite.................. 162 Basalt lamprophre............................ 166 Intrusive near the head of Closed C r e e k ........... 167 Linear dikes ................................... 170 Basalt d i k e s .............. 170. Andesite dikes .............................. 172 Metamorphosed limestone .......................... 177 ORIGIN OF THE VOLCANIC BRECCIAS...................... 182 ORIGIN OF THE VOLCANIC ROCK T Y PES.................... 189 STRUCTURAL GEOLOGT ................................. 191 Structure of the extrusive volcanicrocks .......... 191 Emplacement of the ring-dike c o m p l e x e s ........... 191* TERTIARY GEOLOGIC HISTORY ............................ 197 CONCLUSIONS........................ '............... 199 REFERENCES C I T E D ................................... 203 APPENDIX A ......................................... 208 AUTOBIOGRAPHY....................................... 217 iv List of Illustrations Plate Page I Geologic map of the Hurricane Mesa area .... (pocket) II Geologic cross sections of the Hurricane Mesa a r e a ....................................... (pocket) Figure 1 Index map showing the location of the Hurricane Mesa a r e a .................................... 2 2 Geologic map of the Absaroka Mountains and vicinity .................................... 9 3 Generalized stratigraphic section of Precambrian to Mississippian ro c k s ............... 15 4 Top of Hurricane Mesa, looking we s t ... 28 5 Top of Hurricane Mesa, looking east ............ 28 6 View up the valley of Closed C r e e k ............ 30 7 Cliffing in the Papoose volcanics and the Madison limestone ............................ 32 8 Hoodoo erosional forms...... ............. 32 9 Extreme development of hoodoos ......... • 35 10 Glacial grooves............................... 35 11 Cirques cut into the north side of Hurricane M e s a ....................................... 36 12 Close view of an active rock glacier ..... 39 13 Cirque cut in the ring-dike complex on Hurricane M e s a .............................. 39 11* Type section of the Papoose volcanics.......... 14; 15 Cliffing in the Papoose volcanics south of Crandall C r e e k .............................. 44 v Figure Page 16 Volcanic sandstones and conglomerates in the Papoose volcanics...................... 1*8 17 Granite- and limestone-bearing conglomerate from the lower part of the Papoose volcanics . 1*8 18 Limestone boulder in the Papoose volcanics . 52 19 Andesite breccia from the Papoose volcanics . • 52 20 Breccia-plug on Crandall C r e e k ............. 55 21 Contact along the gully of the volcanic plug on Crandall Creek ........................ 55 22 Monolithologic breccia from the Papoose volcanics................................. 55 23 Typical augite-olivine andesite of the Squaw f l o w s ............................... 61* 21* Metamorphosed limestone near the Squaw flow vent 61* 25 Topical outcrop of Closed volcanics.......... 68 26 Closed volcanics, head of the North Fork of Crandall Creek ............................ 68 27 Andesite-basalt breccias of the Closed volcanics 71 28 Specimen of breccia from Closed volcanics . 71 29 Small vent on Closed Creek ................. 77 30 Hurricane Mesa volcanics over Closed volcanics 77 31 Specimen of basalt flow from the Closed, volcanics......................... ..... 80 32 Intrusive breccia-dike..................... 80 33 Water-laid conglomerate in the Closed volcanics 82 3l* Cirque which cuts the small vent between Timber Creek and Closed Creek ............... 82 35 Disconformable contact between the Closed and post-Closed volcanics ................... 86 36 Specimen of breccia from the post-Closed volcanics 86 vi Figure Page 37 lype section of the Hurricane