Comparison of Sediment-Hosted Cu Mineralization Lisbon and Moab Fault Systems, Utah Item Type text; Electronic Thesis Authors Whitehead, Alex Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction, presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 10/10/2021 19:58:20 Link to Item http://hdl.handle.net/10150/634336 COMPARISON OF SEDIMENT-HOSTED CU MINERALIZATION LISBON AND MOAB FAULT SYSTEMS, UTAH by Alex Whitehead ____________________________ Copyright © Alex Whitehead 2019 A Thesis Submitted to the Faculty of the DEPARTMENT OF GEOSCIENCES In Partial Fulfillment of the Requirements For the Degree of PROFESSIONAL SCIENCE MASTERS ECONOMIC GEOLOGY In the Graduate College THE UNIVERSITY OF ARIZONA 2019 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE As members of the Master’s Committee, we certify that we have read the thesis prepared by Alex Whitehead, titled Comparison of sediment-hosted Cu mineralization Lisbon and Moab fault systems, Utah and recommend that it be accepted as fulfilling the thesis requirement for the Professional Science Masters in Economic Geology Degree. Date: 08/16/2019 Mark D. Barton Date: 08/16/2019 Peter Reiners Date: 08/16/2019 Isabel F. Barton Date: 08/16/2019 Robert Krantz Final approval and acceptance of this thesis is contingent upon the candidate’s submission of the final copies of the thesis to the Graduate College. I hereby certify that I have read this thesis prepared under my direction and recommend that it be accepted as fulfilling Professional Science Masters in Economic Geology Degree requirement. Date: 08/16/2019 Mark D. Barton PSM Thesis Committee Chair Department of Geosciences 2 ACKNOWLEDGEMENTS Financial support for this study was provided by the Lowell Institute for Mineral Resources at the University of Arizona and the W.M. Keck Foundation (grant 929941). William (Billy) Fitzpatrick and Matthew Gabriel assisted with data collection, mapping and core logging. Daniel Favorito assisted with drafting help and Roy Greig, Claire Getz, Michael Kassela are thanked for their geologic insights. Lantz Indergaard, Brian Sparks and the people at the Lisbon Valley mine are also thanked for their knowledge of the Lisbon Valley mine and permitting access to their core samples and geology. 3 TABLE OF CONTENTS LIST OF FIGURES………………….………………………………………...………. 6 LIST OF TABLES……………………………………………………………………... 10 ABSTRACT…………………………………………………….…………...…………. 11 INTRODUCTION……………………………………………………………………... 14 GEOLOGIC SETTING………………………………………………………………… 15 DISTRICT GEOLOGY………………………………………………………………… 17 Lisbon Valley………………………………………………………………….... 17 Northern Moab Fault……………………………………………………………. 18 METHODS....................................................................................................................... 19 DISTRIBUTION OF ALTERATION AND MINERALIZATION…………………..... 20 Lisbon Valley....................................................................................................... 20 Geology and Distribution of Alteration and Mineralization..................... 20 Petrographic Observations........................................................................ 22 Paragenesis............................................................................................... 23 Northern Moab Fault............................................................................................ 24 Geologic patterns along the northern Moab Fault.................................... 24 Geology and Distribution of Alteration and Mineralization.................... 24 Petrographic Observartions...................................................................... 30 4 Mineralogy and Paragenesis.................................................................... 31 Comparing Lisbon Valley and the northern Moab Fault..................................... 31 DISCUSSION.................................................................................................................. 32 Relationship Between Bleaching and Mineralization......................................... 32 Comparative Geologic Histories of Copper Mineralization................................ 33 CONCLUSIONS............................................................................................................. 35 FIGURES........................................................................................................................ 37 TABLE 1......................................................................................................................... 58 TABLE 2......................................................................................................................... 59 REFERENCES CITED.................................................................................................. 60 5 LIST OF FIGURES Figure 1. Location map of study areas (red boxes) showing salt walls (blue polygons), copper occurrences (green circles, uranium occurrences (gray circles), faults in the region (thin black lines), extent of paradox salt (dashed line), and the town of Moab (red star). Black rectangle in map of Utah represents figure area. Figure adapted from Ge et al., (2008). Figure 2. Stratigraphic column of units in the northern Paradox Basin showing copper and uranium occurrences, possible sources of metals, thickness variations, and simplified lithology log (after Doelling & Ross, 1998; Doelling, 2001; Trugdill, 2010). Figure 3. Geologic Map of Lisbon Valley area. Black rectangle represents study area and outline for figure 4. Based on previous work by Doelling (2004). Figure 4. Geologic map and cross sections of Lisbon Valley mine area. Shows the complex nature of various normal faults and the relay of the Lisbon Valley fault into the GTO fault. Red circles represent open pit mining in the area. Geologic cross- section A-A’ represents a faulted synclinal structure within the lower Lisbon Valley area. Red box indicates area where cross-section completed by author using drill hole data. Cross-section completed by Lisbon Valley mine geologists and map adapted from Deolling (2004). Figure 5. Northern Moab fault splays. This is a relay zone of the Moab fault and is where field mapping and analysis was completed. Rectangles represent areas in figures 6 below. Geology and structure adapted from Doelling (2002). Figure 6. Geologic map of the northern Moab fault splays. Red normal faults represent faulting due to increased deformation bands. Blue represents faults due to joints and fractures. Black rectangles represent field areas and representative figures. Geology adapted from Davatzes (2005). Figure 7. Photograph looking West displaying the different units of the Entrada Formation. Moab tongue is on top, followed by the Curtis formation and the Slick Rock member. Figure 8. Thin section photographs of samples taken from the Lisbon Valley mine area. A: Disseminated malachite in Burro Canyon sandstone between detridal quartz grains (UT18LVM-GTO230-686, 20x). B: Disseminated pyrite and chalcopyrite veins in Burro Canyon sandstone (UT18LVM-GTO224, 5x). C: Disseminated chalcocite and chalcopyrite in lower Burro Canyon Sandstone from Centennial drill core (UT18LVM-CMW09). D: Carbonate cement in between sand grains in lower Burro Canyon sandstone from the Centennial pit at Lisbon Valley Mine (UT18LVM- 07). Figure 9. Paragenetic sequence of various minerals within both field areas. A. Paragenetic sequence of select minerals in the Burro Canyon Formation at Lisbon Valley, based on Barton, I. (2018), Altinok (1998), Hahn and Thorson (2005). B. Paragenetic sequence for Moab Tongue member of the Entrada Sandstone based on Garden (2001) and this study. Figure 10. Cross sections based on drill hole logging of six GTO core holes. Cretaceous rocks are broken down into separated beds to show varied lithology. A. Sandstone 7 and shales make up most of the rocks and Beds 3-15 represent various units within the Burro Canyon Formation. Red stars are hand sample locations. B. Carbonate cement dominate the shales while copper grades are higher in fluvial sandstones of the lower Burro Canyon Formation. Pyrite primarily occurs in areas absent of higher- grade copper concentrations. C. Copper is found in the form of chalcocite and malachite. Higher grade appears to be within proximity to the various faults. D. Carbonate cement lies within shales of the Mancos Formation and thin slices within the Burro Canyon Formation. E. Clays were analyzed using short wave infared (SWIR). The dominant clay was kaolinite which was also observed by Jacobs and Kerr (1965) in other areas where the Lisbon Valley fault outcrops. The stars represent individual scans and show the dominant clay within the sample. Bed thicknesses and total copper content were provided by Hahn and Thorson (2006) and Lisbon Valley mine geologists. Figure 11. Anaconda mapping method used to show lithology, mineralization, alteration, and structure inside the Centennial pit at Lisbon Valley mine. Note the varied lithologies in the cretaceous rocks on the left. Method based on Brimhall (2005). Figure 12. West side of Mill Canyon showing geology and alteration. A. Geology and structure based on Eichhubl (2009). B. Alteration map showing oxidized copper and carbonate cement. Partial bleaching of the slick rock member of the Entrada sandstone is also represented. C. Mn-Cu nodules