ICHNOLOGY, MINERALOGY, AND PALEOENVIRONMENTAL IMPLICATIONS OF THE VERDINE AND GLAUCONY FACIES IN SEDIMENTARY ROCKS by Sherie C. Harding A dissertation submitted to the faculty of The University of Utah in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Geology Department of Geology and Geophysics The University of Utah December 2014 Copyright © Sherie C. Harding 2014 All Rights Reserved The University of Utah Graduate School STATEMENT OF DISSERTATION APPROVAL The dissertation of Sherie C. Harding has been approved by the following supervisory committee members: Allan A. Ekdale, Chair May 5, 2014 Date Approved Marjorie A. Chan, Member May 5, 2014 Date Approved Erich U. Petersen, Member May 5, 2014 Date Approved Genevieve Atwood, Member May 12, 2014 Date Approved Daniel Horns, Member May 11, 2014 Date Approved and by John Bartley, Chair of the Department of Geology and Geophysics and by David B. Kieda, Dean of The Graduate School. ABSTRACT The ichnology and mineralogy of selected occurrences of trace fossils and green minerals in verdine and glaucony facies were investigated, and the nature and significance of their association were evaluated. Trace fossils and green marine clays commonly occur together and are genetically related. At each site fecal pellets in marine shelf sediments were determined to be the most likely precursor of the green minerals. Fecal pellets, which are common on shelf sea floor, are organic rich, and they provide microenvironments of reduction for green mineral authigenesis, which promotes the formation of glauconitic pellets or odinite-rich pellets depending upon the paleoenvironmental conditions. Fecal pellets in intensely burrowed sediment represent a direct link between ichnology and green mineral authigenesis. Five Phanerozoic sites representing terrigenous marine shelf deposits were examined: the Middle Eocene Crockett Formation in eastern Texas; two Cambrian sites including the Reno Member, Lone Rock Formation in southern Wisconsin and the Lion Mountain Member, Upper Riley Formation in central Texas; and two Mesozoic sites including the Jurassic Curtis Formation in central Utah and the Cretaceous Shannon Sandstone in central Wyoming. All sites represent times during the geologic past when global temperature was abnormally high. The verdine facies, dominated by odinite-rich pellets, was identified in the “Main Glauconite Bed” (MGB) of the Crocket Formation. Odinite in the modern sea floor is confined to tropical latitudes, and its association with trace fossils made by shallow marine animals suggests a shallower and more tropical paleoenvironment during the Middle Eocene than was previously recognized. Glauconitic pellets were found at all the other sites, where sedimentologic characteristics, stratigraphic occurrence, ichnofabric, and trace fossil assemblages indicate a multistage, reworked depositional history. The story of sea level dynamics unfolds where glauconitic minerals indicate elevated sea level during a marine transgression. Subsequently, quartz grains and shallow-marine burrows indicate an interval of regression. Finally, shallow shifting-sand substrate occupied by burrowing organisms indicates adaptation for life in water too shallow for glauconitic mineral authigenesis. These findings document the paleoenvironment of the marine shelf during times of fluctuating sea level and warm paleoclimate. iv TABLE OF CONTENTS ABSTRACT............................................................................................................................iii ACKNOWLEDGMENTS.....................................................................................................ix CHAPTERS 1. INTRODUCTION ..................................................................................................... 1 Objectives....................................................................................................................1 Green Minerals........................................................................................................... 3 Ichnology.....................................................................................................................5 Applications................................................................................................................ 6 Summary of Chapters.................................................................................................8 References..................................................................................................................17 2. ICHNOLOGY AND MINERALOGY OF THE MAIN GLAUCONITE BED, CLAIBORNE GROUP, MIDDLE EOCENE, TEXAS: PALEOENVIRONMENTAL IMPLICATIONS................................................... 20 Extended Abstract.....................................................................................................21 Ichnology of the MGB....................................................................................... 21 Clay Mineralogy of the MGB............................................................................21 Paleoenvironmental Implications...................................................................... 24 Acknowledgments.....................................................................................................25 References Cited.......................................................................................................25 3. ICHNOLOGY AND SEDIMENTOLOGY OF AN EOCENE GREENSAND IN TEXAS: BEHAVIORAL RESPONSE TO THE MIDDLE EOCENE CLIMATIC OPTIMUM (MECO)...........................................................................27 Abstract .....................................................................................................................27 Introduction.............................................................................................................. 28 Study Locality .......................................................................................................... 29 Trace Fossils and Ichnofabrics.................................................................................30 Pellets.........................................................................................................................32 Sediment Chemistry and Clay Mineralogy.............................................................34 Discussion..................................................................................................................36 Ichnology............................................................................................................ 36 Paleoclimate........................................................................................................40 Conclusion................................................................................................................ 41 Acknowledgments.....................................................................................................43 References..................................................................................................................60 4. MINERALOGY AND GEOCHEMISTRY OF THE MAIN GLAUCONITE BED IN THE MIDDLE EOCENE OF TEXAS: PALEOENVIRONMENTAL IMPLICATIONS FOR THE VERDINE FACIES.......................................................63 Abstract......................................................................................................................64 Introduction.............................................................................................................. 64 Previous Work on the M G B..............................................................................65 Background on Green Clay Minerals...............................................................65 Green clay minerals..................................................................................... 65 Authigenesis..................................................................................................67 Diagenesis and weathering..........................................................................69 Methods......................................................................................................................71 Sampling............................................................................................................. 71 Mineral Identification........................................................................................ 71 X-ray diffraction analysis............................................................................72 Electron microprobe analysis...................................................................... 72 Mossbauer spectroscopy..............................................................................72 QEMSCAN analysis....................................................................................72 Results........................................................................................................................72 Petrography......................................................................................................... 72 Sediment.......................................................................................................72 Pellets............................................................................................................ 73 Color............................................................................................................. 73 Mineral Composition......................................................................................... 73