Brigham Young University BYU ScholarsArchive Theses and Dissertations 2012-10-30 Insights into the Early Transgressive History of Lake Bonneville from Stratigraphic Investigation of Pilot Valley Playa, UT/NV, USA Kevin A. Rey Brigham Young University - Provo Follow this and additional works at: https://scholarsarchive.byu.edu/etd Part of the Geology Commons BYU ScholarsArchive Citation Rey, Kevin A., "Insights into the Early Transgressive History of Lake Bonneville from Stratigraphic Investigation of Pilot Valley Playa, UT/NV, USA" (2012). Theses and Dissertations. 3803. https://scholarsarchive.byu.edu/etd/3803 This Thesis is brought to you for free and open access by BYU ScholarsArchive. It has been accepted for inclusion in Theses and Dissertations by an authorized administrator of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. Insights into the Early Transgressive History of Lake Bonneville from Stratigraphic Investigation of Pilot Valley Playa, UT/NV, USA Kevin A. Rey A thesis submitted to the faculty of Brigham Young University in partial fulfillment of the requirements for the degree of Master of Science Alan L. Mayo, Chair Stephen T. Nelson Barry R. Bickmore Department of Geological Sciences Brigham Young University October, 2012 Copyright © 2012 Kevin A. Rey All Rights Reserved ABSTRACT Insights into the Early Transgressive History of Lake Bonneville from Stratigraphic Investigation of Pilot Valley Playa, UT/NV, USA. Kevin A. Rey Department of Geological Sciences, BYU Master of Science Multiple shallow sediment cores were obtained from Pilot Valley playa, a sub-basin located in the northwestern Bonneville basin. Analysis of stratigraphy, ostracodes, mineralogy, chemistry, total inorganic carbon (TIC), total organic carbon (TOC), and stable isotopes were performed to better place these sediments into proper context with respect to the Lake Bonneville cycle. Results showed Pilot Valley playa contains a nearly full sequence of Lake Bonneville deep-water marl in addition to sediments deposited before and after the Lake Bonneville cycle. Within the marl is a sequence of organic rich algal laminated marl correlated with the Stansbury oscillation. Four 14C ages ranging from ~22.4 k 14C years to ~15.8 k 14C years from preserved algae filaments in this sequence place it well within the time frame of the Stansbury oscillation. Oolitic sand found below this sequence indicates the existence of a shallow (<~5 m), saline lake in Pilot Valley prior to the transgression of Lake Bonneville. Analysis of sediments deposited during the late regressive phase of Lake Bonneville indicates the lake may have fallen to levels below that of Pilot Valley prior to transgressing to the Gilbert level. Keywords: Lake Bonneville, Lake Bonneville marl, Stansbury oscillation, Pilot Valley playa, Pilot Valley stratigraphy ACKNOWLEDGEMENTS I would like to thank my committee chair, Dr. Alan Mayo, for his patience as I worked though the details of this project. I also want to thank my committee members Dr. Steve Nelson and Dr. Barry Bickmore for their insight and advice as I was writing. Dr. Charles G. “Jack” Oviatt, of Kansas State University, was instrumental in helping me understand how to catalog and interpret various aspects of each core used in this project and in analyzing ostracodes. David Tingey provided many hours of laboratory instruction during sample preparation and analysis. Jeffery Rampton and Shawn Wiggins spent time with me in Pilot Valley on blisteringly hot summer days as well as frigidly cold and muddy winter days collecting cores. Their contribution proved invaluable. This entire project would not have been possible were it not for the financial support of the BYU Hydrogeochemistry Laboratory. Finally I must thank my wife, April, who for the past two years has put up with me as I have finished my Master’s Degree. TABLE OF CONTENTS TABLE OF CONTENTS ............................................................................................................... iv LIST OF FIGURES ........................................................................................................................ v LIST OF TABLES ......................................................................................................................... vi INTRODUCTION .......................................................................................................................... 1 Purpose and objectives ................................................................................................................ 4 SITE DESCRIPTION ..................................................................................................................... 5 METHODS ..................................................................................................................................... 6 Field methods .............................................................................................................................. 6 Laboratory Methods .................................................................................................................... 6 Ostracodes ................................................................................................................................... 7 Mineralogy .................................................................................................................................. 7 Chemistry—Major and Trace Elements ...................................................................................... 8 Total Inorganic Carbon and Total Organic Carbon .................................................................. 9 Stable Isotopes—δ13C and δ18O .................................................................................................. 9 Dating ........................................................................................................................................ 10 RESULTS ..................................................................................................................................... 11 Overview of Stratigraphy .......................................................................................................... 11 Detailed Stratigraphy of PVC 15 core ...................................................................................... 14 Ostracodes ................................................................................................................................. 15 Mineralogy ................................................................................................................................ 15 Bulk Chemistry—Major and Trace elements ............................................................................ 18 Total Inorganic Carbon and Total Organic Carbon ................................................................ 19 Stable Isotopes— δ18O and δ13C ............................................................................................... 19 Dating ........................................................................................................................................ 20 DISCUSSION ............................................................................................................................... 20 Unit V ........................................................................................................................................ 20 Unit IV ....................................................................................................................................... 21 Unit III ....................................................................................................................................... 24 Unit II ........................................................................................................................................ 25 Unit I ......................................................................................................................................... 27 CONCLUSIONS........................................................................................................................... 28 REFERENCES ............................................................................................................................. 31 FIGURES ...................................................................................................................................... 36 TABLES ....................................................................................................................................... 54 Appendix A ................................................................................................................................... 58 iv LIST OF FIGURES Figure 1. Map showing major Lake Bonneville levels and study area. ........................................ 37 Figure 2. Pilot valley and surrounding area .................................................................................. 38 Figure 3. Core locations in Pilot Valley........................................................................................ 39 Figure 4. Schematic stratigraphic column .................................................................................... 40 Figure 5. Stratigraphic cross-section across Pilot Valley ............................................................. 41 Figure 6. Unit V: PVC 15 oolitic sand .......................................................................................... 42 Figure 7.