Brigham Young University BYU ScholarsArchive Theses and Dissertations 2019-12-01 Depositional Analysis of a Holocene Carbonate Strand Plain Using High Resolution GPR, Sediment Analysis, and C-14 Dating Kaleb Robert Markert Brigham Young University Follow this and additional works at: https://scholarsarchive.byu.edu/etd Part of the Physical Sciences and Mathematics Commons BYU ScholarsArchive Citation Markert, Kaleb Robert, "Depositional Analysis of a Holocene Carbonate Strand Plain Using High Resolution GPR, Sediment Analysis, and C-14 Dating" (2019). Theses and Dissertations. 7751. https://scholarsarchive.byu.edu/etd/7751 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]. Depositional Analysis of a Holocene Carbonate Strand Plain Using High Resolution GPR, Sediment Analysis, and C-14 Dating Kaleb Robert Markert A thesis submitted to the faculty of Brigham Young University in partial fulfillment of the requirements for the degree of Master of Science John H. McBride, Chair Scott Ritter Sam Hudson Department of Geological Sciences Brigham Young University Copyright © 2019 Kaleb Robert Markert All Rights Reserved ABSTRACT Depositional Analysis of a Holocene Carbonate Strand Plain Using High Resolution GPR, Sediment Analysis, and C-14 Dating Kaleb Robert Markert Department of Geology, BYU Master of Science Understanding modern carbonate depositional systems gives valuable insights into the interpretation of ancient carbonate systems. Ancient carbonate strand plains have the potential to act as productive hydrocarbon reservoirs because of their relatively high porosity. Unfortunately, they are difficult to identify in the rock record because of the lack of work done on modern analogues. San Salvador Island in the Bahamas hosts a well-exposed and easily accessible Holocene strand plain, ideal as a modern analogue. Sandy Hook, located on the southeast part of the island, consists of approximately 35 ridge-swale features that show signs of four distinct zones of deposition. In this study, 20 sediment samples were collected from one meter in depth, and throughout each zone. The sediment analysis reveals remarkably consistent grain-size distributions across the four zones. Carbon-14 ages were taken from the sediment samples. They revealed ages decreasing from 2617 ± 188 YBP to modern moving seaward through zone 4. The ages reveal depositional rates of 0.08 to 0.29 meters of accretion per year. Four pseudo-3D GPR surveys were acquired in Zones B, C, and D, and a 2D GPR survey was acquired that spanned the three zones. The pseudo-3D surveys revealed consistent reflectors through the width of the survey indicating that the 2D surveys represent more than the single line. The 2D survey reveals semi-parallel seaward- dipping reflectors (representing fair-weather deposits) that are truncated by sigmoidal seaward- dipping reflectors (high-energy storm deposits). Indicating that Sandy Hook was built through both fair-weather deposits and high-energy storm events. Keywords: ground penetrating radar, sediment analysis, carbon-14, San Salvador Island, Sandy Hook, strand plain deposition ACKNOWLEDGEMENTS This project would not have been possible without the help of my graduate committee and other faculty of the BYU Geology department. I would like to thank my committee chair, Dr. John H. McBride, for all the tutelage and support that he provided. He allowed me opportunities to work through the process and grow as a scientist. I would like to thank Scott Ritter for helping me navigate the world of carbonates and for his support in collecting the data. I would like to thank Sam Hudson for his help revising my thesis. Thank you to David Tingey for the time that he spent collecting and preparing the samples on San Salvador and for his help exploring the meaning of the data. I am thankful for Kevin Rey’s guidance as I prepared and processed the carbon-14 samples, and for Bill Keach’s help with importing my GPR data into Geoprobe. The data processing and visualization were possible thanks to software grants from Landmark (Halliburton) University Grant Program and from the HIS Kingdom Educational Grant Program. Lastly, I would like to thank my wonderful wife, Isabella, for her love and support through the process. She encouraged me through hard times and gave me the final push needed to complete this project. TABLE OF CONTENTS TITLE PAGE..................................................................................... ...............................................i ABSTRACT .................................................................................................................................. ii ACKNOWLEDGEMENTS ......................................................................................................... iii TABLE OF CONTENTS ............................................................................................................. iv LIST OF FIGURES ......................................................................................................................v INTRODUCTION ....................................................................................................................... 1 BACKGROUND .......................................................................................................................... 2 Previous Research ..................................................................................................................... 4 Beach-Ridge Systems............................................................................................................ 4 Sandy Hook .......................................................................................................................... 5 METHODS .................................................................................................................................. 6 Sediment Analysis .................................................................................................................... 8 RESULTS ....................................................................................................................................10 Sediment Analysis Results .......................................................................................................10 C-14 Results.............................................................................................................................11 GPR Results.............................................................................................................................11 DISCUSSION..............................................................................................................................13 Radar Facies .............................................................................................................................13 Radar Facies Distribution .........................................................................................................15 Sea-Level Fluctuations .............................................................................................................17 Storm vs. Fair-Weather ............................................................................................................18 CONCLUSION ............................................................................................................................19 REFERENCES ............................................................................................................................20 iv LIST OF FIGURES Figure 1........................................................................................................................................23 Figure 2........................................................................................................................................24 Figure 3........................................................................................................................................25 Figure 4........................................................................................................................................26 Figure 5........................................................................................................................................27 Figure 6........................................................................................................................................28 Figure 7........................................................................................................................................29 Figure 8........................................................................................................................................30 Figure 9........................................................................................................................................32 Figure 10. .....................................................................................................................................34 Figure 11. .....................................................................................................................................35 Figure 12. .....................................................................................................................................36 v INTRODUCTION Carbonate strand plains are important to