EVALUATING THE PRESERVATION OF HURRICANE DEPOSITS IN FLORIDA COASTAL SEDIMENTS By MARYLEA HART A THESIS PRESENTED TO THE GRADUATE SCHOOL OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE UNIVERSITY OF FLORIDA 2003 Copyright 2003 by Marylea Hart This thesis s dedicated to my grandmother (Mimi) who has provided support and encouragement to three generations of my family while studying for their advanced degrees. Her educational values inspired me to continue my education beyond my bachelor’s degree. ACKNOWLEDGMENTS I wish to thank my advisor, Dr. John Jaeger, for his patience and guidance throughout my thesis work. I would also like to thank my committee members, Dr. Mark Brenner and Dr. Paul Ciesielski, for their countless advice; and Dr. Jason Curtis for his assistance with lab work. Also, I wish to thank William Kenney for his lab assistance and for always having time to answer my endless questions. I also thank Lisa Marie Mertz for her help with lab work; and Donald Hardison and Jango Bhadha for hours of discussion and advice. iv TABLE OF CONTENTS page ACKNOWLEDGMENTS ................................................................................................. iv LIST OF TABLES............................................................................................................ vii LIST OF FIGURES ......................................................................................................... viii ABSTRACT.........................................................................................................................x CHAPTER 1 INTRODUCTION ...........................................................................................................1 2 BACKGROUND INFORMATION ................................................................................7 Signal .............................................................................................................................. 7 Preservation of Hurricane Deposits .............................................................................. 10 Coastal Ponds................................................................................................................ 12 Study Area .................................................................................................................... 13 Known Hurricanes of St. Vincent Island Region.......................................................... 14 3 METHODS ....................................................................................................................28 4 RESULTS ......................................................................................................................33 General Lithology ......................................................................................................... 33 Analyses of 210Pb .......................................................................................................... 35 Analyses of 137Cs .......................................................................................................... 36 Magnetic Susceptibility ................................................................................................ 36 Grain Size...................................................................................................................... 37 Micropaleontology........................................................................................................ 38 Salinity .......................................................................................................................... 39 Weight %C and %N...................................................................................................... 39 5 DISCUSSION................................................................................................................59 Geochronology.............................................................................................................. 59 Signal ............................................................................................................................ 66 Preservation Potential ................................................................................................... 75 v 6 CONCLUSION..............................................................................................................87 REFERENCES CITED......................................................................................................89 BIOGRAPHICAL SKETCH .............................................................................................94 vi LIST OF TABLES Table page 2-1. Data on hurricanes to affect St. Vincent Island from 1880 to 2001 .........................23 2-2. Predicted recurrence interval based on the model developed by Overland..............25 2 5-1. Results for the calculation of the Peclet number for a Kd value of 10 and an L value of 10 cm........................................................................................................62 5 5-2. Results for the calculation of the Peclet number for a Kd value of 10 and an L value of 10 cm........................................................................................................63 2 5-3. Results for the calculation of the Peclet number for a Kd value of 10 and an L value of 5 cm..........................................................................................................63 5 5-4. Results for the calculation of the Peclet number for a Kd value of 10 and an L value of 5 cm..........................................................................................................63 5-5. Sedimentation and mixing rates for several coastal ponds.......................................65 5-6. Synopsis of detection of hurricanes by each of the proxies tested ...........................75 vii LIST OF FIGURES Figure page 1-1 Location of St. Vincent Island ..............................................................................6 2-1 Location map drafted of the two coastal bays studied along the west-central coast. ...................................................................................................................18 2-2 Diagram drafted of the three storm facies...........................................................19 2-3 Location map drafted for cores taken at (A) Lake Shelby and Middle Lake, Alabama and (B) Western Lake, Florida . ..........................................................20 2-4 Location map drafted of a study of coastal Louisiana hurricane deposits in salt marshes. ..............................................................................................................21 2-5 Location maps drafted for cores taken in (A) New Jersey and (B) Rhode Island...................................................................................................................22 2-6 Figure of the hurricanes to strike the Florida panhandle from 1885 to 1994 .....26 2-7 Path of hurricane eyewalls passing near St. Vincent Island. ..............................27 3-1 Coring locations..................................................................................................32 4-1 Photographs of cores...........................................................................................40 4-2 Gamma bulk density and x-radiograph data for core OP1. ................................41 4-3 Gamma bulk density and x-radiograph data for core OP2 .................................42 4-4 Red-green-blue data for cores.............................................................................43 4-5 Pixel density and x-radiograph data for cores.....................................................44 4-6 Plots of gray scale pixel density versus gamma bulk density for cores..............45 4-7 Gamma bulk density and x-radiograph data for cores A) FP1 and B) FP2. .......46 4-8 Total and excess 210Pb activity for cores.............................................................47 4-9 Measurements of total and excess 210Pb for core FP2 ........................................48 viii 4-10 137Cs activity for cores A) OP1 and B) FP1........................................................49 4-11 Measurements of 137Cs activity for core FP2......................................................50 4-12 Magnetic susceptibility measurements for cores ................................................51 4-13 Percent sand data for cores. ................................................................................52 4-14 Mean and median grain sizes for cores...............................................................53 4-15 Sorting and mode measurements for cores. ........................................................54 4-16 Plots of percent sand versus gamma bulk density (gm/cc) for cores..................55 4-17 Foraminifera abundances per 0.3 g of sample for cores. ....................................56 4-18 Salinity profiles for cores....................................................................................57 4-19 Percent organic carbon and nitrogen for cores. ..................................................58 5-1 210Pb inventory for cores.....................................................................................81 5-2 Sediment accumulation rates for cores. ..............................................................82 5-3 Plot of percent sand versus percent organic carbon for cores.............................83 5-4 Diagram of the preservaton of an event layer after its deposition.