University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Masters Theses Graduate School 8-2007 Late Holocene Charcoal Stratigraphy and Modern Charcoal Deposition in the Pine Rocklands of Great Abaco Island, the Bahamas David N. West University of Tennessee, Knoxville Follow this and additional works at: https://trace.tennessee.edu/utk_gradthes Part of the Geography Commons Recommended Citation West, David N., "Late Holocene Charcoal Stratigraphy and Modern Charcoal Deposition in the Pine Rocklands of Great Abaco Island, the Bahamas. " Master's Thesis, University of Tennessee, 2007. https://trace.tennessee.edu/utk_gradthes/4439 This Thesis is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Masters Theses by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a thesis written by David N. West entitled "Late Holocene Charcoal Stratigraphy and Modern Charcoal Deposition in the Pine Rocklands of Great Abaco Island, the Bahamas." I have examined the final electronic copy of this thesis for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Master of Science, with a major in Geography. Kenneth H. Orvis, Major Professor We have read this thesis and recommend its acceptance: Sally P. Horn, Henri D. Grissino-Mayer Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) To the Graduate Council: I am submitting herewith a thesis written by David N. West entitled "Late Holocene Charcoal Stratigraphy and Modem Charcoal Deposition in the Pine Rocklands of Great Abaco Island, the Bahamas." I have examined the final paper copy of this thesis forform and content and recommend that it be accepted in partial fulfillment of the requirements for the degree of Master of Science, with a major in Geography. /"Dr. Kenneth H. Orvis,Major Professor We have read this thesis and recommend its acceptance: �E_.Dr.Sally.Hom, Committee Member� ��� Dr. Henri D. Grissino-Mayer, Committee Member Accepted for the Council: LATE HOLOCENE CHARCOAL STRATIGRAPHY AND MODERN CHARCOAL DEPOSITION IN THE PINE ROCKLANDS OF GREAT ABACO ISLAND, THE BAHAMAS A Thesis Presented forthe Master of Science Degree The University of Tennessee, Knoxville David Norman West August 2007 Copyright © 2007 by David Norman West All rights reserved 11 DEDICATION This thesis is dedicated to my parents, Johnnie E. West and Grace M. West lll ACKNOWLEDGEMENTS I owe special thanks to the students in the Laboratory of Paleoenvironmental Research forfield and laboratory assistance, especially Allison Stork, Martin Alford, Joe Burgess, Chad Lane, and Zack Taylor. I would also like to thank the members of my committee, Dr. Ken Orvis, Dr. Sally Horn, and Dr. Henri Grissino-Mayer, fortheir assistance and support over the course of this project. They, along with Dr. Anita Drever, Dr. Ronald Foresta, Dr. Lydia Pulsipher, Dr. John Rehder, andDr. Bruce Ralston, have trained and encouraged me in all aspects of geography and in all else required for success in the pursuit of a Masters degree. The sediment core I analyzed was. recovered during a field expedition led by Drs. Hornand Orvis and funded by the Global Environmental Change Research Group (GECRG) at the University of Tennessee. The GECRG also funded initial radiocarbon determinations on the core. Other radiocarbon dates critical to this thesis were kindly provided to me by Dr. Timothy Jull and the NSF-Arizona AMS Laboratory. My field sampling of charcoal during a pine rockland fire on Abaco Island took advantage of a controlled burn funded and coordinated by The Nature Conservancyand the USDA Forest Service in collaboration with Bahamianresource agencies. For allowing me to conduct my research as part of this burnand for their support in the field, both of my study and so much other work on pine rockland ecology, I thank ChrisBergh and Alison Higgins of The Nature Conservancy, and Dr. Mac Callaham and Dr. Joe O'Brien of the USDA Forest Service. My laboratory analyses of modern and fossil charcoal samples were conducted in the Laboratory of Paleoenvironmental Research in the Department of IV Geography at the University of Tennessee. The aerial photographs included in thisthesis were takenby Dr. Ken Orvis with fundingfrom the National Geographic Society. V ABSTRACT The paleoecological history of the Bahamas archipelago is one of change throughout the Holocene, and is recorded in the sediments deposited in solution holes. However, with its karstic pine rocklands landscape, Great Abaco Island has virtually no overland flow of water, neither riversnor sheet-flow. This means that transportof charcoal produced through biomass burning and deposited in local ponds and solution holes is primarily microscopic in size and is probably transported by wind. Fires in the pine rocklands are mainly low-intensity ground firesthat result in very little aerial transport of charcoal. Unless a fireoccurs immediately adjacent to a pond, very little microscopic or macroscopic charcoal is deposited in it. Split Pond, located in the northeastportion of Great Abaco Island, yieldeda 2. 7 m long core retrieved beneath 30 cm of water. A piece of charcoal recovered fromnear the base of the core has been dated to 5830 ± 50 14C yr BP. At approximately 250 cm in the core, there is a discontinuity in the sediments, with a layer of dense, clayey material below 230 cm abruptly changing to organic-laced marl above. This is possibly due to a period when the lake became completely dry, exposing the sediments to erosive processes. The 5830 ± 50 14C yr BP date was recovered from the dense clay layer, but because of the condition of the sediments, a fullexamination of material fromthis layer was not practical. Immediately above the discontinuity, at approximately 220 cm, material yielding a date of 1503 ± 3 7 14C yr BP was recovered, which serves as the basal date forthe studied portion of the core. Two dates above the discontinuity (2910 ± 40 Vl and1152 ± 36 14C yr BP) areconsidered to be older, redeposited material andhave been discussed as such. Pollen preservation is poor throughout the core, with pine pollen, presumably of Pinus caribaea var. bahamensis, robust enough to be present in sufficientamounts to allow forcounting, but even that is poorly preserved at certain levels possibly due to water alkalinity or periods of drying. Charcoalanalysis of the core indicates a period of increased burningin the area of Split Pond ca. 1300 14C yr BP, which correlates with the suggested arrival time of the Lucayans in the Bahamas. In the upper portion of the core, the data indicate a prolonged period of increased burningsince ca. 1000 14C yr BP. Pine pollen also increased during this period. In most levels of the core neither microscopic nor macroscopic charcoalfragments are foundin abundance, a findingthat fitswith other paleoenvironmentalstudies conducted in the pine rocklands. As a second portion of the study, samples of air-fallcharcoal were collected in open Petri-dish traps during a controlled burnin the recently chartered Great Abaco National Park. The firewas a low-intensity ground firetype that most commonly occurs in the pine rocklands. For those traps placed down-wind of the burn, microscopic charcoal was deposited in significantamounts, but macroscopic charcoal was not found in quantity. The traps placed approximately 1 km upwind of the burnas controls yielded no charcoalof any size. This supports the hypothesis that the low intensity ground fires in the pine rocklands produce low amountsof microscopic charcoalthat is wind­ transportedinto local ponds, but are not intense enough to transport appreciable amounts of macroscopic charcoal. This helps explain the relatively low amounts of charcoal vu foundin my Split Pond study and in other paleoecological studies conducted in the Bahamian archipelago. vm TABLE OF CONTENTS CHAPTER! INTRODUCTION ...............................................................................................................1 CHAPTER2 LITERATURE REVIEW ...................................................................................................... 7 Paleoecological Studies in the Tropical Atlantic and Caribbean Region ............... 7 Paleoecological Studies from Mainland Florida..................................................... 9 Previous Paleoecological Research in the Bahamas............................................. 11 Charcoal Transport During Fire Events ............................................................... 14 Charcoal as a Proxy for Past Fires ....................................................................... 16 Evidence of the Timing of Human Migration into the Bahamian Archipelago ..... 16 CHAPTER3 ENVIRONMENT AL AND CULTURAL SETTING ................................................................. 19 Study Area .............................................................................................................. 19 Site Description...................................................................................................... 19 Geologic and Physiographic Setting ..................................................................... 24 Climate ..................................................................................................................