University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 5-2011 Holocene Climate and Environmental History of Laguna Saladilla, Dominican Republic Maria Anne Caffrey [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Part of the Paleobiology Commons Recommended Citation Caffrey, Maria Anne, "Holocene Climate and Environmental History of Laguna Saladilla, Dominican Republic. " PhD diss., University of Tennessee, 2011. https://trace.tennessee.edu/utk_graddiss/955 This Dissertation 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 Doctoral Dissertations 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 dissertation written by Maria Anne Caffrey entitled "Holocene Climate and Environmental History of Laguna Saladilla, Dominican Republic." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Doctor of Philosophy, with a major in Geography. Sally P. Horn, Major Professor We have read this dissertation and recommend its acceptance: Henri Grissino-Mayer, Liem Tran, David Finkelstein 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.) Holocene Climate and Environmental History of Laguna Saladilla, Dominican Republic A Dissertation Presented for the Doctor of Philosophy Degree University of Tennessee, Knoxville Maria Anne Caffrey May 2011 Copyright © by Maria Anne Caffrey All rights reserved ii ACKNOWLEDGEMENTS I have many people to thank for their support and guidance while I completed this research. First and foremost I would like to thank my advisor, Sally Horn, for introducing me to Laguna Saladilla and for her insights into all aspects of this research. I appreciate all of her advice over the years on all matters related to not only this research, but also academia in general. This research was supported by the National Science Foundation (NSF) under Grant No. BCS-0550382 to Sally Horn, Ken Orvis, and Claudia Mora. The recovery and initial dating of the Saladilla core was supported by a grant to Ken Orvis from the National Geographic Society. NSF doctoral dissertation research improvement grant BCS-0550382 supported additional fieldwork in December 2009 and allowed for participation in conferences across the US. I would also like to thank the NSF-Arizona AMS Laboratory and Sigma Xi for supporting additional dating. I further thank Andrés Ferrer and the Moscoso Puello Foundation for logistical support in the Dominican Republic. I am very grateful for the assistance of my colleagues at the University of Tennessee and other universities. I would like to thank my dissertation committee members, Henri Grissino-Mayer, Liem Tran, and David Finkelstein, for their guidance, help with statistics, and edits on the dissertation. I also thank David Finkelstein for his help in the analyses of water samples and the identification of manganese fragments. In addition to his role in obtaining funds for this project, Ken Orvis, together with Sally Horn and Duane Cozadd, retrieved the Laguna Saladilla sediment core in 2001, and iii opened and described core sections. Ken later identified shell remains from the lower levels in the profile. Lawrence (Larry) Conyers at the University of Denver was instrumental in the collection and analyses of the ground penetrating radar data. Kurt Haberyan at Northwest Missouri State University assisted in the identification of diatoms. To undertake a work of this magnitude over the past four years has required the help of many people, most notably my colleagues in the University of Tennessee’s Laboratory of Paleoenvironmental Research, who have been a constant source of support and good humor. Their support has been invaluable, whether it be for bouncing ideas off of each other, commiserating when I have encountered setbacks, or celebrating an achievement. In particular, I thank Ian Slayton, Brian Watson, Joshua Albritton, Alisa Haas, Matthew Valente, and Alicia Smith. Alicia Smith assisted by counting manganese fragments from Laguna Saladilla on pollen slides. Grant Harley in the University of Tennessee’s Laboratory of Tree-Ring Science provided help with graphics. I would especially like to thank Ian Slayton for his help in the lab and in the field in the Dominican Republic. His valor in the face of countless cold showers and mosquitoes while visiting Laguna Saladilla went beyond the call of duty for any field assistant. I would further like to thank Javier Hernandez from Carbonera, Dominican Republic for his assistance in the field. None of this would have been possible without the support of my family, particularly my parents, John and Clem Caffrey, and my brother, Rob Caffrey. They are a constant source of love and support. Finally, I would like to thank my husband, Don Sullivan, who has shown a seemingly endless amount of love and encouragement while his wife travelled between Tennessee and Colorado to pursue her passion for mud. iv ABSTRACT Stratigraphic analyses of lacustrine sediments provide powerful tools for reconstructing past environments. The records that result from these analyses are key to understanding present-day climate mechanisms and how the natural environment may respond to anthropogenic climate change in the future. This doctoral dissertation research investigates climate and environmental history at Laguna Saladilla (19° [degrees] 39' N, 71° [degrees] 42' W; ca. 2 masl), a large (220 ha) lake along the north coast of Hispaniola. I reconstructed changes in vegetation and environmental conditions over the mid- to late Holocene based on pollen, microscopic charcoal, and diatoms in an 8.51 m sediment core recovered from the lake in 2001. Fieldwork in December 2009 included the use of ground penetrating radar to identify subaqueous deltas that indicate past positions of the Masacre river, which flows into the lake from the Cordillera Central. Laguna Saladilla was deeper and more saline from the base of the sediment profile approximately 8030 cal yr BP to about 3500 cal yr BP. Mangrove (Rhizophora) pollen percentages were highest around 7650 cal yr BP, when mollusk shells in the core suggest marine conditions. The lake became progressively brackish ca. 3500 cal yr BP, followed by a transition ca. 2500 cal yr BP to its current freshwater state. This shift in water chemistry was likely due in part to a change in the position of the Masacre river. Diatoms show that lake levels decreased as evaporation/precipitation ratios increased. Amaranthaceae and other herbs dominated the pollen record under the drier conditions of v the last 2500 cal yr BP; pollen of fire-adapted taxa, particularly Pinus, increased in the last 800 years. Patterns of microscopic charcoal influx at Laguna Saladilla over the Holocene are similar to patterns at Lake Miragoane, Haiti and Laguna Tortuguero, Puerto Rico. The changes in fire frequency or extent indicated by these Caribbean charcoal records may be driven by increased winter insolation at ca. 5000 cal yr BP that led to earlier winter drying. Comparing the charcoal record to archeological data and other paleoenvironmental records facilitated the disentangling of changes in climate from anthropogenic impacts. vi TABLE OF CONTENTS Acknowledgements…………………………………………………………………. iii Abstract……………………………………………………………………………... v List of tables………………………………………………………………………… ix List of figures……………………………………………………………………….. x 1. Introduction and overview……………………………………………………….. 1 1.1 Introduction…………………………………………………………………... 1 1.2 Drivers of Caribbean climate change………………………………………… 6 1.3 Tectonic drivers of Caribbean environmental change……………………….. 7 1.4 Research questions and objectives………………………………………….... 10 1.5 Dissertation organization…………………………………………………….. 13 References………………………………………………………………………... 15 2. Study area and research context………………………………………………….. 19 2.1 Laguna Saladilla and its physical and human setting………………………... 19 2.1.1 Geologic setting…………………………………………………………. 19 2.1.2 Climate………………………………………………………………….. 23 2.1.3 Vegetation and fire……………………………………………………… 23 2.1.4 Modern human settlement within the Laguna Saladilla watershed……... 31 2.2 Background and literature review……………………………………………. 32 2.2.1 Previous paleoenvironmental studies…………………………………… 32 2.2.2 Charcoal records………………………………………………………… 34 2.2.3 Humans and the archeological record of the Caribbean region………… 45 2.2.4 Tropical pollen…………………………………………………………... 50 2.2.5 Reconstructions of lacustrine environments using diatoms…………….. 51 2.2.6 Caribbean records relating to salinity and sea level…………………….. 64 2.2.7 Ground penetrating radar (GPR) and its applications to paleolimnology. 70 2.2.8 Sedimentary properties and GPR……………………………………….. 76 2.2.9 Other geophysical techniques of relevance……………………………... 81 References……………………………………………………………………...… 81 3. Using ground-penetrating radar to profile lake sediments in Laguna Saladilla, Domincan Republic…………………………………………………………………. 101 Abstract…………………………………………………………………………... 101 3.1 Introduction…………………………………………………………………... 102 3.2 Literature review……………………………………………………………... 104 3.3 Site description……………………………………………………………….