SEQUENCE STRATIGRAPHY OF THE ARCADIA FORMATION, SOUTHEAST FLORIDA: AN INTEGRATED APPROACH by Caroline M. Wright A Thesis Submitted to the Faculty of the Charles E. Schmidt College of Science in Partial Fulfillment of the Requirements for the Degree of Master of Science Florida Atlantic University Boca Raton, Florida August 2014 ACKNOWLEDGEMENTS I would like to thank my committee and the professionals at the USGS for their support and patience. Dr. Kevin Cunningham‟s expertise on Oligocene/Miocene ichnotaxa and carbonate microfacies analysis was invaluable. Ron Reese‟s guidance and help on lithologic, geophysical, and sequence analysis was instrumental and much appreciated. A special thanks to the entire staff at the USGS Florida Water Science Center for their support and help in obtaining the material and equipment for the study. Dr. Root and Dr. Comas were helpful in reviewing the manuscript and providing useful geophysical and hydrogeologic advice. To my family, friends, and all those who encouraged me to continue, thank you. Finally, I would like to thank my major professor Dr. Anton Oleinik for his unwavering support, guidance and patience as well his helpful expertise on sedimentology and stratigraphy; the completion of this study would not have been possible without his continued dedication. iii ABSTRACT Author: Caroline M. Wright Title: Sequence Stratigraphy of the Arcadia Formation, Southeast Florida: An Integrated Approach Institution: Florida Atlantic University Thesis Advisor: Dr. Anton Oleinik Degree: Master of Science Year: 2014 The Arcadia Formation is a mixed carbonate-siliciclastic rock unit that existed as a shallow carbonate ramp to platform environment during the Late Oligocene to Early Miocene Epoch. It can be divided into two distinct, informal sections based on lithological properties: the upper Arcadia Formation and lower Arcadia Formation. The sections are part of a major, third-order sequence that can be further divided into four higher-frequency, lower magnitude sequences: ARS1, ARS2, ARS3, and ARS4. The sequence boundary separating ARS2 and ARS3 represents a drastic change in the depositional regime from a high-energy, inner ramp/platform to a lower-energy, deep outer ramp environment. ARS3 represents the period of maximum flooding and constitutes a major portion of the regressive system tract (RST) of the third order iv depositional sequence. In certain sections, the Arcadia Formation is heavily bioturbated including ichnotaxa from the glossifungites, cruziana, and scolithos inchofacies. Thalassinoides sp. burrows of the glossifungites ichnofacies were found to be commonly associated with firmground substrates and breaks in sedimentation. The lithofacies associations were grouped into paleodepositional environments that ranged from restricted marine to deep outer ramp with lithology ranging from grainstone to wackestone to mudstone with variable amounts of siliciclastic and phosphatic constituents. Each sequence boundary extends regionally south from Broward County to southern Miami-Dade County utilizing gamma-ray geophysical signatures unique to each sequence. v SEQUENCE STRATIGRAPHY OF THE ARCADIA FORMATION, SOUTHEAST FLORIDA: AN INTEGRATED APPROACH 1.0 INTRODUCTION ...................................................................................................1 1.1 Objectives ........................................................................................................... 2 1.2 Hypothesis .......................................................................................................... 3 1.3 Relevance of Study ............................................................................................. 3 1.4 Thesis Organization ............................................................................................ 4 2.0 OVERVIEW OF THE ARCADIA FORMATION .................................................5 2.1 Geologic Setting ................................................................................................. 5 2.2 Global Sea Level during the Oligocene to Miocene ........................................ 10 2.3 Lithology .......................................................................................................... 11 2.4 Age ................................................................................................................... 13 2.5 Stratigraphic Position of the Arcadia Formation in South Florida ................... 16 3.0 PREVIOUS SEQUENCE STRATIGRAPHIC STUDIES ....................................18 4.0 METHODS ............................................................................................................22 4.1 Review of Sequence Stratigraphic Terms ........................................................ 25 5.0 RESULTS ..............................................................................................................30 vi 5.1 List of Lithofacies and Distribution of Ichnofossils in the Arcadia Formation Identified by the Author ................................................................................... 30 5.1.1 Unconformity related surfaces ................................................................35 5.1.2 Lithofacies 2: Glossifungites mudstone to clay ......................................36 5.1.3 Lithofacies 3: Peloidal packstone to grainstone ......................................39 5.1.4 Lithofacies 4: Peloidal, bioturbated wackestone ....................................41 5.1.5 Lithofacies 5: Sandy wackestone-packstone ..........................................43 5.1.6 Lithofacies 6: Mudstone (biomicrite) to cherty claystone ......................45 5.1.7 Lithofacies 7: Molluscan shellbed floatstone .........................................47 5.1.8 Lithofacies 8: Foraminifera-rich wackestone to packstone ....................50 5.1.9 Lithofacies 9: Bioclastic grainstone to molluscan floatstone .................52 5.1.10 Lithofacies 10: Skolithos-Cruziana bioclastic-lithoclastic packstone to grainstone ............................................................................................55 5.1.11 Lithofacies 11: Quartz sand/silt to sandy bioclastic grainstone ..............57 5.1.12 Lithofacies 12: Whole molluscan skeletal floatstone .............................59 5.1.13 Lithofacies 13: Bioturbated carbonate sandstone ...................................61 5.1.14 Lithofacies 14: carbonate sandstone .......................................................63 5.2 Sequence Stratigraphy ...................................................................................... 66 6.0 DISCUSSION ........................................................................................................71 6.1 Paleoenvironments of Lithofacies .................................................................... 71 vii 6.1.1 Restricted lagoon environment ...............................................................72 6.1.2 Open shelf lagoon ...................................................................................73 6.1.3 Inner ramp environment ..........................................................................78 6.1.4 Outer ramp environment .........................................................................79 6.2 Regional Correlation of Sequence Boundaries ................................................ 80 7.0 CONCLUSION ......................................................................................................83 APPENDIX .......................................................................................................................87 BIBLIOGRAPHY ............................................................................................................107 viii LIST OF TABLES Table 1. Comparison of previous sequence stratigraphic interpretations for the Arcadia Formation .............................................................................................. 19 Table 2. Terminology of cycle hierarchies as they relate to base sea-level changes. ....... 26 Table 3. List of ichnotaxa present in the Arcadia Formation ........................................... 30 Table 4. List of lithofacies identified in the G-2984 Core ................................................ 31 Table 5. Sequences and cycles with lithofacies associations throughout the Arcadia Formation ............................................................................................................ 69 Table 6. Profile across the subjacent Suwannee shallow-water carbonate ramp displaying the dominant occurrence of grains, depositional texture, and depositional structures across subenvironments. ................................................ 76 ix LIST OF FIGURES Figure 1. Structural features affecting shallow Tertiary and Quaternary sediments of the Florida Platform ........................................................................................ 6 Figure 2. Location of principle test corehole G-2984 ......................................................... 7 Figure 3. Cross-section of the Florida/Bahamas Platform showing distribution and thickness of basement rocks underlying Tertiary carbonate rocks...................... 8 Figure 4. Paleogeography and evolution of the Suwannee Channel on the southeastern Coastal Plain during the Paleocene and Eocene time..................... 9 Figure 5. Eustatic sea-level curve (Haq et al., 1988) during the late Oligocene to Pleistocene ........................................................................................................