National Park Service U.S. Department of the Interior Natural Resource Stewardship and Science Buck Island Reef National Monument Geologic Resources Inventory Report Natural Resource Report NPS/NRSS/GRD/NRR—2011/462 ON THE COVER Aerial photograph of Buck Island Reef National Monument. National Park Service photograph. THIS PAGE Patch reefs called “haystacks” off the north side of Buck Island Reef lagoon and beyond the barrier reef. Photograph by Zandy Hillis-Starr (St. Croix and Buck Island NPS areas). Buck Island Reef National Monument Geologic Resources Inventory Report Natural Resource Report NPS/NRSS/GRD/NRR—2011/462 National Park Service Geologic Resources Division PO Box 25287 Denver, CO 80225 November 2011 U.S. Department of the Interior National Park Service Natural Resource Stewardship and Science Fort Collins, Colorado The National Park Service, Natural Resource Stewardship and Science office in Fort Collins, Colorado publishes a range of reports that address natural resource topics of interest and applicability to a broad audience in the National Park Service and others in natural resource management, including scientists, conservation and environmental constituencies, and the public. The Natural Resource Report Series is used to disseminate high-priority, current natural resource management information with managerial application. The series targets a general, diverse audience, and may contain NPS policy considerations or address sensitive issues of management applicability. All manuscripts in the series receive the appropriate level of peer review to ensure that the information is scientifically credible, technically accurate, appropriately written for the intended audience, and designed and published in a professional manner. This report received informal peer review by subject-matter experts who were not directly involved in the collection, analysis, or reporting of the data. Views, statements, findings, conclusions, recommendations, and data in this report do not necessarily reflect views and policies of the National Park Service, U.S. Department of the Interior. Mention of trade names or commercial products does not constitute endorsement or recommendation for use by the U.S. Government. Printed copies of this report are produced in a limited quantity and they are only available as long as the supply lasts. This report is available from the Geologic Resources Inventory website (http://www.nature.nps.gov/geology/inventory/ gre_publications.cfm) and the Natural Resource Publications Management website (http://www.nature.nps.gov/publications/nrpm/). Please cite this publication as follows: KellerLynn, K. 2011. Buck Island Reef National Monument: geologic resources inventory report. Natural Resource Report NPS/NRSS/GRD/NRR—2011/462. National Park Service, Fort Collins, Colorado. NPS 163/111477, November 2011 ii NPS Geologic Resources Division Contents List of Figures ................................................................................................................ iv List of Tables ................................................................................................................. iv Executive Summary ....................................................................................................... v Acknowledgements ...................................................................................................... vi Credits ........................................................................................................................................................................ vi Introduction ................................................................................................................... 1 Purpose of the Geologic Resources Inventory ............................................................................................................... 1 Establishment of Buck Island Reef National Monument ................................................................................................. 1 Regional Information ................................................................................................................................................... 1 Geologic Setting .......................................................................................................................................................... 2 Geologic Issues .............................................................................................................. 7 Oceanographic and Meteorological Variables ............................................................................................................... 7 Sea Level Rise............................................................................................................................................................... 9 Sediment Characteristics and Distribution ..................................................................................................................... 9 Erosion ...................................................................................................................................................................... 10 Windblown Particulates ............................................................................................................................................. 10 Seismic Activity .......................................................................................................................................................... 11 Hurricanes ................................................................................................................................................................. 11 Geologic Features and Processes ................................................................................ 19 Caledonia Formation .................................................................................................................................................. 19 Benthic Habitats ......................................................................................................................................................... 19 Reefs ......................................................................................................................................................................... 19 Seagrass Beds ............................................................................................................................................................ 22 Paleontological Resources .......................................................................................................................................... 22 Geologic History .......................................................................................................... 27 Upper Cretaceous Period: Island-Arc Setting ............................................................................................................... 27 Miocene and Pliocene Epochs: Deep-Marine Rocks to Shoaling in the Basin ................................................................ 27 Pliocene and Pleistocene Epochs: Development of Reefs around St. Croix ................................................................... 28 Pleistocene and Holocene Epochs: Reef Formation around Buck Island ........................................................................ 28 Geologic Map Data ...................................................................................................... 33 Geologic Maps ........................................................................................................................................................... 33 Source Maps .............................................................................................................................................................. 33 Geologic GIS Data ...................................................................................................................................................... 33 Geologic Map Overview ............................................................................................................................................. 34 Map Unit Properties Table .......................................................................................................................................... 34 Use Constraints .......................................................................................................................................................... 34 Geologic Map Overview Graphics .............................................................................. 35 Map Unit Properties Table .......................................................................................... 37 Glossary ........................................................................................................................ 43 Literature Cited ............................................................................................................ 47 Additional References ................................................................................................. 53 Appendix: Scoping Session Participants .................................................................... 54 Attachment 1: Geologic Resources Inventory Products CD BUIS Geologic Resources Inventory Report iii List of Figures Figure 1. Boundary expansion. ..................................................................................................................................... 2 Figure 2. Location map for Buck