Guilford Courthouse National Military Park
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National Park Service U.S. Department of the Interior Natural Resource Program Center Guilford Courthouse National Military Park Geologic Resources Inventory Report Natural Resource Report NPS/NRPC/GRD/NRR—2011/338 ON THE COVER The Nathanael Greene statue overlooks the rolling hills of Guilford Courthouse National Military Park in North Carolina. The geologic underpinnings of the monument involve the construction of the Appalachian Mountains and the assembly of the supercontinent Pangaea hundreds of millions of years ago. THIS PAGE Another view of the Nathanael Greene statue, commemorating the Battle of Guilford Courthouse, March 15, 1781. Although technically a British victory, General Greene’s American troops greatly weakened Lord Cornwallis’ British forces, which subsequently withdrew from the Carolinas. Cornwallis surrendered seven months later in Virginia. National Park Service photographs courtesy of Stephen Ware (Guilford Courthouse NMP) Guilford Courthouse National Military Park Geologic Resources Inventory Report Natural Resource Report NPS/NRPC/GRD/NRR—2011/338 National Park Service Geologic Resources Division PO Box 25287 Denver, CO 80225 March 2011 U.S. Department of the Interior National Park Service Natural Resource Program Center Fort Collins, Colorado The National Park Service, Natural Resource Program Center 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: Thornberry-Ehrlich, T. 2011. Guilford Courthouse National Military Park: geologic resources inventory report. Natural Resource Report NPS/NRPC/GRD/NRR— 2011/338. National Park Service, Ft. Collins, Colorado. NPS 316/106984, March 2011 ii NPS Geologic Resources Division Contents List of Figures ................................................................................................................ iv Executive Summary ....................................................................................................... v Acknowledgements ...................................................................................................... vi Credits ........................................................................................................................................................................ vi Introduction ................................................................................................................... 1 Purpose of the Geologic Resources Inventory ............................................................................................................... 1 Park Setting ................................................................................................................................................................. 1 Geologic Setting .......................................................................................................................................................... 1 History of Guilford Courthouse..................................................................................................................................... 2 Geologic Issues .............................................................................................................. 5 Landscape Preservation ................................................................................................................................................ 5 Erosional and Slope Processes ...................................................................................................................................... 6 Modern Anthropogenic Impacts ................................................................................................................................... 7 Suggestions for Further Geologic Research ................................................................................................................... 7 Geologic Features and Processes ................................................................................ 11 Geologic and Historic Connections at Guilford Courthouse National Military Park ....................................................... 11 Regional Geologic Structures...................................................................................................................................... 12 Map Unit Properties .................................................................................................... 15 Rocks at Guilford Courthouse National Military Park ................................................................................................... 15 Geologic History .......................................................................................................... 19 Precambrian (prior to 542 million years ago): Forming the Foundation ........................................................................ 19 Paleozoic Era (542 to 251 million years ago): Building Mountains and Assembling a Supercontinent ........................... 19 Mesozoic Era (251 to 65.5 million years ago): Formation of the Atlantic Ocean ........................................................... 20 Cenozoic Era (65.5 million years ago to present day): Shaping the Modern Landscape ................................................ 20 Glossary ........................................................................................................................ 24 Literature Cited ............................................................................................................ 29 Additional References ................................................................................................. 32 Geology of National Park Service Areas ...................................................................................................................... 32 Resource Management/Legislation Documents ........................................................................................................... 32 Geological Survey Web sites ....................................................................................................................................... 32 Other Geology/Resource Management Tools .............................................................................................................. 32 Appendix A: Overview of Digital Geologic Data ....................................................... 35 Appendix B: Scoping Session Participants ................................................................. 37 Attachment 1: Geologic Resources Inventory Products CD GUCO Geologic Resources Inventory Report iii List of Figures Figure 1. Location of and features within Guilford Courthouse National Military Park ....................................................... 3 Figure 2. Map of the physiographic provinces and geologic sections in North Carolina...................................................... 4 Figure 3. Map showing land acquisition and management history at Guilford Courthouse National Military Park .............. 8 Figure 4. Erosion within Guilford Courthouse National Military Park ................................................................................. 9 Figure 5. British plan of the Battle of Guilford Courthouse .............................................................................................. 10 Figure 6. The gently rolling hills of the park and surrounding area belie the intense history of deformation ..................... 13 Figure 7. Typical bedrock outcrop at Guilford Courthouse National Military Park along Hunting Creek ............................ 13 Figure 8. Aerial view of Guilford Courthouse National Military Park with recent geologic mapping superimposed ........... 14 Figure 9. Structural relationships within the Carolina terrane of the Piedmont in the Carolinas ........................................ 14 Figure 10. Geologic timescale .......................................................................................................................................