National Park Service U.S. Department of the Interior Natural Resource Program Center Antietam National Battlefield, Chesapeake and Ohio Canal National Historical Park, & Harpers Ferry National Historical Park Geologic Resource Evaluation Report Natural Resource Report NPS/NRPC/GRD/NRR—2005/006 Antietam National Battlefield, Chesapeake and Ohio Canal National Historical Park, & Harpers Ferry National Historical Park Geologic Resource Evaluation Report Natural Resource Report NPS/NRPC/GRD/NRR—2005/006 Geologic Resources Division Natural Resource Program Center P.O. Box 25287 Denver, Colorado 80225 January 2005 U.S. Department of the Interior Washington, D.C. The Natural Resource Publication series addresses natural resource topics that are of interest and applicability to a broad readership in the National Park Service and to others in the management of natural resources, including the scientific community, the public, and the NPS conservation and environmental constituencies. Manuscripts are peer-reviewed to ensure that the information is scientifically credible, technically accurate, appropriately written for the intended audience, and is designed and published in a professional manner. Natural Resource Reports are the designated medium for disseminating 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. Examples of the diverse array of reports published in this series include vital signs monitoring plans; "how to" resource management papers; proceedings of resource management workshops or conferences; annual reports of resource programs or divisions of the Natural Resource Program Center; resource action plans; fact sheets; and regularly-published newsletters. Views and conclusions in this report are those of the authors and do not necessarily reflect policies of the National Park Service. Mention of trade names or commercial products does not constitute endorsement or recommendation for use by the National Park Service. Printed copies of reports in these series may be produced in a limited quantity and they are only available as long as the supply lasts. This report is also available from the Geologic Resource Evaluation Program website (http://www2.nature.nps.gov/geology/inventory/ gre_publications) on the internet, or by sending a request to the address on the back cover. Please cite this publication as: Thornberry-Ehrlich, T. 2005. Antietam National Battlefield, Chesapeake and Ohio Canal National Historical Park, & Harpers Ferry National Historical Park, Geologic Resource Evaluation Report. Natural Resource Report NPS/NRPC/GRD/NRR—2005/006. National Park Service, Denver, Colorado. NPS D-310, January 2005 Table of Contents List of Figures .............................................................................................................. iv Executive Summary ...................................................................................................... 1 Introduction ................................................................................................................... 3 Purpose of the Geologic Resource Evaluation Program ............................................................................................3 Geologic Setting .........................................................................................................................................................3 Geologic Issues............................................................................................................. 5 Erosion and Slope Processes.....................................................................................................................................5 Stream Flow, Channel Morphology, and Sediment Load ...........................................................................................6 Historical Landscapes ................................................................................................................................................7 Paleontologic Potential ...............................................................................................................................................8 Water Issues...............................................................................................................................................................8 Wetlands ....................................................................................................................................................................9 Karst Related Issues ..................................................................................................................................................9 General Geology and Ecosystem Concerns.............................................................................................................10 Geologic Features and Processes............................................................................. 15 Antietam National Battlefield ....................................................................................................................................15 Chesapeake & Ohio Canal National Historical Park .................................................................................................15 Harpers Ferry National Historical Park .....................................................................................................................16 Map Unit Properties .................................................................................................... 23 Formation Properties Table ......................................................................................................................................24 Geologic History.......................................................................................................... 27 References Cited......................................................................................................... 31 Appendix A: Geologic Map Graphics ........................................................................ 33 Appendix B: Scoping Summary................................................................................. 36 ANTI-CHOH-HAFE Geologic Resource Evaluation Report iii List of Figures Figure 1: High water damage at Antietam National Battlefield. ....................................................................................11 Figure 2: Historic structure losing ground to Shenandoah River ..................................................................................12 Figure 3: Slope processes at Harpers Ferry ................................................................................................................13 Figure 4: Slopes along Antietam Creek........................................................................................................................14 Figure 5: High ground at Antietam National Battlefield.................................................................................................18 Figure 6: Low ground at Antietam National Battlefield. ................................................................................................19 Figure 7: Wall rock geology of Chesapeake & Ohio Canal ..........................................................................................20 Figure 8: Lock 30 of the Chesapeake & Ohio Canal ....................................................................................................21 Figure 9: View of Harpers Ferry. ..................................................................................................................................22 Figure 10: Rock units at Harpers Ferry. .......................................................................................................................29 Figure 11: Geologic Time Scale..................................................................................................................................30 iv NPS Geologic Resources Division Executive Summary This report has been developed to accompany the digital geologic maps produced by Geologic Resource Evaluation staff for Antietam National Battlefield, Chesapeake & Ohio Canal National Historical Park, and Harpers Ferry National Historical Park in Maryland, Virginia, Washington, D.C., and West Virginia. It contains information relevant to resource management and scientific research. The story of the three parks featured in this report, • Erosion and Slope Processes. The relatively wet Antietam National Battlefield, Chesapeake & Ohio Canal climate of the eastern U.S., combined with the steep National Historical Park, and Harpers Ferry National slopes of the Potomac and Shenandoah River valleys, Historical Park is one of the interaction between man and the Antietam Creek basin, creates a setting which and geology. Each park preserves this story in different is especially susceptible to slumping and landslide ways. The experience of the parks begins with the problems. This is due to a lack of stabilizing plant geology, with the processes that established the growth combined with substantial seasonal runoff and groundwork from which today’s environments, history, frequent occurrence of intense seasonal rainstorms. and scenery arise. Knowledge of the geologic resources Runoff can dramatically alter the landscape, creating should directly impact resource management decisions new hazard areas in the