National Park Service US Department of the Interior Natural Resource Stewardship and Science Hot Springs National Park Geologic Resources Inventory Report Natural Resource Report NPS/NRSS/GRD/NRR—2013/741 ON THE COVER View from the top of the display spring down to the Arlington Lawn within Hot Springs National Park. THIS PAGE Gulpha Creek flows over Stanley Shale downstream from the Gulpha Gorge Campground. Photographs by Trista L. Thornberry-Ehrlich (Colorado State University) Hot Springs National Park Geologic Resources Inventory Report Natural Resource Report NPS/NRSS/GRD/NRR—2013/741 National Park Service Geologic Resources Division PO Box 25287 Denver, CO 80225 December 2013 US 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 These reports are 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/). To receive this report in a format optimized for screen readers, please email [email protected]. Please cite this publication as: Thornberry-Ehrlich, T. L. 2013. Hot Springs National Park: Geologic resources inventory report. Natural Resource Report NPS/NRSS/GRD/NRR—2013/741. National Park Service, Fort Collins, Colorado. NPS 128/123089, December 2013 ii NPS Geologic Resources Division Contents Lists of Figures and Tables ........................................................................................... iv Executive Summary ....................................................................................................... v Acknowledgements ..................................................................................................... vii Credits ....................................................................................................................................................................... vii Introduction ................................................................................................................... 1 Geologic Resources Inventory Program ......................................................................................................................... 1 Park Setting ................................................................................................................................................................. 1 Geologic Setting .......................................................................................................................................................... 2 Geologic Features and Processes .................................................................................. 7 Geothermal Hot Springs............................................................................................................................................... 7 Folds, Fractures, and Faults of the Ouachita Mountains .............................................................................................. 12 Geologic Connections to Park Stories and Resources .................................................................................................. 13 Paleontological Resources .......................................................................................................................................... 15 Geologic Issues ............................................................................................................ 17 Geothermal Water Quantity and Quality .................................................................................................................... 17 Radon Exposure ......................................................................................................................................................... 20 Slope Movements ...................................................................................................................................................... 20 Disturbed Lands, Unauthorized Collecting, Vandalism, and Artificial Ponds ................................................................. 23 Flooding .................................................................................................................................................................... 24 Geologic History .......................................................................................................... 27 Paleozoic Era (541–252 million years ago): Building the Ouachita Mountains, Assembling Pangaea, Developing the Geothermal System ................................................................................................................................................... 27 Mesozoic Era (252–66 million years ago): Pangaea Separation, Ouachita Mountains Erosion, and Igneous Intrusion .... 31 Cenozoic Era (the past 66 million years): Ouachita Mountains Erosion and Surface Processes ...................................... 31 Geologic Map Data ...................................................................................................... 33 Geologic Maps .......................................................................................................................................................... 33 Source Maps .............................................................................................................................................................. 33 Geologic GIS Data ..................................................................................................................................................... 33 Geologic Map Graphic ............................................................................................................................................... 34 Map Unit Properties Table .......................................................................................................................................... 34 Use Constraints .......................................................................................................................................................... 34 Glossary ........................................................................................................................ 35 Literature Cited ............................................................................................................ 41 Additional References ................................................................................................. 45 Geology of National Park Service Areas ...................................................................................................................... 45 NPS Resource Management Guidance and Documents ............................................................................................... 45 Geological Surveys and Societies ................................................................................................................................ 45 US Geological Survey Reference Tools ........................................................................................................................ 45 Appendix A: Scoping Meeting Participants ............................................................... 47 Appendix B: Geologic Resource Laws, Regulations, and Policies ............................. 49 Geologic Map Graphic ...................................................................................... in pocket Map Unit Properties Table ............................................................................... in pocket Geologic Resources Inventory Products CD .................................................... attached HOSP Geologic Resources Inventory Report iii List of Figures Figure 1. Map of Hot Springs National Park and surrounding area. ............................................................................... 1 Figure 2. Detail map of Bathhouse Row. .....................................................................................................................