MD-14-SP009B4M Martin O’Malley, Governor James T. Smith, Jr., Secretary Anthony G. Brown, Lt. Governor Melinda B. Peters, Administrator STATE HIGHWAY ADMINISTRATION RESEARCH REPORT GEOLOGY AND SINKHOLE DEVELOPMENT OF THE HAGERSTOWN VALLEY: PHASE II SUMMARY REPORT David K. Brezinski MARYLAND DEPARTMENT OF NATURAL RESOURCES RESOURCE ASSESSMENT SERVICE MARYLAND GEOLOGICAL SURVEY FINAL REPORT June 2014 The contents of this report reflect the views of the author who is responsible for the facts and the accuracy of the data presented herein. The contents do not necessarily reflect the official views or policies of the Maryland State Highway Administration. This report does not constitute a standard, specification, or regulation. Technical Report Documentation Page 1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. MD-14-SP009B4M 4. Title and Subtitle 5. Report Date Geology and Sinkhole Development of the Hagerstown Valley: Phase II Summary June 2014 Report 6. Performing Organization Code 7. Author/s 8. Performing Organization Report No. David K. Brezinski 9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) Maryland Geological Survey 2300 St. Paul Street 11. Contract or Grant No. Baltimore MD 21218 SP009B4M 12. Sponsoring Organization Name and Address 13. Type of Report and Period Covered Maryland State Highway Administration Final Report Office of Policy & Research 14. Sponsoring Agency Code 707 North Calvert Street (7120) STMD - MDOT/SHA Baltimore MD 21202 15. Supplementary Notes 16. Abstract As a part of this study, karst areas of the Hagerstown, Mason Dixon, Williamsport, Clear Spring, and Hedgesville quadrangles (western half of the Hagerstown Valley) were mapped in detail to determine the distribution of karst features relative to bedrock geologic units using a global positioning system. More than 2,100 karst features were identified and located and the following observations were made: There was a generally identifiable relationship between the type of karst features and the bedrock units. In addition to bedrock composition, joints, and faults appear to have played important roles in the development of the karst systems in the study area. Preliminary findings suggest the impact of human activities on karst development is less pronounced than in the Frederick Valley. Unlined drainageways appear to just as frequent culprits in sinkhole activity as they are in the Frederick Valley. Likewise, areas surrounding quarries and stormwater runoff ponds are common sites of sinkhole development. This study illustrates that future development will benefit from the current studies of karst development in the Hagerstown Valley. Planners can now employ the relative karst susceptibility on the different rock units as a basis for preliminary examination of areas of the Valley that are underlain by these soluble rocks. 17. Key Words 18. Distribution Statement: No restrictions Sinkholes, carbonate rocks, geologic mapping, karst, limestone, marble, This document is available from the Research Division upon request. dolomite, Hagerstown Valley 19. Security Classification (of this report) 20. Security Classification (of this page) 21. No. Of Pages 22. Price None None None 18 Form DOT F 1700.7 (8-72) Reproduction of form and completed page is authorized. PHASE II EXECUTIVE SUMMARY This report discusses findings of the second phase of a study by the Maryland Geological Survey and sponsored by the Maryland State Highway Administration Office of Materials Technology on the relationship between geology and sinkhole development in the Hagerstown Valley. Along with the bedrock geology, karst features were identified and located utilizing a global positioning system. More than 2,100 karst features were identified and located. There was a generally identifiable relationship between types of karst features and the bedrock units. In addition to bedrock composition, joints and faults appear to have played important roles in the development of the karst systems of the western half of the Hagerstown Valley. Preliminary findings suggest that human impact on karst development is less substantial than hypothesized prior to the study. The geology and karst maps produced by this study, can be utilized by homeowners, developers, planner, and engineers when questions arise about the karst development in the Hagerstown region. The study’s results provide highway officials an a priori knowledge about locations that pose a high risk for sinkhole potential. With this understanding of the geologic variables that impact karst development, detailed and localized site studies have a foundation on which to build. i TABLE OF CONTENTS Introduction……………………………………………………….……………………....1 Setting…………………………………………………………….……………………….1 History of Investigation…………………………………………….……………………..2 Lithostratigraphy……………………………………………….………………………….3 Elbrook Formation..…………………………………….…………………………3 Conococheague Formation……………………………….……………………….3 Stonehenge Limestone…………..………………………..……………………….4 Rockdale Run Formation………………………………….………………………5 Pinesburg Station Dolomite………………………………….……………………5 St. Paul Group……………………………………………….…………………….6 Chambersburg Limestone…………………………………………………………6 Martinsburg Formation……………………………………………………………7 Karst Feature Distribution………………………………………………………………...7 Karst Feature Summary…………………………………………………………...9 Geologic Factors Affecting Karst Feature Distribution…………………………..9 Examples of Geologically Controlled Karst ……….………………………….………..12 Human Factors Affecting Karst Feature Development…………………….……14 Implications for Highway Site Evaluation………………………………………………14 Acknowledgements………………………………………………………………………16 References……..…………………………………………………………………………16 Glossary of Geological Terms…………………………………………………………...18 ii LIST OF FIGURES Figure 1. Location map………………………………………………………….………..1 Figure 2. Generalized geologic cross-section of the Hagerstown Valley..……..………...2 Figure 3. Generalized stratigraphic column for the Hagerstown Valley…………………2 Figure 4. Idealized karst…………………….……………………………………………7 Figure 5. Types of karst features identified..…………………………………….……….8 Figure 6. Pie diagram of relative percentages of karst features,……………….………....9 Figure 7 Stacked bar chart of karst features found in rock units,.………………………10 Figure 8. Pie diagrams of karst features from each rock unit……..…………………….10 Figure 9. Sketch of preferential dissolution in the Conococheague Formation,..……….10 Figure 10. Photograph of solution widened fractures...………………………….….…..11 Figure 11. Rose diagrams of azimuths of joint planes measured during Phase II…....…11 Figure 12. Solution widened bedding surface………………………………….……….12 Figure 13. Pinnacle karst created from dissolution of intersecting joint surfaces.….…..12 Figure 14. Alignment of springs along the Williamsport fault..………………….…..…13 Figure 15. Preferential alignment of sinkholes along stream valleys………………..….13 Figure 16. Some human-induced karst features…………………………………….…..14 Figure 17. Stratigraphic distribution of karst along Interstate 81……………………….15 Figure 18. Incipient sinkhole in unlined median drainage along I 81…………………..16 iii INTRODUCTION Areas underlain by carbonate rocks such of karst features in any particular terrane as limestone, marble, and dolomite are prone without first assembling data and evaluating to dissolution by ground-water. Such solution the distribution of the features with respect to of bedrock produces distinctive topographic the distribution of mapped bedrock units, their features that characterize what is known as intrinsic geologic structure, and proximity to karst terrane. While karst terranes are present major hydrologic features such as streams or to some degree in all areas underlain by all rivers. carbonate rocks, they develop at varying levels Phase II of this study, the subject of this based on changes in the chemical makeup and report, deals with the western half of the geologic structure of the bedrock. Thus, there valley and encompasses the Maryland portions is no such thing as a typical karst terrane. It is of the Hagerstown, Mason-Dixon, therefore impossible to characterize or predict Shepherdstown, Williamsport, Hedgesville, the distribution, type, abundance, or size and Clear Spring 7.5´quadrangles (Figure 1). Figure 1. Areas underlain by carbonate rocks in Maryland (red) and location of Phase II quadrangles (gray). SETTING into tight folds that have been partially eroded The Hagerstown Valley, also known as the into the landforms we see today. The Great Great Valley (Cumberland or Lehigh Valley in Valley is a broad down warp or fold in the Pennsylvania and Shenandoah Valley in Earth’s crust known as the Massanutten Virginia), is a continuous geologic structure synclinorium. It is bordered to the east by a that stretches from New Jersey to Georgia. large up fold known as the South Mountain This nearly 800-mile long valley is underlain anticlinorium (Cloos, 1971) (Figure 2). The by easily erodible shale and dissolvable South Mountain anticlinorium comprises the carbonate rocks (limestone and dolomite). Maryland part of the Blue Ridge These rocks were formed during the Cambrian Physiographic Province, while the and Ordovician Periods between 540 to 445 Massanutten synclinorium, to the west, is the million years ago. Mountain building eastern section of the Ridge and Valley episodes during the late Paleozoic (350-250 Physiographic Province. million years ago) configured these rock layers 1 Figure 2. Idealized geologic cross section from the Frederick Valley in the Piedmont Physiographic