In cooperation with the U.S. Environmental Protection Agency Arsenic, Boron, and Fluoride Concentrations in Ground Water in and Near Diabase Intrusions, Newark Basin, Southeastern Pennsylvania NORTHAMPTON COUNTY LEHIGH COUNTY BERKS COUNTY Delaware River BUCKS COUNTY LANCASTER COUNTY CHESTER COUNTY MONTGOMERY COUNTY Scientific Investigations Report 2006–5261 U.S. Department of the Interior U.S. Geological Survey Arsenic, Boron, and Fluoride Concentrations in Ground Water in and Near Diabase Intrusions, Newark Basin, Southeastern Pennsylvania By Lisa A. Senior and Ronald A. Sloto In cooperation with the U.S. Environmental Protection Agency Scientific Investigations Report 2006-5261 U.S. Department of the Interior U.S. Geological Survey U.S. Department of the Interior DIRK KEMPTHORNE, Secretary U.S. Geological Survey Mark D. Meyers, Director U.S. Geological Survey, Reston, Virginia: 2006 For sale by U.S. Geological Survey, Information Services Box 25286, Denver Federal Center Denver, CO 80225 For more information about the USGS and its products: Telephone: 1-888-ASK-USGS World Wide Web: http://www.usgs.gov/ Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorse- ment by the U.S. Government. Although this report is in the public domain, permission must be secured from the individual copyright owners to repro- duce any copyrighted materials contained within this report. Suggested citation: Senior, L.A., and Sloto, R.A., 2006, Arsenic, boron, and fluoride in ground water in and near diabase intrusions, Newark Basin, southeastern Pennsylvania: U.S. Geological Survey Scientific Investigations Report 2006-5261, 105 p. iii Contents Abstract . 1 Introduction . 2 Background. 4 Purpose and Scope . 4 Study Area . 4 Previous Investigations. 4 Hydrogeologic Setting . 5 Geology. 5 Geologic Structure . 5 Geologic Units. 5 Precambrian and Paleozoic Rocks . 5 Mesozoic Rocks . 7 Stockton Formation . 7 Lockatong Formation . 7 Brunswick Group . 8 Hammer Creek Formation. 8 Limestone Fanglomerate . 8 Quartzite Fanglomerate . 8 Diabase . 9 Jacksonwald Basalt . 9 Sedimentary Strata at Jacksonwald and Aspers. 9 Effects of Thermal Metamorphism . 9 Mineral Deposits in the Newark Basin . 10 Magnetite Skarn and Skarn/Replacement Deposits . 10 Hornfels Copper Deposits . 12 Diabase-Hosted Vein and Late-Stage Igneous Segregation Deposits . 13 Sediment-Hosted and Stratabound Replacement Deposits . 13 Evaporites . 14 Ground-Water System . 14 Arsenic, Boron, and Fluoride in Ground Water . 15 Geochemical Controls on Arsenic, Boron, and Fluoride in Ground Water . 15 Review of Available Data. 15 Arsenic . 15 Boron . 21 Fluoride . 23 Methods of Data Collection and Analysis . 24 Ground-Water Sample Collection. 24 Sample Analysis. 28 Summary of Ground-Water Composition . 28 Major Ions and Characteristics . 28 Trace Elements. 32 Boron Isotopes. 36 iv Relation to Hydrogeologic Setting . 36 Congo Road Area. 37 Jacksonwald Area . 42 Kibblehouse Quarry Area. ..