U.S. Geological Survey Open-File Report 01-187 README FILE CONTENTS 1) CITATION INFORMATION 2) OVERVIEW 3) CD DIRECTORY LAYOUT 4) MAP DATA 5) GRAPHICS 6) METADATA 7) SOFTWARE 8) GETTING STARTED 9) DISCLAIMER 1) CITATION INFORMATION ======================= U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY In cooperation with the Virginia Division of Mineral Resources (1) and the Maryland Geological Survey (2) Preliminary Lithogeochemical Map Showing Near-Surface Rock Types in the Chesapeake Bay Watershed, Virginia and Maryland by John D. Peper (3), Lucy B. McCartan (3), J. Wright Horton, Jr. (3), and James E. Reddy (3) Open-File Report 01-187 2001 version 1.0 _______________________________ (1) Virginia Department of Mines, Minerals and Energy; Division of Mineral Resources, P.O. Box 3667, Charlottesville, VA 22903; (804) 951-6340; http://www.mme.state.va.us/DMR/home.dmr.html (2)Maryland Geological Survey, 2300 St. Paul Street, Baltimore, MD 21218; (410) 554-5500; http://www.mgs.md.gov/index.html (3) U.S. Geological Survey; Reston, Virginia 20192 2) OVERVIEW =========== This CD contains explanatory text, digital map data in four data formats, and graphic files of the map in .PDF and .EPS formats. This preliminary experimental lithogeochemical map shows the distribution of rock types as lithogeochemical units in the Virginia and Maryland parts of the Chesapeake Bay watershed, and small flanking areas in western Maryland and eastern Virginia. Earlier studies by others in some parts of the map area have related some solute loads in ground and stream waters to some aspects of rock type. The map was produced digitally by classifying geologic-map units according to composition, mineralogy, and texture; rather than by age and stratigraphic relationships as shown on traditional geologic maps. This map differs from most lithologic maps in that the lithogeochemical unit classification distinguishes rock units with key water- reactive minerals that may induce acid neutralization, or reduction, of hosted water at the weathering interface. The bulk chemical composition of these rock units, however, is independent of suggested water chemistry. The rock units are derived from geologic maps and rock descriptions. Areas of high soil carbon content, and sites of sulfide deposits (metallic ore deposits) are also shown. Water-reactive minerals and their weathering reactions suggest five classes of lithogeochemical units: 1) carbonate rocks and calcareous rocks and sediments, the most acid-neutralizing; 2) carbonaceous-sulfidic rocks and sediments, likely to be oxygen- depleting and reducing; 3) quartzofeldspathic rocks and siliciclastic sediments, mostly relatively weakly reactive with water; 4) mafic silicate rocks and sediments, likely to be oxygen consuming and high solute-load delivering; and, 5) the rarer calcareous-sulfidic (carbonaceous) rocks that may be neutralizing and reducing. Preliminary tests of relationships between four of the classes of mapped lithogeochemical units and ground water chemistry in the Mid-Atlantic area using this map, have supported the suggested nitrate-reducing and acid-neutralizing properties of some rock types. Additional testing of relationships among the lithogeochemical units and aspects of ground and surface water chemistry could help to refine the lithogeochemical classification of this map. The testing could also improve the qualitative and quantitative usefulness of the map for assessing aquifer reactivity and the transport properties of reactive contaminants such as acid rain, and nitrate from agricultural sources, in the Chesapeake Bay watershed. 3) CD DIRECTORY LAYOUT ========================== |--README.TXT | | | |--OF01187.AEP__ArcExplorer project for viewing data | | | |--OF01187.PDF___Adobe Portable Document Format of text pamphlet | | | | |--README.TXT | | | | | | | | |__MARYLAND____(Contains five map | |--ABICAS-------| themes, relate tables, | | |__VIRGINIA and conversion AMLs) | | | | | | | | |__MARYLAND____(The files in these | |--AEP----------| directories support | | |__VIRGINIA the file "of01187.AEP") | | |--DATA---------| | | | | |__MARYLAND____(Contains five map | |--COVERS-------| themes and relate | | |__VIRGINIA tables) | | | | | | | | |__MARYLAND____(Contains five map | |--EXPORT-------| themes and relate | | |__VIRGINIA tables) | | | | | | | | |__MARYLAND____(Contains five map | |--SHAPE--------| themes and relate | |__VIRGINIA tables) | | | |--GRAPHICS-----|--OF01187P1.EPS | |--OF01187P1.PDF | | | | |--METADATA.DIF | |--METADATA.ERR | |--METADATA_ERR.HTML | |--METADATA_FAQ.HTML |--METADATA-----| | |--METADATA.HTML | |--METADATA.MET | |--METADATA.SGML | |--METADATA.TXT | |--METADATA.XML | | | | |--README.TXT | | | | |--SOFTWARE-----| |--ACROBAT------|--AR500ENU.EXE____(Adobe Acrobat Reader executable file | for Windows 98/2000/NT) | | | | |--AE2SETUP.EXE____(ArcExplorer2 executable file | | for Windows 98/2000/NT) |--EXPLORER-----| |--ARCEXPLORER.PDF____(ArcExplorer User Guide) 4) MAP DATA =========== Four geologic themes, or data layers, and one base cartographic theme are provided in ABICAS, ARC/INFO Coverage, ARCVIEW Shapefile, and ARC/INFO Export formats. Data are organized into four directories, one for each format. Within each data format directory, map data are organized by state. Each state directory contains five map themes. Base cartographic themes were downloaded from the Chesapeake Bay Program's Geographic Information Systems website at www.chesapeakebay.net/data/. Refer to the README file in the DATA folder for additional information. 5) GRAPHICS =========== Graphic image files are provided in EPS and PDF formats. These images depict the entire map area including marginalia. The PDF file (of01187p1.pdf) can be viewed and printed using Adobe Acrobat Reader provided on this CD in the SOFTWARE directory. Adobe Acrobat Reader version 4.x or later is required to view the PDF file. The paper map accompanying this report is included on the CD as an EPS formatted file (of01187p1.eps). The paper map is 32" tall x 48" wide and was designed and tested on a Hewlett Packard DesignJet 1055 series printer capable of plotting PostScript files. This file has been successfully printed from Arc/Info, Adobe Illustrator, and from the MS-DOS prompt using the "print" command. 6) METADATA =========== FGDC compliant metadata for the entire report exists in several output file formats. These files were created using the Tkme and mp metadata creation tools available from: http://geology.usgs.gov/tools/metadata/ These files are located within the Metadata folder on the CD. 7) SOFTWARE =========== We provide the Adobe Acrobat Reader software needed to read and display the Portable Document Format (PDF) files included on this CD. Environmental Systems Research Institute's ArcExplorer software is also provided with this CD. ArcExplorer is used for data display and query and is compatible with the map data in ArcView shapefile and Arc/Info coverage formats. Refer to the README file in the SOFTWARE folder for installation instructions. 8) GETTING STARTED ================== To view the Adobe Portable Document text pamphlet or map included with this report, install the Adobe Acrobat Reader software by double clicking on the executable file located in the Software>Acrobat folder and following the installation instructions. Once installed, start Adobe Acrobat Reader and open the text pamphlet of01187.pdf or view the map of01187p1.pdf located in the Graphics folder. Adobe Acrobat Reader version 4.x or later is required to view the PDF files. To view and query the digital data included with this report, install the ESRI ArcExplorer 2 software by double clicking on the executable file located in the Software>Explorer folder and following the installation instructions or read "How to install ArcExplorer" in the ArcExplorer User Guide (arcexplorer.pdf) also located in the Software>Explorer folder. Once installed, start ArcExplorer and open the project file of01187.aep Refer to the User Guide for help using ArcExplorer. 9) DISCLAIMER ============== This report is preliminary and has not been reviewed for conformity with U.S. Geological Survey editorial standards (or with the North American Stratigraphic Code). Any use of trade, product, or firm names is for descriptive purposes only and does not constitute endorsement by the USGS. Although this data base has been used by the U.S. Geological Survey, no warranty, expressed or implied, is made by the USGS as to the accuracy and functioning of the data base and related program material, nor shall the fact of distribution constitute any such warranty, and no responsibility is assumed by the USGS in connection therewith. Graphical map depictions on this CD are intended to be used at map compilation scale (1:500,000). Although software enables the user to show images on the CD at any scale, the user is cautioned that enlarging the maps beyond a scale of 1:500,000 is not advisable.