The following is a brief description of the data layers, tables, and their associated attributes that are used in this report. GEOLOGIC DATA: BEDROCK - Polygon data layer of bedrock geologic map units BEDROCK.PAT items: MAPUNIT - Bedrock geologic map unit code COA_ID - Compound object archive identifier, map unit names and descriptions - a data linkage hub in North American Data Model (NADM) 4.3 FAULT - Line data layer of geologic faults and folds FAULT.AAT items: SYMBOL - Symbol number from FAULT.LIN or ALCNEW61.LIN linesets, used for plotting SYMBOL-ARC - Symbol number from GDS1.LIN lineset, used for plotting FEATURE - Geologic Data Systems (GDS) assigned feature description ELEVATION - GDS assigned attribute TYPE - Type of fault TYPE Code Description AC Anticline AF Antiform ARO Arrow showing movement along strike-slip fault FZ Fault zone N Normal fault NT Normal fault re-activated as thrust fault OT Overturned thrust fault SC Syncline SF Synform SS Strike-slip fault T Thrust fault TA Thermal aureole UF Unclassified fault ULF Unclassified linear feature CODE - Identifies fault segments which are overlaid by surficial deposits (CODE = 2). Used for plotting. Relevant only for those faults which lie within the boundary of the USGS Frederick 1:100000-scale map. QUAD - Identifies the USGS 1:100000-scale map to which the feature belongs QUAD Code Description FB - Fredericksburg FK - Frederick WW - Washington West NEAT - Line data layer of map neatline SINK - Point data layer of sinkhole locations SINK.PAT items: MAPUNIT - Set to 'Sinkhole' STRUCTURE - Point data layer of geologic structure STRUCTURE.PAT items: DIP - Dip value (planar data) or plunge value (linear data) STRIKE_ANG - GDS assigned angle measured from North AZIMUTH - Angle measured from North in right-hand rule (planar data). Routines used to digitize the geologic structure symbols that lie within the boundaries of the USGS Frederick and Washington West 1:100000-scale maps (item QUAD equal to 'FK' and 'WW', respectively) resulted in the azimuth value for those symbols to be calculated based on a northern trend (270<=azimuth<=90). Southern trending azimuth values (90<azimuth<270) for structure symbols associated with the Frederick and Washington West maps were translated to their northern trend equivalents. If necessary, the southern trending azimuth values for these symbols can be restored using the item SYMB_ANG and the following equations: For 180<SYMB_ANG<=270, azimuth = AZIMUTH + 180 For 270<SYMB_ANG<360, azimuth = AZIMUTH - 180 TYPE - Type of geologic structure. Relevant for geologic structure data that lies within the boundaries of the USGS Frederick and Washington West 1:100000-scale maps (item QUAD equal to 'FK' and 'WW') TYPE Code Description AGE Sample site for U-Pb isotopic technique for age date HB Horizontal bed I1C Inclined first-generation Paleozoic cleavage and (or) schistosity I2C Inclined second-generation Paleozoic cleavage and (or) schistosity IEF Inclined early foliation IB Inclined bed IF Inclined Middle Proterozoic foliation IMP Inclined mylonitic and phyllonitic foliations IPF Inclined phyllonitic foliation MA Minor antiform OB Overturned bed QM Quarry or mine RAD Greater than 200 pCi/L of soil gas radon V1C Vertical first-generation Paleozoic cleavage and (or) schistosity V2C Vertical second-generation Paleozoic cleavage and (or) schistosity VB Vertical bed VEF Vertical early foliation VF Vertical Middle Proterozoic foliation VMP Vertical mylonitic and phyllonitic foliations SUB_TYPE - Type of quarry mine SUB_TYPE Code Description Ag Silver Au Gold C Chromite Cu Copper D Diabase F Hematite, limonite, and iron-ore L Limestone M Marble Mg Magnetite Mn Manganese Pb Lead S Building stone Sl Slate Zn Zinc SYMB_ANG - Standard Cartesian angle measured from East. Used for plotting. DIPDIR - Direction of dip (planar data) or trend (linear data) measured from North SYMBOL - Symbol number from the LOUDOUN_AP.MRK markerset or the MPLY.LIN lineset, used for plotting FEATURE - Type of geologic structure. Relevant for geologic structure data that lies within the boundary of the USGS Fredericksburg 1:100000-scale map (item QUAD equal to 'FB') GROUP - GDS assigned attribute METHOD - GDS assigned attribute SOURCE - GDS assigned attribute DIP_DIR - GDS assigned attribute SYMB_ARC - Symbol number from the GDS1.MRK markerset, used for plotting QUAD - Identifies the USGS 1:100000-scale map to which the structure data belongs QUAD Code Description FB - Fredericksburg FK - Frederick WW - Washington West SURFICIAL - - Polygon data layer of surficial geologic map units SURFICIAL.PAT items: MAPUNIT - Surficial geologic map unit code COA_ID - Compound object archive identifier, map unit names and descriptions - a data linkage hub in North American Data Model (NADM) 4.3 BASE DATA: POLBND - Net data layer of state and county boundaries: POLBND.AAT items: POLBND-ID TYPE - State or county boundary POLBND.PAT items: STATE_NAME - State in which county resides CNTY_NAME - County name STATE_FIPS - State FIPS code (character field) CNTY_FIPS - County FIPS code (character field) FIPS - FIPS code for state/county (character field) MAJOR# - DLG code MINOR# - DLG code Major DLG Minor DLG Code Code Description 91 --- State FIPS code (integer field) 92 --- County FIPS code (integer field) ROADS - Line data layer of major highways ROADS.AAT items: MAJOR# - DLG code MINOR# - DLG code Major DLG Minor DLG Code Code Description 170 201 Primary route, class 1, undivided 170 203 Primary route, class 1, divided 170 204 Primary route, class 1, one way 170 205 Secondary route, class 2, undivided 170 207 Secondary route, class 2, divided 170 209 Road or street, class 3 170 210 Road or street, class 4 170 401 Traffic circle 170 402 Cloverleaf or interchange 170 607 Underpassing 170 617 Business route 172 --- Interstate route number 173 --- U.S. route number 174 --- State route number TOPO - Line data layer of elevation contours TOPO.AAT items: MAJOR# - DLG code MINOR# - DLG code Major DLG Minor DLG Code Code Description 20 20O Contour (index or intermediate) 20 201 Carrying contour 20 204 Amended contour 20 208 Closure line 20 611 Depression 24 --- Elevation in whole meters TYPE - Type of contour: index (Index) or intermediate (Inter), used for plotting HYDRO - Polygon data layer of major water bodies HYDRO.PAT items: RINGS_OK - Attribute assigned by the Chesapeake Bay Program RINGS_NOK - Attribute assigned by the Chesapeake Bay Program FEATURE - Type of hydrologic feature (stream, pond, marsh, etc.)
Geology was researched and compiled for use in studies of ecosystem health, environmental impact, soils, groundwater, land use, tectonics, crustal genesis, sedimentary provenance, and any others that could benefit from geographically referenced geological data.
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Use_Constraints:Although all data released in this report have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and related materials and (or) the functioning of the software. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
These data were prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product or process disclosed in this report, and represents that its use would not infringe privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of this data or related materials. Reference therein to any specific commercial product, process, or related service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof.
|Data format:||Bedrock and surficial geologic map units, fault and fold axes, structural geology, political boundaries, elevation contours, and major highways and water bodies. in format ARCE (version 8.0.2) Size: 37.0|