U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY Bedrock Geologic Map of the Grafton Quadrangle, Worcester County, Massachusetts [Scale 1:24,000] by Gregory J. Walsh (1) John N. Aleinikoff (2) and Michael J. Dorais (3) Scientific Investigations Map 3171 2011 version 1.0 Prepared in cooperation with the Commonwealth of Massachusetts, Massachusetts Geological Survey ________________________________ (1) U.S. Geological Survey Montpelier, Vermont 05601 (2) U.S. Geological Survey Denver, Colorado 80225 (3) Brigham Young University Provo, UT 84602 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Source of Geologic Data: Original data. Geology mapped by Walsh, 2005-2006. Geochronology by Aleinikoff, 2005-2008. Geochemistry by Dorais, 2007. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This report is available from: http://pubs.usgs.gov/sim/3171/ U.S. Geological Survey Information Services Box 25286, Denver Federal Center Denver, CO 80225 1-888-ASK-USGS http://ask.usgs.gov/ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Map compiled from the digital bedrock database. GIS database compiled in ARC/INFO version 9.3. Topographic base produced by scanning photo positive separates at 400 dpi. Final cartography compiled in Adobe Illustrator version CS4. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Suggested Citation: Walsh, G.J., Aleinikoff, J.N., and Dorais, M.J., 2011, Bedrock geologic map of the Grafton quadrangle, Worcester County, Massachusetts: U.S. Geological Survey Scientific Investigations Map 3171, 1 sheet, scale 1:24,000, 39-p. text. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Directory layout: http://pubs.usgs.gov/sim/3171/ --SIM3171.PDF---Sheet 1 Geologic map (34" tall x 48" wide) --SIM3171P.PDF---Text pamphlet in PDF; contains explanatory text of the geology (8.5” x 11” letter-size) http://pubs.usgs.gov/sim/3171/Downloads -README.TXT---ASCII text description (this file) -METADATA.HTML---Metadata file in html format -SIM3171B.ZIP---compressed database files -SIM3171B_without_photos.ZIP---compressed database files without photographs | |---EXPORT---Folder contains Arc/Info GIS export-interchange files (e00) | Does not contain PHOTO database, see shapefile instead | |---SHAPE---Folder contains ArcGIS shapefiles & lookup table for CONTX | polygon coverage | |---BASE---Folder contains basemap image files and worldfiles | |---PHOTOS---Folder contains 304 photographs of the geology and landscape | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ A subset of the contents of this readme.txt file are also included in the metadata for this report. This readme.txt, however, contains greater detail than the metadata. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: The bedrock geology of the 7.5-minute Grafton, Mass., quadrangle consists of deformed Neoproterozoic to early Paleozoic crystalline metamorphic and intrusive igneous rocks. The geology was mapped during 2005 and 2006 at a scale of 1:24,000. The bedrock geology was mapped using standard techniques. Location information was collected with a GPS receiver (GPS model: Garmin eTrex Venture) The line and polygon data were compiled in Adobe Illustrator over the topographic basemap. Field sheets were scanned and registered in Illustrator. Topographic basemap separates were scanned at 400 dpi. Line and polygon data were exported from Illustrator in DXF format to Arc/Info version 9.3. Point data were collected with GPS and a hand-held 3COM Palm Pilot III PDA computer. Data from the PDA were imported to ArcGIS version 9.3 as ASCII text files and joined with GPS point data to create shapefiles. The GPS data were collected in Latitude and Longitude in degrees minutes and seconds in WGS84 datum. GPS data were projected to the Massachusetts State Plane Coordinate System (FIPS Zone 2001) in NAD83 datum, with units in meters. GPS locations were compared to the topographic basemap of the area and repositioned to match the base. The original coordinates remain in the STRUCTURE database. After editing in Arc/Info, all arcs, polygons, and points were converted to shapefiles. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Direct questions or comments on this report to: Gregory J. Walsh U.S. Geological Survey P.O. Box 628 Montpelier, Vermont 05601 Tel: 802-828-4528 e-mail: gwalsh@usgs.gov ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Date of latest revision: May 31, 2011 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The GIS data associated with this report are provided in two common GIS formats. The GIS data were created in ARC/INFO version 9.3 on an Dell PC running Windows XP. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Note on Metadata: FGDC compliant metadata for the report exist in several file formats. These metadata files were created with the mp metadata tool available from: http://geology.usgs.gov/tools/metadata/ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Digital data are in: Massachusetts State Plane Coordinate System (FIPS Zone 2001) in NAD83 datum units in meters ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Computer Files: Some files have been archived using WinZip. Useful URL: http://winzip.com ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ******************************************************************** The following is a brief description of the geologic data layers, tables, and non-standard attributes used in this report. ******************************************************************** CONTX - Polygon data layer of bedrock geologic map units CONTX is divided into shapefiles for arcs, polygons, labels, and tic marks. Polygons - CONTX.PAT items: CODE - Bedrock geologic map unit code LITH_UNIT - same as CODE Lookup table - CONTX_LI.TXT - Bedrock lithology attribute lookup table If you are using Arc/Info you can access the data in this table using either the JOINITEM or RELATE functions and the item LITH_UNIT. You will first need to convert the TXT file to a DBF file. CONTX is the Arc/INfo coverage, and includes arcs, polygons, labels, and tic marks. Alternatively, you can use the polygon shapefile where the lookup table CONTX_LI.TXT has already been joined (gr_contx_polygon.shp) Tic marks: 4 corner tic marks from Mass GIS: MassGIS is the Commonwealth's Office of Geographic and Environmental Information http://www.mass.gov/mgis/massgis.htm 1614 1615 + + + + 1514 1515 Corner tic marks from the statewide coverage of USGS 7.5-minute quadrangles. CONTX_LI.TXT items: CODE = map unit designator (same as LITH_UNIT) AGE_SORT = order to sort by age (1 = youngest) LITH_UNIT = map unit designator SURF_BED = surficial or bedrock unit LITHPRI = primary lithology in the map unit LITHSEC = secondary lithology in the map unit ZONE = Avalon or Nashoba zone (or terrane) FORMATION = formation name MEMBER = member name ROCKCLASS = rock type AGE = geologic age of the map unit FOSSIL = Yes means the unit contains fossils outside the map area COLOR = color of unweathered rock MINPRI = most characteristic minerals Arcs - Line data layer of geologic contacts CONTX.AAT or arc shapefile Items: TYPE - fault or contact NAME - names of faults LINETYPE - type of faults, entries used in this database: 'early thrust reactivated as normal fault' 'normal fault' 'thrust fault' _________________________________________________________________ EXPOSURE - Unattributed polygon data layer of bedrock outcrops examined during mapping _________________________________________________________________ STRUCTURE - Point data layer of ductile and brittle structural geology STRUCTURE.PAT items: STATION - Number of field station TYPE - Refers to the general type of geologic feature. Valid entries include 'planar', 'linear', or 'other' SUB_TYPE - Refers to the specific geologic structure STRIKE - Angle measured from North in right-hand rule, units in degrees. DIP - Dip value (planar data) or plunge value (linear data), units in degrees DIPDIR - Direction of dip (planar data) or trend (linear data), units in degrees FRACTURE - 'Y' indicates feature is a fracture PARTING - 'Y' indicates the planar feature exhibits parting or fracturing parallel to the surface measured SYMBOL - Arc/Info symbol number THROUGHOI - 'Y' indicates the measured brittle feature is throughgoing and passes through the entire outcrop. REL_AGE - Refers to the relative age of ductile fabrics. Valid entries include: n = Relative age is the dominant fabric, S2 n+1 = maybe S2 or S3 n+2 = probably S3 POLARITE - not used in this report VERGENCE - vergence of kink bands, East (E) or West (W) FAULTMOVE - movement sense of brittle fault Valid entries include: normal, reverse, left lateral, right lateral, thrust NO_MSMTS - Number of features with same orientation. Valid for SUB_TYPE = 'joint' and 'joint set'. TERMINATIO - Termination of joints where known valid entries include: 'blind', 'abutting', 'crossing' TOPOFEAT - Topographic feature parallel to a geologic structure. Valid entries include: 'cliff' LITHOLOGY - Freeform text indicating the rock type in which the feature was measured. Used for rock type of dikes and sills, and locations where multiple rock types occur at one station SYMBOL - Refers to the symbol number from the GEOLOGY1.MRK markerset; used for plotting in Arcplot. SYMBOL_ANG - Refers to a standard Cartesian angle measured from East; used for symbol rotation and plotting in Arcplot, units in degrees Note -- The following three diagrams show an explanation of the geometry of STRIKE, DIPDIR, and SYMBOL_ANG: For STRIKE and DIPDIR: 0 North = 0 | East = 90 270 -----|----- 90 South = 180 | West = 270 180 For SYMBOL_ANG: 90 North = 90 | East = 0 180 -----|----- 0 South = 270 | West = 180 270 SYMBOL_ANG is used for symbol rotation. In ARC/INFO calculate pseudo item $angle = symbol_ang Planar symbols with symbol_ang = 0 look like this: __________ \/ Linear symbols with symbol_ang = 0 look like this: -----> ROTATION - Rotation sense of minor folds as viewed down plunge. Valid entries: 'cc' = counterclockwise and 'cw' = clockwise. SPACING - Spacing of joints in joint sets, units in meters WIDTH - Width or thickness of dike or vein, units in meters MIN1 - Primary mineral MIN2 - Secondary mineral MIN3 - Tertiary mineral Note on MIN1, MIN2, and MIN3 -- The aforementioned 3 items are used to describe minerals in veins or mineral lineations. The following values from Kretz (1983) are used in the report: bt biotite qtz quartz ep epidote gr graphite dol dolomite plg plagioclase lm limonite sul sulfides car carbonate kfs alkali feldspar chl chlorite sil sillimanite amp amphibole hbl hornblende ms muscovite Kretz, R., 1983, Symbols for rock-forming minerals: American Mineralogist, v. 68, nos. 1-2, p. 277-279. SAMPLE - Freeform text with sample information GPS Coordinate information in LATitude and LONGitude (WGS84 datum) LATDEG - degrees LATMIN - minutes LATSEC - seconds LAT - decimal degrees LONGDEG - degrees LONGMIN - minutes LONGSEC - seconds LONG - decimal degrees PLOT - 'Y' indicate symbol is plotted ____________________________________________________________ FOLDS - Line coverage of axial traces of folds FOLDS.PAT Items: FOLD_TYPE - Valid entries include: 'inferred F1 axial trace' 'F3 antiform' or 'F3 synform' PLUNGE_DIR - cardinal direction of plunge of fold ____________________________________________________________ PHOTO - Point data layer of photographs; includes landscape and outcrop photos PHOTO.PAT items: STATION - Number of field station TYPE - Valid entries include 'other' SUB_TYPE - Refers to the specific geologic feature, in this case 'photo'. PHOTO_FILE - Filename of JPG format color photograph Used for hyperlinks Note - The PHOTO shapefile is designed for use with the ArcMap hyperlink tool. There are 304 digital photos located in the PHOTOS directory on the CD. Users can copy the photos to the same directory as the shapefile, or copy the photos to their own folder and then specify the path: In ArcMap - File, Document Properties, Hyperlink Base ************************************************************************ The following is a description of the base used in this report: The basemaps consists of: Four files as TIFF format bitmaps and worldfiles HYPSO - Hypsography - brown separate HYDRO - Surface water - blue separate CULTURE - Primary culture originally on black and red separates includes roads, buildings, etc. CULTURE2 - Secondary culture from 1969 photorevisions from purple separate TIFF format maps: Scanned black and white bitmap images in uncompressed TIFF format. Scanned at 400 dpi from a film positive of the USGS 7.5-minute Grafton, Mass., topographic map (1969, photorevised 1979). Images registered to the 4 corner tics in Arc/Info. *********************************************************************** ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ END