U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY Bedrock Geologic Map of the Montpelier and Barre West Quadrangles, Washington and Orange Counties, Vermont [Scale 1:24,000] by Gregory J. Walsh (1), Jonathan Kim (2), Marjorie H. Gale (2), and Sarah M. King (2) 2010 version 1.0 Prepared in cooperation with the Vermont Geological Survey ________________________________ (1) U.S. Geological Survey (USGS) P.O. Box 628 Montpelier, VT 05601 (2) Vermont Geological Survey (VGS) 103 South Main St., Logue Cottage Waterbury, VT 05671-2420 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Source of Geologic Data: Original data. Geology mapped by Walsh, Kim, Gale, and King in 2002-2005; assisted by Aaron Satkoski, Leile Pascale, and Caroline Orsi from 2002-2003. Geology digitized by Walsh and Kim. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This report is available from: http://pubs.usgs.gov/sim/3111/ A CD-ROM with all the digital data is available from: 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 9.2 and 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., Kim, Jonathan, Gale, M.H., and King, S.M., 2010, Bedrock geologic map of the Montpelier and Barre West quadrangles, Washington and Orange Counties, Vermont: U.S. Geological Survey Scientific Investigations Map 3111, 1 sheet, scale 1:24,000, 36-p. text. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This report supersedes a provisional map by Kim and others (2003). Kim, J., Gale, M.H., King, S.M., Orsi, C.M., and Pascale, L.R., 2003, Bedrock geology of the Montpelier quadrangle: Vermont Geological Survey Open-File Report VG03-1, scale 1:24,000. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This readme.txt file briefly describes the GIS data. An explanatory text pamphlet on the geology accompanies the map. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Direct questions or comments on the geology or database to: Greg Walsh (USGS, P.O. Box 628, Montpelier, VT 05601) e-mail: gwalsh@usgs.gov ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: The bedrock geology of the Montpelier and Barre West quadrangles consists of deformed Cambrian to Devonian crystalline metamorphic and intrusive igneous rocks. The geology was mapped from 2002 to 2005 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 or similar). The line and polygon data were compiled in Adobe Illustrator over the topographic base map. Field sheets were scanned and registered in Illustrator. Topographic base-map separates were scanned at 400 dpi. Line and polygon data were exported from Illustrator in DXF format to Arc/Info version 9.2. 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 9.2 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 Vermont State Plane coordinate system in NAD83 datum, with units in meters. GPS locations were compared to the topographic base map 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. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Date of latest revision: August 16, 2010 This database was created in ArcGIS version 9.2 and 9.3 on an IBM-compatible personal computer. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ GIS data in Vermont State Plane coordinate system. Digital map units in meters. National Geodetic Horizontal Datum: North American Datum of 1983 (NAD 1983). COORDINATE SYSTEM DESCRIPTION Projection STATE PLANE Zone 5526 Datum NAD83 Units METERS Spheroid GRS1980 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Directory layout: http://pubs.usgs.gov/sim/3111/ --SIM3111.PDF---Sheet 1 Geologic map (52" tall x 41" wide) --SIM3111P.PDF---Text pamphlet in PDF; contains explanatory text of the geology (8.5” x 11” letter-size) http://pubs.usgs.gov/sim/3111/Downloads -README.TXT---ASCII text description (this file) -METADATA.HTM---Metadata file in html format -SIM3052A.ZIP---compressed database files | |---EXPORT---Folder contains Arc/Info GIS export-interchange files (e00) | | |---SHAPE---Folder contains ArcGIS shapefiles and lookup table for CONTX | polygon coverage | |---BASE---Folder contains base-map image files and world files | | Adobe Portable Document Format = PDF | |---GRAPHICS---| | |--SIM3111.GIF---Browse graphic of map sheet | |--SIM3111.JPG---Image graphic of map sheet (150 dpi) | | |---SYMBOLS--- Supporting files for symbology in ArcMap and Arc/Info ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Combined GIS files in ZIP format in Downloads directory: Contents of SIM3111A.zip: EXPORT, SHAPE, BASE, and SYMBOLS files above. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ GEOLOGIC COVERAGES (In ARC/INFO Interchange Format *.e00; or Shapefile) CONTACTS.E00 ... Polygon coverage for GEOLOGIC MAP UNITS Includes attributed lines for faults and contacts OUTCROP.E00 ... Polygon coverage for OUTCROPS FOLPT.E00 ... Point coverage for STRUCTURAL DATA PTSCARTO.E00 ... Point coverage of structural geology Includes subset of FOLPT used only for cartography. Includes annotation for cartography. MINES.E00 ... Point coverage for QUARRIES or PROSPECTS MAFIC.E00 ... Point coverage for MAFIC ROCKS BASE MAP Includes scanned and registered map separates created by this project. Includes world files. Scanned black and white 1-bit images are in TIFF format. Scanned at 400 dpi from film positives of the USGS 7.5-minute topographic maps. Images registered to the 4 corner tics. Scanned Separates: Montpelier (1999 edition) mp_cult02 culture (black separate) mp_hydr02 hydrography (blue separate) mp_hypso03 hypsography (brown separate) Barre West (1978 edition, photorevised 1988) bw_bldgs01 culture/buildings (purple separate - 1988) bw_cult02 culture (black separate) bw_hydr02 hydrography (blue separate) bw_hypso02 hypsography (brown separate) SYMBOLS Arc/Info workstation: Used for plotting structural geology symbols in point coverages. This is older way of plotting point data, but it allows all points to be in the same coverage. Copy the fnt files to your workspace and specify a path to the mrk file in AML. geology1.mrk fnt025 fnt026 fnt035 fnt036 fnt038 fnt039 fnt040 These files are modified from the original versions of Fitzgibbon and Wentworth (1991): Fitzgibbon, T.T., and Wentworth, C.M., 1991, ALACARTE User Interface; AML code and demonstration maps: U.S. Geological Survey Open-File Report 91-587. ArcMap: Layer file - BWMP contacts geology polygon.lyr Contains polygon color definitions. Colors may differ from final colors used on the map. Layer file - BWMP contacts geology arc.lyr Contains arc symbol definitions used on the map. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The following is a description of the ARC/INFO coverages. The same definitions apply to the shapefiles. _________________________________________________________________ CONTACTS - CONTACTS is the Arc/Info coverage and includes arcs, polygons, labels, and tic marks. Polygons - Item "LITH" in CONTACTS.PAT contains the map unit designators. "LITH" stands for lithology. Look-up table CONTX_LUT.TXT (also in .DBF and .XLS) contains the following items: LITH = map unit designator 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 = major unit or terrane BELT = subdivision of zone FORMATION = formation name RMC = location 'east' or 'west' of the RMC (Richardson Memorial Contact) unconformity ROCKCLASS = major rock type AGE = geologic age of the map unit FOSSIL = Yes means the unit contains fossils COLOR = color of unweathered rock MINPRI = most characteristic minerals MINSEC = secondary minerals See the text pamphlet for a complete description of the rocks. 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. In ArcMap, you will see that the lookup attribute table is already joined to the polygon shapefile. Tic marks: Corner tic marks from the statewide coverage of USGS 7.5-minute quadrangles. Six tic marks are in CONTACTS coverage (CONTACTS.TIC) and in the shapefile (CONTACTS_TIC.SHP). The 6 corner tic marks are from VCGI (Vermont Center for Geographic Information): http://www.vcgi.org/ 815 915 + + MONTPELIER + + 814 914 BARRE WEST + + 813 913 Arcs - Line data layer of geologic contacts CONTACTS.AAT or arc shapefile (CONTACTS_ARC.SHP) Type - contact or fault 'ot_thrust' = overturned thrust fault 'reverse' = reverse fault 'contact' = contact 'RMC' = Richardson Memorial Contact (unconformity) _________________________________________________________________ OUTCROP - Unattributed polygon data layer of bedrock outcrops examined during mapping. _________________________________________________________________ STRUCTURAL DATA - The FOLPT.PAT and PTSCARTO.PAT files for the POINT coverages contain the following items: COLUMN ITEM NAME WIDTH OUTPUT TYPE 17 STATION 4 10 B 21 TYPE 8 8 C 29 SUB_TYPE 32 32 C 61 STRIKE 3 3 I 64 DIP 2 2 I 66 DIPDIR 3 3 I 69 FRACTURE 1 1 C 70 PARTING 1 1 C 71 THROUGHGOI 1 1 C 72 REL_AGE 3 3 C 75 FAULTMOV 12 12 C 87 NO_MSMTS 2 2 I 89 TERMINATIO 8 8 C 97 LITHOLOGY 12 12 C 109 ROTATION 2 2 C 111 SPACING 4 4 C 115 WIDTH 8 16 F 123 MIN1 3 3 C 126 MIN2 3 3 C 129 MIN3 3 3 C 132 SAMPLE 8 8 C 140 SAMPLE_TYP 8 8 C 148 PHOTO 8 8 C 156 X_COORD 8 8 I 164 Y_COORD 8 8 I 172 LATDEG 4 10 B 176 LATMIN 4 10 B 180 LATSEC 8 16 F 188 LATDD 8 16 F 196 LONGDEG 4 10 B 200 LONGMIN 4 10 B 204 LONGSEC 8 16 F 212 LONDD 8 16 F 220 SYMBOL_ANG 3 3 I 223 SYMBOL 3 3 I 226 SOURCE 4 4 C 230 POINT 12 12 C ............................................................. Here is an explanation of the items: DIP = dip value (planar data) or plunge value (linear data) STRIKE = STRIKE value measured in Right Hand Rule (planar data) DIPDIR = Direction of dip measured from North (planar and linear data) Geographic Rotation Style used for STRIKE and DIPDIR: 0 North = 0 | East = 90 270 -----|----- 90 South = 180 | West = 270 180 SYMBOL_ANG = refers to a standard cartesian or arithmetic angle measured from East: Geographic Rotation Style used 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: -----> SYMBOL refers to a pattern number in GEOLOGY1.MRK. ROTATION refers to the rotation sense of minor folds as viewed down plunge. Valid entries are: clockwise = cw counterclockwise = cc REL_AGE refers to the relative age of fabrics. Valid entries are: 1, 2, 3, 4, n, n+1, n-1, and so on. TYPE refers to the type of fabric. Valid entries are: Planar or Linear or Other SUB_TYPE refers to the specific fabric. Valid entries used in this report include: SUB_TYPE axial surface bedding bedding with tops cleavage crenulation crenulation cleavage crenulation lineation crinkle lineation deformed schistosity dike fault fold axis fossil glacial grooves granite contact intersection lineation joint joint set layer parallel schistosity mineral lineation other overturned bedding photo porphyroblast prospect quarry rodding sample schistosity slickenlines spring stretching lineation vein warped bedding FRACTURE refers to whether the feature is a fracture. Either 'Y' for yes, or blank. PARTING refers to whether an older metamorphic fabric exhibits parting or fracturing along a planar surface. Either 'Y' for yes, or blank. THROUGHGOIN refers to whether a measured joint or fault is throughgoing, or passes through the entire outcrop. Either 'Y' for yes, or blank. FAULTMOV refers to type of relative motion of outcrop scale brittle faults. valid entries are 'left lateral,' 'reverse,' or 'normal.' 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' LITHOLOGY - Freeform text indicating the rock type in which the feature was measured. Used for rock type of dikes, and locations where multiple rock types occur at one station 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 X_COORD and Y_COORD refers to coordinates in Vermont State Plane, in meters 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 SOURCE refers to the agency that collected the data. Entries are 'USGS' or 'VGS' POINT refers to the name of the location recorded by VGS. STATION refers to the name of the location recorded by USGS. _________________________________________________________________ MINES - Locations of quarries, mines, or prospect pits are included in a separate POINT coverage that was extracted from FOLPT. _________________________________________________________________ MAFIC - Locations of mafic rocks in the Wrightsville belt of the Moretown Formation; included in a separate POINT coverage that was extracted from FOLPT. Points were plotted on the geologic map (sheet 1). ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ END