U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY Bedrock Geologic Map of the Old Lyme Quadrangle, New London and Middlesex Counties, Connecticut [Scale 1:24,000] by Gregory J. Walsh (1) Robert B. Scott (2) John N. Aleinikoff (2) and Thomas R. Armstrong (3) Scientific Investigations Map 3052 2009 version 1.0 Prepared in cooperation with The State of Connecticut Department of Environmental Protection Geological and Natural History Survey ________________________________ (1) U.S. Geological Survey Montpelier, VT 05602 (2) U.S. Geological Survey Denver, CO 80225 (3) U.S. Geological Survey Reston, VA 20192 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Source of Geologic Data: Original data. Geology mapped by Armstrong in 2001 and by Walsh and Scott in 2002. Geochronology by Aleinikoff. The bedrock geology was mapped using standard techniques. Location information was provided by general purpose hand-held GPS receivers or Rockwell PLGR+96 GPS receivers using the Federal precise positioning service. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Suggested Citation: Walsh, G.J., Scott, R.B., Aleinikoff, J.N., and Armstrong, T.R., 2009, Bedrock geologic map of the Old Lyme quadrangle, New London and Middlesex Counties, Connecticut: U.S. Geological Survey Scientific Investigations Map 3052, 2 sheets, scale 1:24,000, 25-p. text. Directory layout: http://pubs.usgs.gov/sim/3052/ --SIM30521.PDF---Sheet 1 Geologic map (30" tall x 50" wide) --SIM30522.PDF---Sheet 2 Brittle structure map (31" tall x 39" wide) --SIM3052P.PDF---Text pamphlet in PDF; contains explanatory text of the geology http://pubs.usgs.gov/sim/3052/Downloads |--README.TXT---ASCII text description (this file) |--METADATA.HTM---Metadata file in HTML format |--SIM3052A.ZIP---compressed database files without base |--SIM3052B.ZIP---compressed database files with base | |---EXPORT---Contains Arc/Info GIS export-interchange files | |---SHAPE---Contains ArcView GIS shapefiles and lookup table for CONTX | polygon coverage in decimal degrees | |---BASE---Contains basemap image file and worldfile | | |---GRAPHICS---| | |--SIM30521.GIF---Browse graphic of Sheet 1 | |--SIM30522.GIF---Browse graphic of Sheet 2 | |--SIM30521.JPG---Image graphic of Sheet 1 (150 dpi) | |--SIM30522.JPG---Image graphic of Sheet 2 (150 dpi) | |---SYMBOLS---Contains Arc/Info symbol and font files for ArcPlot ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Contents of SIM3052A.zip: contx.dbf contx.e00 contx.shp contx.shx contx_li.csv faults.dbf faults.e00 faults.shp faults.shx fnt025 fnt026 fnt035 fnt036 fnt038 fnt039 fnt040 geology1.mrk metadata.htm outcrop.dbf outcrop.e00 outcrop.shp outcrop.shx strux.dbf strux.e00 strux.shp strux.shx readme.txt Contents of SIM3052B.zip: Includes all files in SIM3052A.zip and the following 2 topographic base files: OLbase.tif OLbase.tfw ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ This report is available from: http://pubs.usgs.gov/sim/3052/ 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/ Printed paper maps are available from: USGS Maps on Demand http://rmmcweb.cr.usgs.gov/public/mod/ ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Description: The bedrock geology of the 7.5-minute Old Lyme, CT quadrangle consists of deformed Neoproterozoic to Permian crystalline metamorphic and intrusive igneous rocks. The geology was mapped during 2001 and 2002 at a scale of 1:24,000. The bedrock geology was mapped using standard techniques. Location information was provided by general purpose hand-held GPS receivers or Rockwell PLGR+96 GPS receivers using the Federal precise positioning service. The line and polygon data were compiled on a Mylar greenline of the 7.5-minute quadrangle and scanned at 400 dpi. The raster files (TIF) were converted to vector files (DXF) using raster-to-vector conversion software. The vector files were imported to Arc/Info version 8.3. Point data were collected with GPS and hand-held 3COM Palm Pilot III PDA computers. Data from the GPS and PDAs were combined in ArcView, converted to shapefiles, and then imported into Arc/Info. The GPS data were collected in the UTM coordinate system in zone 18 datum NAD27. Preliminary Arc/Info coverages were registered to the UTM coordinate system in zone 18 datum NAD27. All data were then projected to the polyconic projection, NAD27, with units in meters, to match the published paper topographic map. Raw GPS data were compared to the topographic base map of the area and repositioned to match the base. The original coordinates remain in the database. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Projection information for Shapefiles and Coverages: COORDINATE SYSTEM DESCRIPTION Projection POLYCONIC Datum NAD27 Units METERS Spheroid CLARKE1866 longitude of central meridian -72 18 45.000 latitude of projection's origin 41 15 0.000 false easting (meters) 0.00000 false northing (meters) 0.00000 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Direct questions or comments to: Gregory J. Walsh U.S. Geological Survey P.O. Box 628 Montpelier, VT 05602 Tel: 802-828-4528 e-mail: gwalsh@usgs.gov ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ Date of latest revision: October 30, 2009 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The GIS data associated with this report are provided in common GIS formats. The GIS data were created in Arc/Info workstation version 8.3 on a Dell PC running Windows XP Pro. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ 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.PAT items: CODE - Bedrock geologic map unit code The following table lists the valid fields for CODE and how the units are shown on the State bedrock geologic map by Rodgers (1985): CODE Rodgers (1985) ____ ______________ DSos Obr DSoh Ota DSohrs Ota Pa Zsh Pp Pn Sh SOh PZmig within "Zp" on map, but no equivalent unit Zgd within "Zp+Zsph+Pn?" on map, but no equivalent unit Zgdh within "Zp+Zsph+Pn?" on map", but no equivalent unit Zo Zp Zoa Zp Zog Zp Zolq Zp Zoq Zpq Zos Zp Zgb Zsph Zwr Zwr Zwra Zwr Zgdl Zwr Zgdla Zwr Rodgers, John, comp., 1985, Bedrock geological map of Connecticut: [Hartford,] Connecticut Geological and Natural History Survey, 2 sheets, scale 1:125,000. CONTX_LI.CSV - Lithology attribute table (in comma delimited ASCII format) If you are using Arc/Info you can access the data in this table using either the JOINITEM or RELATE functions and the item CODE. Similarly, if you are using ArcView or ArcMap add the table CONTX_LI.CSV to the project and use either the JOIN or LINK function. CONTX_LI.CSV items: CODE = map unit designator MAP_UNIT = map unit designator SURF_BED = surficial or bedrock unit LITHPRI = primary lithology in the map unit LITHSEC = secondary lithology in the map unit TERRANE = lithotectonic terrane name GROUP = group name FORM = formation name MEMBER = member name ROCKCLASS = rock type AGE = geologic age of the map unit FOSSIL = Yes indicates the unit contains fossils outside the map area COLOR = color of unweathered rock MINPRI = most characteristic minerals FAULTS - Line data layer of geologic faults. FAULTS.AAT items: TYPE - Type of fault Type Description thrust thrust fault strikeslip strike slip OUTCROP - Unattributed polygon data layer of bedrock outcrops examined during mapping. All outcrops in the area are not identified. STRUX - Point data layer of ductile and brittle structural geology. STRUX.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 Note -- Valid entries for TYPE, SUB_TYPE, REL_AGE, SYMBOL, and DIP include: TYPE SUB_TYPE REL_AGE SYMBOL DIP(degrees) linear boudinage n 0 <90 linear boudinage n+1 0 <90 linear crenulation n+1 116 <90 linear fold axis n 115 <90 linear fold axis n 116 <90 linear fold axis n+1 116 <90 linear fold axis n+2 117 <90 linear glacial grooves 0 na linear intersection lineation n 118 <90 linear intersection lineation n+1 119 <90 linear mineral elongation n 120 <90 linear mineral lineation n 120 <90 linear mineral lineation n+1 121 <90 linear rods n 120 <90 linear slickenlines 123 <90 other quarry 67 na other sample 0 na other spring 85 na planar axial surface n 29 <90 planar axial surface n 30 90 planar axial surface n+1 40 <90 planar axial surface n+1 41 90 planar axial surface n+2 44 <90 planar axial surface n+2 45 90 planar cleavage n+1 10 <90 planar cleavage n+1 11 90 planar cleavage n+2 35 <90 planar cleavage n+2 36 90 planar deformed gneissosity n 14 <90 planar deformed gneissosity n-1 32 <90 planar dike 244 <90 planar dike 245 90 planar dike 644 <90 planar fault 125 <90 planar fault 126 90 planar gneissosity n 14 <90 planar gneissosity n 15 90 planar joint 26 <90 planar joint 27 90 planar layer parallel gneissosity n-1 32 <90 planar shear band 38 <90 PARTING - 'Y' indicates 'yes' the planar feature exhibits parting or fracturing parallel to the surface measured. THRUGO - 'Y' indicates the measured brittle feature is throughgoing and passes through the entire outcrop. FRACTURE - 'Y' indicates the measured feature exhibits fracturing along its surface. REL_AGE - Refers to the relative age of ductile fabrics. Valid entries include: n-1 = Relative age is older than dominant fabric; parallel to bedding or S0 n = Relative age is the dominant fabric; age S1 n+1 = S2 n+2 = S3 EAST - UTM Easting value from GPS unit in meters. NORTH - UTM Northing value from GPS unit in meters. Note -- EAST and NORTH values collected in datum NAD27. 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. NOMSMT - Number of features with same orientation. LITH - Freeform text indicating the type of dike. Valid entries include: 'Pw' for Westerly Granite and 'Pn' for Narragansett Pier Granite pegmatite. TOPOFEAT - Type of topographic feature parallel to a geologic structure. Valid entries include: 'cliff', 'slope', 'stream', and 'valley'. SYMBOL - Refers to the symbol number from the GEOLOGY.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 include: 'cc' = counterclockwise and 'cw' = clockwise. SPACING - Spacing of joints in joint sets, units in meters. WIDTH - Width or thickness of dike, units in meters. TERMINATIO - Termination of joints. Valid entries include: 'blind', 'abutting', and 'crossing'. MIN1 - Primary mineral MIN2 - Secondary mineral MIN3 - Tertiary mineral Note on MIN1, MIN2, and MIN3 -- The three aforementioned items are used to describe minerals in lineations. The following values from Kretz (1983) are used in the report: bt biotite hbl hornblende qtz quartz kfs K feldspar sil sillimanite ms muscovite pl plagioclase Kretz, R., 1983, Symbols for rock-forming minerals: American Mineralogist, v. 68, nos. 1-2, p. 277-279. SAMPLE - Freeform text with sample information. FAULTMOV - Relative motion sense for SUB_TYPE = 'fault'. Valid entries include: 'normal' and 'left lateral'. MAP_UNIT - Relate item for CONTX polygon coverage generated with Arc: IDENTITY command. Same as CODE. SOURCE - Source of measurement. Valid entries include, 'GJW' for Walsh, 'RBS' for Scott, and 'TRA' for Armstrong. ************************************************************************ The following is a description of the topographic base included in the database of this report: The basemap consists of: - TIFF format bitmap and worldfile (OLbase.tif and OLbase.tfw) TIFF format bitmap: Scanned black and white bitmap image in uncompressed TIFF format. Scanned at 400 dpi from a film positive of the USGS 7.5-minute Old Lyme, CT topographic map (1958, photorevised 1970). The TIFF image was registered with the Arc: REGISTER command. The world file (OLbase.tfw) contains the projection information. ************************************************************************ Supporting files ************************************************************************ SYMBOLSETS AND FONT FILES: MARKERSET file (copy to any directory, specify a path when using) geology1.mrk FONT FILES (copy to the same workspace as the coverages) fnt025 fnt026 fnt035 fnt036 fnt038 fnt039 fnt040 The symbolset and font 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. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ END