Identification_Information: Citation: Citation_Information: Originator: Gregory J. Walsh Originator: Richard H. Jahns Originator: John N. Aleinikoff Publication_Date: 2013 Title: Bedrock geologic map of the Nashua South quadrangle, Hillsborough County, New Hampshire, and Middlesex County, Massachusetts Edition: 1.0 Geospatial_Data_Presentation_Form: Map Series_Information: Series_Name: Scientific Investigations Map Issue_Identification: 3200 Publication_Information: Publication_Place: Reston, Virginia Publisher: U.S. Geological Survey Online_Linkage: http://pubs.usgs.gov/sim/3200/ Other_Citation_Details: Walsh, G.J., Jahns, R.H., and Aleinikoff, J.N., 2013, Bedrock geologic map of the Nashua South quadrangle, Hillsborough County, New Hampshire, and Middlesex County, Massachusetts: U.S. Geological Survey Scientific Investigations Map 3200, 1 sheet, scale 1:24,000, 31-p. pamphlet. Description: Abstract: The bedrock geology of the 7.5-minute Nashua South, NH-MA quadrangle consists of deformed Silurian to Jurassic crystalline metamorphic and intrusive igneous rocks. The database includes contacts of bedrock geologic units, faults, outcrops, structural geologic information, and photos. Purpose: The bedrock geology was mapped to study the tectonic history of the area and to provide a framework for ongoing hydrogeologic characterization of the fractured bedrock of Massachusetts and New Hampshire. The digital data are intended for use by all government, academic, commercial, or other agencies in need of digital geologic map information. The report contains a GIS database, large format color sheet and explanatory text pamphlet in Adobe Portable Document Format (PDF), and a readme.txt file. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 2006 Ending_Date: 2013 Currentness_Reference: publication date Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -71.499512 East_Bounding_Coordinate: -71.374254 North_Bounding_Coordinate: 42.750157 South_Bounding_Coordinate: 42.625022 Keywords: Theme: Theme_Keyword_Thesaurus: AGI Glossary of Geology Theme_Keyword: geology Theme_Keyword: geologic Theme_Keyword: bedrock Theme_Keyword: geochronology Theme_Keyword: SHRIMP Theme_Keyword: zircon Place: Place_Keyword_Thesaurus: None Place_Keyword: Massachusetts Place_Keyword: New Hampshire Place_Keyword: Hillsborough County Place_Keyword: Middlesex County Place_Keyword: Nashua Place_Keyword: Hudson Place_Keyword: Dunstable Place_Keyword: Tyngsborough Place_Keyword: Westford Place_Keyword: Chelmsford Place_Keyword: Groton Place_Keyword: Lowell Access_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. Use_Constraints: none Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Gregory J. Walsh Contact_Position: Research Geologist Contact_Address: Address_Type: mailing address Address: P.O. Box 628 City: Montpelier State_or_Province: Vermont Postal_Code: 05601 Country: USA Contact_Voice_Telephone: 802-828-4528 Contact_Facsimile_Telephone: 802-828-4465 Contact_Electronic_Mail_Address: gwalsh@usgs.gov Data_Set_Credit: Walsh and others (2013). Supersedes Jahns, R.H., Willard, M.E., and White, W.S., 1959, Preliminary bedrock geologic map of the Lowell-Westford area, Massachusetts: U.S. Geological Survey Open-File Report 59-70, scale 1:31,680, 1 map. Native_Data_Set_Environment: ArcGIS shapefile format Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: All attributes digitized during the creation process were verified by displaying the lines and points in the database with respect to the USGS 7.5-minute topographic base map (1:24,000 scale), but no formal tests were performed. Logical_Consistency_Report: These data are believed to be logically consistent, though no tests were performed. Geometry is topologically clean. Completeness_Report: The geologic contacts were delineated on a USGS 7.5-minute topographic map based on observations at the outcrops shown in the database. Not all outcrops within the area were identified or visited during mapping. The geologic contacts might change if additional outcrops are discovered or exposed as the natural land changes or as the result of development. The features in the database are not based on legal parcels or definitions. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: The data were created on a USGS 7.5-minute topographic map at 1:24,000-scale. Therefore, the horizontal accuracy is assumed to be within National Map Accuracy Standards, with a horizontal accuracy of 45.6 feet at the 95% confidence level. Locational information in the field was provided by a Garmin eTrex Venture GPS receiver. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: The data were delineated on a USGS 7.5-minute topographic map at 1:24,000-scale. Therefore, the vertical accuracy is assumed to be within National Map Accuracy Standards, with a vertical accuracy of 11.9 feet at the 95% confidence level. Lineage: Process_Step: Process_Description: Geology mapped by Walsh in 2006, by Jahns in 1939-40 (MA) and 1951 (NH). Geochronology by Aleinikoff, 2007-08. A preliminary version of the geology of the Nashua South quadrangle was published by Jahns and others (1959). This report supersedes the Nashua South part of the 1959 report. Jahns, R.H., Willard, M.E., and White, W.S., 1959, Preliminary bedrock geologic map of the Lowell-Westford area, Massachusetts: U.S. Geological Survey Open-File Report 59-70, scale 1:31,680, 1 map. The geology was mapped during 2006 and 1939-1951. The bedrock geology was mapped using standard techniques. Location information during modern mapping was collected with a GPS receiver (GPS model: Garmin eTrex Venture). Locational data for historic data (1939-1951) was digitized by Walsh from scanned unpublished map sheets compiled by Richard Jahns. The 7.5-minute Nashua South quadrangle was formerly named the Tyngsborough quadrangle. Jahns mapped the New Hampshire part of the Tyngsborough quadrangle in 1951, and the Massachusetts part from 1939-40. Scanned copies of Jahns’ unpublished manuscript maps were obtained from the Richard Jahns Collection at the Branner Earth Sciences Library, Stanford University, Palo Alto, California. The line and polygon data were compiled in Adobe Illustrator over the topographic basemap. Field and compilation 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 by Walsh 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. Jahn's strike and dip data were heads-up digitized in Arc/Info. The GPS data were collected in Latitude and Longitude in degrees minutes and seconds in WGS84 datum. GPS data were projected to the Massachusetts Stateplane 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. Data in the Massachusetts State Plane coordinate system were re-projected to the New Hampshire State Plane coordinate system. Line and polygon data were edited in Arc/Info and converted to shapefiles. Shapefiles were plotted in ArcMap and exported to Illustrator. Final cartography was done in Adobe Illustrator. Process_Date: 2013 Source_Produced_Citation_Abbreviation: Walsh and others (2013) Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Gregory J. Walsh Contact_position: Geologist Contact_Address: Address_Type: mailing address Address: P.O. Box 628 City: Montpelier State_or_Province: Vermont Postal_Code: 05601 Country: USA Contact_Voice_Telephone: 802-828-4528 Contact_Facsimile_Telephone: 802-828-4465 Contact_Electronic_Mail_Address: gwalsh@usgs.gov Hours_of_Service: 0900 to 1700 Eastern Standard Time Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Vector Point_and_Vector_Object_Information: SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Complete chain Point_and_Vector_Object_Count: 347 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Label point Point_and_Vector_Object_Count: 137 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: GT-polygon composed of chains Point_and_Vector_Object_Count: 137 SDTS_Terms_Description: SDTS_Point_and_Vector_Object_Type: Point Point_and_Vector_Object_Count: 4 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Grid_Coordinate_System: Grid_Coordinate_System_Name: State Plane Coordinate System 1983 State_Plane_Coordinate_System: SPCS_Zone_Identifier: 2001 Lambert_Conformal_Conic: Standard_Parallel: 41.716667 Standard_Parallel: 42.683333 Longitude_of_Central_Meridian: -71.500000 Latitude_of_Projection_Origin: 41.000000 False_Easting: 200000.000000 False_Northing: 750000.000000 Planar_Coordinate_Information: Planar_Coordinate_Encoding_Method: coordinate pair Coordinate_Representation: Abscissa_Resolution: 0.000100 Ordinate_Resolution: 0.000100 Planar_Distance_Units: meters Geodetic_Model: Horizontal_Datum_Name: North American Datum of 1983 Ellipsoid_Name: Geodetic Reference System 80 Semi-major_Axis: 6378137.000000 Denominator_of_Flattening_Ratio: 298.257222 Entity_and_Attribute_Information: Overview_Description: Entity_and_Attribute_Overview: The geologic data layers in the GIS database of this report include (1) CONTAX (contacts) - Polygon and arc data layers of bedrock geologic map units, contacts, and faults, including a polygon attribute table, (2) EXPOSURE - Polygon and arc data layers of bedrock outcrops, (3) PHOTOS - Point locations and photographs of geology, and (4) STRUCTURE - Point data of structural observations. Entity_and_Attribute_Detail_Citation: http://pubs.usgs.gov/sim/3200/Downloads/readme.txt Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Address: Address_Type: mailing address Address: Box 25286, Denver Federal Center City: Denver State_or_Province: Colorado Postal_Code: 80225 Country: USA Contact_Voice_Telephone: 1-888-ASK-USGS Contact_Electronic_Mail_Address: ask@usgs.gov Hours_of_Service: 0900 to 1700 Mountain Standard Time Resource_Description: USGS Scientific Investigations Map 3200 Distribution_Liability: 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, makes any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, product or process disclosed in this report, and represents 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 and related materials. Reference therein to any specific commercial product, process, or related service by trade name, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: ArcGIS Shapefile Format_Version_Number: 9.3.1 Format_Information_Content: Geologic units and related features File_Decompression_Technique: unzip Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://pubs.usgs.gov/sim/3200/downloads/SIM3200.zip Digital_Form: Digital_Transfer_Information: Format_Name: Google Earth Format_Version_Number: 5.2 Format_Information_Content: Geologic units and related features including a 3D model File_Decompression_Technique: unzip Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://pubs.usgs.gov/3200/downloads/SIM3200GE.zip Digital_Form: Digital_Transfer_Information: Format_Name: Adobe Acrobat Format_Version_Number: 1.5 Format_Information_Content: Bedrock geologic map in 1 sheet and explanatory pamphlet File_Decompression_Technique: none Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: http://pubs.usgs.gov/sim/3200/ Fees: none Metadata_Reference_Information: Metadata_Date: 20130104 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: USGS Contact_Person: Gregory J. Walsh Contact_Position: Research Geologist Contact_Address: Address_Type: mailing address Address: P.O. Box 628 City: Montpelier State_or_Province: Vermont Postal_Code: 05601 Country: USA Contact_Voice_Telephone: 802-828-4528 Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998