%0 Map %D 2012 %T Digital conversion of Peck, J.H., 1975, Preliminary bedrock geologic map of the Clinton quadrangle, Worcester County, Mass., U.S. Geological Survey Open File Report 75-658 %A Peck, J.A. %E Joseph P Kopera %K #BedrockMap %K #MGSPub %K andalusite %K ayer granite %K Berlin %K Bolton %K Boylston %K Clinton %K Clinton-Newbury Fault %K Devens %K Harvard %K Lancaster %K Leominster %K nashoba %K Oakdale Quartzite %K Peck %K phyllite %K quartzite %K Reuben's Hill Formation %K Sterling %K tadmuck brook schist %K Tower Hill quartzite %K Wekepeke Fault %K Worcester Formation %X This map is an interim product and will be superseded by an updated bedrock map of the quadrangle in 2016. This map is a digital version of USGS OFR 75-658: http://pubs.er.usgs.gov/publication/ofr75658 There are some cartographic errors in creating a digital version: A Jurassic diabase dike along the western edge of the quadrangle is not shown in the digital version. These errors are being corrected. %B Digital Conversion %7 DC12-01 %I Massachusetts Geological Survey %G eng %2 1:24000 %0 Map %D 2005 %T [Draft] Preliminary bedrock geologic map of the Lawrence quadrangle, Massachusetts %A Castle, R.O. %A Hepburn, J.C. %A Joseph P Kopera %K #BedrockMaps %K #MGSPub %K Andover %K Andover Granite %K Bedford %K Berwick formation %K Clinton-Newbury Fault %K Dracut %K Elliot formation %K Lawrence %K Methuen %K nashoba %K North Andover %K tadmuck brook schist %K Tewksbury %B Open-File Report %I Massachusetts Geological Survey %G eng %2

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%0 Map %D 2005 %T [Draft] Preliminary bedrock geologic map of the South Groveland quadrangle, Massachusetts %A Castle, R.O. %A Hepburn, J.C. %A Joseph P Kopera %K #BedrockMaps %K #MGSPub %K Andover %K Andover Granite %K Boxford %K Boxford formation %K Clinton-Newbury Fault %K Fish Brook gneiss %K Georgetown %K Groveland %K Haverhill %K Methuen %K Middleton %K Nashoba terrane %K North Andover %K Sharpner's Pond diorite %B Open-File Report %I Massachusetts Geological Survey %G eng %2

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%0 Map %D 2006 %T Preliminary bedrock geologic map of the Ayer quadrangle, Massachusetts %A Joseph P Kopera %K #BedrockMaps %K #MGSPub %K arsenic %K Ayer %K ayer granite %K Berwick formation %K Boxborough %K chelmsford granite %K Clinton-Newbury Fault %K Devens %K Fort Devens %K Groton %K Harvard %K Jahns %K LITTLETON %K Merrimack Terrane %K mylonite %K nashoba %K Nashua Trough %K Oakdale formation %K Shepley's Hill Landfill %K Shirley %K tadmuck brook schist %K Worcester Formation %X

This preliminary version of the Bedrock Map of the Ayer Quadrangle (Kopera, 2006) has been removed pending the release of an updated version in the near future. The above version should be considered outdated. If you would like a copy of this map, please contact Joseph Kopera at jkopera[at]geo[dot]geo[dot] umass[dot]edu

%B Open-File Report %7 OFR-06-02 %I Massachusetts Geological Survey %G eng %U http://www.geo.umass.edu/stategeologist/ %2

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%0 Map %D 2014 %T Preliminary Bedrock Geologic Map of the Hudson 7.5' Quadrangle Worcester and Middlesex Counties, Massachusetts %A Joseph P Kopera %A W.R. Hansen %K #BedrockMaps %K #MGSPub %K acton granite %K ayer granite %K Berlin %K Bolton %K Boxborough %K Clinton-Newbury Fault %K gneiss %K Harvard %K Harvard Conglomerate %K Hudson %K magnetite %K Malborough %K marble %K migmatite %K nashoba %K Stow %K tadmuck brook schist %K Vaughn Hills %X The Hudson quadrangle straddles the Clinton-Newbury Fault Zone (CNFZ), which separates low metamorphic grade Silurian turbiditic metasediments and Devonian plutons of the Nashua sub-belt (Robinson and Goldsmith, 1991) of the Merrimack Terrane to the northwest from the high-grade, migmatitic Cambro- Ordovician arc-complex of the Nashoba Terrane (Walsh et al., 2011; Loan 2011). This general area comprises the suture between the Gander and Avalon composite terranes of the Northern Appalachians (cf. Hibbard et al., 2006). Metasedimentary rocks of the Merrimack Terrane are generally poorly exposed, with intrusives (Day, Dayp, SDgdt) and the Clinton-Newbury Fault zone and associated rocks (Ot) forming a prominent northeast trending ridge (Oak Hill in the town of Harvard) marking the eastern bordering slope of the Worcester Plateau (Emerson, 1917, p. 16). Elevation and local topographic relief gradually decreases and glacial cover increases to the east-southeast across the strike of the Nashoba Formation, which, locally, forms low-relief NE-trending strike-parallel ridges. These are cut by dramatic cross-strike cliffs and glacial spillway gorges developed along cross-strike joints and brittle faults, most notably on the western slopes of Rattlesnake Hill, southern slope of Powder House Hill and in Camp Resolute in Bolton in the west-central portion of the quadrangle, and the southern slope of the hill along the west side of Codman Hill Road in Harvard in the north-central portion of the quadrangle. The migmatitic ortho- and paragneisses, schists and associated metavolcanic rocks of the Nashoba Formation (_Sn) form a northeast striking belt underlying the southern two-thirds of the quadrangle. These are intruded by a variety of presumed Ordovician to Silurian intermediate intrusives (OSd, OSaqd) and Devonian or younger tonalites to granites (Dan, Danp, Dac). %B Open File Report %7 14-01 %I Massachusetts Geological Survey %8 09/2014 %G eng %1 Note: This map supersedes "Preliminary bedrock geologic map of the Hudson quadrangle, Massachusetts", MGS map published in 2005 Report accompanies map-- be sure to download both! %0 Map %D 2005 %T Preliminary bedrock geologic map of the Hudson quadrangle, Massachusetts %A Joseph P Kopera %A Hansen, W.R. %K #BedrockMaps %K #MGSPub %K acton granite %K ayer granite %K Berlin %K Bolton %K Boxborough %K Clinton-Newbury Fault %K gneiss %K Harvard %K Harvard Conglomerate %K Hudson %K magnetite %K Malborough %K marble %K migmatite %K nashoba %K Stow %K tadmuck brook schist %K Vaughn Hills %X This map has been superseded by MGS OFR 14-01: Preliminary Bedrock Geologic Map of the Hudson 7.5' Quadrangle Worcester and Middlesex Counties, Massachusetts This map is an interim update to W.R. Hansen's 1956 Bedrock Geology of the Hudson and Maynard 7.5' quadrangles (USGS Bulletin 1038). This draft version of the Bedrock Map of the Hudson Quadrangle (Kopera, 2005) has been removed pending the future release of an updated version. The above version should be considered outdated. If you would like a copy of this map, please contact Joseph Kopera at jkopera[at]geo[dot]geo[dot]umass[dot]edu

%B Open-File Report %I Massachusetts Geological Survey %G eng %2

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%0 Map %D 2009 %T Preliminary bedrock geologic map of the Westford quadrangle, Massachusetts %A Joseph P Kopera %A D.C. Alvord %A Richard H Jahns %A M.E. Willard %A W.S. White %K #BedrockMaps %K #MGSPub %K Acton %K amphibolite %K ayer granite %K Berwick formation %K Boxborough %K calc-silicates %K Carlisle %K Chelmsford %K chelmsford granite %K Clinton-Newbury Fault %K Concord %K diorite %K gneiss %K Groton %K LITTLETON %K magnetite %K marble %K migmatite %K Nashoba Formation %K phyllonite %K tadmuck brook schist %K Tyngsborough %K Westford %X Bedrock Geologic Map contains brittle fracture data Mapping still in progress. For interim fracture database, please contact Joe Kopera %B Open-File Report %7 OFR-09-01 %I Massachusetts Geological Survey %G eng %2

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%0 Map %D 2010 %T Progress report of bedrock geologic mapping of the Lowell quadrangle, Massachusetts %A Richard H Jahns %A Joseph P Kopera %K #BedrockMaps %K #MGSPub %K Berwick formation %K Chelmsford %K Clinton-Newbury Fault %K Dracut %K Dracut diorite %K Dracut gabbro %K Dracut pluton %K gabbro %K Jahns %K Lowell %K Methuen %K nashoba %K Nashoba Formation %K Tewksbury %K Tyngsborough %X

Maps in Progress are not distributed to the public. If you would like to see a copy of this map, please contact Joseph Kopera at jkopera[at]geo[dot]geo[dot]umass[dot]edu

%B Progress Map %7 PM-09-01 %I Massachusetts Geological Survey %G eng %2

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