@proceedings {268, title = {Age-constraints on fabric reactivation in the Tusas Range, northern New Mexico, using electron-microprobe monazite geochronology; implications for the nature of regional approximately 1400 Ga deformation}, volume = {34}, year = {2002}, note = {Accession Number: 2004-044516; Conference Name: Geological Society of America, 2002 annual meeting; Denver, CO, United States; Conference Date: 20021027; Language: English; Coden: GAAPBC; Collation: 1; Collation: 180; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200413; Monograph Title: Geological Society of America, 2002 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2002/10/01/}, pages = {180 - 180}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {A key issue in constructing models for the southward growth of Laurentia during the Proterozoic is distinguishing the effects of approximately 1650 Ma and approximately 1400 Ma tectonism. These events share similar styles of deformation and metamorphism, making it difficult to assign structures, fabrics, and metamorphic phases to a particular event. The fundamental geometry of this orogen in the southwestern United States is defined in many areas by fold-fault pairs and isolated synclines of thick approximately 1700 Ma quartzite. In-situ EMP chemical dating of monazite, combined with detailed structural analysis, indicates that such synclines within the Tusas Range of northern New Mexico (locally F (sub 3) ) were substantially modified, if not developed, during approximately 1400 Ma tectonism. Monazite grains from the Ortega quartzite in the central Tusas Range display a shape preferred orientation parallel to the axial-planar fabric of these folds (S (sub 3) ), with overgrowth rims preferentially developed in the X direction of strain. These monazite grains have either >1700 Ma cores or approximately 1650 Ma cores with approximately 1400 Ma overgrowth rims, or are entirely approximately 1400 Ma in age. Field and microstructural observations show that the upright, east-west trending F (sub 3) and S (sub 3) are reactivations of older, northwest-trending fabrics and structures. The presence of approximately 1650 Ma overgrowth rims on monazite grains from the central and northern Tusas Range implies that these folds and fabrics may have nucleated prior to approximately 1400 Ma tectonism. Previous studies have shown an increase in approximately 1400 Ma monazite ages from north to south within the range, consistent with a similar increase in metamorphic grade. This gradient suggests that the central and northern Tusas may have been at progressively shallower crustal levels during approximately 1400 Ma tectonism, thus increasing the preservation of older fabrics, structures, and metamorphic monazite from south to north within the range. These observations support the hypothesis that approximately 1400 Ma tectonism locally reactivated and utilized pre-existing structures and fabrics, but had also profoundly shaped the geometry and metamorphic character of the orogen.}, keywords = {$\#$StaffPubs, dates, deformation, electron probe data, fabric, folds, geochronology, Geochronology 03, geometry, in situ, Laurentia, Mesoproterozoic, metamorphism, monazite, New Mexico, northern New Mexico, orogeny, Ortega Group, overgrowths, phosphates, Precambrian, preferred orientation, proterozoic, reactivation, Southwestern U.S., strain, structural analysis, Structural geology 16, synclines, tectonics, Tusas Mountains, United States, upper Precambrian, zoning}, isbn = {00167592}, url = {http://silk.library.umass.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true\&db=geh\&AN=2004-044516\&site=ehost-live\&scope=site}, author = {Joseph P Kopera and Williams, Michael L. and Jercinovic, Michael J.} } @proceedings {271, title = {Arsenic in central Massachusetts bedrock and groundwater}, volume = {42}, year = {2010}, note = {Accession Number: 2011-044094; Conference Name: Geological Society of America, 2010 annual meeting; Denver, CO, United States; Conference Date: 20101031; Language: English; Coden: GAAPBC; Collation: 2; Collation: 216-217; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 201125; Monograph Title: Geological Society of America, 2010 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2010/11/01/}, pages = {216 - 217}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {Across the New England "arsenic belt," groundwater arsenic (As) concentrations often exceed the EPA{\textquoteright}s 0.01-mg/L drinking water standard. In overburden groundwater at a site within this belt in north-central Massachusetts, As has been reported at levels up to 7.6 mg/L. Bedrock at the site consists of Silurian Central Maine Terrane metasediments intruded by the Devonian Ayer granodiorite and Chelmsford granite. Exchange of hydrothermal fluids between these lithologies during intrusion and later deformation, faulting, and metamorphism resulted in crystallization of arsenic-bearing minerals, including arsenopyrite. Quaternary deglaciation and unloading dilated joint systems in the bedrock, allowing increased exposure of the mineralogy to meteoric water. Several arsenopyrite alteration products (e.g., scorodite), of varying solubilities, precipitated on fracture surfaces and along grain boundaries between major phases. In the emerging conceptual model for this site, groundwater is recharged in bedrock uplands and moves downgradient through the fracture network, becoming increasingly reducing as it moves along a flow path. Arsenic dissolved from arsenopyrite and arsenic-bearing alteration phases in bedrock remains in solution until the groundwater discharges to lowland areas hydraulically downgradient. In these adjacent lowlands, glacial sand and gravel overburden lies above the bedrock. When the reducing water reaches more oxidizing conditions, As-sorbing hydrous ferric oxides (HFO) precipitate out on the aquifer solids, resulting in accumulation of As in the deep overburden aquifer. A large landfill at this site, now closed and capped, imposed reducing conditions, and As is mobilized into groundwater by reductive dissolution of the HFO. The presence of elevated As in groundwater is consistent with arsenic-bearing phases generated in granitoids at depth during regional metamorphism, which were subsequently altered, and are being solubilized at present by the circulation of shallow groundwater through varying redox environments. This scenario is supported by geochemical and petrographic studies of the granitoids and the occurrence of the highest groundwater and soil arsenic concentrations in the adjacent deep overburden.}, keywords = {$\#$StaffPubs, alteration, arsenic, arsenides, arsenopyrite, Ayer Granodiorite, BEDROCK, central Massachusetts, chelmsford granite, Devonian, dilation, discharge, dissolved materials, drinking water, Eh, fractures, General geochemistry 02A, geochemistry, granites, ground water, igneous rocks, joints, massachusetts, metals, metamorphism, meteoric water, overburden, Paleozoic, petrography, plutonic rocks, pollutants, reduction, solubility, solution, sulfides, theoretical models, United States}, isbn = {00167592}, url = {https://gsa.confex.com/gsa/2010AM/finalprogram/abstract_182430.htm}, author = {McTigue, David F. and Stein, Carol L. and Brandon, William C. and Joseph P Kopera and Keskula, Anna J. and Koteas, G. Christopher} } @proceedings {280, title = {Deep geothermal potential of New England granitoids; the Fall River Pluton, southeastern Massachusetts}, volume = {43}, year = {2011}, note = {Accession Number: 2012-031359; Conference Name: Geological Society of America, Northeastern Section, 46th annual meeting; Geological Society of America, North-Central Section, 45th annual meeting; Pittsburgh, PA, United States; Conference Date: 20110320; Language: English; Coden: GAAPBC; Collation: 1; Collation: 63; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 201217; Monograph Title: Geological Society of America, Northeastern Section, 46th annual meeting; Geological Society of America, North-Central Section, 45th annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2011/03/01/}, pages = {63 - 63}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {Devonian-aged plutonic rocks that are interpreted to be part of the Fall River pluton, along the southern edge of the Narragansett Basin, appear to have potential as a source of deep geothermal energy. The Narragansett Basin covers a approximately 1500 Km (super 2) area in southern Massachusetts and is dominated by complexly deformed and metamorphosed, Pennsylvanian-aged, fluvial and alluvial deposits. A northeast-striking series of brittle faults and discrete shear zones define the southern margin of the basin. Preliminary modeling of igneous and gneissic fabrics from outcrops along the southern edge of the basin show that the granite dips predominantly north, northeast. This pattern suggests that granitoids along the southern edge of the basin continue beneath the Narragansett Basin and correlate with granitoids exposed to the north. Regional joint sets in the Fall River pluton can be grouped into three dominant clusters at 350 degrees , 90 degrees , and 250 degrees based upon 86 field measurements. Low-angle sheeting joints are also common and suggest interconnected fracture networks at depth. Preliminary geochemistry from the Fall River pluton suggests that feldspars and accessory minerals contain the appropriate concentrations of heat producing elements, primarily U, Th, and K, to be a reasonable geothermal resource. K (sub 2) O values range from 2.4 to 5.0 weight percent. U and Th values (in ppm) range from 0.9 to 6.2 and 2.9 to 30.1 respectively. Assuming a relatively consistent composition at depth, a density of 2.6 kg/m (super 3) , and a thermal conductivity of 2.9 W/m degrees C, initial temperature modeling suggests average temperatures of 81 degrees C at depths of 5 kilometers and 93 degrees C at depths of 6 kilometers. Temperature estimates increase to approximately 150 degrees C and approximately 170 degrees C respectively when a two kilometer thick sediment package is modeled overlying the granitoids. The goal of current and future work is to improve assumptions about compositional uniformity as well as the regional position of granitoids at depth. At the conclusion of this work we hope to develop a protocol for studying geothermal potential of buried granitoids in New England in the absence of reliable drill-hole data. Preliminary estimates from this project suggest that basins underlain by granitoids of compositions similar to that of the Fall River pluton have reasonable potential as a deep geothermal resource.}, keywords = {$\#$StaffPubs, depth, Economic geology, geology of energy sources 29A, Fall River Pluton, geochemistry, geothermal energy, gneisses, granites, Igneous and metamorphic petrology 05A, igneous rocks, intrusions, massachusetts, metamorphic rocks, plutonic rocks, plutons, southeastern Massachusetts, United States}, isbn = {00167592}, url = {https://gsa.confex.com/gsa/2011NE/finalprogram/abstract_185900.htm}, author = {Goodhue, Nathaniel and Koteas, G. Christopher and John Michael Rhodes and Stephen B Mabee} } @proceedings {281, title = {Deep geothermal resource potential in Connecticut; progress report}, volume = {44}, year = {2012}, note = {Accession Number: 2012-090080; Conference Name: Geological Society of America, Northeastern Section, 47th annual meeting; Hartford, CT, United States; Conference Date: 20120318; Language: English; Coordinates: N405900N420300W0714800W0734400; Coden: GAAPBC; Collation: 1; Collation: 77; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 201247; Monograph Title: Geological Society of America, Northeastern Section, 47th annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2012/02/01/}, pages = {77 - 77}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {The Connecticut and Massachusetts Geological Surveys are collaborating on a National Geothermal Data Project funded by the US Department of Energy through the Association of American State Geologists.Geothermal resources in Connecticut (CT) to date have been exploited using near surface ground source heat pump technology. This is the first investigation of CT deep geothermal resources. Many CT granitoids contain heat producing elements. The goal is to identify geologic units capable of producing enough heat, at reasonable drilling depths, to operate a viable geothermal power plant. Target rock units must contain enough uranium, thorium and potassium (U/Th/K) in combination with heat generated through the natural geothermal gradient of the Earth to generate electricity and co-produced direct heating. Heat at depth can be concentrated by an overlying insulating layer of sedimentary rocks and glacial sediments. 27 CT bedrock units were selected for sampling using existing mapping. 120 samples were analyzed using X-Ray Fluorescence Spectrometry. Heat production values (HPVs) at or greater than 4 mu W/m (super 3) were considered to be of interest. Values ranging from 4 to 18 mu W/m (super 3) were calculated for 7 of the 27 rock units. Elevated concentrations of thorium, ranging from 10.5 ppm to 245 ppm, were the primary contributors to increased HPVs. Initial results indicate that the warmest rocks are Permian and Precambrian, which is consistent with earlier results from granitoid bodies underlying the Atlantic Coastal Plain of Virginia (Speer et al., 1979). Additional bedrock samples will be analyzed to further characterize geochemical variations and potential HPVs of target rock units. Direct thermal conductivity measurements are being made of select bedrock samples in addition to sedimentary rocks of the Hartford Basin. Theoretical thermal profiles derived from rock geochemistry will provide an estimate of heat generated at depth for geologic units of interest and assist in determining the potential for an insulating layer overlying heat producing granitoids. Direct thermal conductivity measurements of unconsolidated materials throughout CT are also being made to support the ground-source heat pump industry. All data and mapping will be accessible via the National Geothermal Data System (NGDS).}, keywords = {$\#$StaffPubs, Connecticut, Economic geology, geology of energy sources 29A, energy sources, geothermal energy, geothermal exploration, geothermal gradient, granites, heat flow, igneous rocks, New England, plutonic rocks, temperature, thermal conductivity, United States}, isbn = {00167592}, url = {https://gsa.confex.com/gsa/2012NE/finalprogram/abstract_200494.htm}, author = {Gagnon, Teresa K. and Koteas, G. Christopher and Thomas, Margaret A. and Stephen B Mabee and John Michael Rhodes} } @proceedings {283, title = {Embracing the digital revolution; issues of concern to geological surveys}, volume = {41}, year = {2009}, note = {Accession Number: 2009-099684; Conference Name: Geological Society of America, Northeastern Section, 44th annual meeting; Portland, ME, United States; Conference Date: 20090322; Language: English; Coden: GAAPBC; Collation: 1; Collation: 99; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200953; Monograph Title: Geological Society of America, Northeastern Section, 44th annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2009/02/01/}, pages = {99 - 99}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {Advancements in GIS and digital mapping techniques have improved the efficient production and visualization of geologic data. The Office of the Massachusetts State Geologist (OMSG) utilizes these tools extensively to produce geologic maps and fulfill its mission of making geologic data freely accessible to the public. Such tools have increased efficiency at the OMSG in fieldwork preparation and map production, in addition to creating new types of geologic maps. This same technology also creates new problems that need to be addressed: 1.) Accessing digital data inherently requires more specialized knowledge than reading a paper document. Most citizens do not have access to commercial GIS software, know how to use it, or know where to get digital data. 2.) The longevity of digital data at present is problematic. Various proprietary data formats and unstable digital media quickly become antiquated and unusable. 3.) Digital geospatial datasets tend to lack uniform and adequate metadata on their quality, origin, purpose, context, and appropriateness of use. In the rush to embrace digital technology it is useful to keep in mind that such tools should simplify our work as geologists and increase the utility and availability of the data we produce. Issues of accessibility can be addressed by education and the adoption of non-proprietary open-source software, data formats and standards. Problems with the viability of data may eventually be solved by advances in technology. In the meantime, stable paper or mylar maps should be not be abandoned. The creation and maintenance of high-quality metadata and well-organized, thorough, centralized databases is critical in keeping the flood of new digital data navigable. In the end, we must be able to easily modify any new technology we adopt to address the problems it presents, or we risk compromising our discipline to fit the limitations of that technology.}, keywords = {$\#$StaffPubs, cartography, digital cartography, digitization, geographic information systems, Geologic maps 14, information systems, mapping, techniques}, isbn = {00167592}, url = {https://gsa.confex.com/gsa/2009NE/finalprogram/abstract_155603.htm}, author = {Joseph P Kopera} } @proceedings {284, title = {Evidence for arsenic-mineralization in granitic basement rocks, Ayer Granodiorite, northeastern Massachusetts}, volume = {42}, year = {2010}, note = {Accession Number: 2010-100047; Conference Name: Geological Society of America, Northeastern Section, 45th annual meeting; Geological Society of America, Southeastern Section, 59th annual meeting; Baltimore, MD, United States; Conference Date: 20100314; Language: English; Coordinates: N420800N424400W0710200W0715300; Coden: GAAPBC; Collation: 1; Collation: 160; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 201052; Monograph Title: Geological Society of America, Northeastern Section, 45th annual meeting; Geological Society of America, Southeastern Section, 59th annual meeting; joint meeting, abstracts volume; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2010/03/01/}, pages = {160 - 160}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {Core samples of the Ayer Granodiorite along the eastern margin of the Merrimack Belt in northeastern Massachusetts host a series of sulfide and oxide phases that resulted from interaction with sulfide-bearing meta-sedimentary host rocks. Euhedral arsenopyrite grains are found with ilmenite, apatite, and REE phosphates in zones that generally mimic the intersection between a gneissic fabric and a relict magmatic foliation. Arsenopyrite crystals are typically elongate with this lineation. Euhedral to subhedral pyrite crystals have also been observed, but are localized to areas without As-bearing phases. Micro-fractures that parallel either a steep NW-striking joint set or gently-dipping sheeting joints are commonly filled with interwoven calcite cements and As-bearing Fe-oxides. Surface coatings of major fracture sets are also characterized by Fe-As-rich rinds that host micron-scale sub-angular particles of quartz, feldspars, and phyllosilicates. Where micro-fractures are most concentrated, sulfide-bearing minerals are less common; however, subhedral to anhedral arsenopyrite grains do occur along some open micro-fractures. These crystals preserve lobate grain boundaries and are associated with As-bearing Fe-oxide-rich coatings along adjacent fractures. The presence of 1) pyrite, 2) arsenopyrite associated with phosphates, and 3) As-bearing fracture coatings suggests multiple stages of mineralization. We propose that intrusion-related fluid-rock interaction associated with heating of nearby sulfide-bearing schists of the Berwick Formation during Acadian orogenesis may have provided the necessary constituents for growth of sulfide phases in the Ayer. It appears that Late Devonian greenschist facies metamorphism and metasomatism led to mineralization that generated arsenopyrite and accompanying phosphates; however, the role of the cross-cutting Clinton Newbury Fault Zone as a conduit for hydrothermal fluids may also be important. Lower temperature As-bearing Fe-oxide and calcite coatings on open fractures surfaces may be associated with a change from lithostatic- to hydrostatic-pressures during post-glacial regional uplift. This mineralization appears to be synchronous with intense microfracturing that post-dates all other mineralization.}, keywords = {$\#$StaffPubs, acadian, arsenic, arsenides, arsenopyrite, Ayer Granodiorite, Berwick formation, fractured materials, geochemistry, granodiorites, Igneous and metamorphic petrology 05A, igneous rocks, lower Paleozoic, massachusetts, Merrimack Synclinorium, metals, metamorphic rocks, metamorphism, metasedimentary rocks, metasomatism, Middlesex County Massachusetts, migration of elements, mineralization, Mineralogy of non-silicates 01C, northeastern Massachusetts, orogeny, Paleozoic, plutonic rocks, pollutants, pollution, pyrite, sulfides, United States}, isbn = {00167592}, url = {https://gsa.confex.com/gsa/2010NE/finalprogram/abstract_169998.htm}, author = {Koteas, G. Christopher and Keskula, Anna J. and Stein, Carol L. and McTigue, David F. and Joseph P Kopera and Brandon, William C.} } @proceedings {293, title = {Fracture characterization maps; a new type of geologic map for hydrogeologic applications}, volume = {37}, year = {2005}, note = {Accession Number: 2006-039166; Conference Name: Geological Society of America, 2005 annual meeting; Salt Lake City, UT, United States; Conference Date: 20051016; Language: English; Coden: GAAPBC; Collation: 1; Collation: 145; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200612; Monograph Title: Geological Society of America, 2005 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2005/10/01/}, pages = {145 - 145}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {Integration of a wide array of structural data with well-field hydrologic testing is increasingly recognized as a critical step in understanding groundwater flow behavior and recharge in crystalline bedrock aquifers (Lyford et al., 2003, Walsh and Lyford, 2002). As part of its rejuvenated mapping program, The Massachusetts Office of the State Geologist has been producing fracture characterization maps as a value-added accompaniment to traditional 1:24:000-scale bedrock mapping. Fracture characterization maps reclassify bedrock into domains of varying hydrologic significance, by combining rock properties (foliation steepness and development, partings, sheeting development, etc...) and type of overburden (permeable vs. non-permeable). The goal of these maps is to better understand preferential flow directions in the bedrock and the potential hydraulic connections between surficial and bedrock aquifers. Each fracture characterization map contains several summary panels, including standard geologic map bases overlain by typical rose diagrams and stereonets displaying fracture domains and trajectories, sheeting distribution, foliation trajectories, bedrock elevations, generalized piezometric surface configuration, and overburden type and thickness with separations into permeability class. A GIS well database is also included, showing well distribution, yield, bedrock elevation, and "hot-linked" well log images. All maps and raw data are made available to the public in paper, digital (PDF) or GIS format. We believe this approach will provide hydrologists and consultants with basic framework data that will expedite and improve the planning of subsurface investigations, construction activities, and groundwater exploration.}, keywords = {$\#$StaffPubs, applications, aquifers, BEDROCK, characterization, classification, crystalline rocks, exploration, fractures, ground water, hydrodynamics, Hydrogeology 21, mapping, movement, overburden, permeability, potentiometric surface, spatial distribution, surficial aquifers, thickness, water wells, water yield}, isbn = {00167592}, url = {https://gsa.confex.com/gsa/2005AM/finalprogram/abstract_94576.htm}, author = {Stephen B Mabee and Joseph P Kopera} } @proceedings {294, title = {Fracture characterization of crystalline bedrock for groundwater investigations; an example from the Marlborough Quadrangle, Massachusetts}, volume = {36}, year = {2004}, note = {Accession Number: 2005-077195; Conference Name: Geological Society of America, Northeastern Section, 38th annual meeting; Geological Society of America, Southeastern Section, 53rd annual meeting; Washington, DC, United States; Conference Date: 20040325; Language: English; Coordinates: N421800N421800W0713000W0713000; Coden: GAAPBC; Collation: 1; Collation: 113; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200524; Monograph Title: Geological Society of America, Northeastern Section, 38th annual meeting; Geological Society of America, Southeastern Section, 53rd annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2004/03/01/}, pages = {113 - 113}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {Integration of a wide array of structural data with well-field hydrologic testing is increasingly recognized as a critical step in understanding groundwater flow behavior and recharge in crystalline bedrock aquifers (Lyford et al., 2003, Walsh and Lyford, 2002). The Marlborough Quadrangle, about 40 km west of Boston, was selected as a test case of how a state geological survey can most effectively and efficiently collect and present such data in order to better constrain conceptual models of groundwater flow in general and to be of maximum use for hydrologists and consultants working on specific local problems. In this study, 3200 structural measurements were taken by a two-person team over a nine-week period at 68 stations distributed throughout the quadrangle and keyed into a GIS database. Specialized data sheets allowed efficient recording and digitization of orientations, lengths, spacing and mineralization, and separation of various classes of joints and veins. Fault data also included motion direction and sense. Summary maps in GIS format include standard geologic map bases overlain by typical rose diagrams and stereograms and maps such as fracture domains and trajectories, sheeting distribution, foliation trajectories, bedrock elevations, generalized piezometric surface configuration, and overburden type and thickness with separations into permeability class. Geology of the quadrangle can be separated into three zones: (a) north of the Assabet River Fault (ARF), (b) the area between the ARF and 1.5 km-wide Bloody Bluff Fault Zone (BBFZ), and (c) south of the BBFZ. Generalized foliations in the zones are: (a) 215, 50N, (b) 240, 65N, and (c) 270, 45N. Two pervasive, steeply-dipping (>60 degrees ) fracture sets occur throughout the quadrangle: an older 150 degrees set that includes sulfide-bearing veins and fracture surfaces along the ARF and a 015 degrees set of largely unmineralized common joints, macrojoints (>3 m length) and joint zones (av. 1.2 m width). Sheeting and unloading joints are generally coincident with shallow dipping foliation in (c) but cross-cut foliation in (a) and (b). We believe this approach will provide hydrologists and consultants with basic framework data that will expedite and improve the planning of subsurface investigations, construction activities and groundwater exploration.}, keywords = {$\#$StaffPubs, aquifers, Assabet River Fault, BEDROCK, characterization, controls, crystalline rocks, fractured materials, fractures, geographic information systems, ground water, Hydrogeology 21, hydrology, information systems, joints, Marlborough Quadrangle, massachusetts, Middlesex County Massachusetts, permeability, preferential flow, recharge, style, testing, theoretical models, United States}, isbn = {00167592}, url = {https://gsa.confex.com/gsa/2004NE/finalprogram/abstract_70321.htm}, author = {Scott A Salamoff and Stephen B Mabee and Joseph P Kopera and Donald U Wise} } @proceedings {296, title = {Fracture patterns across two terrane boundaries in eastern Massachusetts; implications for regional groundwater flow and recharge}, volume = {38}, year = {2006}, note = {Accession Number: 2010-054322; Conference Name: Geological Society of America, 2006 annual meeting; Philadelphia, PA, United States; Conference Date: 20061022; Language: English; Coden: GAAPBC; Collation: 1; Collation: 434; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 201030; Monograph Title: Geological Society of America, 2006 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2006/10/01/}, pages = {434 - 434}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {The integration of structural data and field-based observations is becoming increasingly critical in understanding groundwater flow behavior and recharge potential. Over the past 3 years, the Office of the Massachusetts State Geologist (OMSG) has collected 8225 fracture measurements from 187 stations across 3 adjacent quadrangles as part of its bedrock geologic mapping program. These data provide a north-south transect across the Nashoba Terrane and its boundaries with the Merrimack Belt and Avalon Terranes in eastern Massachusetts. Areas with similar fracture patterns can be grouped into "hydrostructural domains" with distinct hydrogeologic properties. Within the above transect, hydrostructural domains were observed to closely correspond with bedrock lithology and ductile structure, and therefore, tectonic history. Such domains are commonly bounded by faults or intrusive contacts. Common features observed across all domains include a NE-striking regional foliation with corresponding NW-striking, steeply-dipping cross-joints. Strongly layered metasedimentary and metavolcanic rocks of the Merrimack Belt and the Marlborough Formation in the Nashoba Terrane tend to have the most pervasive and closely-spaced foliation-parallel fractures (FPF). Foliation intensity and FPF generally increases towards shear zones and regional fault systems, especially within granites and gneisses. The moderate to steeply dipping, well-developed FPF in these rocks provides a potentially excellent conduit for vertical recharge and a strong NE-trending regional anistropy that may control groundwater flow. Granitoidal rocks have very consistent NS-EW orthogonal networks of vertical fractures and subhorizontal sheeting joints, providing excellent potential for vertical recharge and near-surface lateral flow. Features such as small brittle faults, fracture zones, fold axes, and fracture sets distinct to each domain may dominate local groundwater flow and recharge. Abstract 116563 modified by 72.70.224.253 on 7-12-2006}, keywords = {$\#$StaffPubs, Avalon Zone, BEDROCK, eastern Massachusetts, faults, foliation, fractures, ground water, Hydrogeology 21, joints, massachusetts, Merrimack Belt, movement, observations, patterns, properties, recharge, shear zones, style, terranes, United States}, isbn = {00167592}, url = {https://gsa.confex.com/gsa/2006AM/finalprogram/abstract_116563.htm}, author = {Stephen B Mabee and Joseph P Kopera} } @proceedings {297, title = {Geochemistry of gneisses and amphibolites in the Uchee Belt of western Georgia and eastern Alabama; an ACRES progress report}, volume = {32}, year = {2000}, note = {Accession Number: 2002-039126; Conference Name: Geological Society of America, Southeastern Section, 49th annual meeting; Charleston, SC, United States; Conference Date: 20000323; Language: English; Coordinates: N322800N322800W0845900W0845900; Coden: GAAPBC; Collation: 1; Collation: 31; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200214; Monograph Title: Geological Society of America, Southeastern Section, 49th annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2000/03/01/}, pages = {31 - 31}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {Undergraduate students, high school teachers, and university faculty representing ACRES (Atlanta Consortium for Research in Earth Sciences) studied lineated gneiss (LG) exposed at Flat Rock Park (FRP) and vicinity in Columbus, GA, and Motts gneiss (MG) in eastern Alabama. The LG and MG are mineralogically and geochemically granitoidal lineated orthogneisses. They contain deformed mafic xenoliths, as well as aplitic, granitic and pegmatoidal dikes that cut the dominant lineation. Based on chemical analyses, the LG from FRP and the MG plot as granite on the IUGS diagrams and the Le Bas diagram. Similarity in incompatible trace element ratios (e.g., Zr/Nb) and highly evolved characteristics of aplite with respect to the host gneisses, indicate there is probably a genetic link between the MG and the FRP LG. These rocks are chemically distinct from other nearby felsic gneiss. Phenix City gneiss amphibolites from Lindsey Creek and North Highland Mills dam in Columbus were also analyzed for major and trace elements. These amphibolites are low K tholeiitic rocks with an island arc affinity and are similar to rocks from the area that have already been analyzed. The amphibolites show a wide range of fractionation (41 to 62 percent SiO (sub 2) ). Consistency in incompatible element ratios over a wide range of fractionation of some of the samples show a probable genetic relationship among the various amphibolites of Lindsey Creek. Future work should involve more extensive collecting and analysis of both felsic rocks and amphibolites in the Uchee belt. More time should also be spent describing the thin sections of the existing collection and comparing the REE patterns for the FRP, MG and other felsic rocks in the Uchee belt.}, keywords = {$\#$StaffPubs, Alabama, amphibolite, chemical composition, Columbus Georgia, dikes, Georgia, gneisses, Igneous and metamorphic petrology 05A, inclusions, intrusions, metamorphic rocks, Muscogee County Georgia, Uchee Belt, United States, xenoliths}, isbn = {00167592}, author = {Joseph P Kopera and Nicholas, Brian and Todd, Dave and Davison, Jeff and Hanley, Tom and Kar, Aditya and La Tour, Timothy E. and Edwards, Tonya} } @proceedings {298, title = {Granite as a geothermal resource in the Northeast}, volume = {44}, year = {2012}, note = {Accession Number: 2012-090078; Conference Name: Geological Society of America, Northeastern Section, 47th annual meeting; Hartford, CT, United States; Conference Date: 20120318; Language: English; Coden: GAAPBC; Collation: 1; Collation: 76; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 201247; Monograph Title: Geological Society of America, Northeastern Section, 47th annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2012/02/01/}, pages = {76 - 76}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {In the absence of volcano-derived hydrothermal activity and high heat flow, granitic plutons provide an alternative geothermal resource from which heat may be usefully extracted. Compared with other crustal rocks, granites contain higher concentrations of the heat producing elements (K, U, Th). Additionally, they are more homogeneous and have simpler fracture systems than surrounding country rock, allowing for stimulation through hydro-fracking of large (>1 km (super 3) ) geothermal reservoirs. However, not all granites are created equal! Those with heat production > 5 mu W/m (super 3) , or with deep batholithic roots, are the most promising. Estimated temperatures at a given depth are related to the heat production, thickness and thermal conductivity of the granite. For example, the Carnmenellis Pluton in Cornwall, England (which will be drilled in 2012) is estimated to have temperatures in excess of 170 degrees C at a depth of 5 km, which is sufficient for co-production of electricity and hot water for heating. More importantly, granite bodies that are buried beneath thick sequences of thermally insulating sediments are also potential geothermal targets. Most successful examples to date include the Soultz sur Foret project in France, with temperatures of 200 degrees C at a depth of 5 km. (and which is currently producing electricity), Innamincka, Australia, with temperatures of 250 degrees C at a depth of 4 km. (which will be producing in 2012), and the seismically ill-fated project in Basel, Switzerland. Surely, if such projects involving the geothermal potential of granites, can succeed elsewhere, they can succeed here in the granite-rich Northeast? The geothermal potential of the Conway Granite, NH has long been recognized. Other possibilities include the Fitchburg Pluton, MA, and granites buried beneath the Carboniferous sediments of the Narragansett Basin and the Triassic sediments of the Connecticut River valley.}, keywords = {$\#$StaffPubs, Cammenallis Pluton, Cornwall England, Eastern U.S., Economic geology, geology of energy sources 29A, energy sources, England, Europe, geothermal energy, geothermal exploration, granites, Great Britain, heat flow, hydrothermal conditions, igneous rocks, intrusions, Northeastern U.S., plutonic rocks, plutons, thermal conductivity, United Kingdom, United States, Western Europe}, isbn = {00167592}, url = {https://gsa.confex.com/gsa/2012NE/finalprogram/abstract_200603.htm}, author = {John Michael Rhodes and Koteas, G. Christopher and Stephen B Mabee} } @proceedings {317, title = {Guiding principles for use of digital technology in geologic data collection and distribution}, volume = {46}, year = {2014}, month = {2014/01/01/}, pages = {75 - 75}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, abstract = {The past decade has seen a dramatic shift in the public perception of a map as a static paper document to a dynamic digital interface for addressing a specific geographic question. The adoption of digital technology for geologic data collection, compilation, and distribution has many advantages but requires a similar shift in attitudes towards the nature of data and resulting maps themselves to ensure that they remain accessible, viable, and relevant in this new paradigm. We propose a set of guiding principles for the use of digital technology in geologic data and map production: 1.) Utilize dedicated digital data professionals (DDPs): It is unreasonable to expect that geologists maintain expertise in their field and be thoroughly versed in complex and rapidly changing best practices for digital data. Following the recommendations of the National Research Council (2009), DDPs should be embedded in any research endeavor from its inception with geologists being savvy enough in digital technology to maintain productive engagement with DDPs. 2.) Use appropriate technology: Fully digital workflows and field equipment are not appropriate for all projects. Free or open-source software (FOSS) and easily available low-cost hardware (i.e., smartphones) have also met or surpassed the utility of many proprietary technology solutions thus reducing the price and increasing accessibility of data. 3.) Practice good data management: Digital data takes considerable resources and sustained effort to remain viable even shortly after its production. Best practices in data accessibility (data standards, open formats, etc.) and maintenance (refreshing, migration, etc.) in addition to robust metadata creation, through all phases of a project, are unquestionably necessary. 4.) Approach maps and digital data as living dynamic entities: Geologic data is out of date the moment it is published. A primary advantage of digital datasets is their ability to be easily updated, queried, and manipulated in infinite ways. Derivative products for specific applications are in arguably higher demand by end users than the data itself. Geologists must design for flexibility, appropriateness of use, and the persistence of their expert interpretations through development of all possible end products of and updates to the map and dataset.}, keywords = {$\#$StaffPubs, data, data preservation, databases, digital, digital data, digital geologic maps, geologic maps, GIS, migration}, isbn = {00167592}, url = {https://gsa.confex.com/gsa/2014NE/webprogram/Paper236362.html}, author = {Joseph P Kopera and House, P. Kyle and Schmidt, Maxine and Clark, Ryan} } @proceedings {300, title = {Identifying and examining potential geothermal resources in non-traditional regions, examples from the northeastern U.S.}, volume = {43}, year = {2011}, note = {Accession Number: 2012-083486; Conference Name: Geological Society of America, 2011 annual meeting; Minneapolis, MN, United States; Conference Date: 20111009; Language: English; Coden: GAAPBC; Collation: 1; Collation: 40; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 201244; Monograph Title: Geological Society of America, 2011 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2011/10/01/}, pages = {40 - 40}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {The search for geothermal resources is rapidly expanding into tectonic regions that have not been previously considered to be suitable for exploitation. Many of these regions, such as the northeastern U.S., have never been the site of extensive geophysical investigations and have few deep borehole temperature measurements. Nevertheless, large portions of the northeastern U.S. are underlain by granitic bedrock that may be a productive energy source by applying enhanced geothermal technologies. In the absence of traditional reconnaissance data, we utilize field studies and sampling together with geochemical analysis to develop models of geothermal resources that can be tested against data from deep boreholes. Heat production is calculated from the measured density of the samples, the concentrations of K, U, and Th from whole-rock geochemical analysis via X-ray fluorescence, and established radiogenic heat production values. Models for a particular area can then be generated by calculating depth-specific temperatures using heat production, measured thermal conductivity for each sample, and assumptions related to local stratigraphy and regional heat flow. Mapping and structural extrapolation are used to establish the subsurface characteristics at a study site and are combined with the thermal and chemical characteristics of contact rocks and overburden materials. Two examples of the application of this technique are the Fall River granite at the margin of the Narragansett Basin in southeastern Massachusetts and the Andover Granite in northeastern Massachusetts. Thermal models of the Fall River Pluton indicate average temperatures of 71 degrees C at depths of 4 km and 97 degrees C at 6 km. Average temperatures increase to 107 degrees C and 132 degrees C, respectively, when a 2 km thick sediment package is modeled overlying the granite. The Andover Granite, which is not associated with a sedimentary basin and is in a more structurally complex configuration, yields an average temperature of 74 degrees C at a depth of 4 km and 101 degrees C at 6 km. While this approach to modeling temperature-depth profiles requires some regional heat flow assumptions, the application of mapping and structural analysis with geochemistry and thermal conductivity studies can be an important reconnaissance tool for identifying non-traditional geothermal resources.}, keywords = {$\#$StaffPubs, Andover Granite, Eastern U.S., Economic geology, geology of energy sources 29A, exploitation, exploration, Fall River Granite, field studies, geochemistry, geothermal energy, identification, mapping, massachusetts, models, Northeastern U.S., overburden, resources, sampling, southeastern Massachusetts, spectra, structural analysis, technology, temperature, United States, whole rock, X-ray fluorescence spectra}, isbn = {00167592}, author = {Koteas, G. Christopher and John Michael Rhodes and Stephen B Mabee and Goodhue, Nathaniel and Adams, Sharon A.} } @proceedings {301, title = {Implications for non-traditional geothermal resources in southern New England; variability in heat potential based on thermal conductivity and geochemistry studies}, volume = {44}, year = {2012}, note = {Accession Number: 2012-090079; Conference Name: Geological Society of America, Northeastern Section, 47th annual meeting; Hartford, CT, United States; Conference Date: 20120318; Language: English; Coordinates: N420000N473000W0670000W0733000; Coden: GAAPBC; Collation: 2; Collation: 76-77; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 201247; Monograph Title: Geological Society of America, Northeastern Section, 47th annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2012/02/01/}, pages = {76 - 77}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {Estimating geothermal potential in southern New England in the absence of borehole heat flow data or geophysical studies has led to a focus on models based on thermal conductivity, geochemistry, and density-based heat production models. Preliminary estimates of geothermal potential generally match borehole-based heat flow data from similar tectonic environments. Nevertheless, microstructural and compositional heterogeneity with depth remain largely unconstrained. The extrapolation of regional structures based on detailed field mapping has helped to improve structural projections adjacent to major basins. However, an additional source of error in models of heat potential-with-depth are thermal conductivity estimates of igneous and meta-igneous rocks throughout Massachusetts (MA) and Connecticut (CT). Over three hundred granitoid localities in MA and CT have been analyzed to date. The southern New England region can be simplified into four major litho-tectonic zones: the Taconic-Berkshire Zone of western MA and northwestern CT, The Bronson Hill Zone associated with the CT River valley, the Nashoba Zone of central MA and eastern CT, and the Milford-Dedham Zone of eastern MA and eastern CT. Granitic rocks adjacent to the CT River valley and the Narragansett Basin vary considerably in thermal conductivity. Granites adjacent to the Narragansett Basin vary from 2.9 to 3.7 W/m * K. Average thermal conductivity values, combined with modeled heat production values, produce temperatures at 3 km depth along the Narragansett Basin that approach 85-115 degrees C. Values of meta-igneous rocks from the margin of the CT River valley in MA and CT vary more considerably in thermal conductivity, from 1.8 to 3.9W/m * K. Modeled heat potentials at 3 km depths along the eastern margin of the CT River valley vary between 74-122 degrees C and appear to be largely related to compositional variation. However, local rock composition is also related to metamorphic grade and fabric development, suggesting that both fabric and composition are first order controls on thermal conductivity. Modeling based on these data set to date suggests that combining thermal conductivity, whole rock geochemistry data, and density measurements can produce accurate reconnaissance estimates of geothermal potential in southern New England.}, keywords = {$\#$StaffPubs, chemical composition, Connecticut, Economic geology, geology of energy sources 29A, energy sources, geothermal energy, geothermal exploration, granites, heat flow, igneous rocks, massachusetts, models, New England, plutonic rocks, thermal conductivity, United States}, isbn = {00167592}, url = {https://gsa.confex.com/gsa/2012NE/finalprogram/abstract_200837.htm}, author = {Koteas, G. Christopher and John Michael Rhodes and Stephen B Mabee and Ryan, Amy and Schmidt, Joe and League, Corey and Goodhue, Nathaniel and Adams, Sharon A. and Gagnon, Teresa K. and Thomas, Margaret A.} } @proceedings {351, title = {The influence of ductile structure and rheological heterogeneity on brittle structures as exhibited by Avalonian granites in southeastern Massachusetts}, volume = {40}, year = {2008}, month = {03/2008}, pages = {3}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, edition = {2}, address = {Buffalo, NY}, abstract = {The orientation and geographic distribution of joints, veins, and brittle faults show a conspicuous correlation with the heterogeneous distribution of foliation and lineation intensity in Neo-Proterozoic granites and their deformed counterparts in southeastern Massachusetts. Field mapping and stereonet analysis of brittle and ductile structural data collected during 1:24,000-scale geologic mapping of the Milford quadrangle yielded the following general observations, which suggest that the ductile deformational history of this region appears to have strongly influenced the later development of brittle structures in the same rocks: The behavior of these fractures in relation to ductile structure have implications for rheological constraints on tectonic models of the post-Alleghenian core of the New England Appalachians, hydrogeologic models of regional fractured bedrock aquifers, and the interpretation of topographic lineaments.}, keywords = {$\#$StaffPubs, acadian, alleghenian, avalon, BEDROCK, dikes, foliation, fracture, fracture system, fracture trace, fractures, granite, granites, Hopkinton, joints, l-tectonites, lineaments, lineation, Milford, Upton}, url = {https://gsa.confex.com/gsa/2008NE/finalprogram/abstract_134899.htm}, author = {Joseph P Kopera} } @proceedings {306, title = {Landslides from Tropical Storm Irene in the Deerfield Watershed, western Massachusetts}, volume = {45}, year = {2013}, note = {Accession Number: 2014-027064; Conference Name: Geological Society of America, Northeastern Section, 48th annual meeting; Bretton Woods, NH, United States; Conference Date: 20130318; Language: English; Coordinates: N411500N425500W0695500W0733000; Coden: GAAPBC; Collation: 2; Collation: 83-84; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 201417; Monograph Title: Geological Society of America, Northeastern Section, 48th annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2013/02/01/}, pages = {83 - 84}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {Four landslides (3 translational debris flows and 1 rotational slide) occurred along the Cold River within the Deerfield River watershed (1440 km (super 2) ) in northwestern Massachusetts closing a six mile section of Route 2, a major east-west transportation corridor, for 3.5 months. These are among the largest landslides to occur in Massachusetts since 1901. Tropical storm Irene dropped 180-250+ mm of rain in a 12 to 15-hour period on the Deerfield watershed preceded by 130-180 mm of rain in the 1.5 weeks leading up to Irene. Soils were saturated, an unusual condition for the month of August, and probably contributed significantly to slope failure. The three translational slides occurred at approximately 10 am on August 28, 2011, involved 765 m of slope at an average angle of 28-33 degrees , covered an area of 1.2 ha and moved about 7645 m (super 3) of material. Bedrock sheeting joints oriented parallel to the slope (284 degrees , 38-40 degrees dip) provided the slip surface upon which the overlying 0.6-1.2 m of colluvium and glacial till slid. The rotational slide occurred along an unarmored section of the Cold River. The slip surface was a 4-8 foot thick layer of laminated lake-bottom sediments overlain by 12-19 feet of stream terrace and debris flow/alluvial fan deposits transported by Trout Brook, a smaller tributary to the Cold River. This section of Route 2 has experienced chronic failures beginning with the storm of 1938. The cost to repair this six-mile section of Route 2 was $22.5 million. Flooding within the Deerfield watershed was extreme with a record-breaking peak flow of 3100 m (super 3) /s (72 year record) where the Deerfield enters the Connecticut River. Approximately 1.6x10 (super 8) m (super 3) of water was discharged through the Deerfield during the event indicating that approximately 112 mm of Irene{\textquoteright}s rainfall was converted directly to runoff, a yield of between 45\% and 62\%. Clays and silts locked in storage in the glacial sediments within the watershed were mobilized resulting in record-breaking sediment loads 5-times greater than predicted from the pre-existing rating curve. Approximately 1.2 Mtonnes of sediment was discharged by the river during Irene. Where the Deerfield and Connecticut Rivers meet, the Deerfield watershed area is one tenth the size of the Connecticut River, yet the Deerfield produced as much as 40\% of the total sediment observed on the lower Connecticut.}, keywords = {$\#$Landslides, $\#$NaturalHazards, $\#$StaffPubs, Cold River, Deerfield Watershed, effects, Environmental geology, geologic hazards, Irene, landslide, landslides, mass movements, massachusetts, natural hazards, storms, Tropical Storm Irene, United States, western Massachusetts}, isbn = {00167592}, url = {https://gsa.confex.com/gsa/2013NE/webprogram/Paper215998.html}, author = {Stephen B Mabee and Jonathan D Woodruff and Fellows, John and Joseph P Kopera} } @proceedings {319, title = {The Nashoba Terrane: A new tectonostratigraphy and shared structural styles with the Merrimack belt in Massachusetts}, volume = {47}, year = {2015}, month = {03/2015}, pages = {42}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, edition = {3}, address = {Northeastern Section - 50th Annual Meeting (23{\textendash}25 March 2015), Bretton Woods, NH}, abstract = {Recent STATEMAP-sponsored geologic mapping of several 7.5{\textquoteright} quadrangles in east-central Massachusetts describe a new tectonostratigraphy and structural history for migmatitic gneisses of the Cambro-Ordivician arc complex represented, in part, by the Nashoba Formation. While preserved sedimentary structures are absent, four discrete subunits can be mapped based on distinct lithologies. From structurally lowest to highest, they are: A felsic magnetite-bearing bt gneiss, a magnetite and silliminite rich mu-bearing bt paragneiss, gt-bearing sulfidic bt-gneisses interlayered with sulfidic schist, amphibolite, and marble, and a calc-silicate rich bt-gneiss. The Nashoba terrane exhibits near-identical early and late styles of deformation to those in the adjacent Nashua sub-belt of the Merrimack terrane: Early amphibolite-facies isoclinal folding (D1) overprinted by tight upright folding (D2) and associated thrust faults define the map-scale geometry of tectonostratigraphic units between the two terranes. D2 occurred syn-peak upper amphibolite facies metamorphism in the Nashoba terrane while defined by retrograde greenschist facies fabrics in the Merrimack terrane. These are overprinted by outcrop-scale sinistral strike-slip motion (D3) in the Nashoba terrane progressively transitioning to late chlorite-grade NW-side down oblique extension (D4) exhibited in both terranes. Correlation of the above sequence with existing geochronology, structural petrology, and tectonic studies by other workers in the area suggest that D1 in both terranes occurred prior to and/or during ~370 Ma Acadian orogenesis. Existing geochronology shows D2 fold and fabric development to be diachronous both within and across terranes: occurring both before and after ~363 Ma, with progressive development possibly as late as ~325 Ma, in the Nashoba terrane. D2 in the Nashua sub-belt of the Merrimack terrane occurs after ~330 Ma in the Carboniferous, as late at ~293 Ma in the Permian, during Alleghenian orogenesis. NW-side-down extension and associated rotation of M1 metamorphic isograds in the Merrimack Terrane, and exhumation of the Nashoba terrane, are generally accepted to have occurred during later stages of Alleghenian orogenesis in the Permian. }, keywords = {$\#$StaffPubs, acadian, alleghenian, amphibolite facies, chlorite, deformation, eastern Massachusetts, fabric, folds, Harvard Conglomerate, Hudson, merrimack, Merrimack Belt, nashoba, Nashoba terrane, nashua, Nashua Trough, pin hill, Structural geology, tectonic history, tectonostratigraphy}, url = {https://gsa.confex.com/gsa/2015NE/webprogram/Paper253009.html}, author = {Joseph P Kopera} } @proceedings {267, title = {A new way of looking at, and mapping, bedrock; the hydrostructural domain map of the Ayer Quadrangle, northeastern Massachusetts}, volume = {38}, year = {2006}, note = {Accession Number: 2008-100620; Conference Name: Geological Society of America, 2006 annual meeting; Philadelphia, PA, United States; Conference Date: 20061022; Language: English; Coden: GAAPBC; Collation: 1; Collation: 166; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200816; Monograph Title: Geological Society of America, 2006 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2006/10/01/}, pages = {166 - 166}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {While traditional bedrock geologic maps contain valuable information, they commonly lack data on fractures and physical properties of the rock. The increased need for better understanding of groundwater behavior in bedrock aquifers has made this data critical. Hydrostructural domain maps reclassify bedrock based on fracture systems and physical properties that may have implications for groundwater flow and recharge. These maps are constructed from detailed field observations and measurements of 2000-3000 fractures from 60-70 stations across a 7.5{\textquoteright} quadrangle. Hydrostructural domains are displayed on the map as traditional lithologic units would be, with detailed descriptions and photos of the fracture characteristics and physical properties of each hydrostructural "unit". In the Ayer Quadrangle, such domains closely correspond with bedrock lithology and ductile structural history. Steeply dipping metasedimentary rocks of the Merrimack Belt have pervasive, closely spaced, throughgoing fractures developed parallel to foliation, and therefore provide an excellent potential for vertical recharge. Where these rocks are intensely cut by a strong subhorizontal cleavage, a parallel fracture set dominates providing an opportunity for lateral flow. Massive granites generally have a well developed, widely-spaced orthogonal network of fracture zones which may provide excellent local recharge. High-grade gneisses of the Nashoba Terrane have poorly developed fracture sets except near regional shear zones, where foliation parallel fractures and cross-joints may provide good vertical recharge and provide a strong northeast trending flow anisotropy. These maps are intended to provide a regional-scale information to assist in site-specific groundwater investigations. We believe that such maps are an example of how new types of geologic maps can, and must, be developed to address changing societal needs.}, keywords = {$\#$StaffPubs, aquifers, Ayer Quadrangle, BEDROCK, faults, foliation, fracture zones, fractures, ground water, Hydrogeology 21, joints, mapping, massachusetts, measurement, Merrimack Belt, movement, Nashoba terrane, northeastern Massachusetts, observations, orientation, physical properties, recharge, shear zones, Structural geology 16, style, United States}, isbn = {00167592}, url = {https://gsa.confex.com/gsa/2006AM/finalprogram/abstract_116561.htm}, author = {Joseph P Kopera and Stephen B Mabee} } @proceedings {357, title = {Stratigraphy and structure of the rocks underlying Boston Harbor: new insights on the Cambridge argillite and associated diamictites and diabase sills}, volume = {44}, year = {2012}, month = {03/2012}, pages = {43}, edition = {2}, abstract = {William O. Crosby studied the islands of Boston Harbor in the late 1800s, producing excellent verbal descriptions but no maps. Many of his observations stand unchallenged. His detailed maps of the southern harbor shore are especially valuable as development has since obscured many outcrops. Later compilations (e.g. Billings, Kaye, Bell) imposed stratigraphy developed in Boston onto the islands and harbor perimeter. Lithologic and structural data from new mapping of fifteen Boston Harbor Islands at 1:1000, integrated with data from sewage and outflow tunnels, shed new light on the Boston Bay Group and structures beneath the harbor. Ring fossils, identical to those previously reported in Hingham, are abundant much higher in the Cambridge Argillite on the outer harbor islands, and confirm a late Neoproterozoic age for the whole unit. The Cambridge contains several debris-flow diamictites, including the so-called {\textquotedblleft}Squantum Tillite{\textquotedblright}, at different stratigraphic levels, so that there is no reason to maintain member status for that layer nor to correlate all other diamictites with the Squantum. This more complex stratigraphy allows for a simpler interpretation of structures than in previous compilations. The Inter-Island Tunnel exposes continuations of the gently ENE-plunging Central Anticline of Boston and Brewster Syncline of the islands. These (Alleghanian?) folds are cut by numerous minor faults and truncated by a major NE-trending fault zone north of Peddocks Island. Soft-sediment slump folds are common throughout the Cambridge, but tectonically overturned beds are observed only near the south margin of the harbor, where the Cambridge Argillite was apparently thrust southwards by the Rock Island fault over a thin, previously deformed, north-facing sequence atop basement. Subalkaline tholeiitic diabase sills in the outer islands intruded the Cambridge Argillite before deformation and lower greenschist regional metamorphism. Diabase/argillite contacts show tan-weathering, mafic chilled margins against gray, felsic, recrystallized melts with angular argillite clasts. A 30-m wide peperite-like breccia with similar gray fine-grained matrix is exposed on Green Island. A few steep, E-W dikes that cut the folded sills and argillite are more alkaline and resemble Paleozoic dikes on the mainland. }, keywords = {$\#$StaffPub, $\#$StaffPubs, Boston Basin, Boston Bay Group, Boston Harbor, Cambridge Argillite, diabase, dolerite, harbor islands, sills}, author = {Thompson, Peter J. and Joseph P Kopera and Solway, Daniel R} } @proceedings {316, title = {A structural framework for the Nashoba Terrane in eastern Massachusetts.}, volume = {45}, year = {2013}, pages = {107}, abstract = {The exhumation and tectonic significance of the migmatitic Cambro-Ordovician arc-complex of the Nashoba terrane, located between lower-grade rocks of the Avalon and Merrimack terranes in Massachusetts, has historically presented an enigma, in part, due to a lack of detailed analysis of internal structure. We propose a new terrane-scale structural model based on nearly a decade of detailed geologic mapping to provide a framework for future study. A subvertical NE-striking composite fabric (S (sub n/n-1) ) forms the dominant structural grain of the terrane. S (sub n) commonly deforms an older layer-parallel foliation (S (sub n-1) ) about meter- to kilometer-scale, upright to steeply inclined, NE- and SW-plunging, tight disharmonic folds (F (sub n) ). In the Nashoba Formation migmatites, S (sub n) commonly transposes a subhorizontal S (sub n-1) enveloping surface into spaced meter-scale subvertical shear bands that are absent in the dominantly metavolcanic Marlborough Formation. Fold axis-parallel mineral stretching and intersection lineations (L (sub n) ) are locally overprinted on S (sub n) by subhorizontal peak metamorphic to retrograde mineral lineations (L (sub n/n+1) ). Ambiguous D (sub n) kinematics in the NE transition SW along strike to top-to-NW normal fold vergence and drag along steep north-dipping S (sub n) axial planes and S (sub n) - S (sub n+1) shear bands. Later strain (S (sub n+1) - S (sub n+2) ) appears to be progressively partitioned at lower grade to pre-existing S (sub n) shear bands and discrete internal and terrane bounding fault zones which display early high-grade top-to-SE dextral or sinistral motion (S (sub n-1) - S (sub n) ) broadly overprinted by lower-grade top-NW movement (S (sub n+1) ). We propose a tentative tectonic history incorporating sparse existing geochronologic and petrologic studies: Top SW D (sub n-1) motion coeval with approximately 425 Ma sill-grade metamorphism and possible accretion. D (sub n) initiating syn approximately 395 Ma peak metamorphism with migmatite generation along S (sub n) and progressive bulk fabric development largely complete by the intrusion of the relatively undeformed approximately 349 Ma Indian Head Hill granite. Exhumation can be accommodated by well-documented syn-to-post D (sub n) regional sinistral motion combined with progressively lower grade top-NW extension along discrete structures continuing through deposition and deformation of presumed Carboniferous basin sediments along the terrane boundary.}, keywords = {$\#$StaffPubs, Cambrian, eastern Massachusetts, exhumation, fabric, fault zones, faults, foliation, massachusetts, metamorphism, Nashoba terrane, Ordovician, Paleozoic, Structural geology, tectonics, United States}, issn = {00167592}, url = {https://gsa.confex.com/gsa/2013NE/webprogram/Paper215867.html}, author = {Joseph P Kopera and Matthew A Massey} } @proceedings {269, title = {An update of geologic mapping in Massachusetts}, volume = {36}, year = {2004}, note = {Accession Number: 2005-048993; Conference Name: Geological Society of America, Northeastern Section, 38th annual meeting; Geological Society of America, Southeastern Section, 53rd annual meeting; Washington, DC, United States; Conference Date: 20040325; Language: English; Coden: GAAPBC; Collation: 1; Collation: 58; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200518; Monograph Title: Geological Society of America, Northeastern Section, 38th annual meeting; Geological Society of America, Southeastern Section, 53rd annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic}, month = {2004/03/01/}, pages = {58 - 58}, publisher = {Geological Society of America (GSA) : Boulder, CO, United States}, address = {United States}, abstract = {Despite the state{\textquoteright}s relatively high population density and decades of detailed study of the bedrock geology, only about half of the 7.5{\textquoteright} quadrangles in Massachusetts have been published as GQ series geologic maps. As the state{\textquoteright}s population continues to grow, the availability of basic geologic data becomes increasingly crucial for informed land-use and water-management decision making. Much of the published 1:24000 scale geologic mapping predates recent advances in the understanding of regional tectonics, and needs to be updated. The Office of the State Geologist has begun a geologic mapping program in Massachusetts to address these needs. Two mapping projects were conducted through the STATEMAP component of the National Cooperative Geologic Mapping program in 2003. These projects focused on 7.5{\textquoteright} quadrangles along the I-495 corridor, which is experiencing extensive population growth and development. The first project involved conversion of published 1:24,000-scale surficial geology to digital form for 10 quadrangles in southeastern Massachusetts. A semi-automated process was developed for this project that easily converts published paper geologic maps into vectorized, georeferenced datalayers. The second project involved 1:24000-scale geologic mapping of the Marlborough quadrangle in east-central Massachusetts. Products include traditional maps of bedrock and surficial geology as well as two new prototype products: a fracture characterization map and a surficial materials map. These projects mark the first time in Massachusetts{\textquoteright} history that quadrangle-scale geologic data will be available in digital form to consultants and stakeholders, thus greatly expediting and improving the use and analysis of all geologic data. In addition, the inclusion of fracture characterization and surficial materials maps adds substantially to the value of traditional geologic map products. The new maps provide supplemental data on the hydrologic characteristics of the bedrock and the vertical stacking of surficial deposits that previously was unavailable. STATEMAP projects in 2004 will continue to focus along the I-495 corridor, and will involve revision and new mapping in the Wilmington, Reading, South Groveland, Lawrence, Hudson, and Oxford quadrangles.}, keywords = {$\#$StaffPubs, data, data acquisition, data processing, digital data, Geologic maps 14, mapping, massachusetts, National Cooperative Geologic Mapping Program, programs, publications, regional, review, STATEMAP, United States}, isbn = {00167592}, author = {Joseph P Kopera and Stephen B Mabee and Scott A Salamoff and Hildreth, Carol} } @article {335, title = {The Massachusetts Geothermal Data Project}, year = {2013}, publisher = {Massachusetts Geological Survey}, abstract = {A series of geothermal maps and datasets for Massachusetts derived from data collected by the MGS for Massachusetts and Connecticut. These data include whole rock geochemistry, rock and soil thermal conductivity, hot spring aqueous geochemistry, and derivative thermal and heatflow modeling. The project includes multiple datasets and products which can be accessed here or via the National Geothermal Data System (http://search.geothermaldata.org/dataset?q=Massachusetts). These datasets and products are: Maps: Comprising MGS Miscellaneous Maps 13-01 through 13-08 Data: can be downloaded from the links below