TY - Generic T1 - Arsenic in central Massachusetts bedrock and groundwater T2 - Abstracts with Programs - Geological Society of America Y1 - 2010 A1 - McTigue, David F. A1 - Stein, Carol L. A1 - Brandon, William C. A1 - Joseph P Kopera A1 - Keskula, Anna J. A1 - Koteas, G. Christopher KW - #StaffPubs KW - alteration KW - arsenic KW - arsenides KW - arsenopyrite KW - Ayer Granodiorite KW - BEDROCK KW - central Massachusetts KW - chelmsford granite KW - Devonian KW - dilation KW - discharge KW - dissolved materials KW - drinking water KW - Eh KW - fractures KW - General geochemistry 02A KW - geochemistry KW - granites KW - ground water KW - igneous rocks KW - joints KW - massachusetts KW - metals KW - metamorphism KW - meteoric water KW - overburden KW - Paleozoic KW - petrography KW - plutonic rocks KW - pollutants KW - reduction KW - solubility KW - solution KW - sulfides KW - theoretical models KW - United States AB - Across the New England "arsenic belt," groundwater arsenic (As) concentrations often exceed the EPA'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. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 42 SN - 00167592 UR - https://gsa.confex.com/gsa/2010AM/finalprogram/abstract_182430.htm IS - 55 N1 - 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 JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - Characterizing fractured crystalline bedrock aquifers using hydrostructural domains in the Nashoba Terrane, eastern Massachusetts T2 - Abstracts with Programs - Geological Society of America Y1 - 2006 A1 - Alex K Manda A1 - Stephen B Mabee A1 - David F Boutt KW - #StaffPubs KW - anisotropy KW - aquifers KW - BEDROCK KW - characterization KW - connectivity KW - crystalline rocks KW - eastern Massachusetts KW - fractures KW - ground water KW - heterogeneity KW - hydraulic conductivity KW - Hydrogeology 21 KW - massachusetts KW - Nashoba terrane KW - outcrops KW - physical properties KW - site exploration KW - United States KW - water wells AB - Fractured crystalline bedrock aquifers are good sources of potable water in many parts of the world. However, siting of highly productive wells in these rock units remains a challenging and expensive task because fracture development at the regional scale is both heterogeneous and anisotropic. Using low cost field data to define units of rock that have similar lithologic and fracture characteristics can significantly reduce time and energy spent on determining areas with better than average aquifer productivity. These physical characteristics that impart a particular hydraulic character on rocks are used to delineate regions with similar hydrologic characteristics called hydrostructural domains (Mackie, 2002). Hydrostructural domains are delineated from fracture characterization data that were collected from 79 outcrops located in the Nashoba Terrane of eastern Massachusetts. Information collected and used to delineate the domains include the number and distribution of fracture sets, types of fractures present or absent, the degree of fracture development, fracture intensity/density, fracture connectivity and rock type. Discrete fracture networks are generated from the fracture characterization data to simulate groundwater flow in the region. Conductivity of particular units is evaluated and compared to results from existing pumping tests obtained from the US Geological Survey. Preliminary results indicate that there is great value in utilizing fracture characteristic data obtained from surface outcrops to predict subsurface groundwater flow characteristics of fractured bedrock aquifers. Water managers, developers and decision makers are eager to know which areas are the most promising for encountering highly conductive zones in the subsurface. Collecting extensive structural data from surface outcrops, although not as accurate as drilling wells, is a cheaper alternative that could provide at least a rough estimate of the hydraulic properties of fractured rocks leading to effective siting of new water wells. Hydrostructural domain maps may pinpoint specific areas that have a high potential for wells to encounter highly conductive zones and could therefore be a powerful tool in transferring information from one site to another without having to repeatedly undertake extensive site characterization. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 38 SN - 00167592 UR - https://gsa.confex.com/gsa/2006AM/finalprogram/abstract_113075.htm IS - 77 N1 - Accession Number: 2007-032741; Conference Name: Geological Society of America, 2006 annual meeting; Philadelphia, PA, United States; Conference Date: 20061022; Language: English; Coden: GAAPBC; Collation: 1; Collation: 25; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200709; Monograph Title: Geological Society of America, 2006 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - Factors influencing groundwater inflows in a newly constructed cross-strike tunnel, eastern Massachusetts; 2, Fracture-supported coincident lineaments and subsurface structures T2 - Abstracts with Programs - Geological Society of America Y1 - 1999 A1 - Hardcastle, Kenneth C. A1 - Curry, Patrick J. A1 - Williams, Katherine W. A1 - Stephen B Mabee KW - #StaffPubs KW - BEDROCK KW - controls KW - eastern Massachusetts KW - factors KW - fractures KW - ground water KW - Hydrogeology 21 KW - imagery KW - lineaments KW - massachusetts KW - movement KW - New England KW - outcrops KW - Structural geology 16 KW - tectonics KW - tunnels KW - United States AB - As part of the evaluation of the ability of lineaments to map subsurface structures, the coincident lineaments which intersect the tunnel (Curry et al., this volume), were evaluated to isolate those lineaments considered to be "fracture-supported". By definition, fracture-supported coincident lineaments are those which parallel nearby surface fracture sets, mapped faults, lithologic contacts, and/or primary ductile structures; features which may be influential to subsurface groundwater flow. Of the 37 coincident lineaments delineated on the three scales of imagery studied, approximately 70% are considered to be fracture-supported: 9 of the 13 on the 1:58,000 scale images, 10 of 14 on the 1:80,000, and 8 of 10 on the 1:250,000. However, the general lack of surface exposure precludes high confidence in the assignment of fracture-supported status to most lineaments. Large areas devoid of outcrops necessitated extrapolation of regional, surface fracture patterns (domains) to help define some fracture-supported coincident lineaments. There are two occurrences where fracture-supported coincident lineaments from all three scales overlap and are parallel. One occurrence successfully maps the zone of greatest fracture density and highest groundwater inflow (>560 l/min). The other occurrence maps an area of high fracture density and significant subsurface flow (95 l/min). In addition, one other high flow zone (>190 l/min) is mapped by a fracture-supported coincident lineament from the 1:80,000 scale imagery. However, many subsurface fractures and flow zones (<75 l/min) are not mapped by the coincident lineaments regardless of whether or not they are fracture-supported. When considering all fracture-supported coincident lineaments and parallel subsurface structures, the median flow (13,600 l/day) for the mapped structures is greater than the unmapped structures (6,800 liters/day). However, this difference is only significant at the 60% confidence level.Although the tunnel sections with the greatest fracture density and highest groundwater inflows are successfully mapped by fracture supported coincident lineaments, not all water-bearing zones are delineated. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 31 SN - 00167592 IS - 77 N1 - Accession Number: 2001-037344; Conference Name: Geological Society of America, 1999 annual meeting; Denver, CO, United States; Conference Date: 19991025; Language: English; Coden: GAAPBC; Collation: 1; Collation: 348; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200111; Monograph Title: Geological Society of America, 1999 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - Factors influencing groundwater inflows in a newly constructed cross-strike tunnel, eastern Massachusetts; 4, Occurrence and characterization of groundwater inflows T2 - Abstracts with Programs - Geological Society of America Y1 - 1999 A1 - Williams, Katherine W. A1 - Stephen B Mabee A1 - Hardcastle, Kenneth C. A1 - Curry, Patrick J. KW - #StaffPubs KW - BEDROCK KW - boreholes KW - characterization KW - design KW - discharge KW - eastern Massachusetts KW - flows KW - fractures KW - Framingham Quadrangle KW - ground water KW - Hydrogeology 21 KW - massachusetts KW - movement KW - Natik Quadrangle KW - occurrence KW - outcrops KW - surface water KW - topography KW - tunnels KW - United States AB - All occurrences of groundwater inflows in a 9 km long, 5-m diameter section of tunnel, 70 to 90 m below grade, were compared with subsurface fracture density, bedrock topography, surface topography, type of surficial deposits, proximity to surface water bodies, and the geographic distribution (domains; Mabee et al., this volume) of surface and subsurface fractures. Subsurface fracture density was calculated for the 320 fractures (through-going fractures) that intersect the entire circumference of the tunnel. Bedrock topography was determined using bore hole data collected during the design phase of the tunnel project. Surface topography is from 1:25,000 scale topographic maps and surficial geology is based on maps of the Framingham and Natick Quadrangles. Seven surface water bodies, primarily brooks and rivers, overlie the tunnel. Five surface fracture domains are based on 1513 fracture measurements collected from 21 outcrops within 3 km of the tunnel. In the tunnel, 413 fractures (all fractures, dips>45 degrees ) comprise seven subsurface fracture domains. High groundwater inflows generally correlate with areas of high subsurface fracture density and where four or more subsurface fracture domains overlap. In addition, high groundwater inflows are also generally located near surface water bodies and below permeable surficial deposits and topographic depressions, especially those with corresponding lows in the bedrock surface. Moreover, subsurface structures which correlate with prominent surface fracture domains produce the highest volume of groundwater inflow. However, not all tunnel sections exhibiting high fracture density and overlapping fracture domains exhibit high groundwater inflows. Also, there is no correlation between areas where two or more surface fracture domains overlap and the volume of groundwater discharging to the tunnel. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 31 SN - 00167592 IS - 77 N1 - Accession Number: 2001-037345; Conference Name: Geological Society of America, 1999 annual meeting; Denver, CO, United States; Conference Date: 19991025; Language: English; Coden: GAAPBC; Collation: 1; Collation: 348; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200111; Monograph Title: Geological Society of America, 1999 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - Factors influencing groundwater inflows in a newly constructed cross-strike tunnel, eastern Massachusetts; 1, Lineaments and subsurface structures T2 - Abstracts with Programs - Geological Society of America Y1 - 1999 A1 - Curry, Patrick J. A1 - Hardcastle, Kenneth C. A1 - Stephen B Mabee A1 - Williams, Katherine W. KW - #StaffPubs KW - BEDROCK KW - eastern Massachusetts KW - fractures KW - geophysical surveys KW - ground water KW - Hydrogeology 21 KW - lineaments KW - massachusetts KW - metamorphic rocks KW - movement KW - New England KW - remote sensing KW - SLAR KW - strike KW - surveys KW - tectonics KW - tunnels KW - United States AB - Lineaments derived from three platforms; 1:250,000 Side-Looking Airborne Radar (SLAR) images, 1:58,000 Color Infrared (CIR) and 1:80,000 Black and White aerial photographs (BW), were compared to water bearing structures (n = 99) within a 9 km, 70 to 90 meter deep, east-west tunnel being constructed in eastern Massachusetts. Lineaments were drawn by three observers during two independent trials to produce 18 sets of lineaments (n = 9137) covering approximately 1,000 km (super 2) centered over the tunnel. All lineaments for each platform were compared. Three or more overlapping lineaments (azimuths within 5 degrees and within 1 mm at the scale of the imagery) define a single coincident lineament. This analysis generated three sets of coincident lineaments (n = 794), of these 37 cross the tunnel. Buffers were placed around the coincident lineaments at a distance of 1 mm from the center of the lineament at the scale of the platform (e.g. 250 m for the SLAR image). The Mann-Whitney U test was used to determine if the median flow from all tunnel structures which underlie the lineament buffer zones is significantly greater than that of all structures outside of the buffer zones. Results indicate that median flow (11,000 l/day) from structures located within the buffer zones of the BW are significantly greater at the 90% confidence level than the median flow (5,500 l/day) of structures located outside the buffer zones. No significant differences in flow were found for the other two platforms. Subsurface structures that parallel coincident lineaments (all platforms) and occur within the buffer zones have higher median flow (10,500 l/day) than those structures outside the buffer zones (6,600 l/day). However, this difference is significant at the 70% confidence level. These results suggest that, in some instances, a thorough lineament analysis can predict water-bearing subsurface structures in poorly exposed, glaciated, metamorphic terrain that has a high degree of suburban development. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 31 SN - 00167592 IS - 77 N1 - Accession Number: 2001-037333; Conference Name: Geological Society of America, 1999 annual meeting; Denver, CO, United States; Conference Date: 19991025; Language: English; Coden: GAAPBC; Collation: 2; Collation: 347-348; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200111; Monograph Title: Geological Society of America, 1999 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - Factors influencing groundwater inflows in a newly constructed cross-strike tunnel, eastern Massachusetts; 3, Surface vs. subsurface fracture characteristics T2 - Abstracts with Programs - Geological Society of America Y1 - 1999 A1 - Stephen B Mabee A1 - Williams, Katherine W. A1 - Curry, Patrick J. A1 - Hardcastle, Kenneth C. KW - #StaffPubs KW - BEDROCK KW - controls KW - eastern Massachusetts KW - factors KW - fractures KW - ground water KW - Hydrogeology 21 KW - massachusetts KW - measurement KW - movement KW - New England KW - outcrops KW - spatial distribution KW - tunnels KW - United States AB - Major fracture sets (dip >45 degrees ), their geographic distributions (domains), and their characteristics (spacing, trace length, and planarity) were measured in surface outcrops and in a 9 km section of the tunnel (Curry et al., this volume) to determine how well fracture data collected at widely-spaced surface exposures can be extrapolated to a depth of 70 to 90 meters. For the surface fracture data set, fracture sets and domains were determined from 1513 measurements collected at 21 outcrops located within 3 km of the trace of the tunnel. Spacing, trace length, and planarity were determined from scanline measurements (n = 899). For the tunnel data set, 413 fracture measurements were made to determine major sets and domains and a smaller subset (n = 156) was used to estimate fracture characteristics.Five fracture sets (14, 38, 86, 117, and 171) were identified in the outcrops and seven sets (13, 29, 41, 62, 132, 159, and 175) in the tunnel. The 14 and 171 sets correspond well with the 13 and 175 sets in the tunnel. The 38 set observed at the surface includes parts of the 29 and 41 sets in the tunnel. The 86 set does occur in the tunnel but is undersampled because it is aligned with the tunnel. The 62 and 159 sets occur in the tunnel but are not seen at the surface. Although large areas are devoid of outcrops, comparison of surface and subsurface fracture domains indicates that only the 14 and 171 sets show a reasonable overlap with the 13 and 175 domains in the tunnel. These latter sets are the fractures generating most of the groundwater inflow into the tunnel. Median fracture spacing and trace lengths for the 13 and 175 sets in the tunnel are significantly wider and longer than the corresponding 14 and 171 sets at the surface. Fracture planarities showed no significant differences between any of the surface and subsurface fracture sets. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 31 SN - 00167592 IS - 77 N1 - Accession Number: 2001-037340; Conference Name: Geological Society of America, 1999 annual meeting; Denver, CO, United States; Conference Date: 19991025; Language: English; Coden: GAAPBC; Collation: 1; Collation: 348; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200111; Monograph Title: Geological Society of America, 1999 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - Field mapping and fracture characterization techniques predict groundwater preferential flow paths in fractured bedrock aquifers, Nashoba Terrane, MA T2 - AGU Fall Conference, 2005 Y1 - 2005 A1 - Alex K Manda A1 - Stephen B Mabee A1 - Hubbs, S. A. KW - #StaffPubs KW - aquifers KW - BEDROCK KW - characterization KW - fractured materials KW - fractures KW - ground water KW - Hydrogeology 21 KW - mapping KW - massachusetts KW - Middlesex County Massachusetts KW - movement KW - Nashoba terrane KW - patterns KW - preferential flow KW - recharge KW - reservoir properties KW - substrates KW - United States AB - A study examining the relationship between fracture characteristics and groundwater was undertaken in the crystalline Nashoba Terrane of eastern Massachusetts. The Nashoba Terrane, a fault-bounded, highly deformed sliver of Paleozoic igneous and metamorphic rocks, covers an area of 600 sq km about 50 km northwest of Boston. Increasing industrial development coupled with population growth place significant pressure on developers to provide sufficient potable water for the population. To aid water development and management, this study examined fracture characteristics at regional, quadrangle and wellfield scales. The regional-scale work involved recording over 4000 structural measurements from 80 outcrops in the terrane. Fracture information recorded at each data station included strike and dip, trace length, spacing, termination, and fracture type. Preliminary results show that hydrostructural domains can be defined from combinations of fracture characterization and rock types. These domains are used to conceptualize general groundwater flow patterns in the subsurface: steeply dipping fractures, such as partings parallel to foliation enhance recharge potential and impose strong flow anisotropy. A different character is observed if steeply dipping joints intersect sheeting joints. In this instance, both recharge and lateral flow will be enhanced and flow anisotropy will be reduced. The distribution and intensity of particular fracture sets varies as a function of rock type, proximity to major features and local stress states. Partings parallel to foliation are prevalent in gneissic rocks whereas sheeting joints are more common in igneous rocks. Common joints are the most prevalent fractures, present in all rock types across the entire terrane. Quadrangle and wellfield scale data can be used to validate the regional-scale conceptual models. A comprehensive well-yield database was created to test the proposed models. Over 500 water wells in the terrane were evaluated to determine regions with high and low yield. The findings were evaluated in terms of location with respect to newly defined hydrostructural domain maps at both regional and quadrangle scales. Application of these hydrostructural domains in field studies can be useful not only in characterizing fracture intensity and distribution, but can shed more light on the potential of intersecting subsurface zones that could be exploited for economic gain. JF - AGU Fall Conference, 2005 PB - American Geophysical Union : Washington, DC, United States CY - United States VL - 86 SN - 00963941 IS - 52, Suppl.52, Suppl. N1 - Accession Number: 2009-053313; Conference Name: American Geophysical Union 2005 fall meeting; San Francisco, CA, United States; Conference Date: 20051205; Language: English; Coordinates: N420800N424400W0710200W0715300; Coden: EOSTAJ; Collation: -1; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 200930; Monograph Title: AGU 2005 fall meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Eos, Transactions, American Geophysical Union ER - TY - Generic T1 - Fracture characterization maps; a new type of geologic map for hydrogeologic applications T2 - Abstracts with Programs - Geological Society of America Y1 - 2005 A1 - Stephen B Mabee A1 - Joseph P Kopera KW - #StaffPubs KW - applications KW - aquifers KW - BEDROCK KW - characterization KW - classification KW - crystalline rocks KW - exploration KW - fractures KW - ground water KW - hydrodynamics KW - Hydrogeology 21 KW - mapping KW - movement KW - overburden KW - permeability KW - potentiometric surface KW - spatial distribution KW - surficial aquifers KW - thickness KW - water wells KW - water yield AB - 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. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 37 SN - 00167592 UR - https://gsa.confex.com/gsa/2005AM/finalprogram/abstract_94576.htm IS - 77 N1 - 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 JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - Fracture characterization of crystalline bedrock for groundwater investigations; an example from the Marlborough Quadrangle, Massachusetts T2 - Abstracts with Programs - Geological Society of America Y1 - 2004 A1 - Scott A Salamoff A1 - Stephen B Mabee A1 - Joseph P Kopera A1 - Donald U Wise KW - #StaffPubs KW - aquifers KW - Assabet River Fault KW - BEDROCK KW - characterization KW - controls KW - crystalline rocks KW - fractured materials KW - fractures KW - geographic information systems KW - ground water KW - Hydrogeology 21 KW - hydrology KW - information systems KW - joints KW - Marlborough Quadrangle KW - massachusetts KW - Middlesex County Massachusetts KW - permeability KW - preferential flow KW - recharge KW - style KW - testing KW - theoretical models KW - United States AB - 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. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 36 SN - 00167592 UR - https://gsa.confex.com/gsa/2004NE/finalprogram/abstract_70321.htm IS - 22 N1 - 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 JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - Fracture characterization; valuable inputs for modeling groundwater flow in fractured bedrock T2 - Abstracts with Programs - Geological Society of America Y1 - 1996 A1 - Stephen B Mabee A1 - Hardcastle, Kenneth C. KW - #StaffPubs KW - BEDROCK KW - boreholes KW - California KW - discontinuities KW - experimental studies KW - field studies KW - fractured materials KW - fractures KW - ground water KW - Hydrogeology 21 KW - Madera County California KW - models KW - movement KW - observation wells KW - Raymond California KW - site exploration KW - spatial distribution KW - transmissivity KW - United States KW - wells JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 28 SN - 00167592 IS - 33 N1 - Accession Number: 1996-065028; Conference Name: Geological Society of America, Northeastern Section, 31st annual meeting; Buffalo, NY, United States; Conference Date: 19960321; Language: English; Coordinates: N364500N374500W1190100W1203800; Coden: GAAPBC; Collation: 1; Collation: 77; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 199620; Monograph Title: Geological Society of America, Northeastern Section, 31st annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - Fracture patterns across two terrane boundaries in eastern Massachusetts; implications for regional groundwater flow and recharge T2 - Abstracts with Programs - Geological Society of America Y1 - 2006 A1 - Stephen B Mabee A1 - Joseph P Kopera KW - #StaffPubs KW - Avalon Zone KW - BEDROCK KW - eastern Massachusetts KW - faults KW - foliation KW - fractures KW - ground water KW - Hydrogeology 21 KW - joints KW - massachusetts KW - Merrimack Belt KW - movement KW - observations KW - patterns KW - properties KW - recharge KW - shear zones KW - style KW - terranes KW - United States AB - 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 JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 38 SN - 00167592 UR - https://gsa.confex.com/gsa/2006AM/finalprogram/abstract_116563.htm IS - 77 N1 - 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 JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - Ground truth? Relationship between lineaments and bedrock fabric T2 - Abstracts with Programs - Geological Society of America Y1 - 1989 A1 - Stephen B Mabee A1 - Hardcastle, Kenneth C. A1 - Donald U Wise KW - #StaffPubs KW - aerial photography KW - BEDROCK KW - fabric KW - faults KW - fractures KW - granites KW - ground truth KW - igneous rocks KW - joints KW - lineaments KW - Maine KW - orientation KW - pegmatite KW - plutonic rocks KW - quartz veins KW - SLAR KW - structural analysis KW - Structural geology KW - Structural geology 16 KW - United States KW - veins JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 21 SN - 00167592 IS - 66 N1 - Accession Number: 1991-043915; Conference Name: Geological Society of America, 1989 annual meeting; St. Louis, MO, United States; Conference Date: 19891106; Language: English; Coden: GAAPBC; Collation: 1; Collation: A68; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 1991; Monograph Title: Geological Society of America, 1989 annual meeting; Monograph Author(s): Dymek, Robert F. [chairperson]; Shelton, Kevin L. [chairperson]; Reviewed Item: Analytic JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - The influence of ductile structure and rheological heterogeneity on brittle structures as exhibited by Avalonian granites in southeastern Massachusetts T2 - Geological Society of America Abstracts with Programs Y1 - 2008 A1 - Joseph P Kopera KW - #StaffPubs KW - acadian KW - alleghenian KW - avalon KW - BEDROCK KW - dikes KW - foliation KW - fracture KW - fracture system KW - fracture trace KW - fractures KW - granite KW - granites KW - Hopkinton KW - joints KW - l-tectonites KW - lineaments KW - lineation KW - Milford KW - Upton AB - 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. JF - Geological Society of America Abstracts with Programs PB - Geological Society of America (GSA) : Boulder, CO, United States CY - Buffalo, NY VL - 40 UR - https://gsa.confex.com/gsa/2008NE/finalprogram/abstract_134899.htm ER - TY - Generic T1 - Lineaments; their value in assessing regional groundwater availability and quality in bedrock aquifers of glaciated metamorphic terrains; a case study T2 - Abstracts with Programs - Geological Society of America Y1 - 1993 A1 - Stephen B Mabee KW - #StaffPubs KW - amphibolite KW - aquifers KW - Atlantic Coastal Plain KW - BEDROCK KW - central Maine KW - fractures KW - Georgetown Maine KW - ground water KW - hydraulic conductivity KW - hydrogeology KW - lineaments KW - Maine KW - metamorphic rocks KW - structural controls KW - United States KW - water quality JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 25 SN - 00167592 IS - 22 N1 - Accession Number: 1993-017600; Conference Name: Geological Society of America, Northeastern Section, 28th annual meeting; Burlington, VT, United States; Conference Date: 19930322; Language: English; Coden: GAAPBC; Collation: 1; Collation: 35; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 1993; Monograph Title: Geological Society of America, Northeastern Section, 28th annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - A new way of looking at, and mapping, bedrock; the hydrostructural domain map of the Ayer Quadrangle, northeastern Massachusetts T2 - Abstracts with Programs - Geological Society of America Y1 - 2006 A1 - Joseph P Kopera A1 - Stephen B Mabee KW - #StaffPubs KW - aquifers KW - Ayer Quadrangle KW - BEDROCK KW - faults KW - foliation KW - fracture zones KW - fractures KW - ground water KW - Hydrogeology 21 KW - joints KW - mapping KW - massachusetts KW - measurement KW - Merrimack Belt KW - movement KW - Nashoba terrane KW - northeastern Massachusetts KW - observations KW - orientation KW - physical properties KW - recharge KW - shear zones KW - Structural geology 16 KW - style KW - United States AB - 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' 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. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 38 SN - 00167592 UR - https://gsa.confex.com/gsa/2006AM/finalprogram/abstract_116561.htm IS - 77 N1 - 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 JO - Abstracts with Programs - Geological Society of America ER - TY - JOUR T1 - Analyzing outcrop-scale fracture features to supplement investigations of bedrock aquifers JF - Hydrogeology Journal Y1 - 1997 A1 - Stephen B Mabee A1 - Hardcastle, Kenneth C. KW - #StaffPubs KW - aquifers KW - BEDROCK KW - boreholes KW - California KW - dip fractures KW - field studies KW - fractures KW - framework silicates KW - ground water KW - hydrodynamics KW - Hydrogeology 21 KW - laumontite KW - Madera County California KW - mapping KW - mineralization KW - movement KW - Raymond California KW - roughness KW - silicates KW - United States KW - zeolite group AB - A case study was conducted of 79 outcrops within 150 meters of the nine, 7590 m deep boreholes at the Lawrence Berkeley Laboratory (LBL) Fracture Hydrology Field Site in Raymond, California, USA, in order to make preliminary comparisons between surface fracture data and geophysical and hydrologic testing conducted in the boreholes. The orientation, trace length, spacing, roughness, planarity, associated mineralization, and domains (the geographic distribution of specific fracture sets) of 471 fractures were measured. Five families of steeply-dipping fractures and one family of shallow dipping fractures comprise 75 percent of the data and trend 52, 62, 130, 147, 173, and 35, respectively. The geographic distributions (domains) of the families, however, show the well field to be within the domains of the 62-, 173- and 35-trending families. The steeply-dipping fractures detected in the boreholes by LBL via acoustic televiewer logging trend about 65, 173, and 30 corroborating the findings of the fracture-domain analysis. Results indicate that the boreholes are located within a laumontite-mineralized area, including a steeply-dipping, 160-trending zone, 520 cm wide, of laumontite-rich pods that transects the boreholes. Independent hydrologic tests by LBL revealed a 160-trending barrier to groundwater flow between some of the boreholes, precisely where the 160-trending zone of laumontite-mineralized pods was mapped. PB - Verlag Heinz Heise : Hanover, Federal Republic of Germany CY - Federal Republic of Germany VL - 5 SN - 1431217414350157 UR - http://link.springer.com/article/10.1007/s100400050106 IS - 4 N1 - Accession Number: 1998-019185; Language: English; Language of Summary: French; Spanish; Coordinates: N364500N374500W1190100W1203800; Collation: 16; Publication Types: Serial; Updated Code: 199808; Illustration(s): illus. incl. 3 tables, sketch maps; Number of References: 28; Reviewed Item: Analytic JO - Hydrogeology Journal ER - TY - JOUR T1 - Comparison of three fracture sampling methods for layered rocks JF - International Journal of Rock Mechanics and Mining Sciences [1997] Y1 - 2010 A1 - Alex K Manda A1 - Stephen B Mabee KW - #StaffPubs KW - Big Quarry KW - carbonates KW - case studies KW - data acquisition KW - data processing KW - dolomite KW - Door Peninsula KW - fractures KW - geographic information systems KW - ground water KW - information systems KW - joints KW - layered materials KW - mapping KW - methods KW - movement KW - multiple scanline method KW - northeastern Wisconsin KW - numerical models KW - permeability KW - sampling KW - selection method KW - simulation KW - single scanline method KW - statistical analysis KW - Structural geology 16 KW - style KW - three-dimensional models KW - United States KW - Wisconsin AB - Three methods of fracture data collection are tested against each other in layered dolomitic rocks to evaluate the effectiveness of each method in sampling fracture properties. The methods tested are the single scanline method (SSM), selection method (SM), and multiple scanline method (MSM). Finite element techniques were first used to build a base model with the exact locations, sizes and orientations of each fracture observed in the natural fracture network. Then, a second set of models were stochastically generated using statistics from each sampling technique. For each network, the overall fracture intensity was used to assess the effectiveness of each sampling technique in capturing the real fracture properties. Fracture network permeability was also calculated for each of two directions to evaluate the transmissive properties of the networks. Although all three methods produced good matches of relative intensity and permeability between natural and synthetic fractures, the results reveal that a well-placed scanline performed the best at recreating natural fractures. However, the results from one variation of the SSM were only slightly better than the results from both versions of the SM. In general, the SSM provides the best results but possibly at heavy costs in time and labor, whereas the SM gives comparable results with less expenditure of energy and time. Thus, the SM is an adequate technique and recommended for use at large outcrops or where time, access or budget constraints are a concern. PB - Elsevier : Oxford-New York, International CY - International VL - 47 SN - 13651609 UR - http://www.sciencedirect.com/science/article/pii/S1365160909001804 IS - 22 N1 - Accession Number: 2010-041538; Language: English; Coordinates: N441500N452000W0865600W0880000; Coden: IJRMA2; Collation: 9; Publication Types: Serial; Updated Code: 201023; Illustration(s): illus. incl. 4 tables; Number of References: 25; Reviewed Item: Analytic JO - International Journal of Rock Mechanics and Mining Sciences [1997] ER - TY - JOUR T1 - Correlation of lineaments and bedrock fracture fabric; implications for regional fractured-bedrock aquifer studies, preliminary results from Georgetown, Maine JF - Ground Water Management Y1 - 1990 A1 - Stephen B Mabee A1 - Hardcastle, Kenneth C. A1 - Donald U Wise KW - #StaffPubs KW - aquifers KW - fractured materials KW - fractures KW - geophysical surveys KW - Georgetown Maine KW - ground water KW - hydrogeology KW - Hydrogeology 21 KW - imagery KW - Maine KW - remote sensing KW - Sagadahoc County Maine KW - SLAR KW - surveys KW - United States PB - Water Well Journal Pub. Co. : Dublin, OH, United States CY - United States VL - 3 SN - 10479023 UR - http://info.ngwa.org/gwol/pdf/900156672.PDF N1 - Accession Number: 1991-010604; Conference Name: FOCUS conference on Eastern regional ground water issues; Springfield, MA, United States; Conference Date: 19901017; Language: English; Collation: 15; Collation: 283-297; Publication Types: Serial; Conference document; Updated Code: 1991; Illustration(s): illus. incl. 2 tables, sketch maps; Number of References: 15; Monograph Title: Proceedings of the FOCUS conference on Eastern regional ground water issues; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Ground Water Management ER - TY - JOUR T1 - Factors influencing well productivity in glaciated metamorphic rocks JF - Ground Water Y1 - 1999 A1 - Stephen B Mabee KW - #StaffPubs KW - aquifers KW - BEDROCK KW - controls KW - depth KW - drinking water KW - fractures KW - Georgetown Island KW - glacial environment KW - ground water KW - Hydrogeology 21 KW - Maine KW - metamorphic rocks KW - porosity KW - surface water KW - thickness KW - topography KW - transmissivity KW - United States KW - water wells PB - National Water Well Association, Ground-Water Technology Division : Urbana, IL, United States CY - United States VL - 37 SN - 0017467X UR - http://onlinelibrary.wiley.com/doi/10.1111/j.1745-6584.1999.tb00961.x/abstract IS - 11 N1 - Accession Number: 1999-037034; Language: English; Coden: GRWAAP; Collation: 10; Publication Types: Serial; Updated Code: 199913; Illustration(s): illus. incl. 7 tables, geol. sketch map; Number of References: 37; Reviewed Item: Analytic JO - Ground Water ER - TY - JOUR T1 - A field study (Massachusetts, USA) of the factors controlling the depth of groundwater flow systems in crystalline fractured-rock terrain JF - Hydrogeology Journal Y1 - 2010 A1 - David F Boutt A1 - Diggins, Patrick A1 - Stephen B Mabee KW - #StaffPubs KW - aquifers KW - boreholes KW - crystalline rocks KW - eastern Massachusetts KW - fractured materials KW - fractures KW - ground water KW - hydraulic conductivity KW - Hydrogeology 21 KW - massachusetts KW - Nashoba terrane KW - permeability KW - porosity KW - preferential flow KW - shallow-water environment KW - substrates KW - United States AB - Groundwater movement and availability in crystalline and metamorphosed rocks is dominated by the secondary porosity generated through fracturing. The distributions of fractures and fracture zones determine permeable pathways and the productivity of these rocks. Controls on how these distributions vary with depth in the shallow subsurface (<300 m) and their resulting influence on groundwater flow is not well understood. The results of a subsurface study in the Nashoba and Avalon terranes of eastern Massachusetts (USA), which is a region experiencing expanded use of the fractured bedrock as a potable-supply aquifer, are presented. The study logged the distribution of fractures in 17 boreholes, identified flowing fractures, and hydraulically characterized the rock mass intersecting the boreholes. Of all fractures encountered, 2.5% are hydraulically active. Boreholes show decreasing fracture frequency up to 300 m depth, with hydraulically active fractures showing a similar trend; this restricts topographically driven flow. Borehole temperature profiles corroborate this, with minimal hydrologically altered flow observed in the profiles below 100 m. Results from this study suggest that active flow systems in these geologic settings are shallow and that fracture permeability outside of the influence of large-scale structures will follow a decreasing trend with depth. Copyright 2010 Springer-Verlag PB - Springer : Berlin - Heidelberg, Germany CY - Federal Republic of Germany VL - 18 SN - 1431217414350157 UR - http://link.springer.com/article/10.1007%2Fs10040-010-0640-y IS - 88 N1 - Accession Number: 2011-042136; Language: English; Coordinates: N420000N425000W0695500W0714500; Collation: 16; Publication Types: Serial; Updated Code: 201124; Illustration(s): illus. incl. 3 tables, geol. sketch map; Number of References: 58; Reviewed Item: Analytic JO - Hydrogeology Journal ER - TY - JOUR T1 - Influence of rock fabric on fracture attribute distribution and implications for groundwater flow in the Nashoba Terrane, eastern Massachusetts JF - Journal of Structural Geology Y1 - 2008 A1 - Alex K Manda A1 - Stephen B Mabee A1 - Donald U Wise KW - #StaffPubs KW - foliation KW - fractures KW - ground water KW - Hydrogeology 21 KW - joints KW - massachusetts KW - movement KW - Nashoba terrane KW - preferred orientation KW - statistical distribution KW - structural analysis KW - Structural geology KW - style KW - terranes KW - United States AB - Attributes (i.e. trace-length, spacing, termination and orientation) of joints and foliation-parallel fractures (FPFs) are used to assess the influence of lithology and fabric on fracture type and distribution in metamorphic and igneous rocks of the Nashoba terrane, Massachusetts. Orientations of NE-SW and NW-SE trending joints are consistent throughout the region, whereas FPFs are sub-parallel to the axis of the terrane. Joint spacing generally decreases to the northeast across the terrane reflecting lithologic changes from metamorphic to igneous rock types. Although trace-length and spacing frequency distributions of both joints and FPFs are best described by lognormal functions, FPFs possess narrower fracture spacing than joints. Median fracture trace-lengths of all FPFs are comparable to those of all steep joints, but the median fracture spacing is half that of all steep joints. Trace-lengths of FPFs vary as a function of the degree of development of foliation. Fracture attributes and groundwater flow models suggest that FPFs may significantly increase fracture connectivity and potential for groundwater recharge. FPFs may account for as much as 30% of flow in fracture networks suggesting that in addition to joints, FPFs play a significant role in groundwater hydraulics that may include imparting flow anisotropy on the groundwater system. PB - Elsevier : Oxford, International CY - International VL - 30 SN - 01918141 UR - http://www.sciencedirect.com/science/article/pii/S0191814107002362 IS - 44 N1 - Accession Number: 2009-050694; Language: English; Coden: JSGEDY; Collation: 14; Publication Types: Serial; Updated Code: 200928; Reviewed Item: Analytic JO - Journal of Structural Geology ER - TY - JOUR T1 - A method of estimating bulk potential permeability in fractured-rock aquifers using field-derived fracture data and type curves JF - Hydrogeology Journal Y1 - 2013 A1 - Alex K Manda A1 - Stephen B Mabee A1 - David F Boutt A1 - Cooke, Michele L. KW - #StaffPubs KW - aquifers KW - boundary conditions KW - eastern Massachusetts KW - fractured materials KW - fractures KW - ground water KW - Hydrogeology 21 KW - massachusetts KW - Nashoba terrane KW - naturally fractured reservoirs KW - numerical models KW - permeability KW - prediction KW - pump tests KW - simulation KW - two-dimensional models KW - United States AB - A method is devised for estimating the potential permeability of fracture networks from attributes of fractures observed in outcrop. The technique, which is intended as a complement to traditional approaches, is based on type curves that represent various combinations of fracture lengths, fracture orientations and proportions (i.e., intensities) of fractures that participate in flow. Numerical models are used to derive the type curves. To account for variations in fracture aperture, a permeability ratio (R) defined as the permeability of a fracture network in a domain divided by the permeability of a single fracture with identical fracture apertures, is used as a dependent variable to derive the type curves. The technique works by determining the point on the type curve that represents the fracture characteristics collected in the field. To test the performance of the technique, permeabilities that were derived from fractured-rock aquifers of eastern Massachusetts (USA) are compared to permeabilities predicted by the technique. Results indicate that permeabilities estimated from type curves are within an order of magnitude of permeabilities derived from field tests. First-order estimates of fracture-network permeability can, therefore, be easily and quickly acquired with this technique before more robust and expensive methods are utilized in the field. Copyright 2012 Springer-Verlag Berlin Heidelberg PB - Springer : Berlin - Heidelberg, Germany CY - Federal Republic of Germany VL - 21 SN - 1431217414350157 UR - http://link.springer.com/article/10.1007%2Fs10040-012-0919-2 IS - 22 N1 - Accession Number: 2013-055373; Language: English; Coordinates: N421500N424500W0704500W0714500; Collation: 13; Publication Types: Serial; Updated Code: 201334; Illustration(s): illus. incl. 4 tables, geol. sketch maps; Number of References: 41; Reviewed Item: Analytic JO - Hydrogeology Journal ER -