TY - Generic T1 - Comparison of lineaments with bedrock structures along a cross-strike transect, eastern Massachusetts T2 - Abstracts with Programs - Geological Society of America Y1 - 1998 A1 - Curry, Patrick J. A1 - Williams, Katherine W. A1 - Stephen B Mabee A1 - Hardcastle, Kenneth C. KW - #StaffPubs KW - aerial photography KW - BEDROCK KW - eastern Massachusetts KW - faults KW - geophysical surveys KW - imagery KW - lineaments KW - massachusetts KW - remote sensing KW - SLAR KW - Structural geology 16 KW - surveys KW - tectonics KW - United States AB - Lineament data derived from three platforms, 1:58,000 color infrared photography (N = 770), 1:80,000 black and white photographs (N = 1106), and 1:250,000 SLAR imagery (N = 521), were used to determine the degree of coincidence between mapped faults and lineaments along a cross strike transect in eastern Massachusetts. The study area extends 27 km in an east-west direction and 8 km north-south and is located along the trace of a tunnel currently being constructed approximately 90 m below grade. Structural data are presently being collected from surface exposures along the tunnel trace and from within the 5 m diameter tunnel bore. These structural data will be compared with lineament data in the future. Reported here are the results of a comparison between the locations of lineaments and the position of major faults mapped on the Bedrock Geologic Map of Massachusetts (1:250,000). Lineaments were first mapped on acetate overlays in two independent trials and compared to determine which lineaments could be reproduced at the same geographic location. Reproducibility results indicate that 21 to 33% of the lineaments can be reproduced at the same spatial position and are comparable to results obtained from other studies. The length of reproducible lineaments proximal to and approximately parallel with mapped faults was compared with the total length of faults (137 km) within the study area. Results show that a small percentage of the faults are coincident with reproducible lineaments. Three percent of the lengths are mapped by reproducible lineaments observed on the SLAR imagery, 7% by the 1:80,000 scale photographs, and 5% by the 1:58,000 color infrared photography. This indicates that 97%, 93%, and 95% of the reproducible lineaments, respectively, are related to other geologic features in the bedrock or nothing at all. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 30 SN - 00167592 IS - 77 N1 - Accession Number: 1999-032582; Conference Name: Geological Society of America, 1998 annual meeting; Toronto, ON, Canada; Conference Date: 19981026; Language: English; Coden: GAAPBC; Collation: 1; Collation: 278; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 199912; Monograph Title: Geological Society of America, 1998 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; 5, Geochemical interpretation of groundwater inflows T2 - Abstracts with Programs - Geological Society of America Y1 - 1999 A1 - Weaver, Rebecca A. A1 - Stephen B Mabee A1 - Williams, Katherine W. A1 - Curry, Patrick J. KW - #StaffPubs KW - anions KW - BEDROCK KW - cations KW - classification KW - discharge KW - eastern Massachusetts KW - fault zones KW - faults KW - geochemistry KW - ground water KW - hydraulic conductivity KW - hydrochemistry KW - Hydrogeology 21 KW - Isotope geochemistry 02D KW - isotope ratios KW - isotopes KW - massachusetts KW - movement KW - New England KW - nitrate ion KW - O-18/O-16 KW - oxygen KW - samples KW - stable isotopes KW - surface water KW - tunnels KW - United States AB - Samples of ground and surface waters in and above the tunnel (Curry et al., this volume) were collected to characterize the chemistry of groundwater discharging from fractures and faults. Forty-two water samples were collected: 32 along a transect of the tunnel and 10 from surface waters above the trace of the tunnel. All samples were analyzed for major anions and cations, and delta (super 18) O. Analysis of the anion/cation data indicated that these waters are dominated by sulfate+chloride and calcium+magnesium. However, five sub-classifications can be discerned based on the relative concentrations of ions in the samples. The five sub-classifications are Cl > HCO (sub 3) > SO (sub 4) > NO (sub 3) :Ca > Na+K > Mg (15 samples), Cl > HCO (sub 3) > SO (sub 4) > NO (sub 3) :Na+K > Ca > Mg (7 samples), Cl > HCO (sub 3) > SO (sub 4) > NO (sub 3) :Ca > Mg > Na+K (6 samples), Cl > SO (sub 4) > HCO (sub 3) > NO (sub 3) :Na+K > Ca > Mg (3 samples), and HCO (sub 3) > Cl > SO (sub 4) > NO (sub 3) :Ca > Na+K > Mg (2 samples). Results from statistical analyses indicate that alkalinity, calcium, sodium and potassium do vary as a function of bedrock type and that these differences are significant at the 95% confidence level.In addition, preliminary oxygen isotope data indicate that two large, discrete water producing fault zones located in the eastern part of the tunnel are isotopically enriched (average delta (super 18) O = -7.75) relative to other water producing features in the tunnel (average delta (super 18) O = -8.96). The delta (super 18) O values obtained from all surface water bodies located above the tunnel average -7.56 whereas those values in surface ponds immediately above the fault zones average -6.71. Nitrate levels also show elevated levels in two water producing fault zones (>10 mg/L for some samples) and may result from accidental contamination during sampling, the use of explosives at discrete locations in the tunnel, or from leaking septic systems. The results of the oxygen isotope and nitrate analyses also suggest that some of the fault zones in the tunnel may have a rapid and direct hydraulic connection to the surface. 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: 2001-037342; 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 -