@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} } @article {305, title = {Influence of rock fabric on fracture attribute distribution and implications for groundwater flow in the Nashoba Terrane, eastern Massachusetts}, journal = {Journal of Structural Geology}, volume = {30}, year = {2008}, note = {Accession Number: 2009-050694; Language: English; Coden: JSGEDY; Collation: 14; Publication Types: Serial; Updated Code: 200928; Reviewed Item: Analytic}, month = {2008/04/01/}, pages = {464 - 477}, publisher = {Elsevier : Oxford, International}, address = {International}, abstract = {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.}, keywords = {$\#$StaffPubs, foliation, fractures, ground water, Hydrogeology 21, joints, massachusetts, movement, Nashoba terrane, preferred orientation, statistical distribution, structural analysis, Structural geology, style, terranes, United States}, isbn = {01918141}, url = {http://www.sciencedirect.com/science/article/pii/S0191814107002362}, author = {Alex K Manda and Stephen B Mabee and Donald U Wise} }