%0 Conference Proceedings %B Abstracts with Programs - Geological Society of America %D 2006 %T A new way of looking at, and mapping, bedrock; the hydrostructural domain map of the Ayer Quadrangle, northeastern Massachusetts %A Joseph P Kopera %A Stephen B Mabee %K #StaffPubs %K aquifers %K Ayer Quadrangle %K BEDROCK %K faults %K foliation %K fracture zones %K fractures %K ground water %K Hydrogeology 21 %K joints %K mapping %K massachusetts %K measurement %K Merrimack Belt %K movement %K Nashoba terrane %K northeastern Massachusetts %K observations %K orientation %K physical properties %K recharge %K shear zones %K Structural geology 16 %K style %K United States %X 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. %B Abstracts with Programs - Geological Society of America %I Geological Society of America (GSA) : Boulder, CO, United States %C United States %V 38 %P 166 - 166 %8 2006/10/01/ %@ 00167592 %G eng %U https://gsa.confex.com/gsa/2006AM/finalprogram/abstract_116561.htm %N 77 %! Abstracts with Programs - Geological Society of America %0 Map %D 0 %T Bedrock geologic map of the Ayer 7.5’ quadrangle, Worcester and Middlesex Counties, Massachusetts (2015) %A Joseph P Kopera %K Ayer %K ayer granite %K Ayer Granodiorite %K Ayer Quadrangle %K Berwick %K Campbell Hill Fault %K chelmsford granite %K Clinton Newbury Fault %K Devens %K Harvard Conglomerate %K merrimack %K Oakdale formation %K pin hill %K Shepley's Hill %K Shirley Fault %K tadmuck brook schist %K Worcester Formation %X

Editing and review are still underway.  This map should be available in winter 2015/2016

%B Open File Report %7 15-01 %I Massachusetts Geological Survey %G eng %2

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%0 Map %D 0 %T Bedrock geologic map of the Ayer 7.5’ quadrangle, Worcester and Middlesex Counties, Massachusetts %A Kopera J.P. %K Ayer %K ayer granite %K Ayer Granodiorite %K Ayer Quadrangle %K Berwick %K Campbell Hill Fault %K chelmsford granite %K Clinton Newbury Fault %K Devens %K Harvard Conglomerate %K merrimack %K Oakdale formation %K pin hill %K Shepley's Hill %K Shirley Fault %K tadmuck brook schist %K Worcester Formation %X

Editing and review are still underway.  This map should be available in winter 2015/2016

%B Open File Report %7 15-01 %I Massachusetts Geological Survey %G eng %2

1:24000