TY - Generic T1 - Deep geothermal potential of New England granitoids; the Fall River Pluton, southeastern Massachusetts T2 - Abstracts with Programs - Geological Society of America Y1 - 2011 A1 - Goodhue, Nathaniel A1 - Koteas, G. Christopher A1 - John Michael Rhodes A1 - Stephen B Mabee KW - #StaffPubs KW - depth KW - Economic geology, geology of energy sources 29A KW - Fall River Pluton KW - geochemistry KW - geothermal energy KW - gneisses KW - granites KW - Igneous and metamorphic petrology 05A KW - igneous rocks KW - intrusions KW - massachusetts KW - metamorphic rocks KW - plutonic rocks KW - plutons KW - southeastern Massachusetts KW - United States AB - 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. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 43 SN - 00167592 UR - https://gsa.confex.com/gsa/2011NE/finalprogram/abstract_185900.htm IS - 11 N1 - 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 JO - Abstracts with Programs - Geological Society of America ER - TY - Generic T1 - Granite as a geothermal resource in the Northeast T2 - Abstracts with Programs - Geological Society of America Y1 - 2012 A1 - John Michael Rhodes A1 - Koteas, G. Christopher A1 - Stephen B Mabee KW - #StaffPubs KW - Cammenallis Pluton KW - Cornwall England KW - Eastern U.S. KW - Economic geology, geology of energy sources 29A KW - energy sources KW - England KW - Europe KW - geothermal energy KW - geothermal exploration KW - granites KW - Great Britain KW - heat flow KW - hydrothermal conditions KW - igneous rocks KW - intrusions KW - Northeastern U.S. KW - plutonic rocks KW - plutons KW - thermal conductivity KW - United Kingdom KW - United States KW - Western Europe AB - 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. JF - Abstracts with Programs - Geological Society of America PB - Geological Society of America (GSA) : Boulder, CO, United States CY - United States VL - 44 SN - 00167592 UR - https://gsa.confex.com/gsa/2012NE/finalprogram/abstract_200603.htm IS - 22 N1 - 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 JO - Abstracts with Programs - Geological Society of America ER -