%0 Conference Proceedings %B Abstracts with Programs - Geological Society of America %D 2011 %T Deep geothermal potential of New England granitoids; the Fall River Pluton, southeastern Massachusetts %A Goodhue, Nathaniel %A Koteas, G. Christopher %A John Michael Rhodes %A Stephen B Mabee %K #StaffPubs %K depth %K Economic geology, geology of energy sources 29A %K Fall River Pluton %K geochemistry %K geothermal energy %K gneisses %K granites %K Igneous and metamorphic petrology 05A %K igneous rocks %K intrusions %K massachusetts %K metamorphic rocks %K plutonic rocks %K plutons %K southeastern Massachusetts %K United States %X 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. %B Abstracts with Programs - Geological Society of America %I Geological Society of America (GSA) : Boulder, CO, United States %C United States %V 43 %P 63 - 63 %8 2011/03/01/ %@ 00167592 %G eng %U https://gsa.confex.com/gsa/2011NE/finalprogram/abstract_185900.htm %N 11 %! Abstracts with Programs - Geological Society of America %0 Conference Proceedings %B Abstracts with Programs - Geological Society of America %D 2000 %T Geochemistry of gneisses and amphibolites in the Uchee Belt of western Georgia and eastern Alabama; an ACRES progress report %A Joseph P Kopera %A Nicholas, Brian %A Todd, Dave %A Davison, Jeff %A Hanley, Tom %A Kar, Aditya %A La Tour, Timothy E. %A Edwards, Tonya %K #StaffPubs %K Alabama %K amphibolite %K chemical composition %K Columbus Georgia %K dikes %K Georgia %K gneisses %K Igneous and metamorphic petrology 05A %K inclusions %K intrusions %K metamorphic rocks %K Muscogee County Georgia %K Uchee Belt %K United States %K xenoliths %X Undergraduate students, high school teachers, and university faculty representing ACRES (Atlanta Consortium for Research in Earth Sciences) studied lineated gneiss (LG) exposed at Flat Rock Park (FRP) and vicinity in Columbus, GA, and Motts gneiss (MG) in eastern Alabama. The LG and MG are mineralogically and geochemically granitoidal lineated orthogneisses. They contain deformed mafic xenoliths, as well as aplitic, granitic and pegmatoidal dikes that cut the dominant lineation. Based on chemical analyses, the LG from FRP and the MG plot as granite on the IUGS diagrams and the Le Bas diagram. Similarity in incompatible trace element ratios (e.g., Zr/Nb) and highly evolved characteristics of aplite with respect to the host gneisses, indicate there is probably a genetic link between the MG and the FRP LG. These rocks are chemically distinct from other nearby felsic gneiss. Phenix City gneiss amphibolites from Lindsey Creek and North Highland Mills dam in Columbus were also analyzed for major and trace elements. These amphibolites are low K tholeiitic rocks with an island arc affinity and are similar to rocks from the area that have already been analyzed. The amphibolites show a wide range of fractionation (41 to 62 percent SiO (sub 2) ). Consistency in incompatible element ratios over a wide range of fractionation of some of the samples show a probable genetic relationship among the various amphibolites of Lindsey Creek. Future work should involve more extensive collecting and analysis of both felsic rocks and amphibolites in the Uchee belt. More time should also be spent describing the thin sections of the existing collection and comparing the REE patterns for the FRP, MG and other felsic rocks in the Uchee belt. %B Abstracts with Programs - Geological Society of America %I Geological Society of America (GSA) : Boulder, CO, United States %C United States %V 32 %P 31 - 31 %8 2000/03/01/ %@ 00167592 %G eng %N 22 %! Abstracts with Programs - Geological Society of America %0 Conference Proceedings %B Abstracts with Programs - Geological Society of America %D 2012 %T Granite as a geothermal resource in the Northeast %A John Michael Rhodes %A Koteas, G. Christopher %A Stephen B Mabee %K #StaffPubs %K Cammenallis Pluton %K Cornwall England %K Eastern U.S. %K Economic geology, geology of energy sources 29A %K energy sources %K England %K Europe %K geothermal energy %K geothermal exploration %K granites %K Great Britain %K heat flow %K hydrothermal conditions %K igneous rocks %K intrusions %K Northeastern U.S. %K plutonic rocks %K plutons %K thermal conductivity %K United Kingdom %K United States %K Western Europe %X 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. %B Abstracts with Programs - Geological Society of America %I Geological Society of America (GSA) : Boulder, CO, United States %C United States %V 44 %P 76 - 76 %8 2012/02/01/ %@ 00167592 %G eng %U https://gsa.confex.com/gsa/2012NE/finalprogram/abstract_200603.htm %N 22 %! Abstracts with Programs - Geological Society of America