TY - Generic T1 - Deep geothermal resource potential in Connecticut; progress report T2 - Abstracts with Programs - Geological Society of America Y1 - 2012 A1 - Gagnon, Teresa K. A1 - Koteas, G. Christopher A1 - Thomas, Margaret A. A1 - Stephen B Mabee A1 - John Michael Rhodes KW - #StaffPubs KW - Connecticut KW - Economic geology, geology of energy sources 29A KW - energy sources KW - geothermal energy KW - geothermal exploration KW - geothermal gradient KW - granites KW - heat flow KW - igneous rocks KW - New England KW - plutonic rocks KW - temperature KW - thermal conductivity KW - United States AB - The Connecticut and Massachusetts Geological Surveys are collaborating on a National Geothermal Data Project funded by the US Department of Energy through the Association of American State Geologists.Geothermal resources in Connecticut (CT) to date have been exploited using near surface ground source heat pump technology. This is the first investigation of CT deep geothermal resources. Many CT granitoids contain heat producing elements. The goal is to identify geologic units capable of producing enough heat, at reasonable drilling depths, to operate a viable geothermal power plant. Target rock units must contain enough uranium, thorium and potassium (U/Th/K) in combination with heat generated through the natural geothermal gradient of the Earth to generate electricity and co-produced direct heating. Heat at depth can be concentrated by an overlying insulating layer of sedimentary rocks and glacial sediments. 27 CT bedrock units were selected for sampling using existing mapping. 120 samples were analyzed using X-Ray Fluorescence Spectrometry. Heat production values (HPVs) at or greater than 4 mu W/m (super 3) were considered to be of interest. Values ranging from 4 to 18 mu W/m (super 3) were calculated for 7 of the 27 rock units. Elevated concentrations of thorium, ranging from 10.5 ppm to 245 ppm, were the primary contributors to increased HPVs. Initial results indicate that the warmest rocks are Permian and Precambrian, which is consistent with earlier results from granitoid bodies underlying the Atlantic Coastal Plain of Virginia (Speer et al., 1979). Additional bedrock samples will be analyzed to further characterize geochemical variations and potential HPVs of target rock units. Direct thermal conductivity measurements are being made of select bedrock samples in addition to sedimentary rocks of the Hartford Basin. Theoretical thermal profiles derived from rock geochemistry will provide an estimate of heat generated at depth for geologic units of interest and assist in determining the potential for an insulating layer overlying heat producing granitoids. Direct thermal conductivity measurements of unconsolidated materials throughout CT are also being made to support the ground-source heat pump industry. All data and mapping will be accessible via the National Geothermal Data System (NGDS). 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_200494.htm IS - 22 N1 - Accession Number: 2012-090080; Conference Name: Geological Society of America, Northeastern Section, 47th annual meeting; Hartford, CT, United States; Conference Date: 20120318; Language: English; Coordinates: N405900N420300W0714800W0734400; Coden: GAAPBC; Collation: 1; Collation: 77; 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 - TY - Generic T1 - Identifying and examining potential geothermal resources in non-traditional regions, examples from the northeastern U.S. T2 - Abstracts with Programs - Geological Society of America Y1 - 2011 A1 - Koteas, G. Christopher A1 - John Michael Rhodes A1 - Stephen B Mabee A1 - Goodhue, Nathaniel A1 - Adams, Sharon A. KW - #StaffPubs KW - Andover Granite KW - Eastern U.S. KW - Economic geology, geology of energy sources 29A KW - exploitation KW - exploration KW - Fall River Granite KW - field studies KW - geochemistry KW - geothermal energy KW - identification KW - mapping KW - massachusetts KW - models KW - Northeastern U.S. KW - overburden KW - resources KW - sampling KW - southeastern Massachusetts KW - spectra KW - structural analysis KW - technology KW - temperature KW - United States KW - whole rock KW - X-ray fluorescence spectra AB - The search for geothermal resources is rapidly expanding into tectonic regions that have not been previously considered to be suitable for exploitation. Many of these regions, such as the northeastern U.S., have never been the site of extensive geophysical investigations and have few deep borehole temperature measurements. Nevertheless, large portions of the northeastern U.S. are underlain by granitic bedrock that may be a productive energy source by applying enhanced geothermal technologies. In the absence of traditional reconnaissance data, we utilize field studies and sampling together with geochemical analysis to develop models of geothermal resources that can be tested against data from deep boreholes. Heat production is calculated from the measured density of the samples, the concentrations of K, U, and Th from whole-rock geochemical analysis via X-ray fluorescence, and established radiogenic heat production values. Models for a particular area can then be generated by calculating depth-specific temperatures using heat production, measured thermal conductivity for each sample, and assumptions related to local stratigraphy and regional heat flow. Mapping and structural extrapolation are used to establish the subsurface characteristics at a study site and are combined with the thermal and chemical characteristics of contact rocks and overburden materials. Two examples of the application of this technique are the Fall River granite at the margin of the Narragansett Basin in southeastern Massachusetts and the Andover Granite in northeastern Massachusetts. Thermal models of the Fall River Pluton indicate average temperatures of 71 degrees C at depths of 4 km and 97 degrees C at 6 km. Average temperatures increase to 107 degrees C and 132 degrees C, respectively, when a 2 km thick sediment package is modeled overlying the granite. The Andover Granite, which is not associated with a sedimentary basin and is in a more structurally complex configuration, yields an average temperature of 74 degrees C at a depth of 4 km and 101 degrees C at 6 km. While this approach to modeling temperature-depth profiles requires some regional heat flow assumptions, the application of mapping and structural analysis with geochemistry and thermal conductivity studies can be an important reconnaissance tool for identifying non-traditional geothermal resources. 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 IS - 55 N1 - Accession Number: 2012-083486; Conference Name: Geological Society of America, 2011 annual meeting; Minneapolis, MN, United States; Conference Date: 20111009; Language: English; Coden: GAAPBC; Collation: 1; Collation: 40; Publication Types: Abstract Only; Serial; Conference document; Updated Code: 201244; Monograph Title: Geological Society of America, 2011 annual meeting; Monograph Author(s): Anonymous; Reviewed Item: Analytic JO - Abstracts with Programs - Geological Society of America ER -