Feasibility study of the Conway Granite as a geothermal energy resource

• Main Authors: Osberg, P. H., Wetterauer, R., Rivers, M., Bothner, W. A., Creasy, J. W.
• Format: Report
• Language: English
• Published: Maine Univ., Orono (USA). Dept. of Geological Sciences 1978
• Subjects: Granites; Quartz; Geology; Geophysical Surveys; Geothermal Legacy; Mathematical Models; Oxides; 15 Geothermal Energy; Usa Geothermal Legacy; Chalcogenides; Rocks; North Atlantic Region; Two-Dimensional Calculations; Silicon Oxides; Silicon Compounds; New Hampshire; Igneous Rocks; Oxygen Compounds; Geothermal Resources; Gravity Surveys; North America; Three-Dimensional Calculations; Resources; Conway; North Atlantic
• Online Access: https://doi.org/10.2172/5780116; https://digital.library.unt.edu/ark:/67531/metadc1098764/

The eastern part of the White Mountain batholith is dominated by four intrusive complexes, which contain similar sequences of intrusive rocks. Although the details of the sequence of intrusion differ from complex to complex, the Osceola Granite is generally an early phase, followed by the development of ring dikes of Albany Porphyritic Quartz Syenite and finally the intrusion of Conway Granite. One intrusive complex contains riebeckite granite as a late phase, and at least two complexes fed volcanic eruptions, some of the products of which are preserved in subsided blocks. A specialized study of the orientation of joints was made in the eastern halo of the batholith. Measurement of gravity over the eastern part of the batholith and reduction of these data allows gravity residuals to be calculated and two- and three-dimensional models for the eastern part of the batholith to be constructed. The gravity models are consistent with steeply dipping contacts with the country rocks, and the maximum depth of the eastern part of the batholith is between 4 km and 5.25 km. The temperature distribution within the eastern part of the batholith can be determined using existing parameters for heat flow, heat production, and conductivity augmented by new data for heat production. The geologic boundaries and the gravity model provide the geometric constraints for the temperature distribution. Both one- and two-dimensional models are developed. The temperature distribution varies both vertically and laterally within the batholith. Estimates of temperature beneath the batholith are 170/sup 0/C at 6 km and 220/sup 0/C at 8 km.