Evaluation and targeting of geothermal energy resources in the southeastern United States. Progress report, April 1, 1977--June 30, 1977

Technical Report · Sat Oct 01 04:00:00 EDT 1977

DOI:https://doi.org/10.2172/5290352· OSTI ID:5290352

Costain, J K; Glover, L III; Sinha, A K

Progress is reported in the detailed study of the Winnsboro complex, South Carolina, as part of a broader project to provide insight into the behavior of uranium and thorium in syn- and post-metamorphic granitic plutons. In the area of the Winnsboro complex, a regional medium-pressure metamorphic event which reached amphibolite facies was followed by deformation and uplift with decrease in regional temperature and pressure. The Winnsboro complex was intruded with a resultant low-pressure contact metamorphism which reached hornblende hornfels grade in the xenoliths of the relatively dry Winnsboro biotite. In a continuing effort to develop a correlation between bulk chemistry and U and Th, the index CaO/(K/sub 2/O + Na/sub 2/O) was applied to the core from the Rion pluton. A good negative correlation was found between this index and the uranium content of the core from the Rion pluton. There is a good positive correlation between U and SiO/sub 2/ in the Rion core. An excellent correlation between near-surface heat flow, q, and near-surface heat generation, A, was found for drill sites in the Winnsboro-Rion, Liberty Hill-Kershaw, and Roxboro plutons. These plutons span a distance of about 450 km and span an age of about 275 m.y. The equation of the straight-line relationship is q = 0.66 + 7.2 x 10/sup 5/A. The existence of the linear relationship in the southeast United States is encouraging, since it strengthens the capability for prediction of subsurface temperatures based on a radiogenic model. Partial confirmation of a radiogenic model was provided by a geothermal gradient of 37.4/sup 0/C/Km (2/sup 0/K/100 ft) in an existing hole in sediments of the Atlantic Coastal Plain at Stumpy Point, North Carolina. The bottomhole temperature at a depth of 1.35 km (4430 ft) is 66/sup 0/C. The gradient is consistent with theoretical predictions using reasonable values of thermal conductivity and heat generation in a buried radiogenic source. (JGB)

• Research Organization: Virginia Polytechnic Inst. and State Univ., Blacksburg (USA). Dept. of Geological Sciences
• OSTI ID: 5290352
• Report Number(s): VPI-SU-5103-4
• Country of Publication: United States
• Language: English

Related Subjects

15 GEOTHERMAL ENERGY
150201* -- Geology & Hydrology of Geothermal Systems-- USA-- (-1989)
150301 -- Geothermal Exploration & Exploration Technology-- Geophysical Techniques & Surveys
150302 -- Geothermal Exploration & Exploration Technology-- Geochemical Techniques & Surveys
ACTINIDES
AMPHIBOLE
BIOTITE
CHALCOGENIDES
CHEMICAL COMPOSITION
CHEMISTRY
DRILL CORES
ELEMENTS
EXPLORATION
GEOCHEMISTRY
GEOLOGY
GEOTHERMAL EXPLORATION
GEOTHERMAL GRADIENTS
GEOTHERMAL RESOURCES
GRANITES
Geothermal Legacy
HEAT FLOW
HEAT SOURCES
HORNBLENDE
IGNEOUS ROCKS
METALS
MICA
MINERALOGY
MINERALS
NORTH AMERICA
NORTH CAROLINA
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
RADIOISOTOPE HEAT SOURCES
RESOURCES
ROCKS
SEDIMENTS
SILICA
SILICON COMPOUNDS
SILICON OXIDES
SOUTH CAROLINA
TEMPERATURE GRADIENTS
THERMAL CONDUCTIVITY
THERMODYNAMIC PROPERTIES
THORIUM
URANIUM
USA
WELL LOGGING