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Petrology and Geochemistry of Neoproterozoic Arc Plutons Beneath the Atlantic Coastal Plain, SRS, SC

Description: In this report is presented first a brief review of the regional geologic setting of the Savannah River Site, descriptions of the plutonic rock units sampled here, whole rock geochemical data on the plutonic igneous rocks, and finally, a discussion of how the crystalline basement rocks of the Savannah River Site formed and how they may correlate with other terranes exposed in the Piedmont of the Carolinas, Georgia, and Virginia.
Date: October 21, 1998
Creator: Maryak, M.
Partner: UNT Libraries Government Documents Department

Subsurface Geology of the Fenton Hill Hot Dry Rock Geothermal Energy Site

Description: The Precambrian rock penetrated by wells EE-2A and -3A belongs to one or more granitic to granodioritic plutons. The plutonic rock contains two major xenolith zones of amphibolite, locally surrounded by fine-grained mafic rock of hybrid igneous origin. The granodiorite is cut by numerous leucogranite dikes that diminish in abundance with depth. The most prominent structural feature is the main breccia zone, in which the rock is highly fractured and moderately altered. This zone is at least 75 m thick and is of uncertain but near-horizontal orientation. Fracture abundance decreases with increasing depth below the main breccia zone, and fractures tend to be associated with leucogranite dikes. This association suggests that at least some of the fractures making up the geothermal reservoir are of Precambrian age or have long-range orientations controlled by the presence of Precambrian-age granitic dikes.
Date: December 1, 2010
Creator: Levey, Schon S.
Partner: UNT Libraries Government Documents Department

Miscellaneous investigations series: Bedrock geologic map of the Lone Mountain pluton area, Esmeralda County, Nevada

Description: The joint attitudes were measured in the field and plotted on aerial photos at a scale of 1:24,000. The pluton is intensely jointed, primarily as a result of cooling and movement of the magma within a northwest-trending stress field. Foliation, in general, is poorly developed, and quality varies from area to area, but it is best developed close to the contacts with the metasedimentary rocks. A prominent northwest foliation direction was observed that parallels the northwest elongation of the exposed pluton. Faults in the pluton are difficult to identify because of the homogeneity of the rock. Several faults were mapped in the northern part of the area where they have a northeast trend and intersect the northwest-trending lamprophyre dikes with little apparent displacement. A major fault that bounds the northern part of the pluton is downthrown to the north and strikes northeast. This fault offsets the alluvium, the metasedimentary rocks, and the pluton and forms fault scraps as high as 10 m. Aeromagnetic data (US Geological Survey, 1979) suggest the following: (1) the local magnetic highs in the central part of the Lone Mountain pluton are probably related to topographic highs (peaks) where the flight lines are closer to the pluton; (2) a magnetic low in the northeastern part of Lone Mountain coincides with the pluton-country rock contact, which may be very steep; (3) the contours for the southwestern part of the mapped area indicate that the pluton-country rock contact is not as steep as that in the northeastern part and that the pluton probably coalesces at depth with the Weepah pluton, a pluton exposed south of the mapped area; and (4) the contours for the area of the Lone Mountain pluton express a northwest-trending gradient that parallels the northwest elongation of the Lone Mountain pluton and the northwest-trending stress ...
Date: December 31, 1984
Creator: Maldonado, F.
Partner: UNT Libraries Government Documents Department

Constructing a large-scale 3D Geologic Model for Analysis of the Non-Proliferation Experiment

Description: We have constructed a regional 3D geologic model of the southern Great Basin, in support of a seismic wave propagation investigation of the 1993 Nonproliferation Experiment (NPE) at the Nevada Test Site (NTS). The model is centered on the NPE and spans longitude -119.5{sup o} to -112.6{sup o} and latitude 34.5{sup o} to 39.8{sup o}; the depth ranges from the topographic surface to 150 km below sea level. The model includes the southern half of Nevada, as well as parts of eastern California, western Utah, and a portion of northwestern Arizona. The upper crust is constrained by both geologic and geophysical studies, while the lower crust and upper mantle are constrained by geophysical studies. The mapped upper crustal geologic units are Quaternary basin fill, Tertiary deposits, pre-Tertiary deposits, intrusive rocks of all ages, and calderas. The lower crust and upper mantle are parameterized with 5 layers, including the Moho. Detailed geologic data, including surface maps, borehole data, and geophysical surveys, were used to define the geology at the NTS. Digital geologic outcrop data were available for both Nevada and Arizona, whereas geologic maps for California and Utah were scanned and hand-digitized. Published gravity data (2km spacing) were used to determine the thickness of the Cenozoic deposits and thus estimate the depth of the basins. The free surface is based on a 10m lateral resolution DEM at the NTS and a 90m lateral resolution DEM elsewhere. Variations in crustal thickness are based on receiver function analysis and a framework compilation of reflection/refraction studies. We used Earthvision (Dynamic Graphics, Inc.) to integrate the geologic and geophysical information into a model of x,y,z,p nodes, where p is a unique integer index value representing the geologic unit. For seismic studies, the geologic units are mapped to specific seismic velocities. The gross geophysical structure of ...
Date: April 9, 2008
Creator: Wagoner, J & Myers, S
Partner: UNT Libraries Government Documents Department

Geology of the Desert Hot Springs-Upper Coachella Valley Area, California (with a selected bibliography of the Coachella Valley, Salton Sea, and vicinity)

Description: The Desert Hot Springs area is in the upper Coachella Valley at the junction of three natural geomorphic provinces of California--the Transverse Ranges, the Peninsular Ranges, and the Colorado Desert. The mapped area is about 100 miles east of Los Angeles and lies principally in north central Riverside County. The oldest rocks in the area are Precambrian(?) amphibolitic and migmatized paragneisses of the San Gorgonio igneous-metamorphic (Chuckwalla) complex. They are intruded by Cretaceous diorite porphyry, Cactus Granite, quartz monzonite, intrusive breccia, and basic plutonic rocks. Of probable late Paleozoic age are the metamorphic rocks of the San Jacinto Mountains which form spurs projecting into San Gorgonio Pass and Coachella Valley.
Date: January 1, 1968
Creator: Proctor, Richard J.
Partner: UNT Libraries Government Documents Department

Acquisition and preparation of specimens of rock for large-scale testing

Description: The techniques used for acquisition and preparation of large specimens of rock for laboratory testing depend upon the location of the specimen, the type of rock and the equipment available at the sampling site. Examples are presented to illustrate sampling and preparation techniques used for two large cylindrical samples of granitic material, one pervasively fractured and one containing a single fracture.
Date: February 1, 1981
Creator: Watkins, D.J.
Partner: UNT Libraries Government Documents Department

Tests pits for calibrating well logging equipment in fractured hard-rock environment

Description: The calibration facility consists of three pits containing fine-grained granite, coarse-grained granite, and medium-grained metamorphosed granodiorite. Each pit contains large quarried blocks of rock that are 8 ft octagons and form a 20 ft stack. The blocks are saturated with water and sealed in watertight fiberglass containers that are recessed so that the top of the upper block is approximately level with the ground. The blocks contain simulated fractures that are formed by the joints between the blocks and by saw cuts at several locations. Cored boreholes through the blocks are 7 7/8 in. in diameter, with a fiberglass-cased ''rat hole'' extending 30 ft below the bottom block. Laboratory and well logging studies (United States Geological Society, Schlumberger, and Dresser Atlas logs) have been made to determine the physical properties of rocks in the three pits, and preliminary results are reported. Porosities of individual samples (core measurements) taken at 1 ft intervals in the three pits range from 0.00 to 0.90%, densities from 2.64 to 2.79 g/cm/sup 3/, and sonic velocities from 18,700 to 22,500 ft/sec. Radio-element of individual samples (core measurements) taken at 5 ft intervals from these test pits range from 0.62 to 4.08% K (potassium) content, from 0.34 to 5.01 ppM RaeU (uranium) content and from 0.46 to 19.6 ppM Th (thorium) content. Access to the pits for calibrating well logging equipment can be arranged by contacting the United States Geological Survey (phone number 303-236-5913) in Denver, Colorado. 4 refs., 38 figs., 4 tabs.
Date: January 1, 1985
Creator: Mathews, M.A.; Scott, J.H. & LaDelfe, C.M.
Partner: UNT Libraries Government Documents Department

Fracture mapping for radionuclide migration studies in the Climax granite

Description: As part of LLNL's program on radionuclide migration through fractured rock, major geologic discontinuities have been mapped and characterized at the 420 m level in the Climax Stock, adjacent to LLNL's Spent Fuel Test. Persistence or continuity of features was the principal sampling criterion, and ninety major fractures and faults were mapped in the main access and tail drifts. Although the purpose and nature of this study was different from previous fracture surveys in the Climax Stock, the results are generally consistent in that three predominant fracture sets are identified: NW strike/vertical, NE strike/vertical, NW strike/subhorizontal. The frequency of major features in the main access drift is somewhat higher than in the tail drift. Those mapped in the main access drift are generally braided, stepped, or en echelon, while those in the tail drift appear to be more distinct and planar. Several of the fractures in the tail drift lie in the NE/vertical set, while most form an entirely different set oriented N5E/55NW. Subhorizontal fractures were common to both drifts. An area of seepage associated with some of these low-angle features was mapped in the main access drift.
Date: May 1, 1981
Creator: Thorpe, R. & Springer, J.
Partner: UNT Libraries Government Documents Department

Low radioactivity spectral gamma calibration facility

Description: A low radioactivity calibration facility has been constructed at the Nevada Test Site (NTS). This facility has four calibration models of natural stone that are 3 ft in diameter and 6 ft long, with a 12 in. cored borehole in the center of each model and a lead-shielded run pipe below each model. These models have been analyzed by laboratory natural gamma ray spectroscopy (NGRS) and neutron activation analysis (NAA) for their K, U, and Th content. Also, 42 other elements were analyzed in the NAA. The /sup 222/Rn emanation data were collected. Calibrating the spectral gamma tool in this low radioactivity calibration facility allows the spectral gamma log to accurately aid in the recognition and mapping of subsurface stratigraphic units and alteration features associated with unusual concentrations of these radioactive elements, such as clay-rich zones.
Date: January 1, 1986
Creator: Mathews, M.A.; Bowman, H.R.; Huang, L., H.; Lavelle, M.J.; Smith, A.R.; Hearst, J.R. et al.
Partner: UNT Libraries Government Documents Department

Statistical fracture mechanics approach to the strength of brittle rock

Description: Statistical fracture mechanics concepts used in the past for rock are critically reviewed and modifications are proposed which are warranted by (1) increased understanding of fracture provided by modern fracture mechanics and (2) laboratory test data both from the literature and from this research. Over 600 direct and indirect tension tests have been performed on three different rock types; Stripa Granite, Sierra White Granite and Carrara Marble. In several instances assumptions which are common in the literature were found to be invalid. A three parameter statistical fracture mechanics model with Mode I critical strain energy release rate as the variant is presented. Methodologies for evaluating the parameters in this model as well as the more commonly employed two parameter models are discussed. The experimental results and analysis of this research indicate that surfacially distributed flaws, rather than volumetrically distributed flaws are responsible for rupture in many testing situations. For several of the rock types tested, anisotropy (both in apparent tensile strength and size effect) precludes the use of contemporary statistical fracture mechanics models.
Date: June 1, 1981
Creator: Ratigan, J.L.
Partner: UNT Libraries Government Documents Department

Nuclear logging and geothermal log interpretation: formation temperature sonde evaluation

Description: The theory and methodology of the neutron-based technique for the determination of the formation temperature in geothermal fields are discussed. The feasibility of the method was demonstrated before start of the present development phase. The present work is intended to evaluate the response of the temperature probe in a simulated fracture porosity granite matrix at temperatures likely to be encountered in known geothermal reservoirs. An above ground borehole model has been designed and constructed. The effect of high ambient temperatures on the response of the neutron detectors in the probe mockup used in the measurements was investigated and used to correct the detector counts. An improved data analysis method has been developed to account properly for the effects of low porosity and high temperatures. Measurements, using the above ground borehole model, have shown that a linear correlation between the ratio of thermal counts from a Gd-filtered detector to counts from a bare detector and formation temperature is good at temperatures as high as 380/sup 0/F. The present results are consistent with earlier data obtained in high-porosity laboratory models at lower temperatures (T < 167/sup 0/F). Further measurements at high temperature at various porosities and formation neutron absorption cross sections would be necessary for a more extensive comparison.
Date: January 1, 1982
Creator: Ross, E.W.; Vagelatos, N.; Dickerson, J.M. & Nguyen, V.
Partner: UNT Libraries Government Documents Department

Petrographic analysis and correlation of volcanic rocks in Bostic 1-A well near Mountain Home, Idaho

Description: Detailed examination of volcanic rock cuttings from the Bostic 1-A well near Mountain Home, Idaho, provides data that correlate the stratigraphy of the well with the regional stratigraphy of the western Snake River Plain. The Bostic 1-A well penetrates basalt of the Middle Pleistocene Bruneau Formation and underlying sedimentary rocks of the Upper Pliocene Glenns Ferry Formation. Basalt underlying the Glenns Ferry Formation is most likely Banbury Basalt of Middle Pliocene age or Banbury equivalent. A 350-ft interval of felsic volcanics is then intersected above another 600 ft of basalt. The well bottoms in altered felsic volcanics. The lowest 600 ft of basalt flows has not been correlated with any basalt observed on the surface. From the established stratigraphy of the region, and from petrographic evidence, the silicic volcanic rocks occurring both above and below the lowermost basalts in the well are probably lower Pliocene Idavada Volcanics. North of the well, in the Mt. Bennett Hills, Idavada Volcanics overlie crystalline rocks of the Idaho batholith. No estimate of depth to plutonic bedrock can be made from the well data alone. Stratigraphic comparisons suggest as little as 0.2 to 0.3 km more of Idavada lie beneath the Bostic 1-A well. Results of geophysical studies suggest additional basalt lies beneath the Bostic 1-A rather than granitic rocks of the batholith.
Date: January 1, 1984
Creator: Arney, B.H.; Gardner, J.N. & Belluomini, S.G.
Partner: UNT Libraries Government Documents Department

Geology of magma systems: background and review

Description: A review of basic concepts and current models of igneous geology is presented. Emphasis is centered on studies of magma generation, ascent, emplacement, evolution, and surface or near-surface activity. An indexed reference list is also provided to facilitate future investigations.
Date: March 1, 1981
Creator: Peterfreund, A.R.
Partner: UNT Libraries Government Documents Department

Anistotropic yielding of rocks at high temperatures and pressures

Description: The anisotropic deformation of foliated and linealed rocks has been investigated, primarily to predict the mechanical response of rocks surrounding buried magma chambers to the stress fields generated by deep drilling. The principal application in this regard has been to evaluate, the scientific feasibility of extracting geothermal energy from buried magma chambers. Our approach has been to perform triaxial extension and compression tests at temperatures and pressures representative of the borehole environment on samples cored along six selected orientations and to fit the data to an orthohombric yield criterion. We have investigated Four-Mile gneiss (a strongly layered gneiss with well defined lineation), a biotite-rich schist, and Westerly granite (using a block oriented with respect to the granite's rift, grain, and hardway). Progress has been made in three areas: the experimental determination of strength anisotropies for the three starting materials, theoretical treatment and modeling of the results, and characterization of fabrics surrounding magma bodies resulting from their diaperic emplacement into shallow portions of the Earth's crust. In addition, results have been obtained for the tensile fracture of quartzite, basal slip and anisotropy of biotite single crystals, and anisotropic flow of bedded rocksalt.
Date: October 14, 1990
Creator: Kronenberg, A.K.; Russell, J.E. & Carter, N.L.
Partner: UNT Libraries Government Documents Department

Mechanical and transport properties of rocks at high temperatures and pressures. Task I, the physical nature of fracturing at depth. Technical progress report No. 1, 1 March 1980-30 November 1980

Description: Research progress is reported in the following areas: (1) the delineation of the boundary separating elastic-brittle and transient-1 semibrittle behavior of granite and of its volcanic and metamorphic equivalents, rhyolite and granite gneiss; (2) the variation of fracture permeability in Sioux Quartzite, Westerly Granite and a fine-1 grained gabbro as a function of effective pressure and hydrothermal alterations; and (3) determine the mechanical properties of selected rocks at high temperatures and pressures. (ACR)
Date: December 15, 1980
Creator: Carter, N.L.
Partner: UNT Libraries Government Documents Department

Hydraulic and mechanical properties of natural fractures in low-permeability rock

Description: The results of a comprehensive laboratory study of the mechanical displacement, permeability, and void geometry of single rock fractures in a quartz monzonite are summarized and analyzed. A metal-injection technique was developed that provided quantitative data on the precise geometry of the void spaces between the fracture surfaces and the areas of contact at different stresses. At effective stresses of less than 20 MPa fluid flow was proportional to the mean fracture aperture raised to a power greater than 3. As stress was increased, contact area was increased and void spaces become interconnected by small tortuous channels that constitute the principal impediment to fluid flow. At effective stresses higher than 20 MPa, the mean fracture aperture continued to diminish with increasing stress, but this had little effect on flow because the small tortuous flow channels deformed little with increasing stress.
Date: January 1, 1987
Creator: Pyrack-Nolte, L.J.; Myer, L.R.; Cook, N.G.W. & Witherspoon, P.A.
Partner: UNT Libraries Government Documents Department

Effects of water-saturation on strength and ductility of three igneous rocks at effective pressures to 50 MPa and temperatures to partial melting

Description: Instantaneous-failure strengths and ductilities of water-saturated cylindrical specimens of Charcoal Granodiorite, Mount Hood Andesite, and Cuerbio Basalt are determined at a strain rate of 10{sup -4}s{sup -1} and at effective confining pressures (Pe) of 0 and 50 MPa and at temperatures to partial melting. The data indicate: (1) at Pe = 0 and 50 MPa (Pc and Pp of 50 MPa and of 100 and 50 MPa, respectively) the granodiorite does not water-weaken; (2) at these same Pe the more porous and finer-grained andesite begins to exhibit water-weakening at about 600/sup 0/C; (3) at Pe = 0 and 870-900{sup 0}C the andesite's wet strength averages 20 MPa compared to 100 MPa, dry; (4) at Pe = 50 MPa and 920{sup 0}C its wet strength is 45 MPa compared to 160 MPa dry; (5) at Pe = 0, the basalt appears to be water-weakened above 800{sup 0}C; (6) water-saturated specimens deformed at temperatures less than T{sub m} exhibit ultimate strengths at less than 2 percent shortening and then work-soften along faults; and (7) both dry and wet specimens deform primarily by brittle fracture. Extrapolations indicate: (1) crystalline rocks should be drillable because they remain brittle until partial melting occurs, and penetration rates should increase with temperature because there is a corresponding decrease in brittle fracture strength; (2) boreholes in ''water-filled'' holes will be stable to >10 km at temperatures <T{sub m}; (3) if temperatures are kept to less than or equal to 700{sup 0}C, even open boreholes in granodiorite are apt to be stable to >10 km; and (4) open boreholes in the andesite are apt to be much less stable, and at similar temperatures would fail at 2 to 5-km depth.
Date: January 1, 1981
Creator: Bauer, S.J.; Friedman, M. & Handin, J.
Partner: UNT Libraries Government Documents Department

Evaluation of the IRAD flexible probe sonic extensometer

Description: Evaluation of the IRAD sonic extensometer was initiated with an electronic-circuit analysis which indicated an accuracy of +-0.001 in. (0.025 mm). Readings from two sonic probes consistently were low by 2% for distances between magnetic anchors, but were accurate to +-0.002 and +-0.003 in. (0.051 and 0.076 mm) for small displacements. Although a series of high explosive tests subjected magnetic anchors to peak accelerations of from 2100 g to 32,000 g the anchors generally did not experience detectable damage. Sonic probe readings exhibited a sensitivity to temperature changes with two of the four segments monitored exceeding the correction factor cited by the manufacturer.
Date: August 1, 1986
Creator: Glenn, H.D.; Patrick, W.C.; Rector, N.L. & Butler, L.S.
Partner: UNT Libraries Government Documents Department

Fracture and hydrology data from field studies at Stripa, Sweden

Description: The purpose of this report is to present the basic fracture and hydrology data collected as part of the joint LBL-KBS fracture hydrology program at Stripa, Sweden. A detailed description of the fracture-core logging and hydrology borehole testing procedures is included as well as a description of how the fracture and hydrology data were coded and organized. Based on this coding a series of computer data files for the fracture and hydrology borehole data have been constructed and these are described in detail. The fracture data file for one borehole is presented as an example in an appendix along with all of the raw and some partially processed and analyzed fracture hydrology data files. A detailed description of how this data will be analyzed to develop a thorough understanding of the fracture system and hydrogeologic characteristics of the Stripa site is presented.
Date: April 1, 1981
Creator: Gale, J.E.
Partner: UNT Libraries Government Documents Department

Fracture mapping in the ventilation drift at Stripa: procedures and results

Description: Detail maps of the fracture system in the ventilation drift at the Stripa mine have been prepared. The procedures used in preparing the maps of the floor and walls of the ventilation drift are documented in this report. The fracture data presented in the detailed maps are heavily supplemented by a coded data file. Each discrete fracture, vein, or fracture zone has been identified by a number on the map and this number has been used to link the map to the data file. This approach permits maximum use of the fracture data by other researchers interpreting completed and on-going experiments or as an aid in planning and interpreting future experiments. 9 refs., 7 figs., 2 tabs.
Date: March 1, 1981
Creator: Rouleau, A.; Gale, J.E. & Baleshta, J.
Partner: UNT Libraries Government Documents Department

Field assessment of the use of borehole pressure transients to measure the permeability of fractured rock masses

Description: A field experiment to evaluate the transient pressure pulse technique as a method of determining the in-situ hydraulic conductivity of low permeability fractured rock was made. The experiment attempted to define: the radius of influence of a pressure pulse-test in fractured rock and the correlation between pressure-pulse tests and steady-state flow tests performed in five boreholes drilled in fractured granite. Twenty-five test intervals, 2 to 3 m in length, were isolated in the boreholes, using air-inflated packers. During pressure pulse and steady-state tests, pressures were monitored in both the test and observation cavities. Rock-mass conductivities were calculated from steady-state test results and were found to range from less than 10/sup -11/ to 10/sup -7/ cm/sec. However, there was no consistent correlation between the steady-state conductivity and the pressure pulse decay characteristics of individual intervals. These conflicting test results can be attributed to the following factors: differences in volumes of rock affected by the test techniques; effects of equipment configuration and compliance; and complexity of the fracture network. Although the steady-state flow tests indicate that hydraulic connections exist between most of the test cavities, no pressure responses were noted in the observation cavities (located at least 0.3 m from the test cavities) during the pulse tests. This does not mean, however, that the pressure-pulse radius of influence is <0.3 m, because the observation cavities were too large (about 7 liters). The lack of correlation between steady-state conductivities and the corresponding pressure pulse decay times does not permit use of existing single-fracture type curves to analyze pulse tests performed in multiple-fracture intervals. Subsequent work should focus on the detailed interpretation of field results with particular reference to the effects of the fracture system at the test site.
Date: June 1, 1981
Creator: Forster, C.B. & Gale, J.E.
Partner: UNT Libraries Government Documents Department

Autoradiographic studies of actinide sorption in groundwater systems

Description: Autoradiography is a convenient and sensitive technique for the study of spacial distributions of alpha radioactive nuclides on slabs of rock or on other planar surfaces. The autoradiographic camera contains an arrangement for placing in firm contact Polaroid sheet film, a plastic scintillator screen, and the radioactive face of the specimen. As an example of the use of the autoradiographic method, a series of sorption experiments were carried out in which synthetic groundwater solutions of americium, neptunium, uranium, and plutonium were contacted with Climax Stock granite under aerated and anoxic conditions at pH 8 to 9. The sorption observed at specific mineral sites was correlated with data on sorption of these actinides on pure minerals.
Date: January 1, 1980
Creator: O'Kelley, G.D.; Beall, G.W. & Allard, B.
Partner: UNT Libraries Government Documents Department

Values for conductive heat transfer in geothermal technologies

Description: Thermal conductivity and diffusivity of the subsurface are evaluated as critical parameters in the application of certain geothermal technologies. The variability of these parameters as a function of other subsurface properties is investigated. A simple method of estimating thermal conductivity and diffusivity from available information at specific locations is explained, and an interactive computer program that has been developed to assist in this task is described.
Date: January 1, 1983
Creator: Intemann, P.R. & Sharp, R.D.
Partner: UNT Libraries Government Documents Department