Joseph W. Berg

Thermal and electrical conductivities of sandstone rocks and ocean sediments

Relationships between electrical and thermal conductivities of consolidated sandstone rocks and sediments were investigated. Equations given by Archie (1942) and Woodside and Messmer (1961) were combined to give an equation which relates the two conductivities for the rocks. Equations relating conductivity and porosity, given by Maxwell (1881), Bruggeman (1935), and Woodside and Messmer (1961) were combined to give two equations which relate thermal and electrical conductivities for sediments. Data from 65 rock samples and 105 sediment samples (including data for 37 rock samples published by Zierfuss and Van der Vliet, 1956) were use establishing the reliability and parameter values of the equations. The derived equations can be used to determine thermal conductivities from electrical conductivities providing thermal conductivities of the solid constituents can be approximated. For samples of sandstone rock, deviations of the data from values predicted by the equations are shown to be related to the varia...

Regional Gravity Survey of the Northern Great Salt Lake Desert and Adjacent Areas in Utah, Nevada, and Idaho

From 1957 to 1961 a regional gravity survey was made over the northern part of the Great Salt Lake Desert and adjacent areas in Utah, eastern Nevada, and southeastern Idaho. A total of 1040 stations were taken over an area of about 7000 square miles. The results were compiled as a Bouguer gravity anomaly map with a contour interval of 2 mgal. The Bouguer values ranged from a high of about —120 mgal over the outcrop areas to a low of about —196 mgal over the alluvium-covered graben areas. The gravity high over the Raft River Mountains apparently corresponds with the Raft River Mountains anticline. A belt of gravity contours, with a total relief of 15–20 mgal, extending for 40 miles between the Wildcat Hills and the southern part of the Grouse Creek Mountains and beyond, is interpreted provisionally as caused partly by abrupt thickening and/or downwarping of the rocks of late Paleozoic age in a general northwestward direction, perhaps to form a foredeep (part of the Butte-Deep Creek trough of Steele, 1960) south of the Raft River Mountains; however, this anomaly could also be partly caused by overthrusting. Many Basin and Range faults, grabens, and horsts are indicated by the gravity data. In the northern part of the surveyed area, Junction Valley, Upper Raft River valley, and Curlew Valley are indicated to be grabens. The Newfoundland Range, in the northeastern part of the Great Salt Lake Desert, is a horst flanked by a graben on each side. The northwestern margin of the Great Salt Lake Desert comprises a complex pattern of Basin and Range fault blocks, large and small, that lie along a generally northward-trending belt or zone. The Silver Island-Pigeon fault block, which comprises the Silver Island Mountains, the Little Pigeon Mountains, and Pigeon Mountain, forms an elongate, arcuate horst that is flanked by a belt of grabens on the west (Pilot Valley, Lucin, and Grouse Creek grabens) and east (Wendover, Crater Island, Little Pigeon, and Pigeon grabens). A major fault zone is indicated along the east margin of the Pilot Range. The Pilot-Grouse Creek rift belt, at least 90 miles long, extends northward between Pilot Valley and the Upper Raft River valley and constitutes a major lineament in the earth9s crust along which the graben blocks were displaced downward relative to the adjacent mountain blocks. In the southern part of the rift belt, the grabens are separated by blocks (the Lemay and Lucin horsts) that were probably downfaulted relative to the large mountain blocks, but became lodged at intermediate height; in the northern part, however, the blocks (for example the Junction Valley graben), apparently merely broke from the main crustal unit along this belt of weakness. The indicated thickness of the valley fill of Cenozoic age in some of the graben areas ranges up to about 6000 feet.

Magnetic Anomalies off the Northwest Coast of the United States

Total-magnetic-intensity anomaly maps have been prepared for the region off the coasts of Washington, Oregon, and northern California. Two anomaly lineations reported in 1961 are shown to extend across the Continental Slope, and one of these extends to the mouth of the Strait of Juan de Fuca. The results of anomaly-source depth calculations made at 49 points in the survey area are presented. Some apparent conclusions that can be made from the calculations are these: the crust off northern Oregon has an anomalous magnetic character at depth; the Mendocino fracture zone contains high-susceptibility material (possibly intruded) which dips toward the continent; and anomaly sources are located irregularly throughout the crust, the greatest source depth being 14.6 km for an anomaly off northern Oregon.

Electrical properties of synthetic metalliferous ore

Ninety small cores of synthetic metalliferous ore were constructed from solid glass spheres averaging 0.5 mm in diameter, lead spheres 1.0 mm in diameter, and refractory cement. The lead content of the cores varied from zero to 50 percent by frame volume. The effective porosity was controlled by the manufacturing pressure and ranged from 10 to 20 percent. The cores were saturated with NaCl solution. The apparent impedance of the cores was measured with a modified Wheatstone bridge as a function of frequency and current density. The low‐frequency effects of induced polarization were separated from the over‐all decrease of impedance with increase of frequency by taking advantage of the dependence of these effects upon current density. The over‐all decrease of the impedance with frequency and the polarization effects were found dependent upon the effective porosity and the lead content. Both the polarization effects and the over‐all decrease of the impedance with frequency increased with decreasing porosity....

SEISMIC VELOCITY STUDY OF SYNTHETIC CORES

The velocity of a longitudinal elastic wave through rock at room temperature and at atmospheric pressure depends upon the nature of the rock frame, the porosity of the rock, and the nature of the pore‐filling fluid. In the present investigation longitudinal elastic wave velocities were measured for sixty synthetic cores. The rock frame consisted of sorted quartz sand grains and cement, the percentage of cement varying from ten to fifty percent. The core porosities varied from 8.8 percent to 22 percent. The velocities were measured for dry air‐filled cores and for cores saturated with various liquids. These pore‐filling liquids were distilled water, ethyl alcohol, benzene, carbon tetrachloride, and chloroform. The measured velocities ranged from 2,360 feet per second to 14,710 feet per second. The wave velocity in liquid‐filled cores of 10 percent porosity was approximately twice the velocity for cores of 20 percent porosity, the same type of cement being used in both instances. For any given core, flooded...

EFFECT OF POROSITY, GRAIN CONTACTS, AND CEMENT ON COMPRESSIONAL WAVE VELOCITY THROUGH SYNTHETIC SANDSTONES

Compressional wave velocities through 36 synthetic sandstone cores were measured and related to several of their physical properties, namely, porosity, manufacturing pressure, grain contacts, and amount of cement. The cores were composed of Ottawa sand grains averaging 0.12 mm in diameter and commercial Grefco cement; the manufacturing pressure was varied from 4,000 to 10,000 psi; the cement content by volume was varied from 10 to 100 percent; the effective porosities ranged between 2.1 and 30.4 percent; and the compressional wave velocities ranged between 9,170 and 17,420 ft.sec. All velocity measurements were taken at room temperature and atmospheric pressure using cores that contained only air in the pore space. The results are presented in graphic form, showing the relationship between the compressional wave velocity and manufacturing pressure, porosity, and cement content. For Grefco cement contents between 10.0 and 17.5 percent, the compressional wave velocity is controlled by the manufacturing pres...

Reply by authors to discussion by L. P. Stephenson and R. D. Tooley

In order that an understanding can be obtained of the analysis of the data presented in the subject paper by Viksne, Berg, and Cook, the following discusses the work in detail and compares the assumptions made in that work with the results of the analysis of the same data performed by Stephenson and Tooley in the preceding discussion. The topics that are considered are: (1) a discussion of the variables; (2) a review of the analysis performed by Viksne, Berg, and Cook, and (3) specific comments on the discussion by Stephenson and Tooley.