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Charles J. Zablocki

Publications and source records attributed to Charles J. Zablocki.

14 recordsLinked to original sources
USGS2012

A deep research drill hole at the summit of an active volcano, Kilauea, Hawaii

Drilling and geophysical logging data for a 1,262 m‐deep bore hole in the area inferred to overlie the magma reservoir of Kilauea Volcano, Hawaii, support earlier interpretations based on surface geophysical surveys that a zone of brackish or saline water lies above the reservoir. Temperatures encountered within the hole are not sufficiently high to warrant commercial interest; the maximum temperature, 137°C, is at the hole bottom. However, the temperature gradient toward the bottom of the hole (approximately 160 m below sea level) increases sharply to about 370°C/km, perhaps partly reflecting the effect of decreased water circulation as suggested by the geophysical logging data. If this gradient persists or increases with depth, magmatic temperatures would be attained within 3 km from the hole bottom (i.e., approximately 4 km from ground surface)—a depth in accord with data from ground‐deformation and seismic studies.

Hawaii↗
USGS2012

Field measurements of apparent Curie temperatures in a cooling basaltic lava lake, Kilauea Iki, Hawaii

Magnetic susceptibility and temperature measurements have been made in two of three holes drilled in 1975 through the crust and into the still molten lens of tholeiitic basalt in Kilauea Iki lava lake (formed in 1959). The temperature above which magnetic susceptibility drops to zero—the apparent Curie temperature—is 540°C. at depths of 34.7‐35.9 m below the lake surface. These field measurements suggest that the dominant ferromagnetic mineral in the cooling basalt is titanomagnetite containing about 10 mol percent ulvöspinel.

Hawaii↗
USGS1987

Geoelectric characteristics of portions of the Raha fault zone and surrounding rocks, Jabal As Silsilah Quadrangle, Kingdom of Saudi Arabia

Telluric-electric and auto-magnetotelluric measurements obtained in and around the Raha fault zone in the Buqaya area indicate that it dips steeply to the southwest. Large contrasts in the electrical properties of Qarnayn and Maraghan metasedimentary rocks located on either side of the fault are characteristic of the rocks within the fault zone. However, no large electrical contrasts were detected along several segments of a southern branch of the main fault in the Shiaila area, indicating that the rocks on either side of the fault are of similar composition. Extremely low resistivity readings in the Buqaya and Shiaila areas are associated with fracturing and clay-bearing gouge that accompany known shear zones. The locations of several shallow plutons have been inferred from these studies, one of which is probably a source of gold-bearing quartz veins in the metasedimentary rocks of the Shiaila area.

Open-File Report↗
USGS1984

An evaluation of the applicability of the telluric-electric and audio-magnetotelluric methods to mineral assessment on the Arabian Shield, Kingdom of Saudi Arabia

Feasibility studies of two electromagnetic methods were made in selected areas of the Jabal Hibshi (1:250,000) quadrangle, 26F, in the Kingdom of Saudi Arabia in March of 1983. The methods tested were the natural source-field telluricelectric and audio-magnetotelluric methods developed and extensively used in recent years by the U.S. Geological Survey in some of its domestic programs related to geothermal and mineral resource assessment. Results from limited studies in the Meshaheed district, the Jabal as Silsilah ring complex, and across a portion of the Raha fault zone clearly demonstrate the appropriateness of these sub-regional scale, reconnaissance-type studies to mineral resource assessment. The favorable results obtained are largely attributed to distinctive and large contrasts in the electrical resistivity of the major rock types encountered. It appears that the predominant controlling factor governing the rock resistivities is the amount of contained clay minerals. Accordingly, unaltered (specifically, non-argillic) igneous and metamorphic rocks have very high resistivities; metasedimentary rocks of the Murdama group that contain several percent clay minerals have intermediate values of resistivity; and highly altered rocks, containing abundant clay minerals, have very low values of resistivity. Water-filled fracture porosity may be a secondary, but important, factor in some settings. However, influences from variations in interstitial or intercrystalline, water-filled porosity are probably small because these types of porosity are generally low. It is reasonable to expect similar results in other areas within the Arabian Shield.

Open-File Report↗
USGS1977

Mapping the lateral boundaries of a cooling basaltic lava lake, Kilauea Iki, Hawaii

Two types of electromagnetic (EM) profiling techniques were used to delineate the surface projection of the edges of the still-molten basaltic lava lens that exists in Kilauea Iki Crater, Hawaii. These studies were made as part of an intensive geophysical program aimed at defining the overall configuration of the liquid core and the attendant hydrothermal fluids. The results of the profiling studies were presented orally at the Annual Fall Meeting of the American Geophysical Union held in San Francisco, Calif., December 6, 1976. This report summarizes in more detail the techniques, results, and some conclusions related to the EM profiling studies. The complete results of an intensive VLF study made by L. A. Anderson (U.S. Geol. Survey, oral communication, 1976) will be presented in a separate report. Only a few of these results are discussed here.

Hawaii↗
USGS1968

Geochemical and geophysical anomalies in the western part of the Sheep Creek Range, Lander County, Nevada

Extensive geochemical anomalies are present along the west side of the Sheep Creek Range in Lander County, Nev. Anomalous concentrations of zinc, arsenic, mercury, silver, copper, lead, and to some extent gold, molybdenum, and antimony occur in iron-rich material along fracture planes and in quartz veins in Paleozoic formations. A magnetic anomaly occurs over a pediment at the southern part of the range, close to one of the geochemical anomalies. Gravity and electrical resistivity measurements suggest that the magnetic anomaly is caused by an intrusive igneous mass rather than by a block of downfaulted basalt. A limited amount of shallow drilling would clarify the geochemical and geophysical data.

Circular↗