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V. J. Flanigan

Publications and source records attributed to V. J. Flanigan.

28 records · Page 2Linked to original sources
USGS1982

Phase 3 geophysical studies in the Wadi Bidah District, Kingdom of Saudi Arabia

Detailed geophysical measurements have been made in the Rabathan area, Wadi Bidah district, Kingdom of Saudi Arabia, at the site of diamond drill holes RAB-1, -2, and -3; these measurements suggest that the causative source for the anomalous EM (electromagnetic) and SP (self-potential) responses is probably highly conductive zones of Precambrian siliceous-carbonaceous rocks. Although many of the zones are no more than a few meters wide, they commonly contain 50 to 80 percent carbonaceous material and locally abundant pyrite. In places, several thin layers of highly concentrated carbonaceous material interlayered with chert form a multiple conductive zone that is seen in the geophysical data as complex anomaly patterns. In the geologic environment of Wadi Bidah, massive sulfide-bearing zones cannot be distinguished from siliceous-carbonaceous zones on the basis of the EM-SP responses. In North America in similar environments, complex resistivity methods used in experimental research have successfully discriminated between sulfide and carbonaceous conductors. Tests of such methods in the Wadi Bidah district are recommended. Geologic, geochemical, and geophysical data at the Jabal Mohr prospect suggest the possibility of mineralized rocks at depth over a possible strike length of 400 m.

Open-File Report↗
USGS1981

Preliminary report on geophysics ground follow-up of the 1977 airborne survey in the Wadi Bidah District, Kingdom of Saudi Arabia

Reconnaissance geologic and geochemical sampling was made during the 1978 field season at most of the 50 or so electromagnetic anomalies detected in the 1977 airborne electromagnetic (AEM) survey of the Wadi Bidah district. These Phase 1 studies also included reconnaissance geophysical traverses of nine of the AEM conductors. In addition the AEM anomalies were classified on the basis of this reconnaissance work into a list of priority targets for use in economic studies, and six AEM anomalies were selected for further studies. During Phase 2 conducted in the 1979 field season, ground geophysical work consisting of electromagnetic (EM), self-potential (SP), and selected magnetic surveys were carried out in the six targets selected in the Phase 1 studies. These target areas in aggregate cover about 30 km 2, and are approximately half of the Wadi Bidah Class 1 and Class 2 priority targets found during the 1977 airborne electromagnetic (AEM) survey of parts of the Arabian Shield. The results indicate possible extension of known reserves at the Rabathan area (AEM anomaly B-29), with possible potential for mineralization in the area extending 15-20 km north (anomaly B-13), where the geologic and geophysical environment is similar. An important observation is that mineralization in the B-29 (Rabathan) zone is coincident with narrow SP anomalies superimposed on the larger, broader, and more formational-type SP anomalies encountered in both areas B-29 and B-13. AEM anomaly B-25-26 areahas geophysical characteristics that show in the groundwork and that make it an attractive drill target. EM and SP anomalies are associated, in part, with magnetic anomalies and with exposures of significant limonitic gossan. Wadi al Khadra prospect, not included in the 1977 AEM survey, and the AEM anomaly B-25-26 area were also high-mineralization-potential products of the Phase 2 studies. Target area B-35 remains an unknown quantity, and AEM anomaly B-24 is almost certainly due to a carbonaceous schist. Geochemical results, along with detailed geologic mapping and the geophysical data, indicate several potential mineralized targets. Further detailed geophysics (EM and SP) will assist in understanding the geophysical data thus far collected. Further ground follow-up studies are recommended.

Open-File Report↗
USGS1978

Radioactive anomaly and mineralogy of the lower part of the Tabuk Formation, Al Qassim area, Kingdom of Saudi Arabia

A radioactive anomaly about 10 km long was detected by an airborne survey of the Tabuk Formation, about 75 km west-northwest of Buraydah in northeastern Saudi Arabia. The gamma-spectrometer anomaly is 6 to 10 times higher than background over the adjacent Precambrian shield area and indicates anomalous concentrations of thorium-bearing minerals. Radioactive detrital minerals identified are zircon, monazite, xenotime, huttonite, and sphene. These minerals account for the anomaly; uranium and potassium-bearing minerals contribute only slightly to the overall spectrometer response. Several varieties of zircon have different morphologies, inclusions, and degree of freshness. Colorless, possibly relatively young grains showing a bright orange fluorescence, and radiation-damaged probably relatively older zircons without any fluorescence, suggest recycling during more than one erosion cycle and at least two different sources for the sediments of the Tabuk Formation. The antipathetic association of allanite and monazite further supports the thesis of more than one source for the sediments of the Tabuk Formation.

Al Qassim area↗
USGS1978

Mineral exploration in the Wadi Bidah district, 1972-1976, Kingdom of Saudi Arabia

Four deposits in the Wadi Bidah district of southwestern Saudi Arabia were explored during the period 1972-1974. The work consisted of geologic, geochemical, and geophysical investigations and diamond drilling in the subsurface. Thirteen holes were drilled, aggregating a length of 2,397 m. Drilling at three of the deposits, Gehab, Sha'ab El Tare, and Rabathan, indicated mineralized reserves aggregating 6,341,000 tons, the average grade of which is 0.95 percent copper. The deposits are strata-bound in volcaniclastic rocks of the Baish Group and in quartz porphyry, all of which are Precambrian in age. The bodies are lenticular in strike and dip, and are offset and broken by postmineral faults.

Wadi Bidah district↗
USGS1977

Summary of results from electromagnetic and galvanic soundings on Kilauea Iki lava lake, Hawaii

The purpose of this report is to summarize various electrical sounding studies made on the Kilauea Iki lava lake and to present some of the preliminary interpretations that resulted from the measurements. The following discussion is not intended as a complete interpretation, but is intended to summarize the major points made in an invited oral presentation at the American Geophysical Union fall meeting held in San Francisco, Calif. on December 6, 1976. This paper was part of a group of papers dealing with various geophysical studies recently made on the Kilauea Iki lava lake. A general plan map of Kilauea Iki lava lake is shown in figure 1. Electromagnetic (EM) loop-loop soundings, D.C. resistivity soundings, and VLF apparent resistivity measurements were made on the lave lake surface. All of these surveys were made to determine the geoelectric structure of the lava lake and to determine parameters of the molten basaltic lens that exist in the partially solidified lava lake.

Hawaii↗
USGS1970

Recommended geophysical investigations of mineral occurrences at Jabal Samran, Al Marasia, and Wutaileh

A familiarization and reconnaissance trip was made in the vicinity of Jabal Samran during 7-8 April 1968. The trip was suggested by E. Heaton and W. Liddicoat, Ministry of Petroleum and Mineral Resources for the purpose of inspecting the mineral occurrences at Jabal Samran, Al Marasia, and Wutaileh, and recommending feasible geophysical methods which should be applied to the study of these occurrences.

Al Marasia, Jabal Samran, Wutaileh↗