Geology Reports⌕ Search

Geology topics

Thor H. Kiilsgaard

Publications and source records attributed to Thor H. Kiilsgaard.

At least 19 recordsLinked to original sources
USGS1998

Mining properties in Washington that were involved in the DMA, DMEA, OME Mineral Exploration Programs, 1950-1974

Introduction This report and accompanying map (Plate 1) presents information on the Defense Minerals Administration (DMA), Defense Minerals Exploration Administration (DMEA), and Office of Minerals Exploration (OME) mineral exploration programs in Washington. Under these programs, the federal government participated in the exploration costs for certain strategic and critical minerals. Federal funds for mineral exploration under the programs were available from 1950 to 1974, although limited funds for OME administrative work were continued until 1979. The report reviews the three programs, associated regulations, administrative procedures, and operational techniques. It also describes the various types of informative reports generated by the programs, lists mining properties in Washington that were involved in the exploration programs, and advises on location of compiled exploration information that resulted from the work.

Washington↗
USGS1998

Mining properties in Oregon that were involved in the DMA, DMEA, or OME mineral exploration programs, 1950-1974

Introduction This report and accompanying map (Plate 1) presents information on the Defense Minerals Administration (DMA), Defense Minerals Exploration Administration (DMEA), and Office of Minerals Exploration (OME) mineral exploration programs in Oregon. Under these programs, the federal government participated in the exploration costs for certain strategic and critical minerals. Federal funds for mineral exploration under the programs were available from 1950 to 1974, although limited funds for OME administrative work were continued until 1979. The report reviews the three programs, associated regulations, administrative procedures, and operational techniques. It also describes the various types of informative reports on individual mining properties generated by the programs, lists properties in Oregon that were involved in the different exploration programs, and advises on the location of compiled information that resulted from the work.

Oregon↗
USGS1996

Mining properties in Montana that were involved in the DMA, DMEA, OME Mineral Exploration Programs, 1950-1974

Introduction This report and accompanying map (plate 1) presents information on the Defense Minerals Administration (DMA), Defense Minerals Exploration Administration (DMEA), and Office of Minerals Exploration (OME) mineral exploration programs in Montana. Under these programs, the federal government participated in the exploration costs for certain strategic and critical minerals. Federal funds for mineral exploration under the programs were available from 1950 to 1974, although limited funds for OME administrative work were continued until 1979. Federal consideration for exploration at a particular property was initiated by submittal of an application for financial assistance by the owner or operator of the property. Each application received was assigned a docket number and all subsequent correspondence and information resulting from the application was filed under that docket number. The report reviews the three programs and some of the associated regulations and procedures. It also describes the various types of information generated by the programs, presents information on mining properties in Montana that were involved in the exploration programs, and advises on location of compiled mineral exploration information that resulted from the work.

Montana↗
USGS1982

Analytical determinations from samples taken in the Ten Mile West Roadless Area, Boise and Elmore counties, Idaho

A total of 584 stream-sediment and rock samples were collected from within or near the Ten Mile West Roadless Area, Boise and Elmore Counties, Idaho, as part of a geologic study aimed at appraising the mineral resource potential of the area. Emphasis was placed on stream-sediment samples because stream sediments represent the erosional products of a drainage system and offer a rapid means of locating anomalous concentrations of ore-forming elements. An unusually high proportion of the stream-sediment samples contained concentrations of silver and molybdenum. Unaltered rocks of the area contain normal quantities of the common rock-forming elements. Some exposures of altered or mineralized rocks and some quartz veins contain significant quantities of gold and silver.

Open-File Report↗
USGS1982

Geology of areas marked by geophysical anomalies (B-35 and B-34), Wadi Bidah District, Kingdom of Saudi Arabia

Geophysical surveys in the Wadi Bidah district, in the southwestern part of the Kingdom of Saudi Arabia, have revealed anomalies of the type that may be caused by deposits of massive sulfides. Accordingly, a study was undertaken to investigate the geologic environment associated with the geophysical anomalies and to determine whether mineral exploration of the anomalous areas might be warranted. An extensive geochemical sampling program did not disclose any evidence of ore mineral concentrations in the rocks. Detailed geologic mapping shows the anomalous areas to be underlain by Precambrian carbonaceous graywacke, the outcrop patterns of which closely fit the anomaly patterns. Field evidence and petrologic studies indicate that carbonaceous material in the rocks is the cause of the geophysical anomalies. Nothing was found in the anomalous areas that suggests the presence of mineral deposits of commercial grade, and further mineral investigations or exploration in the areas is not recommended.

Open-File Report↗
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↗
USGS1976

Diamond drilling at the Ma'milah Mine, Kingdom of Saudi Arabia

The Ma'millah gold mine is about 90 km southeast of At Ta'if at lat 21°03'N., long 41°18'E., in southwestern Saudi Arabia. The deposit, which was worked extensively by ancient miners, consists of several veins and massive lenses of quartz along a regional fault. The extensive ancient mine workings, large size of some quartz outcrops, and significant gold content of several samples indicated that subsurface exploration was warranted. Accordingly, two holes were drilled into the deposit during the interval December 1972 to February 1973. The drill findings were disappointing; the grade of vein material was found to be too low to be of economic interest and the quartz bodies were found to pinch out both along strike and downdip. The drilling program therefore was terminated. The deposit is not worth further exploration

Ma'milah Mine↗
USGS1975

Mineral deposits in western Saudi Arabia; a preliminary report

Mineral deposits in Saudi Arabia include a variety of deposits which were formed in many geologic environments. These include magmatic and late magmatic deposits in igneous masses, contact metamorphic deposits along the margins of igneous bodies, and stratiform sulfide deposits and veins. Notable deposits of sedimentary origin include deposits of iron oxides and phosphate. Strata-bound massive sulfide deposits containing copper, zinc, and nickel sulfides associated with pyrite and pyrrhotite in complexly deformed volcanic rocks in Saudi Arabia have been the subject of controversy. They are considered by some geologists to be of syngenetic or volcanogenic origin, and by others to be epigenetic. The principal mineral deposits in western Saudi Arabia are localized in mineral belts within tectonic zones that trend northerly, northeasterly, and northwesterly. These belts contain the exploration target areas most promising for future exploration. Noteworthy among these are: 1) the northerly-trending Bidah copper-zinc belt; 2) the Sayid copper-zinc zone; 3) the northwest-trending Nuqrah copper zinc-silver belt; and 4) the north-northwesterly-trending Al Amar belt. Gold and silver deposits are mainly localized in north-trending structural features of the Hijaz geotectonic cycle and northwest Najd trends. Saudi Arabian metal deposits known thus far contain reserves in the 2 billion dollar range. Further exploration should result in discoveries that could significantly increase this amount; Saudi Arabia may well have workable metallic and nonmetallic mineral resources for industrial developments in many parts of the Kingdom. In order to effectively carry on a search for new mineral deposits, the belts should be mapped in detail, with emphasis on the delineation of stratigraphic and structural features that control metallization. In addition, geochemical and geophysical studies should be made of promising areas to outline exploration targets. These targets could then be systematically explored.

Open-File Report↗
USGS1974

Summary of activities, U.S. Geological Survey Saudi Arabian project, 1950 to 1974

The U. S. Geological Survey (USGS) first began work in the Kingdom of Saudi Arabia in 1950 under the sponsorship of the Ministry of Finance and National Economy. The basic objective of the work was to investigate the mineral and water resource potential in western Saudi Arabia, but little was known of the region and it therefore was necessary to prepare geographic and geologic maps. Aerial photographs were taken and controlled mosaics produced, some paid for by the USGS but most paid for by the Saudi Arabian government, and reconnaissance geologic mapping was undertaken until the USGS team left Saudi Arabia in 1955. This mapping, in cooperation with mapping of the Arabian American Oil Company, was compiled as a series of scale 1:500,000 geographic and geologic maps in Arabic and English covering all of Saudi Arabia. A total of 42 of these maps were prepared. Three scale 1:2,000,000 geographic and geologic maps in Arabic and English, covering the Arabian Peninsula, also were prepared from this work. All of the maps were printed in the United States and published by the USGS, the last in 1963. Other work done by the USGS between 1950 and 1955 included locating and examining ancient mines, indentifying the Wadi Fatima oolitic iron deposit and other iron deposits in northwest Saudi Arabia, and advising on many water supply problems including those for Riyadh, Qizan, Qunfudhah, Rabigh, Yenbo, Umm Lejh, and Al Wajh. The mapping work and the geologic investigations laid the groundwork for the more detailed studies that followed.

Open-File Report↗