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Geology topics

Donald G. Hadley

Publications and source records attributed to Donald G. Hadley.

16 recordsLinked to original sources
USGS1983

Summary of Tertiary investigations in western Saudi Arabia, current work by the U.S. Geological Survey and recommended future studies

In 1936, geologic work related to the Tertiary System in western Saudi Arabia began with a study of the Umm Gerad barite deposit by K. S. Twitchell. In 1944, a study focusing specifically on Tertiary rocks was conducted by Steineke and others near Jiddah. Small-scale mapping of Tertiary sequences began in 1950 in southwestern Saudi Arabia and later in northern 3audi Arabia as part of the Kingdom's early mapping program. These studies were part of a larger program being directed by the Government of Saudi Arabia in connection with mineral resource investigations. In the mid- to late-1960's, the Bureau de Recherches Geologiques et Minieres discovered mineralized Tertiary rocks al Jabal Dhaylan and began a study, which continues to the present, of both the Tertiary rocks and the mineralization. Following a number of early local studies, in 1973 the U.S. Geological Survey began detailed study of the Tertiary layered rocks along the Red Sea coastal plain south of Jiddah. More recently, Riofinex and Seltrust have been exploring for selected commodities in Tertiary sequences of northwestern Saudi Arabia and the Red Sea coastal plain. Results of these studies, including work by the Saudi Arabian Directorate General of Mineral Resources and the Saudi government agency preceding it, are summarized in this report. Characteristics of the Tertiary rocks south of lat 23? N. and the Tertiary mineral deposits of western Saudi Arabia are also summarized. Recommendations are made for future geologic studies and mineral assessment of the Tertiary rocks of western Saudi Arabia.

Open-File Report↗
USGS1983

Middle Tertiary continental rift and evolution of the Red Sea in southwestern Saudi Arabia

Middle Tertiary rift volcanism in a continental-rift valley in the Arabian-Nubian Shield was the first surface expression of active mantle convection beneath an axis that was to become the Red Sea. Investigation of the coastal plain of southwestern Saudi Arabia suggests that the rift valley was filled with basaltic and felsic to rhyolitic volcanic rocks (Ad Darb and Damad formations), cherty tuffaceous siltstones (Baid formation), and subordinate Nubian-type quartz sandstone (Ayyanah sandstone) between about 30 and 20 Ma ago. These rocks are named herein the Jizan group. At the same time, alkali-olivine basalt was erupted on the stable Precambrian craton at locations 100 to 200 km east of the rift valley axis. First-stage spreading of the Red Sea began about 20 Ma ago when diabasic dikes and gabbro and granophyre plutons (Tihamat Asir complex) of oceanic-tholeiitic parentage were intruded into the continental-rift deposits. The new oceanic crust was injected into a region of thinned continental crust. Because of thinning, the continental crust was extended and became fractured into a series of fault blocks. Crustal extension in the attenuated zone was accompanied by mafic and silicic volcanism producing a continental rift-valley tectonic environment. Fault blocks of the rift valley were initially rotated toward the Red Sea during the first-stage spreading episode. Inland from the continental rift, the thick continental crust was distended on long parallel fractures that were intruded by gabbroic to quartz syenitic magma to form continental dikes. This period of continental-margin extension was short lived, lasting perhaps only 1 or 2 Ma. The first-stage sea-floor spreading of the Red Sea continued until about 15 or 14 Ma ago at a half-spreading rate of about 2.2 cm/yr. Throughout early Tertiary time, the Arabian Shield erosion surface remained near sea level. First-stage uplift of the Red Sea Escarpment began during middle Miocene time, as evidenced by the coarse polymictic boulder conglomerate of the Bathan formation. Second-stage scarp uplift and second-stage sea-floor spreading followed during Pliocene, Pleistocene, and Holocene time.

Open-File Report↗
USGS1982

Reconnaissance geology of the Wadi Dhahaban Quadrangle, sheet 18/41 D, Kingdom of Saudi Arabia

The Wadi Dhahaban quadrangle (sheet 18/41 D) lies between lat 18?00? and 18?30' N. and long 41?30' and 42?00' E. and encompasses an area of 2,937 km2 located along the Red Sea coast and includes part of the escarpment-mountains province. The geologic formations exposed in the quadrangle are comprised of Precambrian layered and intrusive rocks, Tertiary gabbro dikes, Quaternary basaltic lavas and pyroclastic rocks, and Quaternary surficial deposits. No economic mineral deposits have been found. The Precambrian rocks include layered sedimentary and volcanic rocks that have been assigned to the Baish, Bahah, and Ablah groups. They have been folded, metamorphosed, and invaded by three separate intrusions. The Precambrian rocks are cut by Miocene gabbro dikes that were intruded during the initial stages of the opening of the Red Sea rift. The Quaternary rocks include basalt, and coastal, pediment, and alluvial deposits of various kinds. The area is of special interest because of its unique display of the Tertiary and Quaternary basaltic volcanism that was associated with the opening of the Red Sea rift and that has continued in other parts of the Kingdom until historic times.

Open-File Report↗
USGS1979

Proterozoic sedimentary rocks and basins of the Arabian shield and their evolution

Proterozoic sedimentary rocks of the Arabian Shield consist of three depositional phases. Phase I (the oldest) includes the Baish, Bahah, and Jiddah groups, which consist of an immature assemblage dominated by fine-grained metagraywacke, graphitic schist, chert, marble, and subordinate polymictic conglomerate and metasiltstone. Clastic rocks of Phase I are composed solely of volcanic material and do not contain plutonic or sialic detritus. Metasandstone, polymictic conglomerate, coarse-grained metagraywacke, and abundant marble (stromatolitic in places) constitute Phase II, the Ablah, Halaban, and Murdama groups. Plutonic and volcanic components are abundant in the clastic suite; K-feldspar detrital fragments are common in the Halaban and Murdama. The Shammar and Jubaylah groups form Phase III. Sedimentary rocks of this phase are fine- to coarse-grained terrigenous clastic rocks, boulder conglomerate, and stromatolitic limestone and dolomite. All phases include abundant volcanic rocks. Sedimentary basins, excluding those containing Phase III rocks, generally trend north, especially in the central and southern parts of the shield. In the central and northern parts of the shield, north-trending basins and structures are truncated abruptly by parallel northwest-trending sedimentary troughs (Jubaylah basins) formed by sinistral wrench-fault tectonics. Textural and compositional characteristics of the Proterozoic sedimentary rocks together with spatial relations of the depositional basins document a progressive change from oceanic to shallow marine and continental sedimentation with time, and a shift in the basin axes from west to east. Sedimentary parameters during this lengthy timespan show general increases in compositional and textural maturity, carbonate content, grain size, the ratio of sedimentary rocks to volcanic rocks, and plutonic and K-feldspar-bearing detritus. The sedimentary style of each phase was a function of tectonic conditions during deposition.

Open-File Report↗
USGS1979

Ultramafic inclusions and host alkali olivine basalts of the southern coastal plain of the Red Sea, Kingdom of Saudi Arabia

A variety of mafic and ultramafic inclusions occur within the pyroclastic components of the Al Birk basalt, erupted on the southern Red Sea coastal plain of Saudi Arabia from Pleistocene time to the present. Depleted harzburgites are the only inclusions contained within the basalts that were erupted through Miocene oceanic crust (15 km thick) in the vicinity of Jizan, whereas to the north in the vicinity of Al Birk, alkali basalts that were erupted through a thicker Precambrian crust (48 km thick) contain mixtures of harzburgites, cumulate gabbro, and websterite inclusions accompanied by large (> 2 cm) megacrysts of glassy alumina-rich clinopyroxene, plagioclase, and spinel. Microprobe analyses of individual minerals from the harzburgites, websterites, and cumulate gabbros reveal variations in composition that can be related to a complex mantle history during the evolution of the alkali basalts. Clinopyroxene and plagioclase megacrysts may represent early phases that crystallized from the alkali olivine basalt magma at depths less than 35 km. Layered websterites and gabbros with cumulate plagioclase and clinopyroxene may represent continuing crystallization of the alkali olivine basalt magma in the lower crust when basaltic magma was not rapidly ascending. It is significant that the megacrysts and cumulate inclusions apparently form only where the magmas have traversed the Precambrian crust, whereas the harzburgite-bearing basalts that penetrated a much thinner Miocene oceanic crust reveal no evidence of mantle fractionation. These alkali olivine basalts and their contained inclusions are related in time to present-day rifting in the Red Sea axial trough. The onshore, deep-seated, undersaturated magmas are separated from the shallow Red Sea rift subalkaline basalts by only 170 km. The contemporaneity of alkaline olivine and subalkaline basalts requires that they must relate directly to the separation of the Arabian plate from the African plate.

Open-File Report↗
USGS1977

Graded layering in the Al Hadah pluton near At Ta'if, Kingdom of Saudi Arabia

To assess urban storm-water-quality characteristics in the metropolitan area of Portland, Oreg., seven drainage basins were selected with varying drainage areas, basin slopes, impervious areas, land uses, and active construction areas. Automatic water-quality samplers, rain gages, and stream gages were installed in each basin. From September 1, 1975, to May 1, 1976, data were collected to determine rainfall intensities and stream discharge. Almost 500 samples from the seven basins were analyzed to describe pollutants for at least four complete storms on each of the basins. In addition to the storm samples, several base-flow samples were collected and analyzed for each site. Stream discharge and water-quality data are tabulated. (Woodard-USGS)

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USGS1974

Nonglacial origin for conglomerate beds in the Wajid Sandstone of Saudi Arabia

Conglomerate beds containing sparse boulders in the upper part of the Wajid Sandstone of Permian or older(?) age have been interpreted as Gondwana glacial deposits (Helal, 1965). These beds, exposed in the Bani Khatmah area near the southeastern edge of the Arabian Shield of Saudi Arabia, contain normally graded polymictic conglomerate, commonly in fluvial channels cut into mature quartz sandstone. None of the features observed suggest deposition in a glacial environment. The conglomerate beds constitute a laterally and vertically restricted facies about 150 km wide in the quartz-sand facies of the Wajid. Recent palynological evidence suggests that the Wajid Sandstone is of Cambrian or Ordovician age. The conglomerate of the Wajid is probably derived from locally uplifted Precambrian rocks in the southern part of the Arabian Peninsula. This is in contrast with an otherwise extensive, stable, deeply weathered, and low-lying Precambrian Shield that was the source of the predominant quartz sandstone of the Wajid during early Paleozoic time.

Open-File Report↗
USGS1972

Availability of low-sulfur coal in Clay County, West Virginia

Clay County is located in central West Virginia in the Appalachian coal field. It is underlain by Middle and Upper Pennsylvanian coal-bearing sedimentary rocks that total about 2,070 feet and consist of the Kanawha, Allegheny, Conemaugh, and Monongahela Formations. The stratigraphic relations and distribution of coal beds in the county were studied by the U.S. Geological Survey in conjunction with the low-sulfur coal program of the U.S. Bureau of Mines. The rocks are light gray to grayish red, and are composed mostly of interbedded shale, siltstone, sandstone, underclay, and coal. Conglomerate occurs, also, in the Allegheny Formation. There are 28 coal beds of high-volatile A or B bituminous rank, the thickest of whichis as much as 82 inches. Twelve of the coals are minable and consist chiefly of bright-banded and splint varieties. Four coal beds contain an average of less than 1.0 percent sulfur, and two others contain anaverage of between 1.1 and 3.0 percent. Analyses are unavailable for the remaining six beds, and their sulfur content is unknown. The rocks are light gray to grayish red, and are composed mostly of interbedded shale, siltstone, sandstone, underclay, and coal. Conglomerate occurs, also, in the Allegheny Formation. There are 28 coal beds of high-volatile A or B bituminous rank, the thickest of whichis as much as 82 inches. Twelve of the coals are minable and consist chiefly of bright-banded and splint varieties. Four coal beds contain an average of less than 1.0 percent sulfur, and two others contain anaverage of between 1.1 and 3.0 percent. Analyses are unavailable for the remaining six beds, and their sulfur content is unknown.

West Virginia↗
USGS1972

Availability of low-sulfur coal in Fayette County, West Virginia

Fayette County is in central West Virginia. Rocks exposed at the surface are about 3,200 feet thick and comprise the Pocahontas, New River, Kanawha, and Allegheny Formations of Pennsylvanian age. The stratigraphic relations and distribution of coal in these formations were studied by the U.S. Geological Survey in connection with a low-sulfur coal program of the U.S. Bureau of Mines. The coal in Fayette County is medium-volatile and high-volatile A and B bituminous ranks. Of 51 coal beds in the county, 22 are 28 inches to as much as 9 feet thick and contain substantial reserves. Several coals have been mined locally in the past by underground, stripping, and auger methods. Of the 22 coals discussed, 17 contain less than 1.0 percent sulfur, and the remainder average less than 2.0 percent sulfur. Of an original 2,210 million tons of recoverable coal estimated for Fayette County, 678 million tons were mined between 1888 and 1966. Thus, the remaining recoverable coal reserves at the end of 1966 were 1,530 million tons. Of this amount, 86 percent or 1,320 million tons of coal is classified as low sulfur, and 210 million tons is classified as medium sulfur.

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