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Richard B. Wanty

Publications and source records attributed to Richard B. Wanty.

65 records · Page 4Linked to original sources
USGS1997

Geochemical processes controlling uranium mobility in mine drainages

Comprehensive models of ore genesis incorporate metal sources, transport and concentration mechanisms, and preservation mechanisms. Analogous concepts apply to the problem of metal migration from mines, mine wastes, and mine tailings, including: the concentrations, mineralogical occurrence, and availability of metals in mineral deposits, host rocks, mine wastes, and tailings (the source); the mechanisms for metal mobilization and transport during weathering; the mechanisms for metal fixation and the permanence of the fixation. Similarly, undisturbed mineral deposits or alteration zones that are exposed at the Earth's surface may be natural sources from which metals can be solubilized during weathering. Uranium (U), a naturally-occurring radioactive element, may be present in mineral deposits in sufficient concentrations that in itself constitutes ore. It may also be present in ores of other metals at concentrations that exceed average crustal abundances. Any uranium that is not completely removed from these ores in the mining and milling process may be available for mobilization into ground or surface waters via the weathering and oxidation of solid tailings or mine waste piles. This chapter discusses the relative importance of various geochemical processes that control uranium mobility via weathering in both mined and unmined mineralized environments. The data presented in this paper focus on mined areas because the great extent of historic mining in the field areas examined for this study preclude extensive consideration of undisturbed areas.

Book chapter↗
USGS1992

A theoretical model for the flux of radon from rock to ground water

A model is derived to predict the abundance of 222 Rn in ground water in contact with a rock of known uranium content. The model assumes that secular equilibrium is attained in the rock-water system as a whole, but is independent of any microscopic geometric properties of the system. The key variables in the model are bulk properties such as porosity, uranium content of the rock, emanating efficiency, and rock density, all of which are measurable. Thus, the model is simplified by the averaging effects of a macroscopic view of the system. Although less rigorous than other models presented in the literature, it is more generally applicable to natural systems because it does not rely on microscopic properties of the system, which are impossible to quantify. Application of the model to crystalline aquifers in the eastern United States shows that bulk emanation rates of radon are generally less than about 30%.

GSA Special Papers↗
USGS1990

Genesis of the tabular-type vanadium-uranium deposits of the Henry Basin, Utah

Tabular-type vanadium-uranium deposits occur in fluvial sandstones of the Salt Wash Member of the Morrison Formation of Late Jurassic age The mineralized intervals and the weakly mineralized lateral extensions are bounded both above and below by zones rich in dolomite cement. Carbon isotope values of dolomite cements indicate that at least two sources of carbon existed. One source appears to be the same as that which formed the bedded carbonates in the evaporites in the Tidwell Member of the Morrison Formation stratigraphically below the mineralized interval. The second carbon source is typical of terrestrially deposited carbonates generally associated with meteoric water-dominated environments. Oxygen isotope values of these dolomites show the same trend of isotopically light values above the mineralized interval and isotopically heavier values in and below that interval; they indicate that two isotopically distinct fluids were involved in the mineralizing process. Some aspects of the origin of gangue and ore phases are explainable on the basis of processes which occurred solely within the saline fluid, but key aspects of ore genesis involved the interaction of the saline and meteoric waters. It is postulated that the solution interface migrated vertically within the stratigraphic section. -from Authors

Utah↗
USGS1990

Iron sulfide minerals at Cement oil field, Oklahoma: Implications for magnetic detection of oil fields

Aeromagnetic anomalies at Cement oil field (Anadarko basin, Oklahoma) have been attributed to authigenic magnetite. The following characteristics of the magnetite, however, indicate that it is contamination introduced by drilling: (1) occurrence as sharp angular blades and as spheres, commonly with metallographic textures typical of industrial alloys and with associated steel and wustite (FeO); (2) presence only in well cuttings and absence from core and quarry samples; and (3) lack of association with detrital framework grains or with authigenic carbonate and sulfide minerals. Ferrimagnetic pyrrhotite occurs in well cuttings, cores, and quarry samples at Cement and is a possible natural source of the magnetic anomalies. Pyrrhotite, which is intergrown with more abundant FeS 2 minerals, formed as a result of hydrocarbon seepage. Pyrrhotite is confined to beds above oil and gas reservoirs. These beds, which lack detrital organic matter, contain higher mineral sulfide and lower mineral sulfate sulfur (1.7 and 0.1 wt %, respectively) than do correlative beds off the field (0.2 and 1.1 wt %, respectively). In the field, isotopic values of sulfide S show a systematic decrease upward through the Permian section from positive values (maximum, +12 per mil at ∼610-760 m depth) to negative values (-1 to -11 per mil between 32 and 230 m; -26 to -30 per mil at the surface). Geochemical results, together with time-temperature data derived from burial curves, limit the major sources of the sulfide in the Fe-S minerals to two possibilities. Isotopically heavy sulfide was generated either inorganically at temperatures >∼90 °C in beds beneath Permian beds, or by bacterial sulfate reduction at temperatures <∼60 °C in Permian strata. If the latter, microbial sulfate reduction occurred under sulfate-limited conditions. The isotopically light sulfide occurring in minerals near the present surface is attributed to bacterial reduction of sulfate. Sulfate-reducing bacteria derived metabolic energy from leaking hydrocarbons and associated organic compounds.

Oklahoma↗
USGS1989

Sulfide mineralization and magnetization, Cement oil field, Oklahoma

Geochemical, petrographic, and rock-magnetic studies were undertaken to investigate possible sources for reported positive aeromagnetic anomalies over the Cement oil field, Oklahoma. Ferrimagnetic pyrrhotite (monoclinic, Fe 7 S 8 ), intergrown with more-abundant, nonmagnetic pyrite (FeS 2 ), is present in well-cutting, core, and quarry samples at Cement, and it is the only identified source of possible enhanced magnetization in rocks over the field. Magnetite, found only in well cuttings from Cement, is contamination from drilling. Magnetite was considered previously by others to be the source of magnetic anomalies at Cement.

Oklahoma↗
USGS1987

The solubilities of some major and minor element minerals in ground waters associated with a sandstone-hosted uranium deposit

Ground-water samples from 41 wells penetrating basal Oakville sandstone (Miocene) in S Texas were chemically analysed to identify chemical changes related to nearby U orebodies. The coverage included a 240 km 2 area which contains several fault-related U deposits. Factors affecting the hydrochemistry include: 1) relatively high permeabilities of buried fluvial-channel sediments; 2) upwards leakage of brines along growth faults into the aquifer; 3) development of a redox interface (Eh = 0 volts) within the aquifer; and 4) the semi-arid climate. Variations in the saturation index (SI) for chemically reduced minerals of U, As, Mo, Se and for associated minerals such as pyrite outlined the position of known deposits. The SI increases towards zero as the deposits are approached from updip distances of 3-4.5 km, then decreases again downdip. The radiogenic pathfinders Ra and Rn showed very strong anomalies with ore, but diminished to background levels at short distances from ore. A strong He anomaly is deflected in the direction of ground-water flow away from the ore.-R.A.H.

Bulletin de Mineralogie↗