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Wayne E. Hall

Publications and source records attributed to Wayne E. Hall.

8 recordsLinked to original sources
USGS1978

Wood River mining district, Idaho - intrusion-related lead-silver deposits derived from country rock source

Lead-silver deposits in the Wood River mining district occur in shear zones in hornfelsed argillite of the Devonian Milligen Formation near granitic plutons and under the Wood River thrust fault. The principal ore minerals are argentiferous galena and sphalerite; siderite is the principal gangue. The δ 34 S values of the sulfide minerals range from +2.2 to +15.0 permil, indicating that the sulfur had a shallow crustal source. Δ 34 S values between sphalerite and galena range from +2.3 to +3.4 permil, corresponding to sulfur isotope temperatures between 280° and 182 °C. Hydrothermal barite has a δ 34 S of +13.2 permil. Lead isotope ratios are radiogenic, also pointing to a shallow crustal source. Quartz gangue has δ 18 O of +16.4 permil and a calculated δ 18 O H20 at 270°C of +8.4 permil. This value is reasonable for a hydrothermal fluid that had reached equilibrium with the argillite country rock. The siderite gangue has δ 18 O and δ 13 C values of +14.0 and -5.5 permil, respectively. Fluid inclusions have homogenization temperatures of 244°-307°C and average 270°C. Freezing-stage measurements ranged from -1.85 to -2.8°C, suggesting salinities of 3.2 to 4.8 weight percent. The δD values of inclusion fluid in ore and gangue minerals are -110 to -120 permil. The geology, isotope, and fluid-inclusion data are consistent with a model of hydrothermal systems of meteoric water in faulted and shattered Paleozoic rocks near plutonic masses. This environment permitted deep circulation of the hydrothermal fluids, which dissolved the metals and sulfur from the Paleozoic host rocks and deposited ore in favorable beds or structures under the regional Wood River thrust fault.

Idaho↗
USGS1975

Structure and Paleozoic stratigraphy of a complex of thrust plates in the Fish Creek Reservoir area, south-central Idaho

Permian, Pennsylvanian, Mississippian, Devonian, and Silurian marine rocks of diverse facies are brought together in a complex of six thrust sheets in the Fish Creek Reservoir area on the north edge of the Snake River Plain, Idaho. The lowest structural element, the parautochthon, is made of more than 450 m (1,500 ft) of folded and faulted Devonian miogeosynclinal carbonate rocks present in a 6.5-km 2 (2.5-mi 2 ) window. Along the east margin of the window, a sliver of continental margin transitional carbonate rocks of Early Devonian and Late Silurian age assigned to the Roberts Mountains Formation is thrust over the miogeosynclinal rocks. The window of middle Paleozoic rocks is overridden along the Fish Creek thrust fault by the flysch facies of the Copper Basin Formation, a turbidite-submarine-fan sequence more than 1,000 m (3,300 ft) thick, of Mississippian age. About 4.8 km (3 mi) southwest of the window, about 100 m (300 ft) of deepwater siliceous oceanic facies clastic rocks are exposed, which are assigned with question to the Milligen(?) Formation of Devonian age. These clastic rocks are interpreted to be thrust over the Copper Basin Formation. The highest structural elements are sequences more than 610 m (2,000 ft) thick of interbedded sandy and conglomeratic limestones, quartzites, and conglomerates and interbedded siltstones and argillites of the Wood River Formation of Middle Pennsylvanian to Early Permian age. The Wood River Formation is in thrust contact with the Milligen(?) Formation in the southwest part of the mapped area and with Copper Basin Formation along the west side of Fish Creek Reservoir. All the thrust sheets have moved eastward. The minimum distance moved is estimated from sedimentation models and facies reconstructions to range from perhaps several kilometres for the allochthon of the Roberts Mountains Formation to 48 km (30 mi) for the Milligen(?) Formation allochthon. The principal period of thrusting was post-Early Permian (post-Wood River Formation) and preEocene (pre-Challis Volcanics) and is of probable Sevier age. Middle Paleozoic rocks of the Milligen and Roberts Mountains Formations, however, also may have been involved in an earlier period of thrusting of latest Devonian to earliest Mississippian age related to the Antler orogeny. The thrust sheets were deformed into a northwest-trending dome in late Mesozoic time and were broken by basin-range faults during the Tertiary.

Idaho↗
USGS1975

Stratigraphy, conodont dating, and paleotectonic interpretation of the type Milligen Formation (Devonian), Wood River area, Idaho

The Milligen Formation at and near its type locality in the Wood River area is considerably older than and unrelated to rocks of Early Mississippian age called Milligen Formation in the Lost River Range and other ranges of east-central Idaho. Conodont faunas were found in limestones of a thin upper member of the sparsely fossiliferous marine Milligen Formation in its principal reference section at Milligen Gulch, at Fisher Canyon, and near Bellevue, Idaho. The faunas include indigenous conodonts here assigned to the early Late Devonian (early Frasnian) Lower and Middle Polygnathus asymmetricus Zones, and reworked conodonts derived from several Middle and Early Devonian conodont zones. An underlying much thicker argillite member of the Milligen contains fewer limestones, but a thin encrinite interbed near the middle of the member yielded early Middle Devonian (Eifelian) conodonts. This lower member probably represents most of Middle and Early Devonian time. Although its base is nowhere exposed in the Wood River area, the Milligen is inferred to have been deposited on the Silurian Trail Creek Formation, which crops out just to the east in the Pioneer Mountains. The age of the Milligen is therefore wholly Devonian and the highest fossiliferous beds are no younger than early Late Devonian. Reworked Middle and Early Devonian conodonts in limestone turbidites of the upper member of the Milligen Formation are identical to conodonts found in shelf (miogeosynclinal) carbonate rocks farther east. A postulated eastern source for the turbidites is supported by new data on the distribution, thickness, and tectonic facies of Devonian rocks that suggest the presence of a Late Devonian ridge on the continental shelf east of the Milligen depositional area. The Milligen Formation was intensely folded and was emergent during most of the Mississippian time when it formed part of the Antler Highlands, which shed flysch sediments eastward into the Copper basin. The Wood River Formation of Pennsylvanian and Permian age was then deposited over a subdued topography on the Milligen Formation. The Hailey Conglomerate Member at the base of the Wood River filled many irregularities in the surface. This depositional contact later was largely destroyed and the contact between the Milligen and Wood River is now a regional thrust fault at most places.

Idaho↗
USGS1974

Carbon, hydrogen, oxygen, and sulfur isotope study of the Darwin lead-silver-zinc deposit, Southern California

The ores at Darwin occur as massive replacement bodies in silicated limestones of Pennsylvanian and Permian age adjacent to a Jurassic quartz monzonite stock. Three types of ore have a definite spatial relationship to the quartz monzonite: (1) pyrite-sphalerite-galena ores, (2) pyrite-pyrrhotite-magnetite-sphalerite-galena ores, and (3) galena-Ag-Bi-Se ores.The delta 34 S values of all sulfide minerals range from +4.4 to --5.7 permil. The delta 34 S values for individual minerals tend to decrease with respect to both space and paragenetic time. The delta (sub sl-gn) values range from 1.5 to 2.5 permil and correspond to a temperature range of 325 degrees + or - 55 degrees C. The sphalerite-galena sulfur isotope temperatures at a given locality are reproducible to + or -30 degrees C and are consistent with temperatures determined by other means.Analyses of water in three samples of fluid inclusions in sphalerite indicate that the ore fluids had delta D values of --66 + or - permil, a total salinity that reached at least 20 percent, and K/Na atomic ratios of 0.23 + or - 0.03. Isotopic and thermochemical data indicate that the ore fluids had average values of delta 34 S (sub Sigma S) = 3 permil, delta 13 C (sub Sigma O) = -- 3.5 permil, Sigma S = 0.01 mole/Kg H 2 O, f (sub CO 2 ) = 12 + or - 8 bars, and Sigma C = 0.15 + or - 0.06 mole/Kg H 2 O.The delta 18 O values of postsulfide calcites have a range of 12.8 + or - 1.5 permil in the pyrite ores and 17 + or - 2 permil in the pyrrhotite ores. Similar values for relict limestone host rock in these areas indicate that oxygen isotopic equilibrium was established between the calcite precipitating fluids and the wall rock. The delta 13 C values of the calcites, however, range from --5.8 to --3.6 permil and are considerably more negative than the limestone in the host rock, indicating that carbon isotopic equilibrium was not established between the fluids and the wall rock.Thermochemical data indicate that the pH of the ore fluids was about 4.8 as they traveled through the quartz monzonite at T nearly equal 350 degrees C. When the fluids completely equilibrated with the relict limestone and calc-silicate host rock, the pH increased to 6.7. This increase in pH as the fluids traveled upward and away from the quartz monzonite was responsible for the spatial distribution of iron sulfide assemblages, for variations in delta 34 S values of sulfides, and probably caused precipitation of the ore.

California↗
USGS1971

Fractionation of minor elements between galena and sphalerite, Darwin lead-silver-zinc mine, Inyo County, California and its significance in geothermometry

Minor element abundances were determined for galena and sphalerite from the Darwin mine, Inyo County, California. The temperature of deposition was calculated from the distribution coefficients determined experimentally by Bethke and Barton (1971) for cadmium and manganese in coexisting galena and sphalerite. The fractionation of cadmium between coexisting sphalerite and galena indicates a temperature of deposition of 416 degrees C+ or -20 degrees , the fractionation of manganese between the same mineral pair a temperature of 377 degrees C+ or -32 degrees . The fractionation of selenium gave unreasonably high temperatures. Three pairs gave temperatures between 568 degrees and 625 degrees C, the fourth pair a temperature of 889 degrees C. The reason for this descrepancy is not known.

California↗
USGS1968

Distribution of minor elements in ore and host rock, Illinois-Kentucky fluorite district and Upper Mississippi Valley zinc-lead district

This paper presents data on the distribution of minor elements in ore and gangue minerals and in adjacent host rock from the Illinois-Kentucky fluorite district and Upper Mississippi Valley zinc-lead district. Comparisons are made of the minor-element abundances between districts and within the paragenetic sequence in individual districts.The ore of the Illinois-Kentucky fluorite district is characterized by greater abundance of minor elements than in other Mississippi Valley deposits, by large fractionation of silver between galena and sphalerite, and by a low ratio of antimony to silver in galena. Silver and antimony are concentrated in the galena and show a marked zonal pattern within the district. Sphalerite is high in cadmium, gallium, and germanium.The Upper Mississippi Valley zinc-lead district differs markedly from the Illinois-Kentucky fluorite district in minor-element concentrations and distribution. The minor elements are much less abundant, and silver is slightly more concentrated in sphalerite than in galena.Several analyses of minor elements in ore minerals from the Southeast Missouri lead district are given for comparison.It is concluded that the minor elements were largely leached from the basement by convective circulation of heated oilfield brine.

Illinois, Kentucky↗