bluuebunny/crossref_metadata_2025_split huggingface dataset:
Two Distinct Ore Fluids in the Viburnum Trend
Authors: Viets John G. , Leach David L. , Mosier Elwin L. 
Published: August 2024

Abstract
The stable carbonate platform of the U.S. midcontinent is host to the largest concentration of Mississippi Valley-type (MVT) zinc-lead mining districts in the world. Of these districts, the Southeast Missouri Lead District which includes the main Viburnum Trend and Old Lead Belt subdistricts, is unique in several ways. Lead dominates over zinc and the ores have significant amounts of copper, silver, cobalt, and nickel. Hosted in the Upper cambrian Bonneterre Formation, above the basal Cambrian Lamotte Sandstone which is underlain by felsic Precambrian basement, the Viburnum Trend is situated very low in the carbonate section when compared to the other districts of the region. Of the Ozark districts, the Southeast Missouri Lead District is also unique in its proximity to the Reelfoot Rift which is concealed beneath the Mississippi Embayment. The possible importance of the Reelfoot Rift as a pathway for brine migration from a southerly source has recently been demonstrated by Farrand Land (1985) and Farr (1987). Detailed descriptions of the mines of the Viburnum Trend are given in a special issue of ECONOMIC GEOLOGY (V. 72, NO. 3, 1977). Other informative background papers on the ore deposits of the Southeast Missouri Lead District include those by snyder and Gerdemann (1968), Gerdemann and Meyers (1972), Davis (1977) and Sverjensky (1981).
Applications of Ore Microscopy to Processing of the Ores in the Southeast Missouri Lead District
Authors: Hagni Richard D. 
Published: August 2024

Abstract
The significance of applied or process mineralogy in the minerals industry has been fully recognized only in the last ten years. The various mineralogical techniques that are routinely applied by economic geologists and mineralogists to the study of ores can be very usefully applied to the solution of a wide variety of industrial problems and to the improvement of the efficiency of those industrial processes. Publications dealing with applications of process mineralogy have been connected principally with presentations before three professional organizations.
Geology of the Cadillac Tectonic zone
Authors: Desrochers Jean-Philippe , Hubert Claude , Robert François 
Published: August 2024

Abstract
The Cadillac fault is generally thought to be coincident with a highly schistose zone, a few tens of meters thick, composed of chlorite-carbonate and talc-chlorite-carbonate schists (Gunning and Ambrose, 1940; Norman, 1946). However, outcrops on the Orenada zone noo2 property indicate that deformation related to the Cadillac fault has affected different rock types over a width of more than 200 m. It is therefore more appropriate to refer to the Cadi11ac tectonic zone (CTZ) than to the Cadi11ac fau1t. This outcrop zone exposes a lithological succession that can be extended using outcrops and drill hole data for more than 10 km. This succession differs from the one presented on the available compilation maps and has important implications for the regional “stratigraphy”.
Geology of the Belmoral (Ferderber) Gold Mine Val D’OR, Quebec
Authors: Vu Lan 
Published: August 2024

Abstract
The Belmoral (Ferderber) gold mine, owned by Société Les Mines Belmoral Ltee, is situated 10 km NE of Val d’Or (Fig.1) in Bourlamaque Twsp., northwestern Quebec, near the centre of the Bourlamaque batholith. This contrasts with the location of other gold mines that are situated near the margin of the batholith, such as the Perron and Courvan mines at the eastern contact, the Sullivan mine at the western contact, and the Bras d’Or (Dumont) mine at the southern contact (Fig.1).
The Cactus Gold Mine Kern County, California
Authors: Brady Jim , Marsh Tim , McKitrick Scott 
Published: August 2024

Abstract
The Cactus Gold Mine is located in the eastern Mojave Desert part of Kern County, California, about sixty air miles north of the city of Los Angeles and 9 miles southwest of the town of Mojave. The mine is at Middle Buttes, an isolated peak of Miocene volcanic rocks and Cretaceous intrusives surrounded by alluvium. Operated by CoCa Mines Inc. of Denver, Colorado, the mine is a joint venture between CoCa and MinVen Gold Corporation of Lakewood, Colorado.
The mine is an open pit, heap leach operation with an average 10,000 ton per day ore and waste extraction from the Shumake Pit. Crushing output to the heaps is 5,000 tons per day with recovery by Merrill-Crewe.
Introduction to the Salton Trough Rift
Authors: McKibben Michael A. 
Published: August 2024

Abstract
The Salton Trough rift, manifested geomorphically as the Imperial Valley in southern California and the Mexicali Valley in northern Baja California (Figure 1), possesses an abundance of natural resources. These valleys are major areas for agriculture, game fish, and waterfowl migration and management. Major nonrenewable resources include metallic minerals (primarily gold) and industrial minerals (primarily gypsum and aggregate). Finally, two of the world’s largest liquid–dominated geothermal energy fields are located in the rift: the Salton Sea field in California and the Cerro Prieto field in Mexico. The rift is therefore of major economic importance to the population of southwestern North America. The purpose of this field trip is to introduce economic geologists to the diversity of hydrothermal mineralization in this modern continental rift environment.
Viewed in the simplest way the Salton Trough consists of an active continental rift, underlain by a fragmented oceanic ridge spreading system, into which has been deposited the delta of the Colorado River. Deposition of the delta has significantly influenced the character of economic mineralization in the rift. The combination of magmatic heat sources, thick porous sediments, tectonic activity, and saline lakes have provided a unique environment for the accumulation and movement of metalliferous hydrothermal brines. Before considering these aspects, a summary of the tectonic evolution of the Gulf of California and Salton Trough is presented.
The Salton Sea Geothermal Brines
Authors: McKibben Michael A. 
Published: August 2024

Abstract
The sediment—hosted Salton Sea geothermal system (SSGS) contains some of the most saline, metal—rich hydrothermal fluids known from an active system (White et al., 1963; Skinner et al., 1967; Helgeson, 1968). Recent extensive scientific and commercial drilling into this system has provided a wealth of new samples and data relevant to understanding this unique hydrothermal system and its metalliferous brines (Elders and Sass, 1988; McKibben et al., 1988a, 1988b; Williams, 1988; McKibben and Eldridge, 1989; McKibben and Williams, 1989; Williams and McKibben, 1989; McKibben et al., 1990). Only a brief overview of the SSGS is presented here.
Geology, Alteration and Mineralization of the Modoc Hot Springs Gold Prospect, Imperial County, California
Authors: Hillemeyer Frank L. , Johnson Michael D. , Kern Richard R. 
Published: August 2024

Abstract
The Modoc prospect is a Plio-Pleistocene epithermal gold-bearing hot springs system located in the northwestern Salton Trough. To date, Modoc offers the best preserved and developed fossil analogue of the currently active geothermal systems in the continental rift. A surficial hot springs origin for the system is evidenced by interbedded, nearly flat-lying chalcedonic sinter beds exhibiting a strong layered morphology, hummocky pool structures and well preserved fossil reed casts.
The primary structural control on the hot springs system is a major ENE-striking, southerly dipping, oblique-slip fault system separating Jurassic granodiorite on the north from Plio-Pleistocene continental sediments on the south. This “Truckhaven” fault system appears to be coincident with the edge of a large basin related to crustal thinning and progradation of the Colorado River Delta into the proto Gulf of California.
Gold mineralization occurs as electrum and native gold (8 to 1800 microns) and is associated with sheeted and banded chalcedony veins, silicified and adularized sandstone and conglomerate, and siliceous sinter beds. Gold and chalcedony precipitated simultaneously in numerous episodes and preliminary fluid inclusion data indicate temperatures ranging from 90 to 135°C. Gold mineralization is locally high grade (up to 1.4 ounces of gold per ton over a 20′ (6.1 m) width) and is found in highly anomalous concentrations over an area measuring 8,000′ (2,438 m) long by up to 2,000′ (610 m) wide. Correlation coefficient data indicate a strong gold, silver, copper affinity. The typical hot springs pathfinder elements As, Sb and Hg are present in unusually low concentrations.
The Modoc hot springs system is more akin to the active geothermal fields situated on the margins of the rift than those in the center of the Trough. It is strikingly similar to the high-silica Dunes geothermal system, which has no surface expression largely due to the development of hydrothermally induced caprocks. The rediscovery of the Modoc hot springs gold prospect leaves exploration geologists wondering how many other such occurrences underlay the seemingly barren sediments of the Imperial and Mexicali Valleys.
The Origin and Significance of High-Grade Metamorphic Xenoliths, Clear Lake Volcanics, California
Authors: Stimac Jim 
Published: August 2024

Abstract
The Clear Lake Volcanics (~2.1 to 0.01 Ma) are the youngest of a series of volcanic fields in the nothern Coast Ranges of California whose ages roughly parallel the timing of northerly migration of the Mendocino triple junction (Dickinson and Snyder, 1979; Johnson and O’Neil, 1984; Fox et al., 1985). There is compelling chemical, isotopic, and textural evidence that partial melting of crustal rocks played a major role in magmatism at Clear Lake (Futa et al.,1981; Hearn et al., 1981; Johnson and O’Neil, 1984). Physical evidence includes the presence of high-grade metamorphic xenoliths in many basaltic to andesitic lavas of the area (Brice, 1953; Hearn et al., 1981). The xenolith suite is dominated by high-T, low-P granulite facies schist and gneiss, but also includes mafic igneous inclusions interpreted as cognate with the Clear Lake Volcanics (Stimac, 1991). Together, this suite is thought to represent fragments of mid- to lower-crustal mafic intrusions and their contact aureoles (Stimac et al., 1992a).
Exposed basement rocks in the Clear Lake area include the Late Jurassic to Late Cretaceous Franciscan Complex (FC), the Middle Jurassic Coast Range ophiolite (CRO), and the Late Jurassic to Early Cretaceous Great Valley sequence (GVS) (McLaughlin, 1981; McLaughlin and Ohlin, 1984). The metamorphic xenoliths do not resemble exposed graywackes of the FC and GVS, although they could represent the residuum of partial melting and recrystallization of graywacke and intermediate to mafic igneous rocks of the FC or GVS. This indicates that either the exposed country rocks are metamorphosed to higher
Gas Geochemistry and Guide for Geothermal Features in the Clear Lake Region, California
Authors: Goff Fraser , Janik Cathy J. 
Published: August 2024

Abstract
Thermal/mineral waters of the Clear Lake region, California are among the most challenging geothermal fluids in the world to study because they display enormous chemical and isotopic diversity and do not geochemically resemble fluids in typical, high-temperature (≥200°C) geothermal systems (Goff et al., 1993a, 1993b). The Clear Lake region contains no boiling hot springs, hot fumaroles, or springs actively depositing sinter, features commonly linked with high-temperature reservoirs. Regionally, the fluids display tremendous variations in chemical and isotopic composition, caused more by variations in bedrock composition than by subjacent magmatic heat sources (Goff et al., 1977; Thompson et al., 1981a; 1992; Donnelly-Nolan et al., 1993). The distribution of fluids is roughly coincident with the late Tertiary and Quaternary Clear Lake volcanic field (2.1 Ma to 10 ka; Donnelly-Nolan et al., 1981; Hearn et al., 1981). The region lies northeast of The Geysers steam field, the largest geothermal field in the world, yet drilling of approximately 25 exploration wells has not found a commercially exploitable geothermal system. Because conditions in most of these wells are very hot (≥200°C at 2000 m) but relatively impermeable, the Clear Lake region is rated as one of the best hot dry rock geothermal prospects in the United States (Goff and Decker, 1983).
Gas geochemistry is becoming more widely used for geothermal prospecting, especially in areas where spring chemistry is ambiguous or where spring waters are not directly derived from deep reservoirs (Goff et al., 1985; 1991; Janik et al, 1991; 1992). Geothermal gases commonly originate from
The Genesis of the Mclaughlin Mine Sheeted Vein Complex, Fluid Inclusion and Stable Isotope Evidence
Authors: Sherlock Ross L. 
Published: August 2024

Abstract
The McLaughlin Mine is a hot-spring type gold-mercury deposit located in the Coast Ranges of northern California. The “sheeted vein complex” is the center of the hot-spring system that formed the McLaughlin deposit. The sheeted vein complex merges from a subaerial siliceous sinter into a bilaterally symmetric, subparallel, multistage vein swarm. The precious metals are well zoned with gold largely restricted to the upper 200 m of the deposit. Silver can dominate anywhere in the system but is always more abundant than gold below 200 m. Below 350 m, silver is rare, gold has not been observed and mineralization is dominated by base metal sulfides. Fluid inclusion analysis suggest that the ore forming fluids were low salinity NaCl dominated, low CO2 fluids. The deepest samples (&gt; 800 m below the paleosurface) have an average temperature of 235°C. The ascending hydrothermal fluid intersected the hydrostatic boiling curve at ~400 m below the surface and paralleled the hydrostatic boiling curve to the surface. Boiling of an ascending hydrothermal fluid accounts for the metal zoning observed in the sheeted vein complex. During boiling CO2 is partitioned into the vapor phase faster than H2S, resulting in the deeper portion. 3f the ore body being enriched in silver with respect to gold and the shallow portions of the ore body enriched in gold with respect to silver. On the basis of the physical and chemical conditions of the ore forming fluids, gold grade, as well as silica and temperature gradients the hydrothermal fluid is undersaturated with respect to gold prior to the onset of boiling. There is a strong trend for increasingly light δ18Oqtz with depth. The most isotopically enriched samples are from the subaerial sinter and the lightest sample are from the deepest samples. This trend is a temperature effect and is the result of increasing fractionation with decreasing temperature. The oxygen isotopic composition of the hydrothermal fluid remained fairly constant at ~93%o. The oxygen and deuterium composition of the hydrothermal fluids are consistent with a meteoric water origin. The hydrothermal fluids have a pronounced oxygen shift due to water/rock interaction but do not have a deuterium shift. The water/rock ratios are low but similar to other geothermal systems in the Coast Ranges and other epithermal deposits emplaced within sedimentary sequences.
Carlin Trend Geologic Overview
Authors: Christensen Odin D. 
Published: August 2024

Abstract
The Carlin trend is a 60-kilometer-long line of predominantly sedimentary-rock-hosted gold deposits, which has already yielded 477 tonnes of gold production from a total resource exceeding 2500 tonnes of gold. Deposits are hosted predominantly within sedimentary rocks deposited on the Paleozoic continental margin and subsequently compressed through Late Devonian continent-arc collision to form an allochthonous siliceous deep-water stratigraphic assemblage overlying an autochthonous shelf carbonate assemblage. A sequence of compressional, transpressional, and later extensional tectonic events has further shaped the geologic architecture. Gold mineralization is characterized by sub-micron sized “invisible” gold as discrete grains and incorporated within iron sulfides . Deposits are localized within rock volumes rendered sufficiently permeable by primary lithology, chemical alteration, or structural preparation. Alteration styles spatially associated with gold mineralization include decalcification, silicification, argillization, sulfidation, and introduction of the minerals barite and alunite and geochemically anomalous concentrations of As, Sb, Hg, Ag, and Tl. The age of gold mineralization is poorly constrained but believed to be Oligocene. While descriptive models for this type of deposit are well developed, genetic models remain strongly contested.
Geology of the Post Deposit, Eureka County Nevada
Authors: Thoreson Ronald F. 
Published: August 2024

Abstract
The Post deposit is located in Eureka County, Nevada, Section 19, T36N, R50E, approximately 40 km (26 miles) northwest of the town of Carlin and 7 km (4.5 miles) northwest of the Carlin #1 mill (Figure 1).
The Post deposit is located along a spur of the Tuscarora Mountains that also hosts the Blue Star/Genesis and Deep Star deposits. Host rocks for the Post orebody are the sandstones, siltstones, calcareous mudstones, and limestones of the Siluro-Devonian Roberts Mountains and Popovich Formations, and the siliceous mudstones and siltstones of the Devonian Rodeo Creek unit. The Goldstrike diorite intrusion irregularly penetrates the sedimentary rocks as dikes, sills, and stocks producing local hornfels, skarn, and marble.
Gold mineralization occurs along the northern margin of the Goldstrike intrusion in a structural domain dominated by a NW-striking antiform. The eastern limb of this antiform is truncated by the N20W high-angle Post Fault (Figure 2). Gold mineralization, occurring west of the Post Fault, is structurally-controlled along high-angle NE and NW-striking faults, and is stratigraphically-controlled within arenaceous lenses of the Rodeo Creek unit, and within breccias of the lower Popovich and the upper Roberts Mountains Formations. Mineralization is limited within argillized diorite sills and metamorphic rocks to zones that have been structurally-prepared.
Gold mineralization is subdivided into three zones based on geology, morphology, grade, and metallurgical character: Upper Post, Lower Post, and Deep Post. Upper Post represents oxide ore (averaging 0.040 to 0.050 oz/st) hosted in argillized and silicified mudstones, siltstones, and sandstones of the Rodeo Creek
Introduction to the Iberian Pyrite Belt
Authors: Barriga Fernando J.A.S. , de Carvalho Delfim , Ribeiro António 
Published: August 2024

Abstract
This Guidebook contains information to support the three SEG field trips included in the SEG Neves Corvo Field Conference 1997 (Lisbon, May 11–14, 1997). Collectively, these field trips cover the whole Iberian Pyrite Belt and beyond. Given that the Conference is aimed primarily at participants unfamiliar with the geology of the Belt, it was considered appropriate to introduce the subject prior to the field guides. Many studies have presented the overall characteristics of the geology and mineral deposits of the IPB (e.g. Carvalho et al., 1976; Strauss et al., 1977; Carvalho, 1979; Routhier et al., 1980; Barriga, 1990). Very recently, Carvalho et al. (1997) have summarized rather thoroughly the present state of the art concerning the IPB geology and metallogenesis. The present introduction is drawn largely from this.
The Iberian Pyrite Belt (IPB) corresponds to an area of Devonian-Carboniferous volcanic and sedimentary rocks containing massive polymetallic sulfide deposits. This area forms an arcuate belt, about 250 km long and up to 60 km wide, trending westwards from near Seville in Spain to west-northwest in South Portugal. Both the eastward and westward extents of the belt are covered by Tertiary sedimentary rocks (Figure 1).
The IPB is arguably the largest and most important volcanogenic massive sulfide (VMS) metallogenic province in the world. Some of its mineral deposits have been known and mined since the Chalcolithic era such as the Rio Tinto deposit, renowned for its historical role in the study of ore deposits. Only after the discovery of the large and
Deep Regional Resistivity Structure Across the Carlin Trend
Authors: Rodriguez Brian D. 
Published: August 2024

Abstract
The genesis of gold deposits along the Carlin trend is not fully understood. Many of the significant mineral deposits in the Carlin trend were formed during the Tertiary as a result of interrelated high-angle basin-and-range faulting, intrusive igneous activity, and hydrothermal processes (Radtke, 1985). According to Shawe (1991), the linearity of the gold deposits along the Carlin trend and the sub-parallel Battle Mountain-Eureka trend suggests that deep-penetrating regional structures controlled the emplacement of magmas generated in the lower part of the crust or upper mantle, and either provided hydrothermal fluids or caused heating of ground waters that were responsible for transport and deposition of the gold ores. To investigate crustal processes that may have contributed to the genesis of gold deposits along the trend, a regional southwest to northeast profile of magnetotelluric (MT) soundings was acquired in 1996 (line MT-MT′, Fig. 1). Two-dimensional resistivity modeling of the MT profile is being used to place constraints on possible heat or magma sources and possible tectonic controls on the linear distribution of mineral deposits.
Ore Fluids at the Getchell, Carlin-Type Gold Deposit, North-Central Nevada
Authors: Cline Jean S. , Hofstra Albert , Landis Gary , Rye Robert 
Published: August 2024

Abstract
The Getchell gold deposit is one of several Carlin-type gold systems located along the Getchell Trend in north-central Nevada. Deposits located along this trend exhibit all of the characteristics typical of Carlin-type systems including the presence of submicron-sized gold particles in arsenic-rich pyrite. Although Carlin-type deposits have been mined for thirty years and are currently responsible for Nevada being one of the leading gold pr~ducers in the world, there is little consensus concerning the geological processes that concentrated gold in these deposits.
The lack of understanding of formation conditions stems from the submicron size of the gold particles, a paucity of ore stage fluid inclusions in most systems, and a lack of readily datable minerals that are unequivocally related to gold mineralization. The lack of visible gold, even under the microscope, has made it difficult to identify minerals and textures associated with gold precipitation, complicating determination of gold precipitation mechanisms. Fluid inclusions are sparse or absent in the fine-grained replacement ore present in most systems, making it difficult to determine system pressure and temperature, and ore fluid chemistry. The lack of datable minerals has prevented identification of key geological events responsible for gold concentration.
The Getchell deposit is somewhat unusual in that a significant amount of open-space-filling mineralization is hosted within the Getchell fault zone. This mineralization exhibits cross-cutting and textural relationships that provide constraints for the ore paragenesis. Additionally, these slightly more coarse-grained minerals trapped several populations of fluid inclusions, including primary inclusions contained within growth zones. Examination of