bluuebunny/crossref_metadata_2025_split huggingface dataset:
Geologic Overview of the Carlin Trend Gold Deposits and Descriptions of Recent Deep Discoveries
Authors: Teal Lewis , Jackson Mac 
Published: August 2024

Abstract
Including past production, reserves and resources, the Carlin Trend forms the largest and most prolific accumulation of gold deposits in North America. More than 40 separate deposits have been delineated since disseminated gold mineralization in carbonate rocks was discovered in 1961. From this discovery, a classification for this style of gold mineralization has come to be referred to as “Carlin-type” deposits. To date, more than 25 million ounces of gold have been mined on the Carlin Trend from 26 separate operating, or past producing mines (Table 1). Open pit mining on the Carlin Trend began in 1965 at the Carlin Mine, and underground mining began in 1993 on the same deposit.
The scope of this paper is to first present a regional overview of the Carlin Trend, followed by summary descriptions of some of the more recent discoveries of deep, predominantly refractory gold deposits. As part of a concluding discussion, a spectrum of Carlin Trend deposits are categorized on a quaternary diagram to illustrate the I relative influence of structural and stratigraphic controls on each deposit.
Breccia Types in the Betze Orebody, Goldstrike Mine, Eureka County, Nevada
Authors: Peters S.G. , Leonardson R.W. , Ferdock G.C. , Lauha E.A. 
Published: August 2024

Abstract
This paper describes outcrop- and hand specimen-scale breccias in the Betze orebody, which is the largest gold deposit on the Carlin trend (Bettles and Lauha, 1991; Leonardson and Rahn, 1996). The Betze orebody lies in the north-central part of the Carlin trend in the Goldstrike Mine (Fig. 1), and it is part of the Betze-Post deposits (Arehart et al., 1993; Lauha and Bettles, 1993; Smith and Sharon, 1994; Leonardson and Rahn, 1996). The orebody and much of the internal breccia bodies have a general WNW strike, with a sub-horizontal attitude (Peters, 1996; 1997). The open pit Goldstrike Mine exposes the Betze and Post orebodies, the Post anticline (Fig. 2), contacts between the Silurian and Devonian Roberts Mountains Formation, Devonian Popovich limestone and Devonian Rodeo Creek unit, and the northern contact of the Jurassic Goldstrike stock (Volk and Zimmerman (1991).
Breccia bodies host much of the Betze ore body. Breccias are common rock types in most Carlin-type deposits (Williams, 1992, 1993), and they are particularly common in ore bodies of the north-central Carlin trend (Clode, 1993; Griffin et al., 1993; Leach, 1993). The host rocks in the Betze orebody are altered and deformed. The complex descriptive geology of the Goldstrike Mine is detailed by Volk et al. (1996), Peters et al.(1996), and Leonardson and Rahn (1996). The WNW-striking Dillon deformation zone (DDZ) hosts the upper central Betze orebody (Fig. 2) and contains several ore types associated with breccia (Peters, 1996, 1997). Rock types that host the orebody include phyllonitic black to
Isotopic Composition of Sulfur in Carlin-type Gold Deposits
Authors: Hofstra Albert H. 
Published: August 2024

Abstract
The goal of this report is to consider new and existing sulfur isotope data from Carlin-type gold deposits within the context of a modem understanding of the geology of the region and processes of ore formation. Increased understanding of the source(s) of sulfur and mechanisms of H2S generation may help to discriminate between the various models proposed for the deposits. The source of reduced sulfur is very important because available evidence indicates the deposits formed from H2S-rich (SO4-poor) fluids that transported gold as a bisulfide complex. High H2S-concentrations in ore fluids are indicated by (1) the common occurrence of high sulfidation state minerals such as orpiment and realgar, (2) mass transfer studies which show that sulfur was one of the most abundant elements introduced by the hydrothermal fluids, (3) gas analyses of fluid inclusions which show the fluids contained 10-1 to 10-2m H2S, (4) petrographic and geochemical evidence which indicates that sulfidation of host rock iron was an important (but not the only) gold depositional mechanism in most of the deposits, and (5) chemical reaction path modeling which shows that sulfidation can produce the gold grades observed in the deposits (Hofstra et al., 1991; Hofstra, 1994). The predominance of H2S over sulfate is important because the isotopic composition of H2S is then representative of the bulk composition of sulfur in the ore fluids. Given that gold was transported as a bisulfide complex, knowledge of the sites of H2S production and migration pathways will also likely provide information on the source
Sterling Mine, Nye County, Nevada
Authors: Castor Stephen B. 
Published: August 2024

Abstract
Although relatively small, the sedimentary rock-hosted Sterling Mine has been the largest gold producer in the Bare Mountain district in southern Nye County, with total production of about 130,000 troy ounces between 1983 and 1996. Other gold production in the district has come from sedimentary and volcanic rock-hosted ore at the Mother Lode Mine (Mapa, 1990) and the Fluorspar Canyon deposits (Greybeck and Wallace, 1991) about 10 km north and northwest of the Sterling Mine. The district has also produced fluorspar and minor amounts of mercury.
At the Sterling Mine, mineralization is controlled by the intersection of north-northeast striking, high-angle normal faults with a thrust fault that separates siliciclastic rocks of the Late Proterozoic to Early Cambrian Wood Canyon Formation in the upper plate from carbonate rocks of the Middle Cambrian Bonanza King Formation in the lower plate. This mineralization is associated with an alteration assemblage that includes kaolinite, halloysite, illitesmectite, sericite, and alunite (Odt, 1983). Jarosite and limonite are present in most mineralized rock, but primary sulfide ore occurs in places and contains pyrite (Fig. 1 ), marcasite, arsenopyrite, and traces of sphalerite and galena (Joe Marr, personal communication, 1996). Samples ofunoxidized ore consist of quartz± dolomite± kaolinite and contain pyrite± marcasite± stibnite ±galena. On the basis of SEM examination, an unoxidized sample withl38 ppm gold contains pyrite with 1- to 2-micron-thick rims and veins of arsenian pyrite (see the figure below). Very rare micron-size gold is present, but the grade is too high to be accounted for by
Eocene Magmatism of the Tuscarora Volcanic Field, Elko County, Nevada, and Implications for Carlin-type Mineralization
Authors: Henry Christopher D. , Boden David R. 
Published: August 2024

Abstract
The Tuscarora volcanic field (TVF), the largest Eocene volcanic field in Nevada, lies just north of major gold deposits of the Carlin Trend and west of deposits in the Independence Mountains (Fig. 1). Ongoing detailed mapping documents at least five voluminous volcanic-intrusive centers in the southeastern part of the TVF (Figs. 1, 2). 40Ar39 Ar dates show that the five centers developed between 39.9 and 39.2 Ma during a brief, intense period of magmatism. Precious-metal mineralization at Tuscarora formed at about 39.3 Ma, contemporaneous with a major intrusive episode, and is the oldest Tertiary volcanic-hosted epithermal deposit in Nevada. Compilation of 40Ar39 Ar dates indicates that magmatism was particularly intense between 39 and 40 Ma throughout northeastern Nevada. Given that several Carlin-type deposits are now interpreted to have formed in the Eocene (Hofstra, 1995~ Emsbo, 1996~ Leonardson and Rahn, 1996~ Phinisey et al., 1996~ Rota, 1996), contemporaneous with this activity, we suggest that Eocene magmatism was directly or indirectly the heat source to drive hydrothermal circulation that generated Carlin-type deposits (see also Hofstra, 1995).
Blue Star Subdistrict Zoned Alteration Mineralogy and Gold Mineralization, Eureka County, Nevada
Authors: Williams Cindy L. 
Published: August 2024

Abstract
The Blue Star subdistrict in the Carlin Trend, Nevada, includes multiple gold mines with 2 million ounces in reserve and past production totaling 3. 9 million ounces. The deposits are characterized by zoned alteration mineralogy and gold grades. From orebody centers outward the zones include: 1) a silicified core with erratic gold grade; 2) adjacent mill-grade (&gt;0.050 oz/st Au) intense quartz-sericite-pyrite alteration; 3) enveloping leach-grade (0.006 to 0.050 oz/st Au) weaker sericite-kaolinite-quartz-pyrite alteration; 4) surrounding decarbonatized and intensely argillized waste and leach grade ore; 5) pervasively decarbonatized waste rock; and 6) peripheral waste with weak decarbonatization
New K-Ar and 40Ar/39Ar Ages of Plutonism, Hydrothermal Alteration, and Mineralization in the Central Wasatch Mountains, Utah
Authors: John David A. , Turrin Brent D. , Miller Robert J. 
Published: August 2024

Abstract
Twenty-one new K-Ar and 10 new 40Ar/39Ar ages are reported for igneous and hydrothermal minerals from intrusive rocks of the Wasatch igneous belt in the central Wasatch Mountains. Interpretation of our new data combined with previously published K-Ar ages and with new 40Ar/39Ar and U-Pb ages reported by Vogel et al. (1997) suggests that the Clayton Peak stock was emplaced at about 36 to 35 Ma, the Alta stock at about 35 to 33 Ma, and the Little Cottonwood stock at about 31 to 30 Ma. Biotite K-Ar ages progressively increase from west to east in the Little Cottonwood stock, which is consistent with more rapid cooling of the eastern part of the stock and with other evidence suggesting about 15 degrees of eastward tilting of the central Wasatch Mountains following emplacement of the Wasatch igneous belt. Most porphyry stocks in the Park City mining district were emplaced at about 41 to 40 Ma; the Ontario stock was emplaced at about 36 Ma. Vein deposits in the Park City mining district formed at about 36 to 33 Ma. The Park Premier stock was emplaced in several pulses between about 35 to 32 Ma. Alteration related to porphyry copper mineralization in the Park Premier stock formed at 33.5 Ma and advanced argillic alteration and gold mineralization formed at 31.4 Ma. Molybdenum mineralization in the eastern part of the Little Cottonwood stock formed between 26 to 23.5 Ma.
Distribution and Mineralogy of Gold and Silver in the Bingham Canyon Porphyry Copper Deposit, Utah
Authors: Ballantyne Geoffrey H. , Smith Tracy W. , Redmond Patrick B. 
Published: August 2024

Abstract
The Bingham Canyon porphyry copper deposit, prior to mining, is estimated to have contained 40.4 million ounces of gold and 289 million ounces of silver within 3,105 million tons of ore. The gold-mineralized zone mimics the shape of, and is coaxial with, the copper ore shell, but the zone of highest-grade gold mineralization lies at a slightly lower elevation than the zone of highest-grade copper mineralization. Geological observations suggest that high gold grades are associated with abundant bornite. The distribution of silver corresponds closely with that of copper.
Gold and silver recoveries for Bingham porphyry ore have averaged 68 and 81 percent, respectively, since the introduction of froth flotation in 1920. Electron microprobe examinations of head and concentrate samples suggest that most gold occurs as particles less than 25 microns across and is alloyed with less than 15 wt percent silver. Most gold particles occur on the boundaries of chalcopyrite and bornite grains and as inclusions within those minerals. Gold, silver, and bismuth tellurides are present but rare. The mode of occurrence of silver is not well established, but based on the high silver recovery and the response of concentrator products to leach tests, most of the silver is inferred to be present in solid solution in copper sulfide minerals. Sequential leach tests suggest that approximately 10 percent of the gold in the ore is encapsulated in pyrite and approximately 5 percent is encapsulated in silicate minerals.
Copper-Gold Skarn Deposits of the Bingham Mining District, Utah
Authors: Harrison Edwin D. , Reid Julia E. 
Published: August 2024

Abstract
Copper-gold skarns peripheral to the porphyry copper deposit in the Bingham mining district, Utah, contain a geologic resource of over 7 million tons of copper and 9 million ounces of gold. The skarn deposits, hosted by Pennsylvanian limestone beds within the contact metamorphic aureole of the Tertiary Bingham stock, have been mined intermittently since 1896. In the late 1960s, two large deposits were discovered at depth on the north side of the district by The Anaconda Company and Kennecott Copper Corporation: the Carr Fork mine, operated by Anaconda from 1979 to 1981, and the North Ore Shoot deposit, which has not entered production. Recent drilling by Kennecott on the eastern flank of the North Ore Shoot has resulted in discovery of the Fortuna deposit. These three areas are all part of the same, continuous skarn system.
A remarkable horizontal and vertical extent of skarn is displayed within the Bingham district. Mineralized skarn occurs in a zone roughly 2,000 feet wide around the quartz monzonite porphyry phase of the Bingham stock and extends over a mile vertically from surface exposures to the deepest drill-hole intersection. Skarn ore, delineated by the +1 percent copper grade contour, lies outside the porphyry copper ore shell and extends to a lower elevation. The Carr Fork orebodies consist predominantly of chalcopyrite in retrograde-altered garnetite skarn. In the North Ore Shoot and Fortuna deposits, massive sulfide replacement bodies are the principal ore type, although mineralized garnetite is also present. Pyrite-gold mineralization that crosscuts copper-gold skarn has been found in the Bingham skarn deposits, but its relationship to other gold mineralization in the district is unclear. Beyond the zone of copper-iron-gold mineralization, lead-zinc-silver deposits occur in limestone and other host rocks within a broad halo nearly one mile wide.
High-Sulfidation Epithermal Gold Deposit at Klokoč - Podpolom
Authors: Štohl Jaroslav , Žáková Eva , Lexa Jaroslav 
Published: August 2024

Abstract
The paleohydrothermal systems in the central zone of the Javorie stratovolcano are represented at the surface by conspicuous outcrops of secondary quartzites (residual quartz) and much less conspicuous argillized rocks. These zones of advanced argillic alteration were assumed during the early seventies to reflect porphyry copper systems at depth. Subsequent drilling at Banisko (Konecný et al., 1997), and a systematic metallogenetic survey in the central zone of the Javorie stratovolcano (Štohl at al., 1981) confirmed this assumption and provided extensive information concerning the geology, mineralogy, geochemistry and geophysics of this area. The next stage of metallogenetic investigation (Štohl et al., 1985, 1986) was then devoted to the detailed study of individual hydrothermal systems. Geochemical sampling as well as drilling was used to explore for a possible enargite-type Cu mineralization; with the exception of a few occurrences the results were negative. Nobody was aware of the possibility for gold potential at that time. In addition, gold was not analyzed for since sufficiently sensitive analytical methods were not available to carry out systematic gold geochemistry.
In the early nineties the advanced argillic zones of alteration were recognized to represent high-sulfidation epithermal systems with a possible gold potential. In February, 1996, Rhodes mining company began to explore the area. Portions of drill cores from the preceding exploration campaign which were enriched in pyrite were sampled and analyzed for gold; however, the results were mostly negative, with only two samples showing values close to 1 g/t. The discovery of gold mineralization at Klokoc —
Overview of Epithermal Gold Mineralization in Kyushu, Japan
Authors: Izawa Eiji , Watanabe Koichiro 
Published: August 2024

Abstract
Epithermal gold deposits are the principal source of gold in Japan, and mesothermal vein gold or by-product gold from skarn deposits, VMS (the Kuroko type and the Besshi type), and polymetallic veins contribute historically only 10 percent of domestic gold production. Gold production from epithermal gold deposits of Kyushu amounts to 284 tonnes and comprises about 40 percent of total Japanese gold production, 576 tonnes, from the Meiji Restoration (1868) to present (1999). The silver/gold ratio of ores in Kyushu is less than three and differs from the value that exceeds 10 in other areas (Fig. 1). The Yamagano mine in the Edo era and later the Taio and Kushikino mines were the largest gold-silver mines in Kyushu before the discovery of the Hishikari deposit. At present the Hishikari underground operation and three opencut mines of the Nansatsu-type gold deposits at Kasuga, Iwato, and Akeshi are producing gold.
The major gold deposits in Kyushu, typically of the low- sulfidation vein type and locally the high-sulfidation Nansatsu type, occur in extinct or waning geothermal systems of the Pliocene and Pleistocene volcanic areas. The young formation ages relate to the well-preserved shallow bonanza zones and overlying thick argillic alteration zones, and in places surface expression of hydrothermal activity, such as sinters and nearby acid alteration related to steam- heated acid hot springs.
This contribution aims to present supplementary data to a previous review paper (Izawa and Urashima, 1989), which described the relationship
Geology of Sakurajima Volcano, Southern Kyushu, Japan
Authors: Kobayashi Tetsuo 
Published: August 2024

Abstract
Sakurajima is an andesitic stratovolcano situated on the southern rim of Aira caldera, southern Kyushu, Japan. The first eruption from Sakurajima volcano is estimated (using tephrochronology) to have occurred circa 23 ka B.P., following a large ignimbrite eruption from Aira caldera at circa 24.5 ka B.P. The oldest eruption in historic times occurred in the eighth century, and eruptions since the fifteenth century are well documented. They include five flank eruptions and many small-scale summit eruptions. The latest big eruption occurred in 1914 and produced large volumes of pyroclastics and lava flows. Current activity is represented by intermittent explosive eruptions from the summit crater that began in 1955. More than several million cubic meters of volcanic products have been ejected every year, and debris flows occur regularly, especially in the rainy season.
Field Trip Day One
Authors: McLelland James M. 
Published: August 2024

Abstract
This First day of the field trip visits Proterozoic iron deposits at the Podunk and Skiff Mountain iron mines, in the eastern Adirondack Mountains of New York state. Included are roadcuts to see representative lithologies and structures in the region surrounding the iron deposits. The origin of these iron deposits has been controversial, but studies by Foose and McLelland (1995) and more recently by McLelland et al. (2001b, 2001c) provide strong evidence for a high-temperture, intramagmatic origin related to late stages the Lyon Mountain Granite and correlative intrusions during the latter part of the 1090 to 1030 Ma Ottawan orogeny. The great majority of the deposits consist of low Ti magnetite ore accompanied by apatite and aegerine-augite. The apatite has high concentrations of rare-earth elements (REE) indicating to Foose and McLelland (1995) that the deposits are of Kiruna (REE-Au-U-Cu) type. This is further supported by persistent sodic (i.e., albitic) alteration associated with the ores. Most of the iron ores appear to be undeformed although they may occur in strained host rocks. Deposits are intimately associated with late tectonic to posttectonic Lyon Mountain Granitic Gneiss that was emplaced at ca. 1055 Ma, during the waning stages of the ca. 1090 to 1030 Ma Ottawan Orogeny.
Field Trip Day Two
Authors: McLelland James M. , Slack John F. , DeLorraine William F. 
Published: August 2024

Abstract
This Day of the field trip visits the large Chateaugay open pit of the Lyon Mountain group of iron mines, in the northern Adirondack Mountains, following by visits to roadcuts in the Adirondack Lowlands to the west, in the vicinity of the Balmat zinc mine. The Chateaugay open pit has superb exposures of iron ore remaining on walls and in the entrances to stopes, which clearly establish the geologic and paragenetic relations of the magnetite ores and yield compelling evidence for their high-temperature, intramagmatic origin via hydrothermal fluids (McLelland et al., 2001b, 2001c). A wide variety of rock types ranging from leucogranite to mineralized skarns are present.
In the afternoon this day features stops at five roadcuts between the town of Gouverneur, New York, and the Balmat zinc mine to the east. These roadcuts provide a good overview of the regional geologic setting of the Balmat deposit, including stratigraphy, structure, deformation, and metamorphism. Whereas the geochronology in the Adirondack Highlands to the east is well established (e.g., McLelland et al., 2001c), the Lowlands is underlain mostly by metasedimentary rocks hence its precise age range is difficult to determine. One constraint is provided by U-Pb zircon ages of 1284 ±7 Ma, 1236 ± 6 Ma, and 1230 ± 33 Ma for the Gouverneur, Fish Creek, and Hyde School alaskite bodies, respectively, that occur in the Lowlands (Grant et. al., 1986; McLelland and Chiarenzelli, 1990; McLelland et al., 1992). Although these alaskite bodies were interpreted by Carl and Van Diver (1975) to
Introduction
Authors: Seal Robert R. , Hammarstrom Jane M. , Slack John F. , Hathaway Edward M. , Lovely William P. , Kierstead Matthew A. 
Published: August 2024

Abstract
The Purpose of this trip is to examine relations of the economic geology and mining history of the Vermont copper belt to the environmental behavior of these deposits and their potential future reclamation. In contrast, the 1993 Society of Economic Geologists field trip focused on the regional and economic geology of the copper belt (Slack etal., 1993).
The Vermont copper belt, like many other mining districts, has had a long and colorful history (Abbott, 1973). This history spans the period of active mining from the discovery of the Elizabeth deposit in 1793 through its closure in 1958, to the present, as plans to reclaim the site are being made. Like other districts, the history is intimately intertwined with the economic development and early settlement of the region. Production was dominated by three main mines: Elizabeth, near South Strafford; Ely, near West Fairlee; and Pike Hill, near Corinth. In addition, several other smaller mines and prospects are found in the belt. All mines exploited copper-rich massive sulfide deposits, or their weathered equivalents. The earliest mining from Elizabeth was for iron from the gossan zone, followed by mining of pyrrhotite for the manufacture of copperas (hydrated ferrous sulfate). Copperas was produced by roasting the ores to oxidize the pyrrhotite. Resulting ferrous sulfate was leached from the roast beds with water, and concentrated in evaporating vats. During the late 18th and early 19th centuries, copperas was used for curing and setting colors in hides and pelts, and for making dyes, treating timbers and