Yerington, Ann Mason, Blue Hill, Bear
Super Porphyry Cu and Au|
IOCG Deposits - 70 papers|
|All available as eBOOKS|
Remaining HARD COPIES on
sale. No hard copy book more than AUD $44.00 (incl. GST)
Yerington is a porphyry-skarn copper district in western Nevada, USA. It is ~80 km to the south-east of the city of Reno in western Nevada (#Location: 38° 59' 0"N, 119° 11' 40"W).
Skarn mineralisation is developed within Triassic age limestones adjacent to a Jurassic batholith, which is dominatly a granodiorite, but contains quartz-monzonite stocks and dyke swarms that host major porphyry copper mineralisation in a number of centres in the Yerington district. Other mineralisation in the district includes the Pumpkin Hollow iron oxide-copper-gold (IOCG) deposit.
Recorded production in the Yerington district dates back to 1883 (Moore, 1969) when prospectors were attracted to oxide copper staining throughout the
Singatse Range. During the 1940s Anaconda outlined a 60 Mt resource at Yerington, and with US government subsidies commenced underground development and started production in 1952, which continued until1979. In 1976, the Yerington mine along with all other assets of Anaconda were purchased by the Atlantic Richfield Company (ARCO), who in 1979 closed the mine. In 1982 the mine and associated infrastructure was sold to a private developer who scrapped the plant and equipment. In 1989, Arimetco Inc. purchased the mine property and commissioned a 22.5 tonnes-per-day solvent extraction/electrowinning plant, and began heap leaching 'sub-grade' dump rock stripped from the Yerington pit by Anaconda, as well as other residues and trucked acid soluble mineralised material from the MacArthur workings ~9 km to the north. Arimetco produced some 43 000 tonnes copper from 1989 to 1999 before declaring bankruptcy and abandoning the property. In early 2000 the Nevada Division of Environmental Protection assumed operation of the site on a care and maintenance basis for environmental reasons. In 2012, Singatse Peak Services, LLC entered into a voluntary agreement with the U.S. Environmental Protection Agency (EPA) to take over the operation.
Production from the porphyry ores at Yerington from 1953 to 1978 were 162 Mt @ 0.54% Cu (Einaudi, 1982) with 98 Mt @ 0.36% Cu remaining (Howard, 1979). The total production to 1979 included 104 Mt of oxide ore.
Remaining NI 43-101 compliant Mineral Resources at Yerington in 2013 were (Singatse Peak Services, LLC, NI 43-101 Technical Report, 2014) were:
Measured + Indicated Resources
Oxide and chalcocite ore at 0.12% Cu cut-off - 23.5 Mt @ 0.25% Cu;
Hypogene sulphide ore at 0.15% Cu cut-off - 105 Mt @ 0.30% Cu;
TOTAL Measured + Indicated Resources - 128.5.5 Mt @ 0.29% Cu;
Oxide and chalcocite ore at 0.12% Cu cut-off - 26 Mt @ 0.25% Cu;
Hypogene sulphide ore at 0.15% Cu cut-off - 128 Mt @ 0.30% Cu;
TOTAL Inferred Resources - 154 Mt @ 0.23% Cu.
The Bear porphyry copper system was partially delineated by Anaconda and Phelps Dodge in the 1960s and 1970s and has a potential total non NI 43-101 compliant resource of >500 Mt @ 0.40% Cu.
The un-developed (as June 2020) Ann Mason porphyry copper deposit, 7 km west of Yerington, had reserves of 495 Mt @ 0.4% Cu in 1982.
The combined measured and indicated mineral resource in 2015 was ~1.4 Gt @ 0.32% Cu, 0.01% Mo (at a 0.2% Cu cut-off; Sandstorm Gold Royalties, March, 2017) containing 4.49 Mt of Cu, 84 800 t of Mo, and 37.7 t of Au (Kulla et al., 2015). Silver averages 0.6 g/t and gold 0.06 g/t.
The associated Blue Hill deposit, ~1.5 km NW of Ann Mason, is estimated to contain an inferred resource of 72.13 Mt of Oxide/Mixed mineralisation containing 0.126 Mt of copper (Mining Technology website viewed 2020). In 2020, Ann Mason and Blue Hill were being evaluated for production by Hudbay Minerals.
Seven associated skarn deposits produced 3.8 Mt @ 1.5 to 6% Cu between 1906 and 30 (Einaudi, 1982).
The Yerington mine is situated some 80 km to the east of the Sierra Nevada Batholith in the western Great Basin in Nevada, within a belt of Jurassic intrusives. One of these intrusives, the Jurassic Yerington batholith, intrudes strongly folded and faulted Triassic volcanic and sedimentary rocks which have a total thickness of about 3000 m. These volcanics and sedimentary rocks form an east-west trending septum 8 km long and 3 km wide between the Yerington Batholith and the next batholith to the south. The lower half of this section is occupied by metamorphosed andesite and rhyolite flows, breccias and sediments, while the upper parts largely comprise massive limestone, thin bedded black calcareous shale and silicic volcani-clastics. Limestone beds constitute the host rocks for numerous, small copper-bearing skarn deposits located on an outer fringe of a hornfels-skarnoid aureole extending 600 to 1800 m from the Yerington Batholith. The Yerington Batholith consists of medium grained, equigranular granodiorite intruded by quartz monzonite and, later, by quartz-monzonite (adamellite) porphyry dyke swarms. Known porphyry copper mineralisation is restricted to the core of the batholith and is associated with porphyry dyke swarms (Einaudi, 1982).
Volcanic rocks of Tertiary age are represented by more than a 1000 m of flows and pyroclastics, mainly of quartz latite and rhyolitic composition, with local overlying andesites and basalt. These volcanics are underlain by a conglomerate of variable thickness. Basin and range normal faulting resulted in up to a 60° westward tilt of all pre-Miocene rocks; the surface therefore represents a series of fault bounded pre-tilt cross-sections of the original geology, with their upper portions being to the west (Einaudi, 1982).
The principal host rocks to porphyry copper mineralisation are quartz-monzonite (adamellite), which displays marked textural and compositional variations in contrast to the granodiorite of the batholith, ranging from coarse grained and porphyritic to fine grained and equigranular. The finer grained varieties appear to be related to the loci of mineralisation. Typically the quartz-monzonite (adamellite) is composed of phenocrysts of orthoclase, perthite and quartz in a consistently aplitic groundmass of quartz and oligoclase. The ratio of phenocrysts to matrix is of the order of 1:1. Ferro-magnesian minerals are biotite and hornblende. The youngest intrusives are the porphyry dykes, which are locally referred to as tonalite and are abundant as dykes and apophyses. An elongate mass of quartz-monzonite porphyry defines the locus of the orebody, recognised over a distance of 1800 m, with a width of 300 to 650 m, and a 300° trend. Mineralisation also occurs within the adjacent granodiorite on the margins of the quartz-monzonite (Wilson, 1963).
Mineralisation and Alteration
Porphyry dykes with a strike of 290° and dip of 40° to 70° north were intruded in three stages, i). early barren, ii). mineralised, and iii). late barren. Due to the post-ore tilting described above, there is a zoning from east to west, representing a transition from depth to shallow levels in the original porphyry system. These alteration and mineralisation patterns are zoned around the mineralised porphyries. In the eastern end of the pit, pervasive albitic alteration occurs with chalcopyrite. The core, or centre of the deposit is characterised by intense quartz veining, K-silicate alteration and chalcopyrite-bornite-magnetite assemblages. The western end of the deposit is dominated by sericitic alteration and pyrite-chalcopyrite (Howard, 1976). The vertical zonation of alteration and mineralisation over a 6 km interval is summarised below (Einaudi, 1994).
Significant Cu mineralisation is developed over a length of 1650 m with a width varying from a maximum of 500 m to 180 m on the western margin. In the main section it occurs as a flat lying lens around 150 m thick, although to the west where it thins it extends deeper to around 240 m where it has a 'V' shape in cross section, reflecting the shape of the quartz-monzonite host (Wilson, 1963).
A high grade hypogene core is developed in the centre of the orebody, decreasing outwards gradually, but not uniformly to grade boundaries. Primary sulphide minerals are essentially pyrite and chalcopyrite, with a pyrite:chalcopyrite ratio substantially <1:1. Minor bornite and covellite have been observed and trace primary chalcocite has been detected microscopically. Molybdenite is rare. Sulphides typically occur as minute, discrete grains in the groundmass of the porphyry and as narrow, randomly oriented, discontinuous veins. Sulphide grains are not uncommonly enclosed within feldspar and quartz phenocrysts. Aligned sulphide seams and veinlets attain their maximum development in the central, high grade core, accompanied by quartz dyking and pervasive quartz flooding of the porphyry (Wilson, 1963).
Important oxide accumulations were developed, with a sharp, slightly undulating lower limit, with minor fault off-set, but generally conforming to the pre-gravel surface. The maximum vertical extent of oxidised ore is confined to the eastern half of the orebody, where essentially the full vertical column of mineralisation has been converted to oxide. Re-deposition of oxidised Cu products is considered to have occurred for the most part in-situ, with some migration and re-deposition of exotic Cu evidenced by restricted concentrations within the oxide zone and by shallow secondary sulphide enrichment of the primary zone. The principal oxidation product is chrysocolla, which is irregularly dispersed throughout the rock and as narrow seams along fractures. Massive concentrations of this silicate are limited to discontinuous vein-like occurrences along fissures and interstitial filling of breccia zones. Cuprite, tenorite and melaconite all have a wide distribution, but are of limited importance in the main oxide zone. Malachite and azurite are not abundant. In certain areas ore grade zones have no recognisable Cu minerals, with the metal occurring as amorphous, hydrated iron-copper oxide of variable Cu content (Wilson, 1963).
Lying between the primary sulphide and chrysocolla mineralisation is a transition zone in which chalcocite, cuprite, melaconite, native copper and chrysocolla occur, super-imposed upon primary mineralisation. Limits of this zone are irregular, but seldom exceeds 6 m in thickness. Immediately underlying this there is a prominent layer of chalcocite replacement of chalcopyrite and to a lesser degree pyrite, has developed through an average vertical range of 9 to 12 m. Secondary chalcocite has been detected as deep as 30 m below the top of the sulphide zone, but in such instances is confined to narrow widths along recognised post mineral structures (Wilson, 1963).
Skarn mineralisation developed in the surrounding country rock is associated with alteration of the lower Mesozoic volcano-sedimentary section some 3 to 4 km from the porphyry copper mineralisation. Alteration included:
• An early hornfels-skarnoid phase producing garnet-pyroxene hornfels near the batholith contact, possibly an early metamorphic event synchronous with the intrusion of the batholith.
• The main skarn development which followed brecciation of the early hornfels-skarnoid and the formation of chalcopyrite-pyrite bearing skarns. Iron rich skarns formed near the batholith, and andradite-salite skarns formed on the fringes of the skarnoid aureole in dolomitised marbles. Six deposits are located in this zone, two near the contact in the early garnet-pyroxene skarnoid (with low sulphides, low pyrite:chalcopyrite ratios, absence of magnetite and pyrite, a gangue dominated by andradite, strong brecciation and no zoning of calc-silicates and sulphides) and four further removed, at 1 to 2 km from the batholith. The latter four have 10 to 25% sulphides, high pyrite:chalcopyrite ratios of generally >1, trace magnetite, talc and tremolite, a gangue of andradite-salite, no evidence of brecciation, but zoning of calc-silicates and sulphides. The general outward zoning is andradite → andradite-salite-chalcopyrite-pyrite → salite-actinolite-pyrite±magnetite → chalcopyrite-tremolite-magnetite±pyrite → talc-calcite± magnetite → dolomite-calcite.
• Silica-pyrite occurred within a fault breccia at one locality between skarnoid developments and limestone and was associated with an intensely silicified and quartz veined porphyry dyke possibly related to the porphyry copper mineralising event (Einaudi, 1982).
At the Ann Mason porphyry Cu-(Mo-Au) deposit, which is 7 km west of Yerington, mineralisation is associated with the intrusion of the Luhr Hill granite porphyry dykes (Dilles, 1984; Dilles and Einaudi, 1992; Dilles et al., 1992, 2015) and is hosted by several phases of the Jurassic Yerington batholith, including granodiorite and porphyritic quartz monzonite. The deposit, as defined by the 0.15% Cu cutoff, covers an area of ~2.8 km NW-SE by up to 1.3 km NE-SW, while extending to >1.2 km below the surface (Ahmed et al., 2020). A west plunging high-grade zone with dimensions of ~200 x 800 m surrounds the intrusive contact between granodiorite and porphyritic quartz monzonite porphyry. Grades in this zone are dependent upon vein density, sulphide species, frequency and relative age of quartz monzonite porphyry dykes and in the mafic content of the granodiorite.
Chalcopyrite occurs as individual grains in veins and disseminations, while bornite is found as separate grains in veins, disseminated in host rocks and attached to chalcopyrite. Molybdenum is present as molybdenite in quartz and quartz-chalcopyrite veins and on fracture or shear surfaces. Molybdenum above a cut-off of 0.005% Mo is almost entirely within the 0.15% Cu contour.
Sulphides are zoned, with chalcopyrite and chalcopyrite-bornite predominating in the NE, SE and SW sectors of the deposit whilst chalcopyrite and pyrite are dominant to the NW with grades >0.15% Cu and pyrite:chalcopyrite ratios of <7:1. A domain with thick intervals of >0.3% Cu and only minor bornite occurs at depth near the granodiorite-porphyritic quartz monzonite contact (https://miningdataonline.com, viewed 2020).
The main mineralising event is accompanied by potassic alteration, consisting of biotite ± K feldspar (Dilles et al., 1992) and defines a restricted domain in the core of the deposit. Sericite alteration, comprising muscovite or illite + pyrite ±quartz ±rutile, occurs above (west of) Ann Mason (Dilles et al., 1992). Widespread epidote and chlorite are part of the district scale propylitic and sodic-calcic alteration assemblages (Dilles and Einaudi, 1992) and are likely formed synchronously with potassic alteration, although they are localised on the fringes of the mineralised system (Dilles and Einaudi, 1992).
The Blue Hill deposit is located ~1.5 km NW of Ann Mason in a separate fault block but in a similar geologic environment. Both oxide and sulphide mineralisation is present at Blue Hill. The NE striking, low angle Blue Hill Fault passes through the centre of the deposit truncating portion of the near surface oxide resource, with sulphides (pyrite, chalcopyrite and molybdenite) occurring below the fault to the SE. Local, higher grade sulphide mineralisation is found in zones of sheeted veining containing chalcopyrite, magnetite and secondary biotite. The oxide resource occurs as a relatively flat lying zone over an area of ~900 x 450 m, continuing further west as a number of narrow zones. Significant copper oxides persist to an average in depth of ~124 m. Oxides include malachite, chrysocolla, rare azurite, black copper-manganese oxides, copper sulphates and copper bearing limonites. Mineralisation is primarily found on fractured surfaces and in oxide veins and veinlets. Mixed oxide/sulphide zones contain minor chalcocite below the oxide mineralisation to depths of 185 m. The oxide mineralisation is largely due to in situ oxidation of Cu sulphides with very little transport of copper into vugs, fractures, faults and shear zones. No significant secondary sulphide zones have been encountered (https://miningdataonline.com, viewed 2020).
The Bear Deposit is a large porphyry copper system that was discovered in 1961 by Anaconda during condemnation drilling in the sulphide tailings disposal area, and was subsequently partially delineated by Anaconda in the 1960s and by Phelps Dodge in the 1960s and 1970s. It extends onto properties held by other parties and has not been unified. Drilling identified chalcopyrite mineralisation hosted in a porphyry system below 150 to 300 m of alluvium and unmineralised bedrock. The primary copper mineralization of the Bear Deposit, located partially in the NE corner of the Yerington property, is related to micaceous veining rather than A-type quartz veining common in the Yerington Mine porphyry system. In the limited drilling undertaken to date 10 holes have continuous intervals of at least 50 m @ 0.8% Cu or more. Dilles and Proffett, (1995) estimated the amount of mineralised material defined by the Anaconda program to total a non NI 43-101 compliant resource of more than 500 Mt @ 0.40% Cu. Mineralization that is similar in nature to that of the Yerington pit (Singatse Peak Services, LLC, NI 43-101 Technical Report, 2014).
Alteration Zonation in the Yerington District
Dilles and Einaudi (1992) and Einaudi (1994) interpreted the following alteration and mineralisation zonation over an original 6 vertical kilometres within the tilted porphyry deposits of the Yerington district:
• Early potassic, phlogopite-K feldspar alteration, from depths of 2 to 4 km.
Most of the ore grade copper within the deposits of the district was emplaced coeval with potassic alteration, which consisted of phlogopite-(magnetite-rutile) after hornblende and biotite, K feldspar after plagioclase, and abundant quartz-sulphide veinlets. The associated sulphide assemblages include: i). bornite-magnetite-(digenite) which is only found in the Yerington deposit, where it comprises the earliest and central zone, with hypogene grades of 2 to 3 wt.% Cu; ii). bornite-chalcopyrite-magnetite; iii). chalcopyrite, and iv). fringing chalcopyrite > pyrite. The latter zone is characterised by shreddy phlogopite after hornblende, where quartz veinlets are sparse, hydrothermal K feldspar is absent, rock magnetite reappears, and grades drop to <0.2% Cu. These four low-sulphur sulphide assemblages occur as disseminations and in quartz veinlets, with a direct correlation between volume percent quartz veinlets and copper grade. The highest copper grades at Yerington are found in zones containing 10 to 25 vol.% quartz veining. Rather than stockworks linked to localised hydrofracturing, the bulk of the veinlets are semi-sheeted sets, parallel to the regional fracture pattern. Three successive, partly overlapping potassic alteration events at Yerington were associated with three early dyke events. At least one of these early dyke sets did not vent to the surface, but terminated in an upward-flaring, igneous-matrix breccia that fingered-out upwards.
• Early sodic-calcic actinolite-oligoclase alteration, from depths of 4 to 6 km.
This alteration took place both at depth and laterally along the margins of granite cupolas, although it overlapped upward and centrally with potassic alteration. These assemblages are characterised by actinolite after hornblende and biotite, oligoclase after K feldspar, abundant sphene, local epidote, local tourmaline, and the absence of biotite, magnetite and sulphides. Associated veinlets containing oligoclase-quartz-(actinolite), locally with patchy chalcopyrite-pyrite, where superimposed on the potassic alteration and mineralisation. Where most intense, sodic-calcic alteration comprises an oligoclase-quartz-sphene rock with halos of oligoclase-quartz-sphene-actinolite-(epidote), and where weak, is transitional to propylitic assemblages. Detailed mapping at Yerington shows that at depth in the system, sodic-calcic alteration was coeval with the overlying potassic alteration during each of several, separate intrusive events. Superposition of sodic-calcic onto potassic alteration resulted in strong copper depletion in the associated mineralisation. Some late dykes which post-date potassic and sodic-calcic alteration, pre-date the late stages of hydrothermal alteration described below.
• Late sodic, chlorite-albite alteration, from depths of 2 to 4 km.
This alteration was superimposed on all porphyry dykes and on both potassic and propylitic zones. At deeper levels, it comprises albite after feldspars, and chlorite-(sericite) after ferromagnesian minerals, with rutile, sphene and sparse pyrite > chalcopyrite. The sodic assemblages are found along fractures and as halos to sparse quartz-albite veinlets, with flanking zones of chloritised biotite. Higher in the system, at near 2 km depths, sodic assembalges are characterised by albite-sericite-(chlorite) accompanied by tourmaline, with 1 to 2 % pyrite, minor rutile and rare veinlets of quartz-pyrite-(tourmaline). The sericite to chlorite ratio increases upward, probably representing a transition to a sericite-quartz-pyrite assemblage.
• Very late sericitic alteration and tourmaline breccias, from depths of 0 to 2 km.
This alteration comprises sericite-quartz accompanied by 2 to 10 vol.% pyrite, and occurs as well-defined halos, to through-going pyritic fractures and pebble breccias with steep Jurassic dips. All sericitc alteration post-dates all porphyry intrusions within the 2.5 km of vertical exposure at Yerington. The amount of sericitic alteration increases upward, from 1 to 2% of the rock in mineralised potassic zones at 2 to 3 km depths, to ~50% of exposures at 1 km palaeo-depth. Near the palaeosurface in the Buckskin Range, sericite-quartz-pyrite related to the three underlying porphyry copper centres coalesce to form a regional zone of pervasive sericite. Veins within the very late sericitic zone are filled with pyrite and lesser chalcopyrite, hematite, quartz and sericite. Pyrite to chalcopyrite ratios in veins are related to the local background sulphide assemblage and content of the earlier main mineralisation. Potassic ore zones at Yerington with original bornite-magnetite, sericitic veins contain chalcopyrite-(magnetite) or chalcopyrite>pyrite and constitute ore. However, in previously low-grade upper sections of the deposit, sericitic veins typically have pyrite-chalcopyrite ratios that are >50:1. The pyrite veins have sericite-pyrite selvages accompanied by minor quartz and rutile, whilst some, but not most, veins also have an outer chloritic (intermediate argillic) halo. At higher structural levels, the innermost silica-pyrite halos are fringed by outer sericite-pyrite halos.
Tourmaline breccias commence with roots at a palaeo-depth ~2.5 km, and extend upward for at least 2 km. They are up to several metres thick, and comprise 1 to 5 cm long, angular to subrounded matrix-supported clasts, set in a matrix of quartz, tourmaline, ~1% pyrite and trace rutile. Clasts consist of sericitic and sodic assemblages similar to the immediate wall rocks, implying lack of significant upward transport, and are not pebble-dykes. They cut and/or re-open pyrite-sericite veins, indicating they are the youngest event.
• Advanced argillic alteration, at the palaeo-surface.
The extrusive equivalents of the intrusive quartz monzodiorite are represented in the Buskskin Range by an up to 1.5 km thick section of andesite-dacite flows, breccias, tuff and sedimentary rocks. These are cut by flow-banded porphyry dykes that may correlate with late granite porphyry dykes near Ann Mason. Pervasive sericitic alteration overprints the section in many areas. Although intensely leached by weathering at surface, limonite type, distribution and density suggests the original sulphide content increased upward, averaging ~4 % with py:cp ratios of >50:1. Fine-grained, probably hydrothermal specular hematite is locally abundant. Zones of pervasive sericitic alteration contain stratiform silica ledges that replaced mostly tuff or sedimentary units and are up to 75 m thick, with strike lengths of as much as 400 m. These ledges largely comprise fine-grained quartz which appears to have contained abundant fine-grained pyrite. Advanced argillic minerals that include alunite and pyrophyllite are evident within the silica ledges and on their margins, as are andalusite, diaspore, corundum and zunyite.
The most recent source geological information used to prepare this summary was dated: 2019.
Record last updated: 7/6/2020
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
Ahmed, A.D., Fisher, L., Pearce, M., Escolme, A., Cooke, D.R., Howard, D. and Belousov, I., 2020 - A Microscale Analysis of Hydrothermal Epidote: Implications for the Use of Laser Ablation-Inductively Coupled Plasma-Mass Spectrometry Mineral Chemistry in Complex Alteration Environments: in Econ. Geol. v.115, pp. 793-811|
Carten R B 1986 - Sodium-Calcium metasomatism: chemical, temporal, and spatial relationships at the Yerington, Nevada, Porphyry Copper deposit: in Econ. Geol. v81 pp 1495-1519|
Dilles J H 1987 - Petrology of the Yerington Batholith, Nevada: Evidence for evolution of Porphyry Copper ore fluids: in Econ. Geol. v82 pp 1750-1789|
Dilles J H, Einaudi M T 1992 - Wall-rock alteration and hydrothermal flow paths about the Ann-Mason Porphyry Copper deposit, Nevada - a 6-km vertical reconstruction: in Econ. Geol. v87 pp 1963-2001|
Dilles J H, Solomon G C, Taylor H P, Einaudi M T 1992 - Oxygen and Hydrogen isotope characteristics of hydrothermal alteration at the Ann-Mason Porphyry Copper deposit, Yerington, Nevada: in Econ. Geol. v87 pp 44-63|
Einaudi, M.T., 1994 - 6-km Vertical Cross Section Through Porphyry Copper Deposits, Yerington District, Nevada: Multiple Intrusions, Fluids, and Metal Sources: in Society of Economic Geologists, International Exchange Lecture - June 1994, 7p.|
Harris N B, Einaudi M T 1982 - Skarn deposits in the Yerington District, Nevada: metasomatic skarn evolution near Ludwig: in Econ. Geol. v77 pp 877-898|
Runyon, S.E., Steele-MacInnis, M., Seedorff, E., Lecumberri-Sanchez, P. and Mazdab, F.K., 2017 - Coarse muscovite veins and alteration deep in the Yerington batholith, Nevada: insights into fluid exsolution in the roots of porphyry copper systems: in Mineralium Deposita v.52, pp. 463-470.|
Schopa, A., Annen, C., Dilles, J.H., Sparks, R.S.J. and Blundy, J.D., 2017 - Magma Emplacement Rates and Porphyry Copper Deposits: Thermal Modeling of the Yerington Batholith, Nevada : in Econ. Geol. v.112, pp. 1653-1672.|
Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge. It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published. While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants: i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.
Top | Search Again | PGC Home | Terms & Conditions