DOCSLIB.ORG

Trace Element Concentrations in Porphyry Copper Deposits from Metaliferi Mountains, Romania: a Reconnaissance Study

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Trace Element Concentrations in Porphyry Copper Deposits from Metaliferi Mountains, Romania: a Reconnaissance Study Ore Geology Reviews 63 (2014) 22–39 Contents lists available at ScienceDirect Ore Geology Reviews journal homepage: www.elsevier.com/locate/oregeorev Trace element concentrations in porphyry copper deposits from Metaliferi Mountains, Romania: A reconnaissance study Mihaela Elena Cioacă a,⁎, Marian Munteanu a,b, Liang Qi c,GeluCostind a Geological Institute of Romania, Department of Regional and Economic Geology, 1 Caransebeş St., 01271 Bucharest, Romania b University of the Witwatersrand, School of Geosciences, 1 Ian Smuts St., Braamfontein 2000, Johannesburg, South Africa c State Key Lab of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China d Rhodes University, Department of Geology, Artillery Road, 6140 Grahamstown, South Africa article info abstract Article history: There are fifteen Miocene intrusions with porphyry copper mineralization in the Metaliferi Mountains, Romania; Received 18 September 2013 most are associated with epithermal Au–Ag (±Te, Bi, Se, Ge) vein systems. The investigation of fifty samples from Received in revised form 9 April 2014 six deposits (Roşia Poieni, Bucium–Tarniţa, Colnic, Rovina, Valea Morii and Bolcana) indicated bulk rock mean Accepted 24 April 2014 values of 0.16–0.88 ppm Au, b50 ppm Mo, 0.02–0.35 ppm Re, 0.06–0.6 ppm In, 1.3–3.3 ppm Ag, 0.23– Available online 2 May 2014 1.17 ppm Bi, 3.2–5.5 ppm Se, 2.4–3.3 ppm Ge, and 2.6–18 ppm Te. Trace element analyses by electron microprobe suggest that part of the Au, Ag, As, Te and Se may occur as fine-particle inclusions hosted within common sulfide Keywords: Porphyry copper minerals (pyrite, chalcopyrite and bornite). Measured concentrations range from below the minimum limit of Trace elements detection to as much as 1430 ppm Au, 530 ppm Ag, 1920 ppm Te, 10,500 ppm As and 2620 ppm Se in pyrite, Metaliferi Mountains 970 ppm Au, 1180 ppm Ag, 1000 ppm Te, 410 ppm As and 420 ppm Se in chalcopyrite, and 920 ppm Au, Romania 4830 ppm Ag, 1470 ppm Te, 4230 ppm Se and 1540 ppm Bi in bornite. Gold is concentrated preferentially in py- rite, while silver is consistently high (N1000 ppm) in bornite. In the porphyry-type mineralization, galena forms microinclusions in pyrite, chalcopyrite and bornite, and contains up to 3750 ppm Ag, 17,380 ppm Se, 1570 ppm Ge and 780 ppm Te. Galena and pyrite from the epithermal mineralization in the Măgura–Bolcana–Troiţa system contain concentrations of Ag and Se ten times lower than in the same minerals from the porphyry copper min- eralization. The present data show that Te is a significant trace element in the potassic zone of the investigated porphyry systems. The data also shows that this does not correlate with the presence or absence of ophiolitic basement, or with variation in the chemistry of the host intrusions. Tellurium enrichment in porphyry-type de- posits of the Metaliferi Mountains supports their genetic relationship with the spatially associated epithermal systems. © 2014 Elsevier B.V. All rights reserved. 1. Introduction The Metaliferi Mountains (South Apuseni Mountains) in Romania (Fig. 1) host a dense concentration of ore deposits related to Miocene Copper, Au and Mo are the principal commodities in porphyry-style calc-alkaline magmatism (Ghiţulescu and Socolescu, 1941; Ianovici ores, but other metals, notably Ag and platinum group elements (PGEs), et al., 1976; Roşu et al., 2001, 2004; Neubauer et al., 2005). Mineraliza- may be recoverable from some porphyry Cu (–Au, –Ag) deposits. Ele- tion occurs as veins (Au–Ag ± Te and base metal), epithermal breccia ments such as In, Re, Sn, W, Bi, Zn, Te, Se and Ge can also be present in pipes and replacement bodies, and in several subjacent porphyry Cu- porphyry Cu–(Mo–W–Sn) systems at elevated concentrations (Berger type systems. Some of these deposits are ranked as large or very large et al., 2008; Sinclair, 2007) and can potentially be extracted as by- (Borcoş et al., 1998; Milu et al., 2004; UdubaşaandUdubaşa, 2004; products (Ayres et al., 2002). Although data for porphyry systems is lim- Vlad and Orlandea, 2004; Tămaş et al., 2006). The largest of these, the ited, these trace elements are commonly concentrated within the com- Roşia Poieni porphyry Cu deposit contains 431 Mt ore at 0.55% Cu and mon sulfides, notably gold within pyrite (e.g., Cook and Chryssoulis, 0.25 g/t Au (Kouzmanov et al., 2005b). According to Vlad and 1990; Deditius et al., 2011; Reich et al., 2005, 2013a), silver in chalcocite Orlandea (2004), historical gold production in the district totals 630 t or bornite (e.g., Cook et al., 2011; Reich et al., 2013b), indium in sphal- at Roşia Montană, 380 t at Barza–Brad, 330 t at Baia de Arieş and 250 t erite (e.g., Cook et al., 2009a) or rhenium in molybdenite (e.g., at Stănija; all these deposits are of epithermal type. The Săcărâmb Aminzadeh et al., 2011; Ciobanu et al., 2013; Golden et al., 2013). epithermal deposit produced ca. 30 t Au, 55 t Ag and 60 t Te (Udubaşa and Udubaşa, 2004). ⁎ Corresponding author. Tel.: +40 21 3060491; fax: +40 21 31 81 326. The results of substantial research have been published on individu- E-mail address: [email protected] (M.E. Cioacă). al porphyry Cu deposits. These include accounts of the systems at Roşia http://dx.doi.org/10.1016/j.oregeorev.2014.04.016 0169-1368/© 2014 Elsevier B.V. All rights reserved. M.E. Cioacă et al. / Ore Geology Reviews 63 (2014) 22–39 23 Fig. 1. Location of the porphyry copper deposits in the “Golden Quadrangle”—Metaliferi Mountains (modified after Cioflica et al., 1973). 1. Valea Tisei, 2. Trâmpoiele, 3. Muncăceasca, 4. Măgura Poienii, 5. Tălagiu, 6. Cireşata, 7. Musariu, 8. Voia, 9. Deva. Poieni (André-Mayer and Sausse, 2012; Iatan, 2009; Kouzmanov et al., the trace element contents in porphyry-type mineralization. This com- 2005c, 2010; Milu et al., 2004; Popescu et al., 2006); Valea Morii parison is used to show that the well-documented trace element signa- (André-Mayer et al., 2001; Borcoş et al., 1978), Bolcana (Cardon et al., ture of the epithermal assemblages (enrichment in Au, Ag and Te) can 2005, 2008; Cioacă, 2008, 2011; Cioacă et al., 2010; Milu et al., 2003; also be recognized in higher temperature assemblages within the por- Popescu and Cioacă, 2006), Rovina, Colnic and Cireşata (Halga et al., phyry type mineralization, thus further supporting a genetic relation- 2010). Attention has also been given to several of the larger epithermal ship between the two styles of mineralization. deposits, including Roşia Montană (Bailly et al., 2005; Kouzmanov et al., 2005c; Tămaş et al., 2006, 2014), Săcărâmb (Alderton and Fallick, 2000; 2. Geological setting Ciobanu et al., 2008; Cook and Ciobanu, 2005; Popescu et al., 2010, 2013), and Larga (Cook and Ciobanu, 2004, 2005). These articles and a Miocene (14–7 Ma) volcanic-hydrothermal activity in the Metaliferi number of regional studies (Berbeleac, 1985; Borcoş et al., 1998; Mountains was controlled by the regional geodynamic evolution of the Boştinescu, 1984; Harris et al., 2013; Marcoux et al., 2002; Neubauer Carpathian orogen and Pannonian basin during the Cenozoic. This evo- et al., 2005; Popescu and Neacşu, 2007; Roşu et al., 2001, 2004; lution comprised subduction and collision of the European and Moesian Udubaşa and Udubaşa, 2004; Udubaşa et al., 2001; Vlad and Orlandea, plates with the Intracarpathian Alcapa and Tisia blocks, resulting in a 2004) have documented the spatial and genetic relationships between subsequent extensional regime, driven by the translation and clockwise the porphyry Cu deposits and epithermal mineralization. rotation of Tisia block (Neubauer et al., 2005; Roşu et al., 2004). Rotation Remarkably few publications (Cheşu, 1983; Cioacă et al., 2010; Cook of the Tisia block in excess of 60° at 14–12 Ma produced deep and Ciobanu, 2004) deal, however, with the trace element geochemistry transtensional faults and NW–SE-trending graben-like pull-apart ba- of the porphyry copper deposits in the Metaliferi Mountains. Consider- sins, which favored a rapid magma ascent, generating numerous volca- ing this, the research reported here is, in many respects, a reconnais- nic–subvolcanic systems. Although the geochemical studies indicate sance study, aimed at identifying geochemical features and trends that that Miocene magmas from the Metaliferi Mountains have a “subduc- can serve as premises for more detailed investigation. We provide tion signature”, they were generated by decompressional melting of a new trace element geochemical data on bulk rock samples and on sul- heterogeneous source situated at the crust–lithosphere mantle bound- fide grains from mineralization in six porphyry deposits that were ac- ary (Neubauer et al., 2005; Roşu et al., 2001, 2004; Seghedi et al., cessible for sampling: Roşia Poieni, Bucium–Tarniţa, Colnic, Rovina, 2007). Variable and higher Nb and Nb/Y ratio in younger rocks Valea Morii and Bolcana. Our aim is to establish any similarities or dif- (10–7 Ma) suggest the generation of the magma by a mixing of astheno- ferences between these deposits regarding the distribution of the spheric melts (Roşu et al., 2001, 2004). Petrochemical studies indicate a trace elements of potential economic interest, and to document the normal calc-alkaline character for the early magmatic products role of the main sulfide minerals in concentration of trace elements. (14–12 Ma), and an adakite-like calc-alkaline signature for the younger We also provide trace element concentrations in sulfides from the (12–7Ma)rocks(Roşu et al., 2004). This magmatism generated amphi- Măgura–Bolcana–Troiţa epithermal system and compare them with bole andesites with pyroxene ± biotite (particularly well represented 24 M.E.
Load more

Recommended publications
  • Euro Sun Announces Robust Definitive Feasibility Study for the Rovina Valley Gold- Copper Project in Romania
    Euro Sun Announces Robust Definitive Feasibility Study for the Rovina Valley Gold- Copper Project in Romania March 1, 2021 (Source) — Average annual gold equivalent production of 146,000 ounces over first 10 years at an average AISC of $790/gold equivalent ounce Total initial capex of $399 million Pre-tax Net Present Value of $447 million; IRR of 21.3% at $1,550/oz gold and $3.30/lb copper Euro Sun Mining Inc. (TSX: ESM) (“Euro Sun” or the “Company”) is pleased to announce the positive results of the Definitive Feasibility Study (“DFS”) on the Colnic and Rovina open pits – the initial phase of development of its Rovina Valley Gold and Copper Project (the “Rovina Valley Project”) in Romania. Along with the DFS, the Company is also providing an updated mineral resource estimate for the Rovina Valley Project incorporating current metal prices and operating parameters. All amounts are in US dollars unless otherwise indicated. Euro Sun is utilizing a phased development approach for the Rovina Valley Project. The Rovina Valley Project consists of two open pit gold-copper deposits, Colnic and Rovina, and the underground Ciresata gold-copper deposit. The DFS is focused on the exploitation of the two open pit operations. The Ciresata underground deposit is expected to be phased in following the completion of the Colnic and Rovina pits. HIGHLIGHTS Average annual gold equivalent production of 146,000 ounces in year 1-10, consisting of 106,000 ounces of gold and 19 million pounds of copper per annum Average AISC of $790/gold equivalent ounces in years
    [Show full text]
  • Supergene Mineralisation of the Boyongan Porphyry Copper-Gold Deposit, Surigao Del Norte, Philippines
    Supergene Mineralisation of the Boyongan Porphyry Copper-Gold Deposit, Surigao del Norte, Philippines by Allan Maglaya Ignacio B.Sc. Geology, National Institute of Geological Sciences University of the Philippines Thesis submitted in partial fulfilment of the requirements of the Masters of Economic Geology Degree Centre for Ore Deposit Research, University of Tasmania December, 2005 DECLARATION OF ORIGINALITY This thesis contains no material which has been accepted for a degree of diploma by the University of Tasmania or any other institution, except by way of background information and duly acknowledged in the thesis, and contains no previous material previously pub- lished or written by another person except where due acknowledgement is given. Allan Maglaya Ignacio 01 December 2005 _________________________ STATEMENT OF AUTHORITY OF ACCESS This thesis may not to be made available for loan or copying for 1.5 years following the date this statement was signed. Following that time, the thesis may be available for loan and lim- ited copying in accordance with Copyright Act 1968. Allan Maglaya Ignacio 01 December 2005 _________________________ TABLE OF CONTENTS Page (s) LIST OF FIGURES …………………………………………………….. i - iii LIST OF APPENDICES ………………………………………………… iv ACKNOWLEDGMENTS ………………………………………………. v ABSTRACT ……………………………………………………………... vi - vii 1.0 INTRODUCTION ………………………………………………………. 1 - 8 1.1 Introduction …………………………………………………………. 1 1.2 Aims and Objectives ……………………………………………….. 1 1.3 Methods Employed …………………………………………………. 2 1.4 Location and Accessibility …………………………………………. 3 1.5 Climate ……………………………………………………………... 5 1.6 Previous Work ……………………………………………………… 5 2.0 GEOLOGICAL SETTING ………………………………………………. 9 - 37 2.1 Introduction ………………………………………………………. 9 2.2 Regional Tectonics …………….…………………………………. 9 2.3 Regional and Local Stratigraphy ………………………………... 11 2.3.1 Basement (Cretaceous-Paleogene) ………………………. 11 2.3.2 Bacuag Formation (Oliogocene-Miocene) .……………..
    [Show full text]
  • PORPHYRY CU DEPOSITS (MODEL 17; Cox, 1986) by Leslie J. Cox
    PORPHYRY CU DEPOSITS (MODEL 17; Cox, 1986) by Leslie J. Cox, Maurice A. Chaffee, Dennis P. Cox, and Douglas P. Klein SUMMARY OF RELEVANT GEOLOGIC, GEOENVIRONMENTAL, AND GEOPHYSICAL INFORMATION Deposit geology Porphyry copper deposits contain copper, molybdenum, and gold minerals, disseminated or in a stockwork of small veinlets within a large mass of altered rock (Singer and Mosier, 1981). The host rock is commonly a pyrite-rich porphyry ranging in composition from granodiorite to tonalite, but alkalic porphyries are locally important. In the southwestern United States, where porphyry copper deposits are abundant, associated igneous rocks are mainly Mesozoic and Cenozoic. Older plutonic, volcanic, sedimentary, and metamorphic rocks intruded by these porphyries also host ore minerals; the highest grades are found in reactive rocks such as limestone, or rocks, such as diabase, which contain abundant iron-rich minerals prior to alteration. Porphyry deposits exhibit a characteristic pattern of hydrothermal alteration, which includes biotite and K-feldspar assemblages in the center and grades outward to chlorite, actinolite, and epidote assemblages. Most deposits have a late-stage alteration assemblage that contains abundant white mica, clay, and carbonate minerals. Examples Bingham, Utah (Lanier and others, 1978); San Manuel, Ariz. (Lowell and Guilbert, 1970); El Salvador, Chile (Gustafson and Hunt, 1975). Spatially and (or) genetically related deposit types Related deposit types (Cox and Singer, 1986) include porphyry copper, skarn-related (Model 18a), base-metal skarn (Model 18c), porphyry copper-gold (Model 20c), porphyry copper-molybdenum (Model 21a), polymetallic vein (Model 22c), polymetallic replacement (Model 19a), volcanic-hosted copper-arsenic-antimony (Model 22a), quartz- alunite gold (Model 25e), distal disseminated silver-gold (Model 19c; Cox, 1992), and gold-skarn deposits.
    [Show full text]
  • Equity Research EURO SUN MINING INC
    November 29, 2017 Initiating Coverage EURO SUN MINING INC. Rovina Valley Ready to Advance, Time to Buy INVESTMENT THESIS Recommendation: BUY Rovina Valley is Europe’s largest copper resource Symbol/Exchange: ESM/TSX and second largest gold resource. Located in the Sector: Metals & Mining “Golden Quadrilateral” in West-Central Romania, All dollar values in US$ unless otherwise noted. recently the country’s National Agency for Mineral Current price: C$1.08 Resources (“NAMR”) officially endorsed the One-year target: C$2.10 project and initiated the ratification process related Return to Target: 94.4% to the mining license. The Rovina Valley mining Cash on hand: C$13.3 MM license requires signatures from various Ministers (discussed in detail later in this report) and we Financial summary believe this process will likely be concluded in the Shares O/S (M) 57.6 52-week range C$0.62 - C$2.02 next 30-60 days. This would be the single largest Market cap (C$M) C$98 Avg. weekly vol. (MM) 0.10 positive de-risking event in the history of the Market float (C$M) C$94 Fiscal year-end 31-Dec company and the project. As such, we believe Euro Sun is a stock to own now. We are initiating Rovina Valley MMt g/T Au % Cu MMoz Au BBlb Cu coverage with a Buy rating and C$2.10/share target. P&P - - - - - M&I (incl. P&P) 406 0.55 0.16% 7.18 1.42 VALUATION Inferred 27 0.38 0.16% 0.33 0.10 ESM trades at 0.51x our very conservative NAVPS, Total Resource 433 0.54 0.16% 7.51 1.52 and as such, our target has a significant bias to the upside.
    [Show full text]
  • Porphyry Deposits
    PORPHYRY DEPOSITS W.D. SINCLAIR Geological Survey of Canada, 601 Booth St., Ottawa, Ontario, K1A 0E8 E-mail: [email protected] Definition Au (±Ag, Cu, Mo) Mo (±W, Sn) Porphyry deposits are large, low- to medium-grade W-Mo (±Bi, Sn) deposits in which primary (hypogene) ore minerals are dom- Sn (±W, Mo, Ag, Bi, Cu, Zn, In) inantly structurally controlled and which are spatially and Sn-Ag (±W, Cu, Zn, Mo, Bi) genetically related to felsic to intermediate porphyritic intru- Ag (±Au, Zn, Pb) sions (Kirkham, 1972). The large size and structural control (e.g., veins, vein sets, stockworks, fractures, 'crackled zones' For deposits with currently subeconomic grades and and breccia pipes) serve to distinguish porphyry deposits tonnages, subtypes are based on probable coproduct and from a variety of deposits that may be peripherally associat- byproduct metals, assuming that the deposits were econom- ed, including skarns, high-temperature mantos, breccia ic. pipes, peripheral mesothermal veins, and epithermal pre- Geographical Distribution cious-metal deposits. Secondary minerals may be developed in supergene-enriched zones in porphyry Cu deposits by weathering of primary sulphides. Such zones typically have Porphyry deposits occur throughout the world in a series significantly higher Cu grades, thereby enhancing the poten- of extensive, relatively narrow, linear metallogenic tial for economic exploitation. provinces (Fig. 1). They are predominantly associated with The following subtypes of porphyry deposits are Mesozoic to Cenozoic orogenic belts in western North and defined according to the metals that are essential to the eco- South America and around the western margin of the Pacific nomics of the deposit (metals that are byproducts or poten- Basin, particularly within the South East Asian Archipelago.
    [Show full text]
  • Sediment-Hosted Copper Deposits of the World: Deposit Models and Database
    Sediment-Hosted Copper Deposits of the World: Deposit Models and Database By Dennis P. Cox1, David A. Lindsey2 Donald A. Singer1, Barry C. Moring1, and Michael F. Diggles1 Including: Descriptive Model of Sediment-Hosted Cu 30b.1 by Dennis P. Cox1 Grade and Tonnage Model of Sediment-Hosted Cu by Dennis P. Cox1 and Donald A. Singer1 Descriptive Model of Reduced-Facies Cu 30b.2 By Dennis P. Cox1 Grade and Tonnage Model of Reduced Facies Cu by Dennis P. Cox1 and Donald A. Singer1 Descriptive Model of Redbed Cu 30b.3, by David A. Lindsey2 and Dennis P. Cox1 Grade and Tonnage Model of Redbed Cu by Dennis P. Cox1 and Donald A. Singer1 Descriptive Model of Revett Cu 30b.4, by Dennis P. Cox1 Grade and Tonnage Model of Revett Cu by Dennis P. Cox1 and Donald A. Singer1 Open-File Report 03-107 Version 1.3 2003, revised 2007 Available online at http://pubs.usgs.gov/of/2003/of03-107/ Any use of trade, product or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. U.S. DEPARTMENT OF THE INTERIOR U.S. GEOLOGICAL SURVEY 1 345 Middlefield Road, Menlo Park, CA 94025 2 Box 25046, Denver Federal Center, Denver, CO 80225 Introduction This publication contains four descriptive models and four grade-tonnage models for sediment hosted copper deposits. Descriptive models are useful in exploration planning and resource assessment because they enable the user to identify deposits in the field and to identify areas on geologic and geophysical maps where deposits could occur.
    [Show full text]
  • Heinrich&Candela TOG2 For
    Research Collection Book Chapter Fluids and Ore Formation in the Earth's Crust Author(s): Heinrich, Christoph A.; Candela, Philip A. Publication Date: 2014 Permanent Link: https://doi.org/10.3929/ethz-b-000095425 Originally published in: 13, http://doi.org/10.1016/B978-0-08-095975-7.01101-3 Rights / License: Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International This page was generated automatically upon download from the ETH Zurich Research Collection. For more information please consult the Terms of use. ETH Library This is the Green Open Access version of: Heinrich C.A., and Candela P.A. (2014) Fluids and Ore Formation in the Earth's Crust. In: Holland H.D. & Turekian K.K. (eds.) Treatise on Geochemistry, 2nd Edition, vol. 13 (Geochemistry of Mineral Deposits, S. D. Scott, ed.), p. 1-28. Original publication see http://dx.doi.org/10.1016/B978-0-08-095975-7.01101-3 Fluids and Ore Formation in the Earth’s Crust Christoph A. Heinrich1 and Philip A. Candela2 1 ETH Zurich, Department of Earth Sciences, and University of Zurich, Faculty of Mathematics and Natural Sciences, Clausiusstr. 25, 8092 Zurich, Switzerland 2 Laboratory for Mineral Deposits Research, Department of Geology, University of Maryland, College Park, MD,20742, USA Synopsis Ore deposits are rock volumes containing selected elements in sufficient concentration and quantity that they can Be extracted economically. Except for Fe and Al, all technically important metals and other elements are scarce, in total constituting less that 1% of the Earth’s crust. Depending on the element and its mineralogy, a 10- to 10,000-fold enrichment is required for economic extraction today.
    [Show full text]
  • Paleozoic–Mesozoic Porphyry Cu(Mo) and Mo(Cu) Deposits Within the Southern Margin of the Siberian Craton: Geochemistry, Geochronology, and Petrogenesis (A Review)
    minerals Review Paleozoic–Mesozoic Porphyry Cu(Mo) and Mo(Cu) Deposits within the Southern Margin of the Siberian Craton: Geochemistry, Geochronology, and Petrogenesis (a Review) Anita N. Berzina *, Adel P. Berzina and Victor O. Gimon V.S. Sobolev Institute of Geology and Mineralogy, Siberian Branch of the RAS, Koptyug Ave. 3, Novosibirsk 630090, Russia; [email protected] (A.P.B.); [email protected] (V.O.G.) * Correspondence: [email protected]; Tel.: +7-383-333-2304 Academic Editor: Maria Economou-Eliopoulos Received: 31 July 2016; Accepted: 21 November 2016; Published: 29 November 2016 Abstract: The southern margin of the Siberian craton hosts numerous Cu(Mo) and Mo(Cu) porphyry deposits. This review provides the first comprehensive set of geological characteristics, geochronological data, petrochemistry, and Sr–Nd isotopic data of representative porphyry Cu(Mo) and Mo(Cu) deposits within the southern margin of the Siberian craton and discusses the igneous processes that controlled the evolution of these magmatic systems related to mineralization. Geochronological data show that these porphyry deposits have an eastward-younging trend evolving from the Early Paleozoic to Middle Mesozoic. The western part of the area (Altay-Sayan segment) hosts porphyry Cu and Mo–Cu deposits that generally formed in the Early Paleozoic time, whereas porphyry Cu–Mo deposits in the central part (Northern Mongolia) formed in the Late Paleozoic–Early Mesozoic. The geodynamic setting of the region during these mineralizing events is consistent with Early Paleozoic subduction of Paleo-Asian Ocean plate with the continuous accretion of oceanic components to the Siberian continent and Late Paleozoic–Early Mesozoic subduction of the west gulf of the Mongol–Okhotsk Ocean under the Siberian continent.
    [Show full text]
  • Trace-Element Geochemistry of Molybdenite from Porphyry Cu Deposits of the Birgilda-Tomino Ore Cluster (South Urals, Russia)
    Mineralogical Magazine, May 2018, Vol. 82(S1), pp. S281–S306 Trace-element geochemistry of molybdenite from porphyry Cu deposits of the Birgilda-Tomino ore cluster (South Urals, Russia) 1,* 1 1,2 3 OLGA Y. P LOTINSKAYA ,VERA D. ABRAMOVA ,ELENA O. GROZNOVA ,SVETLANA G. TESSALINA , 4 4 REIMAR SELTMANN AND JOHN SPRATT 1 Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry Russian Academy of Sciences (IGEM RAS), Staromonetny per. 35, Moscow 119017, Russia 2 Institute of Experimental Mineralogy Russian Academy of Sciences (IEM RAS), Chernogolovka, Moscow region 142432, Russia 3 John de Laeter Centre for Isotope Research & The Institute for Geoscience Research (TIGeR), Curtin University, Kent St, Bentley, WA 6102, Australia 4 Natural History Museum, London SW7 5BD, UK [Received 16 January 2017; Accepted 23 December 2017; Associate Editor: Krister Sundblad] ABSTRACT Mineralogical, electron microprobe analysis and laser ablation-inductively coupled plasma-mass spectrometry data from molybdenite within two porphyry copper deposits (Kalinovskoe and Birgilda) of the Birgilda-Tomino ore cluster (South Urals) are presented.† The results provide evidence that molybdenites from these two sites have similar trace-element chemistry. Most trace elements (Si, Fe, Co, Cu, Zn, Ag, Sb, Te, Pb, Bi, Au, As and Se) form mineral inclusions within molybdenite. The Re contents in molybdenite vary from 8.7 ppm to 1.13 wt.%. The Re distribution within single molybdenite flakes is always extremely heterogeneous. It is argued that a temperature decrease favours the formation of Re-rich molybdenite. The high Re content of molybdenite observed points to a mantle-derived source. K EYWORDS: molybdenite, LA-ICP-MS, porphyry copper deposits, Urals.
    [Show full text]
  • Magmatic Arc and Associated Gold, Copper, Silver, and Barite Deposits in the State of Goiás, Central Brazil: Characteristics and Speculations
    Revista Brasileira de Geociências 30(2):285-288, junho de 2000 MAGMATIC ARC AND ASSOCIATED GOLD, COPPER, SILVER, AND BARITE DEPOSITS IN THE STATE OF GOIÁS, CENTRAL BRAZIL: CHARACTERISTICS AND SPECULATIONS RAUL MINAS KUYUMJIAN1 ABSTRACT In the western portion of the State of Goiás, Central Brazil, base-metal deposits typical of volcanic-plutonic arcs occur. Up- to-date studies suggest that porphyry Cu-Au, (volcanogenic ?) hydrothermal exhalative Cu-Au and stratiform, submarine exhalative Au-Ag-Ba are present. Although restricted, the present state of knowledge on the geology and mineralizations of the magmatic arc indicates potential resources for metallic mineral deposits in the Brasília Belt. Keywords: mineral deposits, magmatic arc, Goiás, Central Brazil. INTRODUCTION The Magmatic Arc of western Goiás is located during the Brasiliano orogeny, and is associated with recumbent within the Brasilia Belt, a complex fold-and thrust belt of more than isoclinal, open and normal folds. Younger crosscutting foliations one episode of deformation during the Brasiliano orogeny, in the cen- generate crenulations. Shear zones display NS, N100-200W and N200- tral part of the Tocantins Province. The Tocantins Province is a large 400Ed trends. Brasiliano deformation places the Mara Rosa volcanic- Neoproterozoic orogen in Central Brazil (Richardson et al. 1988, sedimentary sequence in the hangingwall of the Rio dos Bois thrust Pimentel et al. 1997, 1998). The magmatic arc is prevalently formed fault, whose footwall consists of Paleoproterozoic Santa Terezinha by Neoproterozoic island-arc terranes consisting of tonalitic to volcanic-sedimentary sequence that occurs to the east (Kuyumjian granodioritic orthogneisses, volcanic-sedimentary associations and 1995). This fault has a dextral oblique and reverse sense of shear late- to post-orogenic intrusions of granites and gabbros.
    [Show full text]
  • Porphyry Copper Deposits of the American Cordillera
    Porphyry Copper Deposits of the American Cordillera Frances Wahl Pierce and John G. Bolm, Editors Arizona Geological Society Digest 20 1995 Geological Summary and Perspective of Porphyry Copper Deposits in Southwestern North America SPENCER R. TITLEY Un iversity of Arizona, Tu cson, Arizona ABSTRACT enci, and Bisbee. Under the impetus of material requirements fo r prosecution of the war, the search for copper ores by 1942 had Porphyry copper deposits in the American southwest focused almost solely on discovery of new disseminated orebodies comprise a distinctive and important metal resource. Their and resulted in identification of 25 porphyry copper deposits by exploration and exploitation during the past hundred years 1980. Among the first recognized as having porphyry copper was accompanied by significant advances in geological knowl­ potential by mid-century were the disseminated ores at Silver Bell, edge and development of increasingly efficient mining and described by Richard and Courtright (1954). Much of the early his­ extraction methods. Cause and effect are indistinguishable be­ tory of these deposits has been recorded from economic and engi­ cause the necessity for increasing mining efficiency resulted in neering perspectives by Parsons (1933, 1957). enhancement of extractive methods and because geological In the early I 990s mining was proceeding at a dozen depos­ study of the ores resulted in recognition of broadly applicable its in Arizona that had survived the economic downturn of the geological and exploration concepts. The early view of linear 1980s: Twin Buttes, Sierrita-Esperanza, San Xavier-Mission, tectonic-based regional controls was supplanted by integra­ San Manuel-Kalamazoo, Ray, Morenci, Pinto Valley and Inspi­ tion of concepts of plate movements.
    [Show full text]
  • Is the EU's Resource Base of Copper Ore Deposits Large? a Fuzzy Set Theory Approach
    resources Article Is the EU’s Resource Base of Copper Ore Deposits Large? A Fuzzy Set Theory Approach Mariusz Krzak Faculty of Geology, Geophysics and Environmental Protection, AGH University of Science and Technology, Mickiewicza 30, 30-059 Krakow, Poland; [email protected] Abstract: Copper raw materials have not been identified as a critical raw material for the economy of the European Union (EU). Demand for metal for use within the EU is satisfied mainly by imports of raw materials in various processing stages and from recycling. Imports include not only copper concentrates, but also refined metals, alloys, and intermediate and finished products. In terms of EU imports, mining supplies represent a minor share of demand. It is likely that copper demand will grow in the coming decades and that global as well as European reserves of copper will be depleted more rapidly. For Europe, no complete and harmonised dataset presenting estimates of total EU copper resources and reserves exists, with the exception of the attempted Minerals4EU project. In colloquial language, many imprecise concepts aim at describing reality. Classic probability tools cannot be used to describe imperfect information. There are no sharp thresholds between the boundaries of many measurements; instead, smooth transitions are observed. This gradation between full and partial membership and non-membership is not included in classical set theory; thus, the capacity for describing such effects is provided by fuzzy set theory. An attempt is made in the present paper at a fuzzy description of the copper reserve base in the EU countries. The basic terminology of fuzzy sets is presented and useful logical operators are indicated.
    [Show full text]