scholarly journals The Geology, Geochemistry, and Origin of the Porphyry Cu-Au-(Mo) System at Vathi, Serbo-Macedonian Massif, Greece

2021 ◽  
Vol 11 (2) ◽  
pp. 479
Author(s):  
Christos L. Stergiou ◽  
Vasilios Melfos ◽  
Panagiotis Voudouris ◽  
Paul G. Spry ◽  
Lambrini Papadopoulou ◽  
...  
Keyword(s):  
Native Gold ◽  
Metallogenic Province ◽  
Potassic Alteration ◽  
Fluid Inclusion Data ◽  
Porphyry Cu ◽  
Basement Rocks ◽  
Metallogenic Belt ◽  
Quartz Monzonite ◽  
Propylitic Alteration ◽  
Stage 1

The Vathi porphyry Cu-Au ± Mo mineralization is located in the Serbo-Macedonian metallogenic province of the Western Tethyan Metallogenic Belt. It is mainly hosted by a latite and is genetically associated with a quartz monzonite intrusion, which intruded the basement rocks of the Vertiskos Unit and the latite, 18 to 17 Ma ago. A phreatic breccia crosscuts the latite. The quartz monzonite was affected by potassic alteration, whereas the latite was subjected to local propylitic alteration. Both styles of alteration were subsequently overprinted by intense sericitic alteration. M-type and A-type veins are spatially associated with potassic alteration, whereas D-type veins are related to the sericitic alteration. Three ore assemblages are associated with the porphyry stage: (1) pyrite + chalcopyrite + bornite + molybdenite + magnetite associated with potassic alteration; (2) pyrite + chalcopyrite related to propylitic alteration; and (3) pyrite + chalcopyrite + native gold ± tetradymite associated with sericitic alteration. A fourth assemblage consisting of sphalerite + galena + arsenopyrite + pyrrhotite + pyrite ± stibnite ± tennantite is related to an epithermal overprint. Fluid inclusion data indicate that the A-type veins and related porphyry-style mineralization formed at 390–540 °C and pressures of up to 646 bars (<2.6 km depth) from boiling hydrothermal fluids. A later condensation of vapor-rich inclusions resulted in a moderately saline fluid (8.4–11.2 wt % NaCl equiv) at temperatures between 311 and 392 °C, which were related to sericitic alteration, D-type veins, and associated metallic mineralization. Subsequent dilution of the moderately saline fluid at lower temperatures (205–259 °C) produced a less saline (1.4–2.9 wt % NaCl equiv.) fluid, which is likely associated with the late epithermal overprint.

scholarly journals Duration of Hydrothermal Alteration and Mineralization of the Don Manuel Porphyry Copper System, Central Chile

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 174
Author(s):  
Amy K. Gilmer ◽  
R. Stephen J. Sparks ◽  
Dan N. Barfod ◽  
Emily R. Brugge ◽  
Ian J. Parkinson
Keyword(s):  
Porphyry Copper ◽  
Porphyry Copper Deposits ◽  
Central Chile ◽  
Potassic Alteration ◽  
Copper Deposits ◽  
The Andes ◽  
Metallogenic Belt ◽  
Argillic Alteration ◽  
Propylitic Alteration ◽  
Time Gap

The Don Manuel porphyry copper system, located in the Miocene–Pliocene metallogenic belt of central Chile, contains spatially zoned alteration styles common to other porphyry copper deposits including extensive potassic alteration, propylitic alteration, localized sericite-chlorite alteration and argillic alteration but lacks pervasive hydrolytic alteration typical of some deposits. It is one of the youngest porphyry copper deposits in the Andes. Timing of mineralization and the hydrothermal system at Don Manuel are consistent with emplacement of the associated intrusions (ca. 4 and 3.6 Ma). Two molybdenite samples yielded consistent ages of 3.412 ± 0.037 and 3.425 ± 0.037 Ma. 40Ar/39Ar ages on hydrothermal biotites (3.57 ± 0.02, 3.51 ± 0.02, 3.41 ± 0.01, and 3.37 ± 0.01 Ma) are associated with potassic alteration. These ages are younger than the youngest intrusion by ~300 k.y. recording the cooling of the system below 350 °C. Such a time gap can be explained by fluxing of hot magmatic fluids from deeper magmatic sources.

scholarly journals Re–Os Pyrite Geochronological Evidence of Three Mineralization Styles within the Jinchang Gold Deposit, Yanji–Dongning Metallogenic Belt, Northeast China

Minerals ◽  
2018 ◽  
Vol 8 (10) ◽  
pp. 448 ◽  
Author(s):  
Shun-Da Li ◽  
Zhi-Gao Wang ◽  
Ke-Yong Wang ◽  
Wen-Yan Cai ◽  
Da-Wei Peng ◽  
...  
Keyword(s):  
Gold Deposit ◽  
Northeast China ◽  
Gold Mineralization ◽  
Metallogenic Belt ◽  
Isotopic Analyses ◽  
Mantle Sources ◽  
Stage 1 ◽  
Geochronological Evidence ◽  
Gold Bearing

The Jinchang gold deposit is located in the eastern Yanji–Dongning Metallogenic Belt in Northeast China. The orebodies of the deposit are hosted within granite, diorite, and granodiorite, and are associated with gold-mineralized breccia pipes, disseminated gold in ores, and fault-controlled gold-bearing veins. Three paragenetic stages were identified: (1) early quartz–pyrite–arsenopyrite (stage 1); (2) quartz–pyrite–chalcopyrite (stage 2); and (3) late quartz–pyrite–galena–sphalerite (stage 3). Gold is hosted predominantly within pyrite. Pyrite separated from quartz–pyrite–arsenopyrite cement within the breccia-hosted ores (Py1) yield a Re–Os isochron age of 102.9 ± 2.7 Ma (MSWD = 0.17). Pyrite crystals from the quartz–pyrite–chalcopyrite veinlets (Py2) yield a Re–Os isochron age of 102.0 ± 3.4 Ma (MSWD = 0.2). Pyrite separated from quartz–pyrite–galena–sphalerite veins (Py3) yield a Re–Os isochron age of 100.9 ± 3.1 Ma (MSWD = 0.019). Re–Os isotopic analyses of the three types of auriferous pyrite suggest that gold mineralization in the Jinchang Deposit occurred at 105.6–97.8 Ma (includes uncertainty). The initial 187Os/188Os values of the pyrites range between 0.04 and 0.60, suggesting that Os in the pyrite crystals was derived from both crust and mantle sources.

scholarly journals Rare and Critical Metals in Pyrite, Chalcopyrite, Magnetite, and Titanite from the Vathi Porphyry Cu-Au±Mo Deposit, Northern Greece

Minerals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 630
Author(s):  
Christos L. Stergiou ◽  
Vasilios Melfos ◽  
Panagiotis Voudouris ◽  
Lambrini Papadopoulou ◽  
Paul G. Spry ◽  
...  
Keyword(s):  
Inductively Coupled Plasma ◽  
Mineral Chemistry ◽  
Critical Metals ◽  
Northern Greece ◽  
Inductively Coupled ◽  
Porphyry Cu ◽  
Icp Ms ◽  
Quartz Monzonite ◽  
Ore Minerals ◽  
Plasma Mass Spectrometry

The Vathi porphyry Cu-Au±Mo deposit is located in the Kilkis ore district, northern Greece. Hydrothermally altered and mineralized samples of latite and quartz monzonite are enriched with numerous rare and critical metals. The present study focuses on the bulk geochemistry and the mineral chemistry of pyrite, chalcopyrite, magnetite, and titanite. Pyrite and chalcopyrite are the most abundant ore minerals at Vathi and are related to potassic, propylitic, and sericitic hydrothermal alterations (A- and D-veins), as well as to the late-stage epithermal overprint (E-veins). Magnetite and titanite are found mainly in M-type veins and as disseminations in the potassic-calcic alteration of quartz monzonite. Disseminated magnetite is also present in the potassic alteration in latite, which is overprinted by sericitic alteration. Scanning electron microscopy and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) analyses of pyrite and chalcopyrite reveal the presence of pyrrhotite, galena, and Bi-telluride inclusions in pyrite and enrichments of Ag, Co, Sb, Se, and Ti. Chalcopyrite hosts bornite, sphalerite, galena, and Bi-sulfosalt inclusions and is enriched with Ag, In, and Ti. Inclusions of wittichenite, tetradymite, and cuprobismutite reflect enrichments of Te and Bi in the mineralizing fluids. Native gold is related to A- and D-type veins and is found as nano-inclusions in pyrite. Titanite inclusions characterize magnetite, whereas titanite is a major host of Ce, Gd, La, Nd, Sm, Th, and W.

The Age of Gold Mineralization in the Yana–Kolyma Metallogenic Belt, Northeastern Russia: First Data of Re–Os Isotope Geochronology of Native Gold

2021 ◽  
Vol 15 (4) ◽  
pp. 293-306
Author(s):  
V. Yu. Fridovsky ◽  
N. A. Goryachev ◽  
R. Sh. Krymsky ◽  
M. V. Kudrin ◽  
B. V. Belyatsky ◽  
...  
Keyword(s):  
Native Gold ◽  
Gold Mineralization ◽  
Northeastern Russia ◽  
Isotope Geochronology ◽  
Metallogenic Belt ◽  
Os Isotope

scholarly journals Sb- Bi-Bearing Metallogeny of the SerboMacedonian-Rhodope Metallogenic Belt (SRMB)

2019 ◽  
Vol 55 (1) ◽  
pp. 34 ◽  
Author(s):  
Ananias Tsirambides ◽  
Anestis Filippidis
Keyword(s):  
European Union ◽  
Mineral Assemblage ◽  
Balkan Peninsula ◽  
The European Union ◽  
Rare Metals ◽  
Ore Deposit ◽  
Porphyry Cu ◽  
Metallogenic Belt ◽  
Critical Metal ◽  
The Eu

Various types of deposits such as carbonate-replacement Pb-Zn-Ag-Au, porphyry Cu-Mo-Au, stratiform volcano-sedimentary, isolated magmatic-hydrothermal and skarns compose the Serbomacedonian-Rhodope Metallogenic Belt (SRMB), which intersects with a NNW-SSE trend the Balkan Peninsula. This arcuate belt is about 500 km long and 130-180 km wide. Sb-Bi alloys and Ag-Cu-Pb-Sb-Bi sulfosalts have been discovered in some metal assemblages in the SRMB. The European Union (EU) is highly dependent on critical and rare metals, such as Sb and Bi, which are very important for a sustainable development. Greece is one of the EU countries with the most potential for supplying the strategic metal Sb in the future, since it hosts a significant ore deposit at Rizana/Lachanas (central Macedonia). Here, the stibnite reserves are 5,000 t (proven) and 50,000-100,000 t (indicated). Both have average Sb=0.3 wt%. In addition, at the same district, there are 1000 t (proven) of wolframite. Another promising Sb-bearing mineral assemblage exists at Alshar (North Macedonia). Here, the stibnite reserves are >20,000 t (indicated) with average Sb=0.5 wt%. At both mineralization districts further investigations are needed to determine the grade and the proven reserves of the critical metal Sb. Until today none encouraging site has been located in the SRMB for remarkable Bi-bearing ore.

Element transport and enrichment during propylitic alteration in Paleozoic porphyry Cu mineralization systems: Insights from chlorite chemistry

2018 ◽  
Vol 102 ◽  
pp. 437-448 ◽  
Author(s):  
Bing Xiao ◽  
Huayong Chen ◽  
Pete Hollings ◽  
Yunfeng Wang ◽  
Juntao Yang ◽  
...  
Keyword(s):  
Porphyry Cu ◽  
Element Transport ◽  
Propylitic Alteration

Discriminating porphyry and endoskarn-forming magmatic-hydrothermal systems: a case study from the Tonglushan Fe-Cu-(Au) deposit, Daye district, China

2020 ◽  
Author(s):  
Fei Zhang ◽  
Ben J. Williamson ◽  
Hannah S.R. Hughes ◽  
Gavyn Rollinson
Keyword(s):  
Hydrothermal Systems ◽  
Econ Geol ◽  
Late Triassic ◽  
Potassic Alteration ◽  
Late Mesozoic ◽  
Metallogenic Belt ◽  
Geological Conditions ◽  
Ore Minerals ◽  
The Many ◽  
Host Rocks

&lt;p&gt;Porphyry magmatic systems emplaced within carbonate host rocks constitute a major source of the world&amp;#8217;s Cu, Mo, Pb, Zn and Au [1]. Mineralisation is generally either porphyry-style or endoskarn-style within, or porphyry-, exoskarn- or manto-style outside the porphyry intrusion(s) [1,2]. Genetic models for porphyry and skarn mineralisation are well established, however questions remain as to why endoskarn- rather than porphyry-style mineralisation predominates within certain systems and regions. This is the case in Japan, for example, where there are very few signs of porphyry mineralisation despite generally favourable geological conditions, but there are large endoskarn and exoskarn deposits [3]. Recent studies show that magmas can assimilate large volumes of crustal carbonates, potentially providing a significant amount of CO&lt;sub&gt;2&lt;/sub&gt; to late and post-magmatic hydrothermal fluids [4]. High levels of CO&lt;sub&gt;2&lt;/sub&gt; in magmatic-hydrothermal systems may favour endoskarn formation and affect metal fractionation and solubility of ore minerals [5]. In this contribution, we test the hypothesis that endoskarn alteration may eliminate porphyry-style Cu mineralisation and mobilise Cu into other parts of the pluton and surrounding carbonate wall-rocks (exoskarns). &amp;#160;&lt;/p&gt;&lt;p&gt;To address this hypothesis, the Daye ore district in the Middle-Lower Yangtze River metallogenic belt was selected for study as it hosts porphyry-, exoskarn- and endoskarn-styles of mineralisation [6]. The porphyry and skarn deposits lie within Late Mesozoic intrusions or along their contacts with Late Triassic carbonates. From among the many porphyry-related systems, the Tonglushan Fe-Cu-(Au) endoskarn-bearing system was selected for detailed field-, light microscopy-, cathodoluminescence-, SEM- and QEMSCAN&amp;#174;-based genetic studies. The current study is mainly based on a comparison of samples from a single core through altered granite, endoskarn and exoskarn. From preliminary data for the Tonglushan system, the granites distal to the endoskarn were affected by Na-Ca alteration (replacement of intermediate composition plagioclase with albite, calcite and chlorite, and hornblende with calcite and chlorite), potassic alteration (replacement of plagioclase with K-feldspar), and later quartz-calcite veining. The endoskarn, which shows relict minerals and textures from the granite, underwent: 1) sericitic alteration, 2) prograde endoskarn formation, 3) retrograde endoskarn formation, 4) potassic alteration and 5) late carbonate veining stage. The textural relationships of oxide minerals in exoskarn and endoskarn indicate that magnetite and hematite likely formed during Stage 3, whereas Cu-(Au) mineralisation in the exoskarn is considered to be genetically associated with the potassic alteration phase, with precipitation of sulphides caused by acid neutralisation within the carbonates.&lt;/p&gt;&lt;p&gt;References:&lt;/p&gt;&lt;p&gt;[1] Sillitoe R (2010) Econ Geol 105:3-41&lt;/p&gt;&lt;p&gt;[2] Meinert L D et al. (2005) Econ Geol 100:299-336&lt;/p&gt;&lt;p&gt;[3] Ishihara S (1980) Mining Geol 30:59-62&lt;/p&gt;&lt;p&gt;[4] Carter L B and Dasgupta R (2016) Geochem Geophys Geosyst 17:3893-3916&lt;/p&gt;&lt;p&gt;[5] Lowenstern J B (2001) Mineral Deposita 36:490-502&lt;/p&gt;&lt;p&gt;[6] Zhai Y S et al. (1996) Ore Geol Rev 11:229-248&lt;/p&gt;

scholarly journals Linking Mineralogy to Lithogeochemistry in the Highland Valley Copper District: Implications for Porphyry Copper Footprints

2020 ◽  
Vol 115 (4) ◽  
pp. 871-901 ◽  
Author(s):  
Kevin Byrne ◽  
Guillaume Lesage ◽  
Sarah A. Gleeson ◽  
Stephen J. Piercey ◽  
Philip Lypaczewski ◽  
...  
Keyword(s):  
Infrared Imaging ◽  
White Mica ◽  
Coarse Grained ◽  
Late Triassic ◽  
Material Transfer ◽  
Rock Composition ◽  
Porphyry Cu ◽  
Propylitic Alteration ◽  
Shortwave Infrared ◽  
Pathfinder Elements

Abstract The Highland Valley Copper porphyry deposits, hosted in the Late Triassic Guichon Creek batholith in the Canadian Cordillera, are unusual in that some of them formed at depths of at least 4 to 5 km in cogenetic host rocks. Enrichments in ore and pathfinder elements are generally limited to a few hundred meters beyond the pit areas, and the peripheral alteration is restricted to narrow (1–3 cm) halos around a low density of prehnite and/or epidote veinlets. It is, therefore, challenging to recognize the alteration footprint peripheral to the porphyry Cu systems. Here, we document a workflow to maximize the use of lithogeochemical data in measuring changes in mineralogy and material transfer related to porphyry formation by linking whole-rock analyses to observed alteration mineralogy at the hand specimen and deposit scale. Alteration facies and domains were determined from mapping, feldspar staining, and shortwave infrared imaging and include (1) K-feldspar halos (potassic alteration), (2) epidote veins with K-feldspar–destructive albite halos (sodic-calcic alteration), (3) quartz and coarse-grained muscovite veins and halos and fine-grained white-mica–chlorite veins and halos (white-mica–chlorite alteration), and two subfacies of propylitic alteration comprising (4) prehnite veinlets with white-mica–chlorite-prehnite halos, and (5) veins of epidote ± prehnite with halos of chlorite and patchy K-feldspar. Well-developed, feldspar-destructive, white-mica alteration is indicated by (2[Ca-C] + N + K)/Al values &lt;0.85, depletion in CaO and Na2O, enrichment in K2O, and localized SiO2 addition and is spatially limited to within ~200 m of porphyry Cu mineralization. Localized K2O, Fe2O3, and depletion in Cu, and some enrichment in Na2O and CaO, occurs in sodic-calcic domains that form a large (~34 km2) nonconcentric footprint outboard of well-mineralized and proximal zones enriched in K. Water and magmatic CO2-rich propylitic and sodic-calcic–altered rocks form the largest lithogeochemical footprint to the mineralization in the Highland Valley Copper district (~60 km2). Calcite in the footprint is interpreted to have formed via phase separation of CO2 from a late-stage magmatic volatile phase. Several observations from this study are transferable to other porphyry systems and have implications for porphyry Cu exploration. Feldspar staining and shortwave infrared imaging highlight weak and cryptic alteration that did not cause sufficient material transfer to be confidently distinguished from protolith lithogeochemical compositions. Prehnite can be a key mineral phase in propylitic alteration related to porphyry genesis, and its presence can be predicted based on host-rock composition. Sodic-calcic alteration depletes the protolith in Fe (and magnetite) and, therefore, will impact petrophysical and geophysical characteristics of the system. Whole-rock loss on ignition and C and S analyses can be used to map enrichment in water and CO2 in altered rocks, and together these form a large porphyry footprint that extends beyond domains of enrichment in ore and pathfinder elements and of pronounced alkali metasomatism.

Sign in / Sign up

Export Citation Format

Share Document