scholarly journals Massive Sulfide Ores in the Iberian Pyrite Belt: Mineralogical and Textural Evolution

Minerals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 653 ◽  
Author(s):  
Gabriel R. Almodóvar ◽  
Lola Yesares ◽  
Reinaldo Sáez ◽  
Manuel Toscano ◽  
Felipe González ◽  
...  
Keyword(s):  
Mineral Exploration ◽  
Spatial Relationship ◽  
Massive Sulfide ◽  
Iberian Pyrite Belt ◽  
Depositional Environments ◽  
Massive Sulfides ◽  
Textural Evolution ◽  
The North ◽  
Proposed Model ◽  
Replacement Process

The Iberian Pyrite Belt (IPB) is recognized as having one of the major concentrations of volcanogenic massive sulfide (VMS) deposits on Earth. Original resources of about 2000 Mt of massive sulfides have been reported in the province. Recent classifications have considered the IPB deposits as the bimodal siliciclastic subtype, although major differences can be recognized among them. The main ones concern the hosting rocks. To the north, volcanic and volcaniclastic depositional environments predominate, whereas to the south, black shale-hosted VMS prevail. The mineral composition is quite simple, with pyrite as the main mineral phase, and sphalerite, galena, and chalcopyrite as major components. A suite of minor minerals is also present, including arsenopyrite, tetrahedrite–tennantite, cobaltite, Sb–As–Bi sulfosalts, gold, and electrum. Common oxidized phases include magnetite, hematite, cassiterite, and barite. The spatial relationship between all these minerals provides a very rich textural framework. A careful textural analysis reported here leads to a general model for the genetic evolution of the IPB massive sulfides, including four main stages: (1) Sedimentary/diagenetic replacement process on hosting rocks; (2) sulfides recrystallization at rising temperature; (3) metal distillation and sulfides maturation related to late Sb-bearing hydrothermal fluids; and (4) metal remobilization associated with the Variscan tectonism. The proposed model can provide new tools for mineral exploration as well as for mining and metallurgy.

Pb-Nd-Sr Isotope Geochemistry of Metapelites from the Iberian Pyrite Belt and Its Relevance to Provenance Analysis and Mineral Exploration Surveys

2021 ◽  
Author(s):  
Filipa Luz ◽  
António Mateus ◽  
Ezequiel Ferreira ◽  
Colombo G. Tassinari ◽  
Jorge Figueiras
Keyword(s):  
Isotope Geochemistry ◽  
Mineral Exploration ◽  
Hanging Wall ◽  
Massive Sulfide ◽  
Iberian Pyrite Belt ◽  
Isotopic Signature ◽  
Sr Isotope ◽  
Provenance Analysis ◽  
Basement Rocks ◽  
World Class

Abstract The boundary in the Iberian Pyrite Belt is a world-class metallogenic district developed at the Devonian-Carboniferous boundary the Iberian Variscides that currently has seven active mines: Neves Corvo (Cu-Zn-Sn) and Aljustrel (Cu-Zn) in Portugal, and Riotinto (Cu), Las Cruces (Cu), Aguas Teñidas (Cu-Zn-Pb), Sotiel-Coronada (Cu-Zn-Pb), and La Magdalena (Cu-Zn-Pb) in Spain. The Iberian Pyrite Belt massive sulfide ores are usually hosted in the lower sections of the volcano-sedimentary complex (late Famennian to late Visean), but they also occur in the uppermost levels of the phyllite-quartzite group at the Neves Corvo deposit, stratigraphically below the volcano-sedimentary complex. A Pb-Nd-Sr isotope dataset was obtained for 98 Iberian Pyrite Belt metapelite samples (from Givetian to upper Visean), representing several phyllite-quartzite group and volcano-sedimentary complex sections that include the footwall and hanging-wall domains of ore horizons at the Neves Corvo, Aljustrel, and Lousal mines. The combination of whole-rock Nd and Sr isotopes with Th/Sc ratios shows that the siliciclastic components of Iberian Pyrite Belt metapelites are derived from older quartz-feldspathic basement rocks (–11 ≤ εNdinitial(i) ≤ –8 and (87Sr/86Sr)i up to 0.727). The younger volcano-sedimentary complex metapelites (upper Tournaisian) often comprise volcanic-derived constituents with a juvenile isotopic signature, shifting the εNdi up to +0.2. The Pb isotope data confirm that the phyllite-quartzite group and volcano-sedimentary complex successions are crustal reservoirs for metals found in the deposits. In Neves Corvo, where there is more significant Sn- and Cu-rich mineralization, the higher (206Pb/204Pb)i and (207Pb/204Pb)i values displayed by phyllite-quartzite group and lower volcano-sedimentary complex metapelites (up to 15.66 and 18.33, respectively) suggest additional contributions to the metal budget from a deeper and more radiogenic source. The proximity to Iberian Pyrite Belt massive sulfide ore systems hosted in metapelite successions is observed when (207Pb/204Pb)i >15.60 and Fe2O3/TiO2 or (Cu+Zn+Pb)/Sc >10. These are important criteria that should be considered in geochemical exploration surveys designed for the Iberian Pyrite Belt.

scholarly journals A self-potential investigation of submarine massive sulfides: Palinuro Seamount, Tyrrhenian Sea

Geophysics ◽  
2017 ◽  
Vol 82 (6) ◽  
pp. A51-A56 ◽  
Author(s):  
Roxana Safipour ◽  
Sebastian Hölz ◽  
Jesse Halbach ◽  
Marion Jegen ◽  
Sven Petersen ◽  
...  
Keyword(s):  
Electric Fields ◽  
Precious Metals ◽  
Massive Sulfide ◽  
Tyrrhenian Sea ◽  
Marine Research ◽  
Massive Sulfides ◽  
The North ◽  
Self Potential ◽  
Hydrothermal Venting ◽  
Field Strengths

The self-potential (SP) method detects naturally occurring electric fields, which may be produced by electrically conductive mineral deposits, such as massive sulfides. Recently, there has been increasing interest in applying this method in a marine environment to explore for seafloor massive sulfide (SMS) deposits, which may contain economic resources of base and precious metals. Although SMS sites that are associated with active venting and are not buried under sediment cover are known to produce an SP signal, the effectiveness of the method at detecting inactive and sediment-covered deposits remained an outstanding question. We built an instrument capable of recording SP data in a marine setting. We carried out a test of the instrument at the Palinuro Seamount in the Tyrrhenian Sea. Palinuro is one of only a few known sites containing an SMS occurrence that is buried under sediment and not associated with active hydrothermal venting, although diffuse seepage of hydrothermal fluids is known to occur at the site. Elevated electric field strengths recorded in and near the site of previously drilled massive sulfide samples are on the order of [Formula: see text]. A second zone of high field strengths was detected to the north of the drilling area where gravity coring later confirmed the existence of massive sulfides. Our observations indicate that an SP signal can be observed at the site of SMS mineralization even when the mineralized zone is shallowly buried and active hydrothermal venting is not present. These observations could aid in the planning of future marine research expeditions that use the SP method in the exploration of seafloor massive sulfides.

HIGH-PRECISION CA-ID-TIMS AGE CONSTRAINTS ON THE NIBLACK Cu-Zn-Au-Ag DEPOSITS: A NEOPROTEROZOIC VOLCANIC-HOSTED MASSIVE SULFIDE DEPOSIT IN THE NORTH AMERICAN CORDILLERA

2021 ◽  
Author(s):  
James Oliver ◽  
Brian McNulty ◽  
Richard Friedman
Keyword(s):  
Mineral Exploration ◽  
Massive Sulfide ◽  
Sulfide Deposit ◽  
Ionization Mass ◽  
The North ◽  
Felsic Volcanism ◽  
Vhms Deposits ◽  
Sound Unit ◽  
Felsic Volcanic ◽  
Age Constraints

Abstract The Neoproterozoic-Cambrian Wales Group and Ordovician-early Silurian Moira Sound unit of Prince of Wales Island, Alaska, USA, host numerous volcanic-hosted massive sulfide (VHMS) deposits and occurrences, including the Niblack VHMS deposits. Previous attempts to determine the age of the felsic volcanic host rocks in the Niblack area have resulted in conflicting results and interpretations. We have utilized chemical abrasion-isotope dilution-thermal ionization mass spectrometry (CA-ID-TIMS) U-Pb zircon geochronology to acquire highly precise crystallization and maximum depositional ages for a total of six samples of felsic volcanic and intrusive rocks from Niblack. This study establishes age constraints for the Niblack felsic succession of (1) crystallization ages of 565.1 ± 0.9 and 564.8 ± 1.0 Ma for coherent rhyolite flows, (2) maximum depositional ages of 565.3 ± 0.9 and 565.2 ± 0.9 Ma for felsic volcaniclastic rocks, (3) a crystallization age of 565.2 ± 0.9 Ma for quartz-feldspar-phyric subvolcanic sill, and (4) a crystallization age of 564.8 ± 1.0 Ma for a felsic dike that crosscuts the Niblack felsic succession. These results indicate that the ~200-m-thick Niblack felsic succession and VHMS deposits formed during one episode of felsic volcanism at ca. 565.1 ± 0.9 Ma and are thus confirmed as part of the Neoproterozoic Wales Group. Results of this study provide the first chronostratigraphic framework for felsic volcanism associated with VHMS deposit formation at Niblack and have implications for mineral exploration on Prince of Wales Island and elsewhere in the Alexander terrane.

Massive sulfide deposits of the Noranda area, Quebec. I. The Horne mine

1991 ◽  
Vol 28 (4) ◽  
pp. 465-488 ◽  
Author(s):  
T. J. Barrett ◽  
S. Cattalani ◽  
W. H. MacLean
Keyword(s):  
Volcanic Rocks ◽  
Massive Sulfide ◽  
Volcanic Edifice ◽  
Sulfide Deposits ◽  
Massive Sulfides ◽  
The North ◽  
Massive Sulfide Deposits ◽  
Volcaniclastic Rocks ◽  
Lower Temperature ◽  
Low K

The Horne massive sulfide deposits occur within volcanic rocks of the Blake River Group of the Archean Abitibi greenstone belt. The orebodies dip subvertically within rhyolitic flows, breccias, and tuffs that are bounded by the Andesite and the Horne Creek faults. Least-altered rhyolites have low K2O contents and other geochemical features that place them within the FII tholeiitic series. Graded volcaniclastic beds, metal zoning in the orebodies, and locations of chloritized–mineralized rhyolites indicate that the volcanic sequence youngs to the north. The volcanics in the fault wedge are variably silicified and sericitized, and local zones in the orebody sidewalls and footwall are chloritized.The H orebodies formed podiform masses up to 120 m wide, 100 m thick, and 300 m in downplunge extent, consisting of chalcopyrite–pyrrhotite–pyrite Au ore. Between 1927 and 1976, 54 × 106 t of ore were recovered, grading 2.2% Cu, 6.1 g/t Au, and 13.0 g/t Ag (Zn and Pb are &lt0.1% and <0.01%, respectively). A semicontinuous Cu-rich base (up to ~15 m thick) exists above the footwall and adjacent to the sidewalls of the orebodies. The ore changes stratigraphically upwards from a chalcopyrite-rich base, through middle pyrrhotite–pyrite-rich zones, to upper pyrite-rich zones. Au enrichments occur in some of the Cu-rich ores but also in overlying pyritic ores and in adjacent host volcanics. Cu–Au-bearing chloritized rhyolites occur mainly in the western and eastern sidewalls and at downplunge terminations of the H orebodies.The No. 5 zone occurs at lower mine levels and consists of numerous, partly overlapping Zn-bearing pyritic lenses up to 30 m thick, within mineralized rhyolitic breccias and tuffs. The No. 5 zone extends up to 750 m along strike and at least 1500 m downdip, with high-pyrite reserves of ~22 × 106 t between the 21st and 39th levels, grading 1.2% Zn, 0.15% Cu, and 1.4 g/t Au. Massive pyritic lenses are richer in Zn (> 50 ×) and Pb, Ag, As, Cd, and Sb relative to the H orebodies but are low in Cu and Au.The restored stratigraphic level of the H orebodies and No. 5 zone was dominated from south to north by rhyolite flows and breccias, then rhyolite breccias and tuffs. The volcanic rocks are interpreted as proximal to distal facies on a volcanic edifice that was affected by widespread silicification and sericitization. A graben system on the flank of the edifice became the depositional site of the H orebodies. High-temperature fluid discharge occurred along the fault-bounded graben margins, producing zones of chloritization and stringer-type Cu mineralization ± Au in rhyolites, and infilling the grabens with Cu-bearing massive sulfides. Lower on the edifice, in the No. 5 zone, Zn-bearing pyritic sulfide lenses accumulated within broader, breccia-based depressions roughly on strike with the H orebodies. Mineralization in the No. 5 zone may reflect lower temperature, more diffuse fluid discharge through a permeable sequence of volcaniclastic rocks.

Depositional environments of limestones from the Taiyuan Formation in the North China Block interpreted from REE proxies

2020 ◽  
Vol 35 (2) ◽  
Author(s):  
Dawei Lv ◽  
Wengui Fan ◽  
John I. Ejembi ◽  
Dun Wu ◽  
Dongdong Wang ◽  
...  
Keyword(s):  
North China ◽  
Depositional Environments ◽  
North China Block ◽  
The North ◽  
Taiyuan Formation

Depositional environments and paleogeography in the Albian Moosebar Formation and adjacent fluvial Gladstone and Beaver Mines formations, Alberta

1984 ◽  
Vol 21 (6) ◽  
pp. 698-714 ◽  
Author(s):  
David R. Taylor ◽  
Roger G. Walker
Keyword(s):  
Brackish Water ◽  
Late Jurassic ◽  
Major Change ◽  
Depositional Environments ◽  
Fluvial Deposits ◽  
Maximum Thickness ◽  
The North ◽  
Major Exception ◽  
Flow Directions ◽  
Sand Bodies

The marine Moosebar Formation (Albian) has a currently accepted southerly limit at Fall Creek (Ram River area). It consists of marine mudstones with some hummocky and swaley cross-stratified sandstones indicating a storm-dominated Moosebar (Clearwater) sea. We have traced a tongue of the Moosebar southward to the Elbow River area (150 km southeast of Fall Creek), where there is a brackish-water ostracod fauna. Paleoflow directions are essentially northwestward (vector mean 318°), roughly agreeing with turbidite sole marks (329°) in the Moosebar of northeastern British Columbia.The Moosebar sea transgressed southward over fluvial deposits of the Gladstone Formation. In the Gladstone, thick channel sands (4–8 m) are commonly multistorey (up to about 15 m), with well developed lateral accretion surfaces. The strike of the lateral accretion surfaces and the orientation of the walls of channels and scours indicate northwestward flow (various vector means in the range 307–339°). The Moosebar transgression was terminated by construction of the Beaver Mines floodplain, with thick, multistorey sand bodies up to about 35 m thick. Flow directions are variable, but various vector means roughly cluster in the north to northeast segment. This indicates a major change in dispersal direction from the Gladstone and Moosebar formations.A review of many Late Jurassic and Cretaceous units shows a dominant dispersal of sand parallel to regional strike. This flow is mostly north-northwestward (Passage beds, Cadomin, Gladstone, Moosebar, Gates, Chungo), with the southeasterly dispersal of the Cardium being the major exception. Only at times of maximum thickness of clastic input (Belly River and higher units, and possibly Kootenay but there are no published paleocurrent data) does the sediment disperse directly eastward or northeastward from the Cordillera toward the Plains.

Overburden geochemical signature of the Lac des Iles platinum group element deposit, northwestern Ontario, Canada

2007 ◽  
Vol 44 (8) ◽  
pp. 1151-1168 ◽  
Author(s):  
Peter J Barnett
Keyword(s):  
Mineral Exploration ◽  
Shallow Groundwater ◽  
Soil System ◽  
Near Surface ◽  
Rock Fragments ◽  
The North ◽  
Northwestern Ontario ◽  
Airborne Contamination ◽  
The Many ◽  
Lac Des Iles

Many previously published studies of the behaviour of Pt and Pd in till and soils have been done in areas of complex stratigraphy or very thin overburden cover, making the interpretation of soil results difficult because of the many variables associated with these settings. At the Lac des Iles mine site in northwestern Ontario, there are excellent exposures of the overburden in a series of exploration trenches. Glacial dispersal trains can be observed in till (C horizon) geochemistry (e.g., Ni, Cr, Cu, and Co). Regional geochemical dispersal trains of elements, such as Ni, Cr, Mg, and Co associated with the North Lac des Iles intrusion, can be detected for about 4 km beyond the western margin of the Mine Block intrusion. Entire dispersal trains range from 5 to 7 km in length and about 1 to 2 km in width. The dispersal of North Lac des Iles intrusion rock fragments tends to mask the response of the Mine Block intrusion. Dispersal trains of Pt and Pd are not well defined and tend to be very short, <1 km in length, due to the initial low concentrations of these elements in C-horizon till samples from the Lac Des Iles area. An exception to this is the Pd dispersal train originating from the high-grade zone that is up to 3 km long. Pd, Pt, Ni, and Cu appear to be moving both within and out of the soil system downslope into surface and shallow groundwater. It is suggested that these elements, to varying degrees, are moving in solution. Airborne contamination from mine operations of the humus has adversely affected the ability to determine the effectiveness of humus sampling for mineral exploration at Lac des Iles. The airborne contamination likely influences the geochemical results from surface water, shallow groundwater, and near-surface organic bog samples, particularly for the elements Pd and Pt.

Isotope geochemistry tracks the maturation of submarine massive sulfide mounds (Iberian Pyrite Belt)

2018 ◽  
Vol 54 (6) ◽  
pp. 913-934 ◽  
Author(s):  
Jesús Velasco-Acebes ◽  
Fernando Tornos ◽  
Abiel T. Kidane ◽  
Michael Wiedenbeck ◽  
Francisco Velasco ◽  
...  
Keyword(s):  
Isotope Geochemistry ◽  
Massive Sulfide ◽  
Iberian Pyrite Belt

scholarly journals Indium and selenium distribution in the Neves-Corvo deposit, Iberian Pyrite Belt, Portugal

2018 ◽  
Vol 82 (S1) ◽  
pp. S5-S41 ◽  
Author(s):  
J. R. S. Carvalho ◽  
J. M. R. S. Relvas ◽  
A. M. M. Pinto ◽  
M. Frenzel ◽  
J. Krause ◽  
...  
Keyword(s):  
Massive Sulfide ◽  
Iberian Pyrite Belt ◽  
Sulfide Deposit ◽  
Massive Sulfide Deposit ◽  
Actual Distribution ◽  
Shear Structures ◽  
Ore Minerals ◽  
High Concentrations ◽  
Ore Types ◽  
Zinc Concentrate

ABSTRACTHigh concentrations of indium (In) and selenium (Se) have been reported in the Neves-Corvo volcanic-hosted massive sulfide deposit, Portugal. The distribution of these ore metals in the deposit is complex as a result of the combined effects of early ore-forming processes and late tectonometamorphic remobilization. The In and Se contents are higher in Cu-rich ore types, and lower in Zn-rich ore types. At the deposit scale, both In and Se correlate positively with Cu, whereas their correlations with Zn are close to zero. This argues for a genetic connection between Cu, In and Se in terms of metal sourcing and precipitation. However, re-distribution and re-concentration of In and Se associated with tectonometamorphic deformation are also processes of major importance for the actual distribution of these metals throughout the whole deposit. Although minor roquesite and other In-bearing phases were recognized, it is clear that most In within the deposit is found incorporated within sphalerite and chalcopyrite. When chalcopyrite and sphalerite coexist, the In content in sphalerite (avg. 1400 ppm) is, on average, 2–3 times higher than in chalcopyrite (avg. 660 ppm). The In content in stannite (avg. 1.3 wt.%) is even higher than in sphalerite, but the overall abundance of stannite is subordinate to either sphalerite or chalcopyrite. Selenium is dispersed widely between many different ore minerals, but galena is the main Se-carrier. On average, the Se content in galena is ~50 times greater than in either chalcopyrite (avg. 610 ppm) or sphalerite (avg. 590 ppm). The copper concentrate produced at Neves-Corvo contains very significant In (+Se) content, well above economic values if the copper smelters recovered it. Moreover, the high In content of sphalerite from some Cu-Zn ores, or associated with shear structures, could possibly justify, in the future, a selective exploitation strategy for the production of an In-rich zinc concentrate.

Sign in / Sign up

Export Citation Format

Share Document