Copper Ore Deposits Research Articles

Prehistoric copper from the Eastern Alps

The rich copper ore deposits in the Eastern Alps have long been considered as important sources for copper in prehistoric Central Europe. It is, however, not so clear which role each deposit played. To evaluate the amount of prehistoric copper production of the various mining regions it was attempted to link prehistoric metal artefacts with copper ores based on the geochemical characteristics of the ore deposits that have been exploited in ancient times. More than 120 ore samples from the well known mining districts Mitterberg, Viehhofen, Kitzbühel and Schwaz/Brixlegg have been analysed so far (lead isotope ratios, trace elements). Furthermore, about 730 archaeological copper/bronze artifacts were investigated and analysed. These results were combined with analytical data generated by previous archaeometallurgical projects in order to compile a substantial database for comparative studies. In the Early Bronze Age, most metal artifacts were made of copper or bronze with fahlore impurity patterns and most finds from this period match excellently the fahlore deposits in Schwaz and Brixlegg. At the end of the Early Bronze Age, a new variety of copper with lower concentrations of impurities appeared. The impurity patterns of these finds match the ores from the Mitterberg district. In the Middle Bronze Age, this variety of copper Dominated while in the Late Bronze Age fahlores from Schwaz and Brixlegg experienced a comeback. The reason for this may be a decline of the chalcopyrite mines or a rising demand for copper which could not be covered by the chalcopyrite mines alone. The finds of the Early Iron Age are of similar composition and continue the traditions of the Late Bronze Age.

Application of 57Fe Mössbauer spectroscopy as a tool for mining exploration of bornite (Cu5FeS4) copper ore

Nuclear resonance methods, including Mossbauer spectroscopy,are considered as unique techniques suitable for remote on-line mineralogical analysis. The employment of these methods provides potentially significant commercial benefits for mining industry. As applied to copper sulfide ores, Mossbauer spectroscopy method is suitable for the analysis noted. Bornite (formally Cu5FeS4) is a significant part of copper ore and identification of its properties is important for economic exploitation of commercial copper ore deposits. A series of natural bornite samples was studied by 57Fe Mossbauer spectroscopy. Two aspects were considered: reexamination of 57Fe Mossbauer properties of natural bornite samples and their stability irrespective of origin and potential use of miniaturized Mossbauer spectrometers MIMOS II for in-situ bornite identification. The results obtained show a number of potential benefits of introducing the available portative Mossbauer equipment into the mining industry for express mineralogical analysis. In addition, results of some preliminary 63,65Cu nuclear quadrupole resonance (NQR) studies of bornite are reported and their merits with Mossbauer techniques for bornite detection discussed.

Dating of U-rich heterogenite: New insights into U deposit genesis and U cycling in the Katanga Copperbelt

The Katanga Copperbelt region of the Democratic Republic of Congo hosts world-class cobalt deposits accounting for ∼50% of the world reserves. Heterogenite (CoOOH) is the most abundant Co-bearing secondary mineral in the region. Its occurrence is the result of oxidation of Cu–Co-sulfides and associated Co reprecipitation in the uppermost part of the deposits, during the Pliocene. In addition to sediment-hosted copper and cobalt ore deposits, the Katanga Copperbelt also hosts numerous uraniferous mineral occurrences and deposits, which can be associated with heterogenite. Within these deposits, heterogenite can have high concentrations of U (up to 3.5%) and Pb (up to ∼4%).In situ SIMS U–Pb ages were obtained for heterogenite samples from the U deposits of Shinkolobwe, Kalongwe and Kambove. These analyses yield distinct Neoproterozoic ages, at ∼876Ma, ∼823Ma and in the ∼720 to ∼670Ma age range. As the geological context prevailing at those times was not favorable for heterogenite formation, these ages most probably record geological events that are not the formation of the mineral itself. For instance, the heterogenites could have inherited the U–Pb signature of a U-rich mineral, most likely uraninite, formed and/or yet reworked at ∼876Ma, ∼823Ma and in the ∼720 to ∼670Ma time interval and spatially associated with primary Co-sulfides. In this hypothesis, the ages obtained in this paper are significant for understanding the cycling and re-deposition of U at given moments in the regional geological history.In such context, the ∼876Ma and the ∼823Ma age are consistent with syn-early diagenetic concentration of uranium in sediments of the Katanga basin. The ∼720 to ∼670Ma ages are interpreted as a phase of U remobilization related to hydrothermal fluid circulation induced by late Nguba proto-oceanic rifting or by early stages of Congo-Kalahari craton convergence, and associated hydrothermal circulation.

English

In contrast to the Neolithic or the Bronze Age, the social realities of the intervening periods are not well known in Anatolian archaeology. Thus, excavations at Camlibel Tarlasi, a site close to the later Hittite capital Hattusa, were undertaken to shed more light on this neglected time period. Camlibel Tarlasi is a small hamlet site dating into the mid fourth millennium BC, i.e. into the Late Chalcolithic. The location was used for a relatively short period of time – slightly longer than a century. Such small settlements are not often the focus of scientific investigation in Anatolia, but can produce quite interesting information. As became apparent, many of the activities at Camlibel Tarlasi were related to the presence of a small copper ore deposit in the vicinity. Plentiful remains of a copper-working cottage industry, including remains of ore, slag, crucibles and finished metal artefacts, were uncovered among the ruins of the prehistoric houses. Somewhat unexpected were indications of far-reaching contacts. Maritime shells must have travelled inland from the shores of either the Mediterranean or the Black Sea. The production and use of artificial steatite micro beads and the custom of cranial deformation point to influences from the upper Euphrates area. A casting mould for ring-shaped figurines establishes a link to the southern Balkans. The inhabitants of Camlibel Tarlasi also had great interest in exotic flint which arrived at the site in the shape of long retouched blades. While the source areas for flint objects are somewhat difficult to trace, the situation is much better for obsidian, which is another exotic material used for making tools at the site. Turkey has many sources of obsidian which were utilised over millennia for the production of stone tools. One of the most significant source areas for Near Eastern obsidian is located some 200km to the south of Camlibel Tarlasi, in Cappadocia. Smaller deposits, however, have recently been discovered in northern Anatolia as well, in much closer proximity to the site. The chemical composition of each separate flow of obsidian has a potentially unique elemental signature which allows for the source identification of obsidian artefacts through chemical analysis. A natural question arises in the context of Late Chalcolithic raw material acquisition strategies: did the residents of Camlibel Tarlasi acquire local obsidian or did they prefer more exotic obsidian materials for the production of their tools? Recent advancements in portable technologies, such as portable XRF analysers, have allowed us to characterise completely the entire assemblage of obsidian artefacts from the site, which using the traditional laboratory-based method would have been a prohibitively expensive and time consuming undertaking. With the help of a BIAA study grant, a representative sample was taken to the French National Centre for Scientific Research (CNRS) in Orleans to test the accuracy of the portable XRF results by using ICPMS – a robust technology which can measure accurately minute quantities of elements down to the scale of parts-per-billion (ppb) – and to identify the source areas. Comparative results indicate not only a clear correlation, verifying the portable XRF data, but also allow us to define clear groups of obsidian. Results indicate that the entire obsidian assemblage derives from exotic Cappadocian sources, namely from the well-known obsidian sources at Acigol, Golludag and Nenezi Dag, and not from more local sources in northcentral Anatolia. This is significant because Cappadocian obsidian can be found at many contemporary sites as far away as the southern Levant. It is clear that geographical proximity of the sources was not the decisive factor in the choice of obsidian supply. Although comparable data from more contemporaneous sites are needed to understand how exactly fourth millennium BC obsidian exchange worked, this study has demonstrated how Camlibel Tarlasi participated in overlapping exchange systems, maintaining communication with the wider world. Selection of obsidian artefacts from Camlibel Tarlasi

Research on Characteristics of Ore-Forming Fluids of Dahongshan Copper Ore Deposit

This paper analyzes the fluid inclusions, micro-thermometry, the pressure, salinity and pH of ore-forming solution, and isotopes of H and O, C and O of the Dahongshan copper deposit in Yunnan Province. The result shows that these inclusions are dominated by liquids (LH2O), gases and liquids (LH2O+VH2O), and daughter mineral-bearing (LH2O+VH2O+SNaCl) three-phase ones and the liquid inclusion accounts for about 50%, and the liquid composition mainly include Na+,K+,F-,Cl-. Homogenization temperatures at the early stage vary from 290°C to 330°C, with the peak value around 350°C, while at the late stage the figures vary from 160°C to 250°C, with the peak value 250°C. The general salinity ranges from 16.0 wt% to 35.9wt%, and the maximum reaches 45wt%. The value of δ18OH2O and δD in the mineral inclusion ranges from-1.15% to 6.61% and from-58% to-78% respectively. These isotopic data imply that the ore-forming fluids were mainly derived from the magmatic water, the metamorphic water and the meteoric water.

Udział Państwowe go Instytutu Geologicznego w rozwoju gospodarki narodowej

Wklad PIG w rozwoj gospodarki narodowej wyraza sie odkryciami kopalin uzytecznych, ktore są podstawą roznych galezi przemyslu, oraz wieloma osiągnieciami w zakresie badan hydrogeologicznych i geologiczno-inzynierskich. Do najwazniejszych osiągniec nalezą odkrycia unikatowych w skali światowej zloz: rud miedzi kolo Lubina, siarki rodzimej kolo Tarnobrzega, lubelskiego Zaglebia Weglowego, a takze wielu zloz: wegla brunatnego, soli kamiennej, polihalitow, cynku i olowiu, tytanomagnetytow z wanadem, kaolinu, barytu i duzej ilości zloz kopalin skalnych. Baza surowcowa Polski opiera sie na kopalinach uzytecznych umiejscowionych w ponad 4200 zlozach o lącznych zasobach powyzej 205 mld t. Na podstawie wartości wydobywanych surowcow mineralnych omowiono pozycje Polski wśrod krajow dysponujących wlasnymi surowcami mineralnymi. SHARE OF THE STATE GEOLOGICAL INSTITUTE IN DEVELOPMENT OF THE NATIONAL ECONOMICS During its 70 years of existence the State Geological institute has carried through the studies of a geological structure of the country to create the basis for exploration, exploitation and conservation of deposits and underground waters, and also for investigations of engineering-geological conditions. A harmonic development of the natural-cognitive assemblage of the Earth sciences connected with app lied and economic geology what is due to statutory foundations, ensures in suitable means for investigations and is a main factor that enables to receive good results of geological exploration works. A share of the institute in development of national economics is expressed by discoveries of deposits of mineral resources that form the basis for development of numerous industrial branches. Results of hydrogeological regional studies and investigations of restoration of underground water resources form also a very important achievement. These works gain a particular significance against common ecological impendency of waters. During reconstructing works and development of the country after the war, engineering-geological studies for large industrial objects as steelworks, electric power stations and hydrotechnical constructions have been of great importance. The most important achievements include unique in the world discoveries of copper ore deposits in the Lubin area, of native sulphur near Tarnobrzeg, of the Lublin Coal Basin and also of numerous deposits of brown coal, mine salt, polyhalites, zinc of numerous deposits of brown coal, mine salt, polyhalites, zinc and lead, titanomagnetites with vanadium, kaolin, barite and abundant deposits of rock materials. A resources basis of Poland is based on mineral raw materials located in over 4200 deposits, total resources of which exceed 205 mld tons. The analysis of values of exploited mineral products being subjected to international exchange proves that a total production value of the country constitutes 1% of the total world production and there-fore, Poland occupies the 22nd place in the world and 5th place in Europe. Abundance of the country in mineral products is larger than results from evaluation of the outpit as many resources (e.g. potash salts, some metal or chemical deposits) are not exploited. In spite of undoubted rich raw resources of Poland there are no sufficient deposits of natural oil and gas. These two products are the most valuable in the world production. If energetic resources are not taken into account (therefore also of the Polish hard and brown coals), then the value of the production of mineral resources puts our country at the 11th place in the world and the first one in Europe. A role played by the State Geological Institute in a discovery of these resources is undoubtful.

The impact of prehistoric mining activities on the environment: a multidisciplinary study at the fen Schwarzenbergmoos (Brixlegg, Tyrol, Austria)

The exploitation of copper ore deposits of the northern Greywacke Zone was initiated by the implementation of metallurgic technologies in the Eastern Alps thousands of years ago. This multi-proxy study aimed to detect prehistoric mining phases in the vicinity of a prominent copper ore deposit in the Lower Inn Valley. Therefore we studied a peat core from a fen using pollen, micro charcoal and geochemical analyses. In the same fen, an archaeological investigation revealed an ore beneficiation site, well dated by dendrochronological analysis to the Late Bronze Age (9th century b.c.). First hints of mining activities reflected by the occurrence of anthropogenic indicators in the pollen diagram, associated with elevated metal values, at the beginning of the Bronze Age might result from early mineral prospecting and metallurgical experiments around the use of fahlore. The local ore deposit was then abandoned until during the Bronze Age mining activities started to increase. This is reflected by an expansion of the pioneer species Pinus and Larix on mine spoil heaps in the proximity. Concomitantly metal ratios and micro charcoal increase. From about 1000 to 850 b.c. a strong impact of mining activities is displayed in the multi-proxy data. The local forest was partly cleared on and in the vicinity of the fen. According to dendrochronological data the ore beneficiation plant was in use from about 900 to 870 b.c. Until about 700 b.c. another period with moderate impact by mining activities in the further vicinity of the fen shows up.

Site Assessment for Astroparticle Detector Location in Evaporites of the Polkowice-Sieroszowice Copper Ore Mine, Poland

The aim of the work was to evaluate the possibilities of excavating a chamber for the Glacier detector, a cylinder with a 74 m diameter and 38 m height filled with 100 kT of liquid argon, in the Polkowice-Sieroszowice copper ore mine in the Legnica-Glogow Copper Area (LGOM). Two potential locations were analyzed in a rock salt layer more than 100 m thick at the depth of 1000 m and in the anhydrite layer of about 100 m thick at the depth of 650 m, both lying above the copper ore deposit. The numerical analyses, based on geological, geophysical, and geomechanical research, were carried out to determine the behavior of the system of the chamber and surrounding rock mass. Two creep laws have been adopted for rock salt in the numerical models, Norton and Lubby2. Their coefficients have been adjusted forin situmeasurements of the mine galleries convergence starting from the results of laboratory tests. Displacement and stresses of the rock salt in the chamber vicinity are much greater for the Lubby2 law. The displacements indicated at the chamber contour are the reason that the alternative location in the anhydrite layer was more advantageous.

Mineralogical and Chemical Constraints on the Provenance of Copper Age Polished Stone Axes of ‘Ljubljana Type’ from Caput Adriae

In this paper we show the results of a study concerning 42 axes, mainly discovered in the Copper Age pile dwellings of Ljubljansko barje (central Slovenia) and in the neighbouring areas of Caput Adriae. The studied shaft‐hole axes, characterized by homogeneous typology but slightly different raw materials, have been called ‘Ljubljana‐type’ axes (Lt). The raw materials show a common OIB‐like signature and metamorphic and spilitization features that recall oceanic conditions. The typological and geochemical characteristics and the very high percentage of Lt axes among the polished stone axe assemblages of Ljubljansko barje suggest that the raw material was probably gathered from one or more relatively small outcrops close to Ljubljansko barje. Similar igneous rock types outcrop in the presumably Palaeozoic diabase/shale complex (Eisenkappler Diabaszug), intruded by the northern Karawanken plutonic belt. A probable provenance from this area, particularly rich in copper ore deposit, would confirm the important role of Ljubljansko barje as a metallurgical district, as well as a strong relation between lithic raw materials and Cu cultivation districts during the Copper age.

Porphyry copper deposits: strike–slip faulting and throttling cupolas

Porphyry copper deposits sometimes form during the solidification of stocks of relatively oxidized magma of intermediate composition. Most workers have assumed ore-forming systems have special chemical attributes, but none has been found that is useful to guide exploration efforts. Stocks can form where strike–slip movements generate pull-apart pathways into which intrusions can rise from batholithic magma chambers. Upwelling of buoyant, bubble-bearing magma along the sides of a stock brings magmatic fluid to shallow depths where large bubbles can separate and pool under the cupola separating solidified igneous rock from mobile magma. Where rapid seismogenic movement on the bounding strike–slip fault ruptures the solidified, but hot and ductile carapace, downward propagating extension fractures can drain an accumulation of magmatic fluid. Decompression and cooling of fluid that jets upward into extension fractures causes mineral precipitation. Where strike–slip movements cause pull-aparts to dilate with sufficient recurrences – from decades to perhaps a century or so, throttling of the fluid accumulation acts as a safety valve that prevents explosive detonation of the system. Concurrently, the upward infiltration of magmatic fluid from the cupola is strongly focused into the pull-apart and generates the characteristic concentric alteration zones that guide exploration drilling. We conclude that porphyry copper ore deposits form where strike–slip movements are concurrent with the early stages of deep-seated bubbling (≳6 km) along the walls of a rapidly cooling stock of magma. Supergiant deposits form where the bubbling front extends into the top of a parent batholith.

Environmental Constraints on Ancient Copper Production in the Aravah Valley: Implications of the Newly Discovered Site of Khirbet Mana'iyah in Southern Jordan

The paper presents the recently discovered copper smelting site of Khirbet Mana'iyah and its relations to the copper ore deposits and ancient production systems in the nearby Timna Valley. The unique location of the site, in the foothills of southern Edom and away from the ore sources, sheds light on the environmental factors that shaped and limited the production of copper in this region through the millennia. The site is one of the largest ancient smelting camps in the southern Aravah known today, containing several hundred tons of slag. Thus, it was probably the search for fuel sources that dictated its location—near an extensive spread of acacia trees that grew on the alluvial fans on the eastern side of the Aravah. It is also suggested that the site, whose smelting technology cannot date earlier than the late 10th century BCE, represents an Iron IIA activity related to the transformation in smelting technology that followed the campaign of Pharaoh Shoshenq I to the southern Levant.

MINERALOGICAL AND PETROLOGICAL INVESTIGATIONS OF EARLY BRONZE AGE COPPER‐SMELTING REMAINS FROM THE KIECHLBERG (TYROL, AUSTRIA)

The prehistoric settlement on the Kiechlberg hilltop is located a few kilometres to the north‐east of Innsbruck, in the Tyrolean Inn Valley. Despite its rather isolated location, a multiphase settlement between the fifth and the second millennium bc was confirmed by archaeological investigations in 2007 and 2008. Metallurgical artefacts, such as copper ore fragments, copper slag and raw copper, as well as finished copper and bronze artefacts, are concentrated mainly in Late Copper Age to Middle Bronze Age layers. The chemical compositions of the slag and raw metals confirm Fe—Zn tetrahedrite–tennantite (fahlore) smelting. The ore was most probably imported from the 30–50 km distant copper ore deposits (mainly fahlore) of Schwaz–Brixlegg, in the Lower Inn Valley. The small amount of slag and the presence of slagged and thermally altered ceramic fragments suggest copper production in small‐scale workshops. Most probably, sulphide‐rich ores were smelted in crucibles in a hearth fire. The process was relatively reducing below the 2Sb + 1.5O2 → Sb2O3 reaction (−8.5 log fO2 at 1100°C), producing Sb‐rich (>10 wt% Sb in metal) raw copper. Inhomogeneous slag remains containing high amounts of sulphide and metal inclusions suggest a poor separation of the metal, matte (copper sulphide) and silicate/oxide melt during the smelting process.

Geology and ages of porphyry and medium- to high-sulphidation epithermal gold deposits of the continental margin of Northeast China

The continental margin of Northeast China, an important part of the continental margin-related West Pacific metallogenic belt, hosts numerous types of gold-dominated mineral deposits. Based on ore deposit geology and isotopic dating, we have classified hydrothermal gold–copper ore deposits in this region into four distinct types: (1) gold-rich porphyry copper deposits, (2) gold-rich porphyry-like copper deposits, (3) medium-sulphidation epithermal copper–gold deposits, and (4) high-sulphidation epithermal gold deposits. These ore deposits formed during four distinct metallogenic stages or periods, at 123.6 ± 2.5 Ma, 110–104 Ma, 104–102 Ma, and 95.0 ± 2 Ma, corresponding to periods of Cretaceous intermediate–acid volcanism and late-stage emplacement of hypabyssal magmas along the northern margin of the North China platform. The earliest stage of mineralization (123.6 ± 2.5 Ma) corresponds to the formation of medium-sulphidation epithermal copper – gold deposits and was associated with a continental margin magmatic arc system linked to subduction of the Pacific Plate beneath the Eurasia. This metallogenesis is closely related to high-K calc-alkaline intermediate–acid granite and pyroxene – diorite porphyry magmatism. The second and third stages of mineralization in the study area (110–104 Ma and 104–102 Ma, respectively) correspond to the formation of gold-rich porphyry copper, porphyry-like copper, and high-sulphidation gold deposits, with metallogenesis closely related to sodic or adakitic magmatism. These magmas formed in a continental margin magmatic arc system related to oblique subduction of the Pacific Plate beneath the Eurasia, as well as mixing of crust-derived remelted granitic and mantle-derived adakitic magmas. During the final stage of mineralization (95.0 ± 2 Ma), metallogenesis was closely related to sodic or adakitic magmatism, with diagenesis and metallogenesis related to the disintegration or destruction of the Pacific Plate, which was subducted beneath the Eurasian Plate during the Mesozoic.

Geological Characteristics and Ore‐forming Time of the Dexing Porphyry Copper Ore Mine in Jiangxi Province

Abstract:The Dexing porphyry copper ore mine is located in the Qin‐Hang metallogenic belt between the Yangtze block and the Cathaysia block. It is a giant porphyry copper mine in China, including 3 ore districts: Tongchang, Fujiawu and Zhushahong. Our analyses of Re in molybdenite indicate that the ore‐forming material of the copper ore deposits in Dexing should be mainly mantle‐derived. Our study fills in a gap in the study of formation time of the Dexing copper mine, and further proves that the copper ore deposits in the three ore districts should be formed simultaneously, about 170 Ma, belonging to the early Yanshan period, and that the formation time of the copper ore deposits should be consistent with the formation time of granodiorite porphyry in which the copper ore deposits are hosted. Promising areas for seeking porphyry copper ore deposits is predicated to be the west or southwest of Dexing.

The earth observing-1 (eo-1) satellite data for geological mapping, southeastern segment of the central Iranian volcanic belt, Iran

This investigation used Earth Observing-1 (EO-1) ALI (advanced land imager) and hyperion data to extract the geological and mineralogical information for identifying hydrothermal alteration zones associated with porphyry copper deposits in southeastern segment of the Central Iranian Volcanic Belt, SE Iran. A band ratio derived from image spectra (4/2, 8/9, 3 in RGB) has been developed to identify lithological units and hydrothermally altered rocks using ALI data in a regional scale. Analytical imaging and geophysics (AIG)-Developed Hyperspectral Analysis processing methods were tested on the shortwave infrared bands of hyperion for mapping mineral assemblages in hydrothermal alteration zones associated with two known copper ore deposits, namely Sar Cheshmeh and Meiduk. The methods produced image map of spectrally predominant minerals in alteration zones using hyperion data. Therefore, phyllic, argillic, and propylitic alteration zones were significantly discriminated from surrounding country rock. The spatial distribution of identified hydrothermal alteration zones has been confirmed by spectral reflectance measurements, XRD analysis and in-situ inspection. The research presented here indicated that lithological units, hydrothermally altered rocks, and hydrothermal alteration zones associated with porphyry copper mineralization can be accurately mapped by ALI and hyperion data at both regional and district scales. Key words: Advanced land imager (ALI), hyperion, analytical imaging and geophysics (AIG)-developed hyperspectral analysis processing methods, Central Iranian Volcanic Belt.

SIMS U–Pb dating of uranium mineralization in the Katanga Copperbelt: Constraints for the geodynamic context

The Katanga Copperbelt, in the southeastern part of the Democratic Republic of the Congo (DRC), occurs within the Pan-African Lufilian fold-and-thrust belt and hosts numerous uraniferous mineral occurrences in addition to the world-class sediment-hosted copper and cobalt ore deposits. In the 1950s and 1960s, Cahen et al. gave a relatively wide range of U mineralization ages, using U–Pb dating on whole-rock samples. Although these ages nowadays appear as inaccurate because of large error ranges, they were frequently used to discuss the regional geodynamic events. This paper offers a reappraisal of the age range previously published, using in-situ SIMS U–Pb analyses. Based on these analyses, two ages are regarded as analytically reliable and significant (652.3 ± 7.3 Ma and 530.1 ± 5.9 Ma), and hence as having implications for the understanding of geological and geodynamic context in the study area. In the Katanga Copperbelt, the siliciclastic rocks of the Lower Roan Group are slightly enriched in uranium. A major U mineralization/(re-)mobilization episode took place at ~ 652 Ma, during proto-oceanic rift basin development. This phase took place in an extensional tectonic regime and led to the (re-)mobilization of U within fractures and voids. Such deposits are observed along the ~ 250 km-long Kalongwe–Luishia tectonic lineament. This metal concentration was reworked at ~ 530 Ma, at the occasion of the climax of Lufilian deformation and metamorphism. This event gave rise to the U deposits in the southern border of the Katanga Copperbelt (and in Northern Zambia). The Kolwezi deposit is a deposit located further to the North. Notwithstanding its initial position further to the south, the deposit is heavily faulted and the thrusts and faults could have focused the fluids associated with the deformation, at ~ 530 Ma.

SHAFT-HOLE AXES FROM CAPUT ADRIAE: MINERALOGICAL AND CHEMICAL CONSTRAINTS ABOUT THE PROVENANCE OF SERPENTINITIC ARTEFACTS*

The change of raw materials used to produce stone axes during the Neolithic to Copper Age transition in northeastern Italy, central and western Slovenia and northwestern Croatia (Caput Adriae) has been recently linked to the development of early European metallurgy. Serpentinite shaft-hole axes occur commonly in the archaeological context of this region and their rounded irregular shape suggests that the raw material was mainly sourced from secondary deposits. The aim of the present study is to characterize with multiple analytical methods, including synchrotron radiation, the axes and locate the primary outcrop(s) of raw materials and related secondary exploitation areas. All the analysed artefacts are manufactured from peridotites and probably pyroxenites completely metamorphosed in greenschist facies and characterized by antigorite, diopside and magnetite, sometimes rimmed by penninite. Mineralogical and petrographic data exclude most Eastern Alps outcrops as possible raw material sources, thus limiting the research to the Hohe Tauern. Chemical data reveal a close homogeneity for the peridotite-derived axes and therefore demonstrate a selection of the most suitable raw material for axe production. Provenance from Hohe Tauern and related secondary deposits of the Drava River hydrographical system agrees with previous studies, as this region is rich in copper ore deposits, which have been exploited since prehistory.

Effect of Mechanical Activation on Pressure Leaching of Küre Massive Rich Copper Ore

The effect of mechanical activation on metal dissolutions by pressure leaching of massive rich copper ore taken from Küre copper ore deposit (Turkey) was investigated. The dissolution efficiencies of sulfide minerals are significantly improved by ultrafine grinding, also known as mechanical activation. This grinding results in decrease of particle size and an increase in crystal distortion of sulfide minerals. Leaching efficiencies of copper, cobalt, and Zinc increased from 45.2%, 25.9%, and 87.7% to 98%, 85%, and 97%, respectively, after 3-h mechanical activation. At the end of the activation, leaching was carried out at a temperature of 110°C, 10-bar oxygen partial pressure, and 150-g/L solid concentration without addition of acid. This study has also indicated that mechanical activation involving fine milling as a pretreatment is not only effective on copper minerals dissolution but also on the dissolution of other associated minerals, such as cobalt and zinc sulfides.

Temporal-spatial distribution and ore-forming material source of gold, copper and silver polymetallic ore deposits in the Fuping mantle structure zone

This study was conducted following research on metallogenesis in the Zhangjiajie-Xuanhua and East Hebei mantle branch structure zones. The Fuping mantle branch structure zone is one where Au, Cu and Ag polymetallic ore resources are concentrated in North Hebei. However, there has existed a long-standing controversy on the temporal-spatial distribution of ore resources and their ore-forming material sources. In terms of age dating and the comprehensive analysis of S, Pb, O, C and Si isotopes, it is considered that the temporal-spatial distribution of ore resources in this mantle branch structure zone is obviously controlled by the Fuping mantle branch structure. In space there is developed such a metallogenic pattern as to be Ag, Pb and Zn polymetallic ore deposits with gold appearing inside and copper appearing outside. Metallogenesis is dated mainly at Yanshanian, the ore-forming materials were derived predominantly from the deep interior of the Earth, and ore-forming fluids were derived largely from Yanshanian magmatism.

COPPER MINERALIZATION PREVENTED BY ARC-ROOT DELAMINATION DURING ALPINE-HIMALAYAN COLLISION IN CENTRAL IRAN

Contrasting geochemical signatures of copper ore hosting Eocene and some barren undeformed Miocene diorites to granites in central Iran temporally overlap with the Alpine-Himalayan collision and provide key implications on the existence and lack of Cu mineralization during collisional magmatism. High Sr and low Y (and Yb) contents of Eocene arc rocks in the Natanz arc segment reflect thickened, Andean-type orogenic arc crust (~45 km), whereas barren Miocene Natanz arc rocks (21–19 Ma) indicate thin arc crust similar to collisional volcanism in Anatolia. Geochemical modeling indicates a change in the mineralogy of the melt residual, from precollisional Eocene basaltic garnet-bearing (5–30%) amphibolite to syn- or postcollisional Miocene metasomatized mantle peridotite, which can be explained by collision-induced delamination of the arc lithospheric root. Subsequent recharge of hot asthenosphere and melting of metasomatized mantle peridotite and lack of interaction with a garnet-bearing arc crustal keel explain the low Sr and high Y (and Yb) contents, the relatively enriched initial Sr isotope ratios of postcollisional Miocene Natanz rocks, and the lack of copper mineralization in postcollisional Miocene Natanz arc rocks. Arc-root delamination removes the copper- and sulfur-enriched metasomatized lithospheric arc root and hydrous cumulate reservoir required to form copper ore deposits. Lack of the dense melt residues also provides an alternative explanation for the elevated, thin crustal Iranian back-arc plateau (38 km) as a result of uplift by isostatic rebound rather than uplift by anomalous shortening. Miocene arc-root delamination implies a minimum age of >21 Ma for the Alpine-Himalayan collision in central Iran.