Ore Minerals and Metal Distribution in Tailings of Sediment-Hosted Stratiform Copper Deposits from Poland and Kazakhstan

This study, carried out in tailings from two sediment-hosted stratiform copper deposits in the Lublin-Głogów Copper District in Poland (Kupferschiefer-type deposit) and Zhezkazgan (cupriferous sandstone-type deposit) in Kazakhstan, analysed the mineralogy of copper, zinc, and lead minerals as related to metal accumulation in sediments. Microscopic study in reflected light and SEM–EDS (Scanning Electron Microscope—Energy Dispersive Spectrometer) analysis, as well as chemical diversity in the used INAA (Instrumental Neutron Activation Analysis), ICP (Inductively Coupled Plasma), and AAS (Atomic Absorption Spectroscopy) methods in 35 samples from Kazakhstan and 35 from Poland were examined due to their diversity. In both tailing deposits in Kazakhstan and Poland, heavy fractions were dominated by copper sulphides: chalcopyrite (CuFeS2), bornite (Cu5FeS4). and chalcocite (Cu2S). Moreover, sphalerite, galena, and cerussite have been recognized as a carriers of Zn and Pb. Their geochemistry was dominated by Cu, showing a mean content of 2500 ppm, in both Poland and Kazakhstan. Zinc and lead also occurred, showing a content of approximately 200 ppm and 500 ppm in Poland, and 1500 ppm Zn and 2500 ppm Pb in Kazakhstan, respectively. Grain size analysis indicated that the dominant grain size in both districts corresponded to the silt and fine sands fractions. Copper, zinc and lead sulphides accumulated in fine fractions in tailings from Kazakhstan (in sandstones and quartz grains), and mainly in coarse fractions in Poland (within carbonates, sandstones, and black shales). Mineralogical and geochemical features should be taken into consideration when assessing potential metal sources of technogenic materials.

Subaqueous debrites of the Grand ConglomÉrat Formation, Democratic Republic of Congo: A model for anomalously thick Neoproterozoic: “Glacial” diamictites

ABSTRACT Very thick (> 1 km) successions of matrix-supported conglomerates (diamictites) are a very distinctive component of many Neoproterozoic basins. Classically interpreted as glacially deposited sedimentary rocks, their thickness has been seen as requiring exceptional depositional conditions such as world-wide “panglacial” climates. The Neoproterozoic Grand Conglomérat Formation (GC) of Katanga Province, southeastern Democratic Republic of Congo, is a 1.8-km-thick diamictite succession hosting one of the world's largest stratiform copper deposits. Examination of more than 300 km of recently acquired large diameter (up to 4 inches, 10.2 cm) core identifies the diamictites of the GC as debrites that accumulated as part of a deep-water “mass-transport complex” in a tectonically active and volcanically influenced anoxic rift basin. Detailed sedimentological descriptions of debrite facies and their lateral and vertical variability permits new insights into processes of debris-flow formation and transport, and their wider paleoenvironmental and paleotectonic significance. A genetic model is herein presented that highlights the importance of slumping and subaqueous downslope mixing of basin-margin fan-delta gravels, fault breccias, volcanic debris from contemporaneous basaltic fissure eruptions with basinal muds, and the downslope ponding of flows in narrow fault-bounded depocenters. Preservation of such an exceptionally thick subaqueously deposited debrite-dominated mass transport complex lacking any evidence of shallow-water deposition, requires rapid subsidence. Any direct sedimentary evidence of a glacial influence on sedimentation in the wider basin hinterland (if present) has been destroyed and homogenized by mass flow. Indirect evidence of a cold-climate setting is possibly expressed as lonestones in laminated turbidite facies dropped by either glacial or seasonal ice, and by exceptionally rare scratched clasts that may have been striated subglacially. Descriptions and interpretations presented here provide clues to the origin of other unusually thick debrite and turbidite successions elsewhere in other Neoproterozoic basins; their primary paleoenvironmental significance is that they appear to record ponding and focusing of mass flows in narrow, rapidly subsiding fault-bounded depocenters, rather than any unique glacial paleoclimate.

The Kupferschiefer Deposits and Prospects in SW Poland: Past, Present and Future

Polish sediment-hosted stratiform copper deposits associated with Zechstein sediments are one of the country’s most valuable natural resources and the basis for its copper industry. The paper presents the history of their research and current exploration. Although documented deposits and their identified resources are described and characterized, much attention is paid to areas located outside of them, including those where geological exploration is currently underway. The gradual depletion of shallow Cu–Ag reserves in the Lubin-Sieroszowice district and elsewhere in the world requires exploration for deeper-seated deposits. To expand resources, time span and scale of copper production in Poland, exploration and definition of new prospects is of great importance. Thirty-five prospective areas with hypothetical and speculative resources have been delineated in SW Poland, including the most prospective areas adjacent to the Cu–Ag Lubin-Sieroszowice deposit. The paper also focuses on those parts of the Fore-Sudetic Monocline where new copper deposits were recently identified. Their resources are described along with the methodology of establishing their boundaries, which differs from recommended Polish threshold parameters not taking into account the depths exceeding 1500 m. Intelligent modern mining and ore processing technologies are considered as a prerequisite for future profitable development of deposits at deeper levels.