Abstract Several existing schemes for Carboniferous stratigraphy officially adopted in regions of the Russian Federation are summarized and discussed. These regions with different geological histories and distinct depositional settings include the Moscow Basin, the Urals, North Timan, Siberia, the Kuznetsk Basin and the Mongol–Okhotsk, Verkhoyansk–Okhotsk and Kolyma–Omolon regions. Broad correlations based on macro- and microfossils are possible between the regions, while all regional schemes are correlated to the official Russian General Stratigraphic Scheme for the Carboniferous, using zonations based on orthostratigraphic fossils. The Russian General Stratigraphic Scheme is correlated to the International Stratigraphic Scale using ammonoids, conodonts, foraminifers and palynomorphs.

Abstract Carlin, epithermal, and orogenic gold deposits, today mined almost exclusively for their gold content, have similar suites of anomalous trace elements that reflect similar low-salinity ore fluids and thermal conditions of metal transport and deposition. Many of these trace elements are commonly referred to as critical or near-critical elements or metals and have been locally recovered, although typically in small amounts, by historic mining activities. These elements include As, Bi, Hg, In, Sb, Se, Te, Tl, and W. Most of these elements are now solely recovered as by-products from the milling of large-tonnage, base metal-rich ore deposits, such as porphyry and volcanogenic massive sulfide deposits. A combination of dominance of the world market by a single country for a single commodity and a growing demand for many of the critical to near-critical elements could lead to future recovery of such elements from select epithermal, orogenic, or Carlin-type gold deposits. Antimony continues to be recovered from some orogenic gold deposits and tellurium could potentially be a primary commodity from some such deposits. Tellurium and indium in sphalerite-rich ores have been recovered in the past and could be future commodities recovered from epithermal ores. Carlin-type gold deposits in Nevada are enriched in and may be a future source for As, Hg, Sb, and/or Tl. Some of the Devonian carbonaceous host rocks in the Carlin districts are sufficiently enriched in many trace elements, including Hg, Se, and V, such that they also could become resources. Thallium may be locally enriched to economic levels in Carlin-type deposits and it has been produced from Carlin-like deposits elsewhere in the world (e.g., Alsar, southern Macedonia; Lanmuchang, Guizhou province, China). Mercury continues to be recovered from shallow-level epithermal deposits, as well as a by-product of many Carlin-type deposits where refractory ore is roasted to oxidize carbon and pyrite, and mercury is then captured in air pollution control devices.

Abstract There are six distinct classes of gold deposits, each represented by metallogenic provinces having hundreds to more than 1,000 tonnes (t) gold production. These deposit classes are as follows: (1) orogenic gold; (2) Carlin and Carlin-like gold deposits; (3) epithermal gold-silver deposits; (4) copper-gold porphyry deposits; (5) iron oxide copper-gold deposits; and (6) gold-rich volcanic-hosted massive sulfide to sedimentary-exhalative (sedex) deposits. This classification is based on ore and alteration mineral assemblages, ore and alteration metal budgets, ore fluid pressure(s) and compositions, crustal depth or depth ranges of formation, relationship to structures and/or magmatic intrusions at a variety of scales, and relationship to the P-T-t evolution of the host terrane. The classes reflect distinct geodynamic settings. Orogenic gold deposits are generated at midcrustal (4–16 km) levels proximal to terrane boundaries, in transpressional subduction-accretion complexes of cordilleran-style orogenic belts; other orogenic gold provinces form inboard by delamination of mantle lithosphere or by plume impingement. Carlin and Carlin-like gold deposits develop at shallow crustal levels (<4 km) in extensional convergent margin continental arcs or back arcs; some provinces may involve asthenosphere plume impingement on the base of the lithosphere. Epithermal gold and copper-gold porphyry deposits are sited at shallow crustal levels in continental margin or intraoceanic arcs. Iron oxide copper-gold deposits form at middle to shallow crustal levels; they are associated with extensional intracratonic anorogenic magmatism. Proterozoic examples are sited at the transition from thick refractory Archean mantle lithosphere to thinner Proterozoic mantle lithosphere. Gold-rich volcanic-hosted massive sulfide deposits are hydrothermal accumulations on or near the sea floor in continental or intraoceanic back arcs. The compressional tectonics of orogenic gold deposits are generated by terrane accretion; high heat flow stems from crustal thickening, delamination of overthickened mantle lithosphere inducing advection of hot asthenosphere, or asthenosphere plume impingement. Ore fluids advect at lithostatic pressures. The extensional settings of Carlin, epithermal, and copper-gold porphyry deposits result from slab rollback driven by negative buoyancy of the subducting plate, and associated induced convection in asthenosphere below the overriding lithospheric plate. Extension thins the lithosphere, advecting asthenosphere heat; promotes advection of mantle lithosphere and crustal magmas to shallow crustal levels; and enhances hydraulic conductivity. Siting of some copper-gold porphyry deposits is controlled by arc-parallel or orthogonal structures that in turn reflect deflections or windows in the slab. Ore fluids in Carlin and epithermal deposits were at near-hydrostatic pressures, with unconstrained magmatic fluid input, whereas ore fluids generating porphyry copper-gold deposits were initially magmatic and lithostatic, evolving to hydrostatic pressures. Fertilization of previously depleted subarc mantle lithosphere by fluids or melts from the subducting plate, or incompatible element-enriched asthenosphere plumes, is likely a factor in generation of these gold deposits. Iron oxide copper-gold deposits involve prior fertilization of Archean mantle lithosphere by incompatible element enriched asthenospheric plume liquids, and subsequent intracontinental anorogenic magmatism driven by decompressional extension from far-field plate forces. Halogen-rich mantle lithosphere and crustal magmas form, and likely are the causative intrusions for the deposits, with a deep crustal proximal to shallow crustal distal association. Gold-rich volcanic-hosted massive sulfide deposits develop in extensional geodynamic settings, where thinned lithosphere extension drives high heat flow and enhanced hydraulic conductivity, as for epithermal deposits. Ore fluids induced hydrostatic convection of modified seawater, with unconstrained magmatic input. Some gold-rich volcanic-hosted massive sulfide deposits with an epithermal metal budget may be submarine counterparts of terrestrial epithermal gold deposits. Real-time analogues for all of these gold deposit classes are known in the geodynamic settings described, excepting iron oxide copper-gold deposits.