Abstract This overview illustrates the processes controlling magma fertility in the formation of porphyry Cu-Au deposits. Magma fertility means all magmatic parameters (e.g., metal and volatile contents, magma and fluid volumes) that might result in higher amounts of metals, which are exsolvable from the magma. Mantle source processes seem to play a fundamental role in the enrichment of primary melts with H 2 O, S, and Cl, all essential ingredients to form porphyry deposits, but do not have a particular role in Cu enrichment. Cu-rich porphyry Cu-Au deposits (i.e., with Au/Cu ~4 X 10 –6 ) are associated with large magmatic volumes accumulated in the lower thick crust of continental arcs during long-lived periods of compression in a synsubduction environment. Mineralization occurs after such accumulations have reached significant volumes and is the result of the transfer of hydrous magmas from deep to shallower crustal levels, probably favored by tectonic stress changes. Au-rich porphyry Cu-Au deposits (i.e., with Au/Cu ~80 X 10 –6 ) are associated with magmatic systems that have evolved at overall shallower crustal levels and for this reason can be found in geodynamic settings characterized by thinner crust (e.g., island arcs with intermediate crust thickness) and/or in variably extensional settings occurring above a slab-metasomatized mantle (postsubduction setting, extensional synsubduction setting). The six largest Au-rich porphyry Cu-Au deposits (>~1,300 tonnes Au) are associated with variably alkaline magmas, which are typical of postsubduction and/or extensional settings, suggesting a petrogenetic control on the Au-rich nature of these deposits.

Abstract The petroleum endowment of the Tethys corresponds to the Middle East/North Africa region (Region 2) assessed by the USGS (2000). Data as of January 1, 1996, demonstrated this region to rank first in the world for oil and natural gas liquid known petroleum and second for natural gas. New natural gas discoveries in this region through 2012 have raised undiscovered natural gas estimates, particularly for offshore areas of the eastern Mediterranean (Nile Delta, Levant Basin) and Essaouira Basin. This paper emphasizes the total petroleum system (TPS) approach and discusses the global petroleum revolution we are now experiencing. Originally 18 provinces, 28 TPSs, which were subdivided into 46 assessment units (AU), were assessed in USGS (2000). In the last decade these assessed areas have grown to 21 provinces, 31 TPS, and 54 AU through 2012, as discussed here. In the USGS (2000) assessment, the Middle East/North Africa region contributed about 44% of the world’s known petroleum. With the addition of more than 400 TCF of natural gas and more than 10 BBNGL in the region in the last decade, principally in the eastern Mediterranean, this region is preeminent in terms of its endowment of oil, natural gas, and natural gas liquids.

Archean cratons are fragments of old continents that are believed to be more richly endowed with mineral deposits than younger terrains. The mineral deposits of different cratons are also diversely enriched with useful (to humankind) chemical elements. Cratons are therefore mineral diversity hotspots that represent regional geochemical heterogeneities of early Earth, the evidence for which remains encoded on each craton as unique metallogenic “fingerprints.” Using six selected elements groups from our extensive in-house GIS database of Gondwana mineral deposits, we derive the metallogenic fingerprints of 11 Archean cratons of the Southern Hemisphere, and compare these against metallogenic fingerprints of the same selected elements in younger crust of three of their host continents (Africa, Australia, and South America). After adjusting the mineral inventory of each craton to account for underexploration of regions lacking infrastructure and other political and economic conditions for mineral investment, we show that mineral deposit density and diversity of Earth's continental lithosphere has decreased with time. We conclude that metallogenic elements were transferred more efficiently from the mantle to the continental lithosphere in the Archean and/or that subsequent (younger than 2.5 Ga) recycling of these elements (mineral deposits) back into the mantle has become more effective. How most of these fragments of old continents inherited their rich and diverse metallogenic characteristics is unresolved, because different cratons are likely to represent only small remnants of once much larger and possibly more varied Archean continents, and part of the total metal inventory of Archean continents must have been recycled back into in the mantle. The latter has implications for understanding the secular change in the redox state of the Archean mantle and fluid envelope.