Zircon geochemistry and geochronology are powerful tools in the study of multistage cratonic settings, yielding information on ages and distinguishing terranes. The Carajas Mineral Province (CMP) SE of the Amazonian Craton is renowned for its complex tectonic evolution and notable mineral deposits endowment, such as the giant iron-oxide-copper-gold (IOCG)-type Sossego and Salobo. Tectonic, magmatic, metamorphic, and hydrothermal event sequences imprint their records regionally and deposit scales that, in most cases, are difficult to identify. Basement and wall-rock samples from the southern portion of the CMP's, Sossego area were selected and analyzed using sensitive high-resolution ion microprobe (SHRIMP). Cathodoluminescence images guided the morphological and textural characterization and spot location. U-Pb and rare earth elements (REE) analyses using SHRIMP provided ages and trace element contents leading to classification of zircon type as magmatic, hydrothermally altered magmatic, or hydrothermal zircon. Hydrothermal zircon is characterized by anomalous morphology and REE and U contents, and these features have prompted the identification of an Archean hydrothermal event in the province. These zircon classifications indicate a circa 2.54 Ga hydrothermal event in the southern region of Carajas, likely associated with main shear zone movements (Carajas Fault). The 2.54 Ga event is well constrained to the Carajas northern zone and has not been indicated in the southern region. The magmatic and hydrothermally altered zircons indicate ages around 2.95 Ga and 2.74 Ga, coinciding with the zone's known ages, with better resolution achieved using SHRIMP. The use of zircon type classification in cratonic terranes to track hydrothermal events offers original possibilities and represents new frontiers in mineral exploration.

The link between porphyry-epithermal deposits and continental-arc magmatism is widely accepted, but in flatslab settings the source of metals is still debated. The Central Andes region hosts numerous important mineral deposits within the flat-subduction zone including the world-class Agua Rica Cu-Au (Mo) porphyry-epithermal deposit, which is associated with the Farallon Negro Volcanic Complex. The suite of mineralization at Agua Rica includes a porphyry-Cu phase, an associated epithermal assemblage and a supergene enrichment overprint. The main mineralization is considered to be related to the Trampeadero and Seca Norte dacite porphyry intrusions, for which U-Pb SHRIMP zircon ages are 6.09 +/- 0.17 and 5.81 +/- 0.32 Ma to 5.41 +/- 0.25 respectively. Rhenium-Os dating of pyrite from the Trampeadero porphyry yielded an isochron with an age of 5.85 +/- 0.42 Ma, and molybdenite yielded a model age of 5.61 +/- 0.03 Ma. The Seca Norte body was responsible for the main porphyry-style mineralization, while the older Trampeadero porphyry served as a host rock. Magmatic-hydrothermal activity at Agua Rica commenced at approximately the same time as it was ending in other parts of the volcanic complex. Pb isotope signatures of sulfide samples from Agua Rica indicate a significant addition of crustal material to a mantle source. Neogene magmatism in the area is likely related to the subduction of the Juan Fernandez Ridge, which was subjacent to the deposit by the time of the porphyry intrusions. Upper crustal MASH (mixing, assimilation, storage, and homogenization) in the melting zone above the slab is inferred as the source of the shallow magma reservoir beneath the Farallon Negro Volcanic Complex.

The Agua Rica and Bajo de la Alumbrera Cu-Au (Mo) porphyry-type deposits, NW Argentina, are genetically associated with the Farallón Negro Volcanic Complex, Miocene age.These world-class deposits of Bajo de la Alumbrera and Agua Rica, located into the tectonic context of the Central Andes, Geological Province of the Sierras Pampeanas, are Cu-Au (Mo) porphyry-type, although the Agua Rica deposit has a number of epithermal features and a supergene enrichment phase.Isotopic studies and high-resolution geochronology were carried out for the two deposits, aiming to investigate the source of the mineralization and crustal influence in its genesis, and ages for the Agua Rica porphyries.Pb isotopes show that the whole-rock samples from Bajo de la Alumbrera are less radiogenic than those from Agua Rica, with close ratio values.The whole-rock samples from Agua Rica show higher dispersion compared to Bajo de la Alumbrera.The pyrite samples from both deposits present similar ratios, which allows grouping them.The Pb isotopic compositions of sulfides and host rocks for the Agua Rica deposit and Bajo de la Alumbrera indicated that, despite the difference in the lithology present in the two deposits, the values obtained are close and very homogeneous.Sulfide samples from Bajo de la Alumbrera show ratios of 206 Pb/ 204 Pb, 207 Pb/ 204 Pb and 208 Pb/ 204 Pb very close to the whole-rock ratios, but with a slight enrichment in radiogenic Pb.Sulfide samples from Agua Rica present variable distribution, however, the pyrite samples from diorite and from metasandstone present ratios close to the pyrite from Bajo de la Alumbrera.This ratios similarity could be interpreted as similar conditions and sources to these sulfides.The Sr and Nd isotopes obtained and combined with literature data may suggest more evidence on the source of magmas and fluids for these deposits.Rocks with juvenile pattern, incorporated during the Andean orogeny, are one group observed, but there are also rocks that indicate the presence of crustal contamination, not homogeneous, with variations in Epsilon Nd(t) positive to negative.U-Pb SHRIMP-IIe zircon ages in the porphyries Trampeadero and Quebrada Seca, from the Agua Rica deposit, presented ages of 6.20 ± 0.16 Ma and 5.66 ± 0.22 Ma, respectively.These ages indicate a short time interval between these intrusions, of about 0.54 Ma, and represent the youngest ages obtained for Agua Rica by U-Pb SHRIMP zircon.A Re-Os isochron obtained in pyrite to the Agua Rica deposit of 6.4 ± 2.8 Ma is consistent with the evolution of this deposit.This age, combined with the U-Pb SHRIMP zircon ages matches the main magmatic phase and shows that the main mineralization phase is coeval to the intrusions.Based on these data, it is suggested that the genesis of the Agua Rica deposit was coeval to the last magmatic stages of Bajo de la Alumbrera, and this marks the youngest ages to the Farallón Negro Volcanic Complex rocks.In addition, the crustal participation was significant in the genesis of these deposits, with a major component in the Agua Rica deposit, because the fluids interaction with the Paleozoic basement.Based on this study, we indicated that in flat-subduction zones, the mineral deposits generated present more significant interaction with the crustal fluids than those normal subduction zones.

Important copper-gold (±molybdenum) porphyry deposits occur in the northwest region of Argentina, part of the Central Andes. This paper provides new isotope information on two of these deposits, Bajo de la Alumbrera and Agua Rica, the latter having an epithermal overprint event. The two deposits are genetically associated with the Miocene Farallón Negro Volcanic Complex. Whole rock and sulfide samples were analyzed for Pb, Sr and Nd isotopes to characterize the sources of magma and mineralization of both deposits. Sr and εNd data made it possible to divide the samples into three distinct groups. Most samples are slightly differentiated, have OIB (Ocean Island Basalts) isotope characteristics, and show some Nd fractionation. Lead isotope also shows distinct groups with an enrichment trend in radiogenic lead. In both deposits, the sulfides are more radiogenic than the host rocks, but are clearly related to them because all plot on a single trend. A crustal contribution to the deposits is suggested on the basis of lead isotope signatures. The similarity on the Pb isotope signatures suggests the same magmatic fluid source, although at Agua Rica the crustal component is more evident than at Bajo de la Alumbrera, possibly because of the assimilation of Paleozoic country rocks at Agua Rica.

The Itajaí Basin is a fault-bounded late- to post-orogenic basin deposited adjacent to the Dom Feliciano Belt in the state of Santa Catarina, Brazil. The basin is composed of alluvial-deltaic and platformal successions followed by a turbiditic complex and fan-delta deposits. U-Pb zircon dating of a tuff and five sandstone samples indicates a maximum depositional age of 563±3Ma for the intermediate and upper sections of the Itajaí Basin, and zircon dating of a rhyolite stock indicates a minimum depositional age of 549±4Ma. These dates are compatible with the previous assignment of an Ediacaran age to the sediments based on the discovery of Ediacara-type fossils such as Parvancorina, Charniodiscus, Cyclomedusa, and Aspidella. The U-Pb detrital zircon ages show a change in the sedimentary input from the base to the top. At the base, zircon grains from the Transamazonian and Brasiliano/Pan-African orogenic cycles occur as major sources with some Archean contribution. The upper section is dominated by Brasiliano/Pan-African zircon grains, most of which range in age from 824 to 770Ma and 656 to 563Ma. Pb and Sm-Nd whole rock isotope data suggest that the main source area for the basin infill was a reworked crust such as the Dom Feliciano Belt. We also present the regional correlation of the Itajaí Basin with the basins formed during the late stages of the SW Gondwana.