Geochronology and Tectonics of the Amazonian Craton

The Amazonian Craton is one of the Earth’s oldest and most extensive continental cores, underlying much of northern South America. Its architecture preserves a succession of magmatic, metamorphic and structural events spanning the Archean to the Mesoproterozoic. High-precision isotopic methods, notably U-Pb zircon dating and Sm-Nd isotopic analysis, have delineated the timing of juvenile arc accretion, collisional orogenies and intracratonic rifting. Major tectonostratigraphic provinces—including the Rio Negro-Juruena, Ventuari-Tapajós and Tapajós mineral provinces—are separated by ancient suture zones such as the Guaporé and Sunsás belts, which record convergent-margin processes during the Rhyacian and Orosirian (ca. 2.2–1.8 Ga).

Subsequent Mesoproterozoic events (ca. 1.6–1.1 Ga) relate to the breakup of the Columbia supercontinent, marked by intracontinental rifting and reactivation of older structures. These tectonic cycles generated a stable cratonic nucleus by about 1.8 Ga, providing a basement for later sedimentary basins and hosting world-class mineral systems, particularly gold and base-metal deposits. The craton’s evolution offers critical insights into early continental growth mechanisms, supercontinent assembly and dispersal, and the establishment of long-lived lithospheric keels that have global significance for reconstructions of Precambrian Earth.

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Geochronology and Tectonics of the Amazonian Craton publication trend

The graph below shows the total number of articles in geochronology and tectonics of the amazonian craton across all publications each year (not limited to Nature Index journals).

Technical terms

U-Pb zircon dating: Radiometric technique measuring decay of uranium to lead in zircon crystals to determine precise crystallisation ages of igneous and metamorphic rocks.

Sm-Nd isotopic system: Chronometer based on decay of samarium to neodymium, used to trace crustal evolution, model reservoir ages and assess source characteristics of magmas.

Magmatic arc: Linear belt of volcanic and plutonic rocks formed above a subduction zone at convergent plate boundaries, reflecting melt generation in the mantle wedge.

Craton: Ancient, stable portion of continental lithosphere that has survived multiple orogenic cycles and retains a thick, buoyant root.

Orogeny: Mountain-building episode involving deformation, metamorphism and magmatism resulting from tectonic plate convergence and collision.

Subduction: Process whereby one tectonic plate descends beneath another into the mantle, driving magmatism, seismicity and crustal recycling.

References

1. Gold in Paleoproterozoic (2.1 to 1.77 Ga) Continental Magmatic Arcs at the Tapajós and Juruena Mineral Provinces (Amazonian Craton, Brazil): A New Frontier for the Exploration of Epithermal–Porphyry and Related Deposits. Minerals (2021).
2. The Guaviare Complex: new evidence of Mesoproterozoic (ca. 1.3 Ga) crust in the Colombian Amazonian Craton. Boletín Geológico (2020).
3. U-Pb SHRIMP dating of basement rocks of the Iriri-Xingu domain, Central Amazonian province, Amazonian craton, Brazil. Brazilian Journal of Geology (2019).
4. A review of the geodynamic setting of the Volcanic Domain in the Juruena Magmatic Arc, southwestern Amazon Craton, Brazil, based on geochemical, U-Pb and Sm-Nd data. Journal of the Geological Survey of Brazil (2019).