6533b861fe1ef96bd12c4eda
RESEARCH PRODUCT
The geological roots of South America: 4.1 Ga and 3.7 Ga zircon crystals discovered in N.E. Brazil and N.W. Argentina
Philippe GoncalvesM. Santos-pintoHervé MartinJean-jacques PeucatJean-louis PaquetteSimone Cerqueira Pereira CruzAngela Beatriz De Menezes LealSébastien RohaisJohildo Salomão Figueiredo Barbosasubject
010504 meteorology & atmospheric sciencesU–Pb zircon datingLaser ablation ICP-MSHadeanGeochemistryAge patternsGeologyCrustHadean010502 geochemistry & geophysics[ SDU.STU.GC ] Sciences of the Universe [physics]/Earth Sciences/Geochemistry01 natural sciencesCretaceousSao Francisco Craton BrazilSalta rift ArgentinaGeochemistry and Petrology[SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/GeochemistryPrimitive crustSão Francisco CratonGeology0105 earth and related environmental sciencesZircondescription
International audience; We present new LA-ICP-MS in situ geochronological results for seven Eoarchean zircons dated at 3.7 Ga coming from Cretaceous ash layers of NW Argentina and one Hadean single crystal sampled within the São Francisco Craton in NE Brazil. This zircon comprises a zoned magmatic core dated at 4.1 Ga surrounded by a 1.9 Ga overgrowth related to Paleoproterozoic reworking. This Hadean age is consistent with previously published Nd model ages on orthogneisses from the same domain. These two results represent among the oldest geological witnesses discovered to date in South America, which demonstrates the occurrence of a primitive crust. The contrasting age patterns recorded in both samples and localities indicate that at least two different nuclei of early crust survived in the continental domain. The São Francisco Craton in Brazil can be now considered as one of the very few areas where rare occurrences of Hadean zircon record the early evolution of the Earth.
| year | journal | country | edition | language |
|---|---|---|---|---|
| 2015-12-01 |