Structural analysis combined with new geothermobarometric and geochronological results of the Além Paraíba shear zone, between Três Rios and Bananal, Ribeira Orogen, SE Brazil

Giraldo, Samuel; Trouw, Rudolph Allard Johannes; Duffles, Patrícia; Costa, Rodrigo Vinagre da; Mejia, Mauricio Ibañez; Marimon, Rodrigo S.

doi:10.1016/j.jsames.2018.11.018

Cited by 20 publications

(2 citation statements)

References 36 publications

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“…The study area has gold placers along the Paraíba do Sul River. This river marks a lineament, the Além-Paraíba Lineament (Almeida et al 1975), which is a mylonitic shear zone (Campanha 1981; Dayan and Keller 1989), developed under amphibolite-facies conditions that were superimposed on granulitic rocks (Campanha 1981; Giraldo et al 2019). Quaternary alluvial deposits are distributed along the Paraíba do Sul River and its northern tributaries (Figure 2).…”

Section: Geological Settingmentioning

confidence: 99%

Palladiferous placer gold from the Paraíba do Sul River in northern Rio de Janeiro (Brazil) and its geological implications

Rocha

Cabral

Lohmeier

et al. 2022

Applied Earth Science

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Placer gold recovered from the Paraíba do Sul River, which flows along a high-grade shear zone in northern Rio de Janeiro, Brazil, has a distinctive component of palladiferous gold. Its finding, reported for the first time in the state of Rio de Janeiro, implies a hydrothermal system of high salinity at relatively low temperatures, in which metal transport is facilitated by hematite-rich rocks and generally precipitated at redox fronts. Such a hydrothermal system is not geologically manifested in the currently exposed high-grade shear zone. The finding of palladiferous gold suggests that its source was eroded during periods of increased denudation rates since the Lower Cretaceous, as indicated by apatite fission-track (AFT) data that have been reported for the region.

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Section: Geological Settingmentioning

confidence: 99%

Palladiferous placer gold from the Paraíba do Sul River in northern Rio de Janeiro (Brazil) and its geological implications

Rocha

Cabral

Lohmeier

et al. 2022

Applied Earth Science

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“…For these conditions, in order to constrain the thermal history in the shear zone, in-situ Rb-Sr and Ar-Ar micas and U-Th-Pb zircon, monazite, titanite, rutile and apatite have been integrated. The latter are resistant to physical and chemical alterations of the system, and in which the reported ages are related to crystallographic deformation process@, since the migration and formation of crystalline faces are subject to development without incorporation of radiogenic Pb in the crystal lattice (Dahl, 1997;Lee et al, 1997;Cherniak and Watson, 2000;Santos et al, 2003;Cherniak et al, 2004;Cocherie et al, 2005;Dahl et al, 2005;Harley et al, 2007;Reddy et al, 2007;Timms et al, 2011;Oyhantçabal et al, 2012;Bonamici et al, 2015;Erickson et al, 2015;Oriolo et al, 2016a;Kirkland et al, 2018 a, b;Giraldo et al, 2019;Odlum and Stockli, 2020;Ribeiro et al, 2020 a, b;Van Daele et al, 2020).…”

Section: Geochronology Of Fault Rocksmentioning

confidence: 99%

Geological-structural mapping and geocronology of shear zones: A methodological proposal

Ortega¹,

Isaza²,

Herrera³

et al. 2021

Bol.geol.

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The deformation registered in rocks in the field can be characterized based on the structures preserved in outcrops, which can related be to wide discontinuity zones named faults and shear zones. The geological-structural mapping and the geochronology of these tectonic structures are a topic of great interest not only for tectonic modeling but also for reconstruction of the geological evolution of the national territory. The methodology suggest for the analysis of faults and shear zones is based on eight steps, including: 1) definition of the geological context in which the structure was developed; 2) photointerpretation, image geoprocessing, and geological-structural mapping of the structural and lithological characteristics of the faults and shear zones; 3) petrographic analysis of field-oriented samples; 4) quantification of strain orientation and geometry through 3D finite strain analyses and quantification of non-coaxiliaty of deformation through vorticity analyses; 5) SEM-TEM-EBSD microanalysis; 6) quantification of the P-T conditions of deformation through phase-equilibria modeling or conventional geothermobarometry; 7) dating of syn-kinematic minerals phases and mylonitic rocks through Ar-Ar analyses, in order to determine the reactivation and deformation ages of the structure, respectively, as well as the implementation of the U-Pb technique in syn-kinematic calcite crystals developed in the fault planes; and 8) dating of geological elements adjacent to the structure, such as syn-kinematic intrusive bodies associated with the deformation event using zircon U-Pb dating, rocks hydrothermally altered through Ar-Ar method, and zircon and apatite fission-tracks dating of the blocks adjacent to the faults for determining exhumation ages.

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Paleoarchean to Neoproterozoic crust formation and migmatization events in the Borborema Province, NE Brazil: Implications for the growth and reworking of the continental crust

Fachetti,

Fuck,

Marimon

et al. 2024

Gondwana Research

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Structural analysis combined with new geothermobarometric and geochronological results of the Além Paraíba shear zone, between Três Rios and Bananal, Ribeira Orogen, SE Brazil

Cited by 20 publications

References 36 publications

Palladiferous placer gold from the Paraíba do Sul River in northern Rio de Janeiro (Brazil) and its geological implications

Palladiferous placer gold from the Paraíba do Sul River in northern Rio de Janeiro (Brazil) and its geological implications

Geological-structural mapping and geocronology of shear zones: A methodological proposal

Paleoarchean to Neoproterozoic crust formation and migmatization events in the Borborema Province, NE Brazil: Implications for the growth and reworking of the continental crust

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