Structural, mineralogical, geochemical and geochronological constraints on ore genesis of the gold-only Tocantinzinho deposit (Para State, Brazil)

Biondi, João Carlos; Borgo, Ariadne; Chauvet, Alain; Monié, Patrick; Bruguier, Olivier; Ocampo, Ruperto

doi:10.1016/j.oregeorev.2018.08.007

Cited by 13 publications

(10 citation statements)

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“…Muscovite and sericite 40 Ar- 39 Ar plateau ages (1854 ± 6 Ma and 1865 ± 5 Ma) might reflect isotopic resetting [30]. The δ 13 C calcite values (−3.45 to −2.29‰) imply a deep-seated carbon source, consistent with a magmatic fluid contribution, as suggested by the calculated δ 18 O H2O values (+0.39 to +8.52‰, at 300 • C) in equilibrium with calcite [117].…”

Section: Tocantinzinho Porphyry-style Gold Depositmentioning

confidence: 69%

“…2007 Ma granodiorite. The multi-phase intrusions represent oxidized, I-type magmas high-K calc-alkaline and metaluminous to peraluminous affinity [24,30,31].…”

Section: Tocantinzinho Porphyry-style Gold Depositmentioning

confidence: 99%

“…All rocks in the Tocantinzinho area are hydrothermally altered, brecciated, and fractured [30]. The hydrothermal alteration resulted in two groups of altered granite rocks.…”

Section: Tocantinzinho Porphyry-style Gold Depositmentioning

confidence: 99%

“…Gold particles, chalcopyrite, sphalerite, galena, altaite, and minor molybdenite petzite, bismuthinite and native silver argentite, Cu-bismuthinite, hedleyite, hessite, and native bismuth occur in the irregular veinlet networks, associated with magnetite, hematite, chlorite-quartz-calcite [24,25]. The Au/Ag ratios in gold particles vary from 2.5 to 11.2 [30].…”

Section: Tocantinzinho Porphyry-style Gold Depositmentioning

confidence: 99%

“…The discovery of a well-preserved high-sulfidation epithermal gold mineralization associated with 1.88 Ga calc-alkaline volcanic rocks by Rio Tinto company [12][13][14][15][16] and porphyry-like gold systems [17][18][19][20] opened the possibility for the occurrence of large Paleoproterozoic gold and Cu-Mo deposits in both provinces, as proposed by [21]. In the following years, due to academic research and mineral exploration programs, several epithermal (low-, intermediate-and high-sulfidation) occurrences related to calc-alkalic and alkalic porphyry-like mineralization, sometimes with Au, Cu or Mo, were identified in both provinces [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36]. This expands the perspectives for the existence of magmatichydrothermal high-grade epithermal and large porphyry-like deposits.…”

Section: Introductionmentioning

confidence: 99%

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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

et al. 2021

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This review paper aims to integrate geological, tectonic and metallogenetic data, including new data, and propose a regional model for the gold (and base metal) mineralization in the south Amazonian Craton to support the mineral exploration concerning magmatic–hydrothermal deposits. The Proterozoic evolution of the Amazonian Craton comprises the accretion of terrains to the Archean Carajás Mineral Province. In the Tapajós and Juruena mineral provinces, located at the south part of the Amazonian craton, a long-lived ocean–continent subduction event produced ca. 2.0 to 1.77 Ga continental magmatic arcs. Extensive lava flows, volcaniclastic, sedimentary, and plutonic rocks were originated during at least four major orogenic magmatic events (ca. 2.1, 1.9, 1.88, and 1.80 Ga) and two post- to anorogenic events (ca. 1.87 and 1.77 Ga). Gold mineralization occurs in: (i) alluvial/colluvial occurrences, (ii) orogenic carbonate–sulfide-rich quartz veins in shear zones, (iii) stockworks, veins, and dissemination in granites, (iv) contact of basic dikes, (v) well-preserved high-, intermediate- and low-sulfidation epithermal mineralization, and (vi) porphyry-like and intrusion-related gold systems associated with late- to post-orogenic epizonal granites. The estimated historical gold production, mainly in secondary deposits, is over 27 Moz at the Tapajós and 6 Moz at the Juruena provinces. A total resource of over 5 Moz Au is currently defined in several small to large primary gold deposits. Andesite to rhyolite, volcaniclastic, and clastic sedimentary rocks (1.96–1.88 Ga) host epithermal (high-, intermediate-, and low-sulfidation) Au–(Ag–Pb–Zn) mineralization, whereas Au–Cu and Cu–M–Au mineralization is hosted in sub-volcanic tonalitic to granitic plutons. Advanced argillic alteration (alunite, pyrophyllite, enargite) associated with high-sulfidation mineralization occurs in ring volcanoes around nested volcanic calderas. This zone grades outward to propylitic or chlorite alteration, often covered by silica caps with vuggy silica. Lava flows and volcaniclastic rocks within faults or associated with volcanic edifices and rhyolitic domes host low- and intermediate-sulfidation mineralization. Low-sulfidation alteration zones typically have adularia and illite or sericite. Chalcopyrite, sphalerite, galena, pyrite, digenite, and manganiferous calcite are related to intermediate-sulfidation gold mineralization. Late- to post-orogenic evolved oxidized I-type granitoids host alkalic-type epithermal and porphyry-like gold mineralization. Porphyry-style hydrothermal alteration is analogous to those of modern systems, with inner sodic and potassic (potassic feldspar ± biotite or biotite) alterations grading to propylitic, muscovite-sericite, chlorite–sericite, and chlorite alterations. Potassic alteration zones are the locus of Cu–Mo mineralization, and gold-rich zones occur in muscovite/sericite–quartz–pyrite alteration. The Paleoproterozoic epithermal and porphyry-like mineralization in these large provinces defines a new frontier for the exploration of world-class gold deposits in the worldwide Proterozoic arc-related magmatic terrains.

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Section: Tocantinzinho Porphyry-style Gold Depositmentioning

confidence: 69%

“…2007 Ma granodiorite. The multi-phase intrusions represent oxidized, I-type magmas high-K calc-alkaline and metaluminous to peraluminous affinity [24,30,31].…”

Section: Tocantinzinho Porphyry-style Gold Depositmentioning

confidence: 99%

“…All rocks in the Tocantinzinho area are hydrothermally altered, brecciated, and fractured [30]. The hydrothermal alteration resulted in two groups of altered granite rocks.…”

Section: Tocantinzinho Porphyry-style Gold Depositmentioning

confidence: 99%