Intraplate Proterozoic Magmatism in the Amazonian Craton Reviewed: Geochronology, Crustal Tectonics and Global Barcode Matches

Teixeira, Wilson; Reis, Nelson Joaquim; Bettencourt, Jorge Silva; Klein, Evandro Luíz; Oliveira, Davis Carvalho de

doi:10.1007/978-981-13-1666-1_4

Cited by 15 publications

(11 citation statements)

References 106 publications

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“…Geochronological, geochemical, and isotopic data show that the Iricoumé Group magmatism in the Erepecuru-Trombetas took place in a post-collisional setting (Barreto et al, 2014), and is likely associated with the development of mantle plume (Teixeira et al, 2019). This setting suggests a strong structural control on the emplacement of Iricoumé Group, in which pre-existing structures would act in two ways: 1) facilitating the Manuscript accepted for publication on Precambrian Research connection with the multiple regional magma reservoirs (Forte and Castro, 2019); 2) governing the development of calderas and fissure ignimbrite.…”

Section: Reconstruction Of the Volcanic Environmentmentioning

confidence: 99%

“…1B, Guiana and Brazil Central shields) and is considered by several authors a Silicic Large Igneous Province (SLIP; Teixeira et al, 2019 and references therein). This Orosirian magmatic province is considered one of the most intriguing magmatic events of the world, with abundant explosive, effusive and intrusive rocks that are still poorly constrained due to dense vegetation cover (Schobbenhaus and Brito Neves, 2003;Brito Neves, 2011;Fernandes et al, 2011;Juliani et al, 2011;Klein et al, 2012;Barreto et al, 2013Barreto et al, , 2014Roverato et al, 2019;Teixeira et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

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Textural analysis and emplacement conditions of well-preserved Orosirian felsic volcanic rocks of Northern Amazon Craton, Brazil

Barreto¹,

Haag²,

Lafon³

et al. 2022

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Located in the Amazon Craton, the Uatumã magmatism (1.89-1.87 Ga) consists in one of the oldest Silicic Large Igneous Provinces (SLIPs) on Earth. For a long time, the access to these deposits in the northern Amazon Craton (Erepecuru–Trombetas Domain) has been set back for volcanological studies due to dense vegetation cover and the absence of roads. Recent studies identify two Orosirian volcanic units in the region: the Iricoumé Group (1.89-1.87 Ga) related to the Uatumã magmatism, and the Igarapé Paboca Formation (1.99-1.94 Ga), associated to an older magmatism. Both units are widespread in the Erepecuru–Trombetas Domain and include effusive and explosive deposits. In this paper, we apply textural analyses and rheological estimations to determine the eruption and emplacement conditions of these two volcanic sequences. Textural analyses were carried out through fieldwork and petrography, including a systematic classification of lavas and volcaniclastic rocks. Rheological parameters were determined using geochemistry data to obtain melt viscosity (η) and temperature, zircon saturation (TZr), liquidus (TL), and glass transition temperatures (TG), for anhydrous and hydrous compositions. Textural analyses indicate the predominance of volcaniclastic facies with abundant eutaxitic and parataxitic textures. Rheological estimations reveal TL of 1020ºC, TZr 650-905ºC, and TG 640-753ºC for anhydrous Iricoumé Group melts. Eruptive viscosity estimations range from 8.4 to 11.7 log η (Pa.s). Igarapé Paboca melts present higher temperatures, with TL of 1050ºC, TZr 710-880ºC, and TG 670-740 ºC. Modeling using hydrous compositions indicate that minute amounts of water can strongly affect the rheology of the studied melts, reducing η, TL, TZr, and TG. The petrographic features indicative of hydrous magma reinforces the role of H2O as a controlling agent in the fragmentation of Iricoumé and Igarapé Paboca melts. The pyroclastic samples are marked by elevated ∆TZr - TG relationships indicative of high emplacement temperatures above the TG. Our results indicate that the high temperatures and the presence of network-modifier cations in the studied melts favored the development of extensive welded ignimbrites associated with low-eruption columns, likely developed in fissural and/or caldera systems.

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Section: Reconstruction Of the Volcanic Environmentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Textural analysis and emplacement conditions of well-preserved Orosirian felsic volcanic rocks of Northern Amazon Craton, Brazil

Barreto¹,

Haag²,

Lafon³

et al. 2022

Preprint

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“…Simplified geo-tectonic map of South America overlaid on gray-scale shaded relief image (DEM), highlighting the approximate outline and terrane boundaries of the Amazonian Craton and the Guiana Shield. Adapted from Cordani & Teixeira (2007), ), Ibañez-Mejia et al (2015, Macambira (1999), andTeixeira et al (2019). Shaded relief image areas with no overlay indicate younger cratonic cover or units in the Andean region.…”

Section: Figurementioning

confidence: 99%

Chapter 4

SGC¹

2019

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The crystalline basement of eastern Colombia, east of the frontal deformation zone of the north Andean Eastern Cordillera, is comprised by Precambrian igneous, metamorphic, and sedimentary rocks of the western Guiana Shield. Designated in the late seventies with the all-embracing stratigraphic name of 'Mitú Migmatitic Complex', the age, petrology, and tectonic history of the Precambrian basement in eastern Colombia has remained one of the least explored issues in South American geology. This chapter aims to present a brief overview of recent advances made to improve our general understanding of the geology of this wide region, using a compilation of the available U-Pb, Sm-Nd, Lu-Hf, and δ 18 O isotopic data obtained using modern methods. Using all the available U-Pb geochronologic data we show that, in general: (i) The Precambrian basement of the western Guiana Shield exhibits magmatic crystallization ages in the range from ca. 1.99 to ca. 1.38 Ga, and (ii) that four broad periods of magmatic activity, two in the mid-to late-Paleoproterozoic (ca. 1.99 and ca. 1.81-1.72 Ga), one in the early Mesoproterozoic (ca. 1.59-1.50 Ga), and one in the mid Mesoproterozoic (ca. 1.41-1.39 Ga) dominate the geology of the area. The (whole-rock) Nd and combined (zircon) Hf-O datasets indicate a general lack of 'depleted mantle' like mid-Paleoproterozoic or Mesoproterozoic crust, thus indicating that either the Proterozoic sub-continental mantle in the region was not as radiogenic as global mantle evolution models would suggest, or that reworking of older crust might have played an important role in the geological and geochemical evolution of the western Guiana Shield. Therefore, although the geochronologic results confirm that most of the exposed basement in eastern Colombia can be broadly considered to be of Rio Negro-Juruena-like affinity, this belt exhibits some distinct isotopic characteristics relative to similar age domains exposed south of the Amazon Basin. Furthermore, we note that the geochronologic data obtained to this date has failed to clearly identify an early-to mid-Mesoproterozoic terrane boundary in the Colombian basement, thus opening the possibility that a Rondonian-San Ignacio-like province is not represented in the Guiana Shield. Based on these recent field, geochemical, and geochronological observations, we consider the long and extensively used term 'Mitú Migmatitic Complex' to be now inadequate and obsolete, and argue that the current state of the knowledge of the Colombian Precambrian basement is such that the community should move towards adopting Proterozoic

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“…Simplified geo-tectonic map of South America, highlighting the approximate outline and terrane boundaries of the Amazonian Craton and the Guiana Shield. Adapted fromTassinari & Macambira (1999),, andTeixeira et al (2019). (CU) Cuyania Terrane, (PA) Pampia Terrane.…”

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Volume 1

SGC¹

2019

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Intraplate Proterozoic Magmatism in the Amazonian Craton Reviewed: Geochronology, Crustal Tectonics and Global Barcode Matches

Cited by 15 publications

References 106 publications

Textural analysis and emplacement conditions of well-preserved Orosirian felsic volcanic rocks of Northern Amazon Craton, Brazil

Textural analysis and emplacement conditions of well-preserved Orosirian felsic volcanic rocks of Northern Amazon Craton, Brazil

Chapter 4

Volume 1

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