Paleoproterozoic basement of Içana Domain, Rio Negro Province, northwestern Amazonian Craton: Geology, geochemistry and geochronology (U-Pb and Sm-Nd)

Veras, Renata da Silva; Nascimento, Rielva Solimairy Campelo do; Almeida, Marcelo Esteves; Paquette, Jean‐Louis; Carneiro, Marcia C.R.

doi:10.1016/j.jsames.2018.07.003

Cited by 8 publications

(4 citation statements)

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“…1.99 Ga and thus presumably belonging to a broader magmatic event in the Guiana Shield known as the Orocaima event (Reis et al, 2000), which in NW Venezuela is dominantly comprised by coarse-and fine-grained biotite granitoids (e.g., Figure 5a, 5b); (ii) intermediate and granitic orthogneisses which are widespread along the Atabapo and Ventuari Rivers (e.g., Figure 5c) and yield igneous crystallization ages ca. 1.8 Ga like those of the Cauaburi Complex and Taiuaçu-Cauera diatexite in NW Brasil (Almeida et al, 2013;Veras et al, 2018). In addition to their penetrative gneissic fabric, these orthogneisses show local evidences of intense mylonitic deformation (Figure 5d); (iii) coarsely porphyritic intrusives like those that make up the "Cerros de Mavecure" inselbergs (Figure 5e, 5f) which yield U-Pb crystallization ages ca.…”

Section: Geology Of Guainía and Vichada Near The Colombia-venezuela Bmentioning

confidence: 95%

“…In NW Brasil, crystallization ages between ca. 1.81 and 1.75 Ga have been described for the Cumati, Cauaburi, and Querari Complexes and the Taiuaçu-Cauera diatexite; these dates have been interpreted to define the Cauaburi and Querari Orogenies (Figure 6; Almeida et al, 2013;Veras et al, 2018), whereas the younger ca. 1.5 Ga intrusives have been associated with the Içana Orogeny (Almeida et al, 2013).…”

Section: Distribution Of Proterozoic U-pb Zircon Crystallization Agesmentioning

confidence: 97%

“…We also make mention of the limited (but relevant) δ 18 O Zrn stable isotope results that have recently become available. Thus, the data used for the purposes of this chapter comes from the following sources (in chronologic order): Tassinari et al (1996), Santos et al (2000), Ibañez-Mejia et al (2011), Bonilla-Pérez et al (2013), Ibañez-Mejia (2014, Ibañez-Mejia et al (2015), Cordani et al (2016b), Veras et al (2018). U-Pb results obtained from this compilation are listed in Table 1, along with the sample coordinates (in degrees, using the WGS84 datum), geographic locality (if known), rock-type that was analyzed, and their unique International Geo Sample Number (IGSN) identifier when available.…”

Section: Figurementioning

confidence: 99%

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Chapter 4

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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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Section: Geology Of Guainía and Vichada Near The Colombia-venezuela Bmentioning

confidence: 95%

Section: Distribution Of Proterozoic U-pb Zircon Crystallization Agesmentioning

confidence: 97%

Section: Figurementioning

confidence: 99%

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“…Nuestras observaciones y resultados nos hacen apoyar la idea de que en Colombia existe una tercera provincia, como lo plantean Cordani y Teixeira (2007) (Figura 1), en donde el Complejo Guaviare forma parte de un basamento ígneo-metamórfico perteneciente a una Provincia Geocronológica intermedia como et al, 2007), y cuyas rocas han sido diferenciadas como un basamento ígneo-metamórfico con edades entre 1,72 y 1,8 Ga (Bonilla, 2019;Bonilla et al, 2019). Los picos que se encuentran hacia 1,6-1,5 Ga están relacionados con la intrusión de granitos tardiorogénicos y anorogénicos aflorantes en todo el NW del Cratón Amazónico (Gaudette et al, 1978;Gaudette y Olszewski, 1985;Ibáñez-Mejía et al, 2015;Cordani et al, 2016;Veras et al, 2018;Bonilla, 2019), y el pico de 1,3 Ga coincide con granitos anorogénicos reportados en el departamento del Guainía (Bonilla et al, 2016), rocas del Complejo Guaviare (Maya-Sánchez et al, 2018;Amaya-López et al, 2020) y las edades de 1317±4 Ma aquí reportadas para rocas del basamento en la vereda Jordán Alto-Cerritos. Finalmente, el pico de 1,0 Ga resalta como fuente las rocas asociadas a la Provincia Sunsás (Tassinari y Macambira, 1999), o también llamada en Colombia Orógeno Putumayo (Ibáñez-Mejía et al, 2015), en relación con la formación del supercontinente Rodinia (Hoffman, 1991), a partir de la colisión de Amazonia-Báltica-Laurentia, evidenciada por intrusiones de gabros relacionadas con rifting continental más al oriente (Bonilla et al, 2020).…”

Section: Geocronología De Neises Del Complejo Guaviare Vereda Jordán ...unclassified

Edad U-Pb LA-ICP-MS en circones de las areniscas de la Formación San José en Ciudad de Piedra y de neises Mesoproterozoicos en Guaviare, Colombia

et al. 2022

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Los resultados aquí presentados describen parte de la geomorfología única al sur de la ciudad de San José del Guaviare, donde areniscas conforman mesetas de poca elevación que han sufrido procesos kársticos en Ciudad de Piedra siguiendo estructuras (NE-SW - NW-SE) preferencialmente. Las areniscas pertenecientes al Miembro Basal Ciudad de Piedra de la Formación San José contienen icnofósiles, y petrográficamente se observa predominancia de cuarzo de grano medio redondeado y cementado por sílice que otorga mayor resistencia, sobre un 5% restante que corresponde a líticos metamórficos y volcánicos, feldespatos, micas, opacos y circones. Análisis U-Pb LA-ICP-MS en estos circones mostraron edades proterozoicas con picos entre 1000 a 1800 Ma, mientras circones extraídos de un neis cerca de Cerritos, El Capricho, revelaron una edad concordante de 1317±4 Ma, interpretada como edad del protolito. Los datos obtenidos confirman que el basamento cristalino en el área de estudio pertenece al Cratón Amazónico y que los sedimentos que dieron origen a las areniscas de la Formación San José provienen de este basamento compuesto principalmente por neises y granitoides. Posteriormente, el basamento fue intruído por la Sienita Nefelínica de San José del Guaviare (~602 Ma), la cual aflora en contacto tectónico fallado con la Formación San José en cercanías a Ciudad de Piedra.

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