A preserved early Ediacaran magmatic arc at the northernmost portion of the Transversal Zone central subprovince of the Borborema Province, Northeastern South America

Abstract

ABSTRACT:Magmatic arcs are an essential part of crust-forming events in planet Earth evolution. The aim of this work was to describe an early Ediacaran magmatic arc (ca. 635-580 Ma) exposed in the northernmost portion of the Transversal Zone, central subprovince of Borborema Province, northeast Brazil. Our research took advantage of several syntheses by different authors, including theses and dissertations, carried out on magmatic rocks of the study area for the last 30 years. The ca. 750 km long and up to 140 km wide arc, trending ENE-WSW, is preserved to the south of the Patos Lineament, between 35º15' and 42º30'W and 7º15' and 8ºS. About 90 different stocks and batholiths of I-type granitic rocks were mapped along this orogenic zone, preferentially intruding low-grade schists of the Cryogenian-Ediacaran Piancó-Alto Brígida (SPAB) belt. Three igneous supersuites are recognized: a) epidote-bearing granodiorites and tonalites ("Conceição" type); b) high-K calc-alkaline granites ("Itaporanga" type); c) biotite granodiorites of trondhjemite affinity ("Serrita" type). A fourth group of peralkalic and shoshonitic rocks occurs to the south of the previous ones, reflecting special tectonic conditions. NNE-SSW trending Paleoproterozoic fold belts, surrounding Archean nuclei, characterize the continental part of the northern lower plate. The oceanic fraction of this lower plate was recycled by subduction and scarce remnants of which may be seen either within the enclosing low-grade schists or as xenoliths within the arc intrusions. The upper continental plate presents WSW-ENE structural trends and is composed of Neoproterozoic fold belts and Paleoproterozoic reworked basement inliers. Available data bear clear evidence of an Ediacaran magmatic arc built at the northern portion of the Transversal Zone in the Borborema Province, northeast Brazil. KEYWORDS: Borborema Province; Transversal zone; Magmatic arc; Epidote-bearing granodiorites and tonalites; Continental boundary transform. RESUMO: O objetivo deste trabalho é introduzir o conceito de um arco magmático eoediacarano (ca. 635-580 Ma) na porção norte da zona transversal, subprovíncia central da Província

Alto Moxotó Terrane, a fragment of Columbia supercontinent in the Transversal Zone interior: Borborema Province, Northeast Brazil

“…1 and 2), which are subject of many previous studies. We highlight the last syntheses by Oliveira (2008), , 2014), Van Schmus et al (2011), and Brito Neves et al (2016. Inside this zone that constitutes the Borborema central subprovince, several tectonostratigraphic terranes (besides TAM), polygonal segments of the basement (basement inliers) of the Archean and Paleoproterozoic orogenic constructions are found: Alto Moxotó, Coremas Dam, São José do Caiana, Icaiçara, and São Pedro.…”

Petrogenesis of the Riacho do Icó Stock: evidence for Neoproterozoic slab melting during accretion tectonics in the Borborema Province?

“…Granitic domains are abundant and precisely record distinct stages of the Brasiliano orogeny (pre-, syn-and post-tectonic magmatism), having been intensively investigated for decades (Almeida et al 1967, Sial 1987 1999, Guimarães & Silva Filho 2000, Guimarães et al 2005, Ferreira et al 2003, Neves et al 2006, Brito Neves et al 2016. A review of the overall petrological aspects of the granites can be found in Ferreira et al (1998), Van Schmus et al (2011), and Sial & Ferreira (2016.…”

“…It comprises the São José do Caiano, Piancó-Alto Brígida, Alto Pajeú, Alto Moxotó, and Rio Capibaribe domains/ terranes. Terrane assembly and plate tectonics processes such as subduction and continental collision have been invoked as responsible for the Neoproterozoic crustal building of this area (e.g., Santos & Medeiros 1999, Kozuch 2003, Medeiros 2004, Santos et al 2010, 2017b, Brito Neves et al 2016, Basto et al 2019, but intracontinental orogenesis is also regarded (Neves 2015).…”

Petrologia dos Stocks Santa Maria, Monte Pedral, Bom Jardim, Boa Esperança e Niterói, Suíte Intrusiva Serra do Catu, Estado de Sergipe, NE Brasil

“…A região em que estão localizados os batólitos e stocks da SISC possui história petrológica complexa (e.g., Oliveira et al, 2010Oliveira et al, , 2017. Os corpos da SISC localizam-se predominantemente no SOS e no Superterreno Pernambuco-Alagoas (STPEAL ;Brito Neves et al, 2016;Brito Neves e Silva Filho, 2019). Davison e Santos (1989) definiram o SOS, anteriormente nomeado de Faixa Sergipana, como um conjunto de terrenos distintos e formados por seis domínios geológicos.…”