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

Abstract

In the central part or central subprovince of the Borborema Province, in the so-called Transversal Zone, an assemblage of Paleoproterozoic (predominantly Rhyacian) rocks occurs together with sparsely distributed Neoarchean nuclei. These rocks constitute the main basement of the Tonian (Cariris Velhos Cycle) and Ediacaran (Brasiliano Cycle) mobile belts. They are older tectonostratigraphic terranes and par excellence ramifying elements (as "inliers") of the Neoproterozoic orogenic constructions. This tectonostratigraphic terrane known as Alto Moxotó composes a litho-structural context typical of accretionary orogens, with the presence of granitic, granodioritic, and trondhjemitic orthogneisses (≈ arc-type associations) that stretch out for some hundreds of kilometers (Floresta Suite) and are partially covered by medium-grade pelitic-psammitic sequences (Sertânia Supergroup). This basement outline (Floresta Suite + Sertânia Supergroup) depicts an irregular sigmoidal shape, from the interior of Pernambuco (meridian 39ºW) to the Paraíba coastal area (meridian 34º45'W), along about 450 km, varying from 40 to 80 km in width, resulting in a total area of ca. 28,000 km 2. This Rhyacian petrotectonic scenario is conditioned and delimited by extensive (shear + thrust) faults that configure a tectonostratigraphic terrane. Moreover, there are pieces of continuity evidence of this tectonostratigraphic terrane not only in the basement of the adjacent Neoproterozoic mobile belts to the North and South of the TAM in Brazil, but also in Northern Cameroon, in Africa. Within this broader predominantly Rhyacian belt, some small Neoarchean gneissic and migmatitic nuclei were identified. The Rhyacian lithologies reveal evidence (T DM ages) of sources from a Neoarchean paleosubstrate. During the Statherian, the whole Rhyacian context was affected by a series of small-scale magmatic manifestations of varied petrologic composition: syenitic, granitic, granodioritic, and gabbro-anorthositic. In this paper, a synthesis of the bibliographic data is presented, including a series of unpublished (geologic and geochronologic) data that together validate our conviction that we are dealing with an extensive (reworked) fragment (TAM) derived from the basement of a Paleoproterozoic supercontinent (Columbia).

Tectonic inversion assessed by integration of geological and geophysical data: The intracontinental Rio do Peixe Basin, NE Brazil

“…(a) Sedimentary basins (yellow area) and main shear zones (black lines) in NE Brazil. The sedimentary basins and shear zones are based on Matos (1992) and Brito Neves, Santos, and Van Schmus (2000), respectively. The red box comprises Figure 1b.…”

Accretionary models for the Neoproterozoic evolution of the Borborema Province: advances and open questions

“…One of the best candidates is the Cariris Velhos Belt, which represents a setting of early Tonian rocks distinct from any other, composing the basement of the blocks derived from the hypothetical Central African Block. Other fragments have also been proposed as probable remnants of Columbia (Brito Neves et al 2020). These elements are key to conciliate between the introverted Wilson Cycle models, the extroverted accretionary models, and the intracontinental reworking models proposed for portions of the BP.…”

“…570 Ma; and anorogenic granites aged at ca. 540-510 Ma (Guimarães et al 2004, Ganade de Araújo et al 2014b, Sial and Ferreira 2016, Santos et al 2020.…”

Gamma-ray spectrometry, magnetic and gravity signatures of Archean nuclei of the Borborema Province, Northeastern Brazil

“…However, these Archean nuclei are scattered throughout the province (Figure 1), thus also allowing affiliations with other cratons. For instance, for the Alto Moxotó terrane, Brito Neves et al (2020) proposed a derivation from the Paleoproterozoic Supercontinent Columbia.…”