The Pernambuco-Alagoas Superterrane (PEAL) of the Borborema Province: an essay for geotectonic regionalization

Abstract

The Pernambuco Alagoas superterrane, previously coined as “massif” or “terrene”, is a tectonic segment that was identified immediately to the south of the Pernambuco Lineament. It presents triangular-shaped area, with basis between Recife and Maceió, and western vertex near Santa Cruz, west of Pernambuco, with a geographic area around 60,000km². Its composition is rather varied, presenting high grade terranes – Archean, Paleoproterozoic and early Neoproterozoic ones, as well as Neoproterozoic  volcanosedimentary supracrustal belts. These different rocks are pierced by different types of Ediacaran granitic intrusions, linear batholiths of great dimensions and by relatively isolated batholiths and stocks. The tectonic behavior of this superterrane – positioned between the Neoproterozoic fold belts of the Transversal Zone and those of the northern part of the São Francisco Craton (i. e. part of the so-called “meridian domain of Borborema”)- has been rather studied, discussed and named, nevertheless the general knowledge is still perfunctory. It displays a complex lithostructural framework, and it is possible (under a preliminary scope, for expositive reasons) to recognize three distinct contexts: the westernmost part (with many Archean and Paleoproterozoic relics); the central portion (Paleoproterozoic basement reworked by the supracrustal belts); and the easternmost part, with the exposures of a long and linear batholith (parallel to the coastal area) and a particular type of supracrustal belt.