@InProceedings{PadilhaVitoPádu:2015:ThMaIm,
author = "Padilha, Antonio Lopes and Vitorello, {\'{\I}}caro and
P{\'a}dua, Marcelo Banik",
affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {University
of Arizona} and {Instituto Nacional de Pesquisas Espaciais
(INPE)}",
title = "Three-dimensional magnetotelluric imaging of crustal structure
beneath the Central Domain of the Borborema Province, NE Brazil",
year = "2015",
organization = "IUGG General Assembly, 26.",
abstract = "The Borborema province, in northeast Brazil, consists of a complex
set of crustal blocks of different ages, origin and evolution,
with final amalgamation during the late Neoproterozoic Brasiliano
orogeny. Its Central Domain is characterized by elongate NE-SW
terranes largely affected by the Brasiliano metamorphic
overprinting and by a suite of early Neoproterozoic metavolcanic
rocks reflecting a distinct tectonic event (Cariris Velhos).
Magnetotelluric (MT) data were collected at 64 stations along four
profiles across this central region of the province to assess its
deep electrical resistivity structure. Dimensionality analysis
shows that the subsurface is electrically dominated by 3D
structure, and 3D inversions of the full impedance tensor and
vertical magnetic transfer function (tipper) were carried out. The
dominant features in the final model are north-dipping crustal
conductors, which can be correlated between the different MT
profiles and cross contrasting terranes at the surface of the
province. Considering the geometry and distribution of the
conductors, they are interpreted as reflecting remnants of a
pre-Neoproterozoic north-directed subduction zone with enhanced
conductivity associated with graphitized biogenic material in
metasedimentary rocks originally deposited in a restricted oceanic
environment and subsequently metamorphosed and introduced into the
deep crust by the subduction of the oceanic lithosphere. As the
extent of crustal remobilization by the Brasiliano event seems to
be restricted to the brittle upper crust, it is proposed that the
Neoproterozoic geodynamic evolution in this domain of the
Borborema Province occurred in an intracontinental setting.",
conference-location = "Prague, Czech Republic",
conference-year = "22 June - 02 July",
urlaccessdate = "28 mar. 2024"
}