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Adamastor – an ocean that never existed?
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-05-08)<p>Existing models of tectonic evolution of the Neoproterozoic orogenic system rimming the shores of the South Atlantic Ocean (the Araçuaí–Ribeira–Congo and Dom Feliciano–Kaoko–Gariep belts) interpret the belts as subduction-related orogens and emphasize the role of the “Adamastor Ocean” in their pre-collisional evolution. A critical problem in such an interpretation is the confined nature of the ... -
Comment to “Neoproterozoic magmatic arc systems of the central Ribeira belt, SE-Brazil, in the context of the West-Gondwana pre-collisional history: A review”
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-11-25) -
A critical discussion of the subduction-collision model for the Neoproterozoic Araçuaí-West Congo orogen
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-03-22)The Neoproterozoic Araçuaí-West Congo orogen in Brazil and Congo represents a branch of the Brasiliano/Pan-African orogenic system that is considered to terminate northward into a confined cratonic environment defined by the horseshoe-shaped pre-Atlantic São Francisco-Congo craton. The prevailing interpretation is that this orogen formed as a result of 50 m.y. of subduction leading to a classical ... -
Deformation mechanisms accommodating progressive simple shear thrusting of quartzite and metacarbonate in the southwestern Espinhaço Range, Brazil
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-10-09)The accommodation of low-temperature ductile deformation in foreland fold-and-thrust belts is often described in terms of outcrop-based geometric analysis, but microtextural observations are also important, as they relate stress, strain, fluids and temperature and thus the rheology in the peripheral part of the orogen. Such microtextural observations are lacking from the foreland part of the Araçuaí ... -
Quartz textural analysis from an anastomosing shear zone system: Implications for the tectonic evolution of the Ribeira belt, Brazil
(Journal article; Tidsskriftartikkel; Peer reviewed, 2020-07-18)Strain localization and influence of grain-size reduction processes were investigated from field and microstructural observations, and from quartz textural analysis using EBSD, in rocks deformed along an anastomosing network of shear zones in the Ribeira belt in Brazil. Rocks deformed along the Lancinha shear zone (LSZ) display high percentage of recrystallized grains, in which quartz recrystallized ... -
The role of Ediacaran synkinematic anatectic rocks and the late-orogenic charnockitic rocks in the development of the hot Araçuaí belt
(Journal article; Tidsskriftartikkel; Peer reviewed, 2021-09-13)The orogenic evolution of the hot Araçuaí belt is characterized by continuous magmatic activity, with magmas of different compositions recording a long-lived (∼630 to ∼530 Ma) tectono-thermal evolution in response to convergence between the Congo and São Francisco continents during the West Gondwana amalgamation. Geochemical data from the Carlos Chagas domain (CCD) and the Nova Venécia Complex (NVC), ... -
TitaniQ temperatures and textural analysis as a record of the deformation history in a major continental shear zone system, Borborema Province, Brazil
(Journal article; Tidsskriftartikkel; Peer reviewed, 2022-09-01)We combine quartz textural analysis with Titanium-in-quartz (TitaniQ) geothermometry to investigate the late stages of deformation in mylonitic rocks from the Sucuru dike swarm in the Borborema Province. The wide range in TitaniQ temperatures (>340 to 740 °C) closely related to grain sizes are attributed to inefficient Ti resetting during bulging (BLG) and subgrain rotation (SGR) recrystallization. ...
