Relating differential crustal architecture to passive margin evolution : a case study from the Colatina Fracture Zone (SE Brazil) using apatite fission‐track thermochronology

The Colatina Fracture Zone (CFZ) defines a distinct NNW-SSE-oriented linear zone of fractures and brittle faults that represents an inherited weak zone in the current crustal structure of the (Pre)Cambrian Ara & ccedil;ua & iacute; Orogen. In the Early Cretaceous, the CFZ was reactivated dur...

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Bibliographic Details
Published in:Geological Journal
Main Authors: Costa, Deniro Felipe Gonçalves, Liberal Fonseca, Ana Carolina, De Grave, Johan, Novo, Tiago
Format: Article in Journal/Newspaper
Language:English
Published: 2024
Subjects:
Earth and Environmental Sciences
Ara & ccedil
ua & iacute
Orogen
reactivation
South Atlantic
structural inheritance
thermochronology
SOUTH-AMERICAN PLATFORM
CONTINENTAL-MARGIN
BREAK-UP
TECTONIC REACTIVATION
LANDSCAPE EVOLUTION
STATISTICAL-MODELS
WILSON CYCLE
SANTOS BASIN
CAMPOS BASIN
DENUDATION
South Atlantic Ocean
Online Access:https://biblio.ugent.be/publication/01J4466N97HPMWR27XY156ZG53
http://hdl.handle.net/1854/LU-01J4466N97HPMWR27XY156ZG53
https://doi.org/10.1002/gj.5027
https://biblio.ugent.be/publication/01J4466N97HPMWR27XY156ZG53/file/01J446AS88JRYZ6D6XZTSMY953
Description
Summary:The Colatina Fracture Zone (CFZ) defines a distinct NNW-SSE-oriented linear zone of fractures and brittle faults that represents an inherited weak zone in the current crustal structure of the (Pre)Cambrian Ara & ccedil;ua & iacute; Orogen. In the Early Cretaceous, the CFZ was reactivated during rifting of West Gondwana and subsequent opening of the South Atlantic Ocean, as evidenced by the emplacement of dykes along its structural network and the development of major depocentres of the Campos Basin in the offshore segments of the CFZ. Previous thermochronological studies have demonstrated that the CFZ was also rejuvenated during the drift phase of the South Atlantic. However, a number of questions regarding differential surface uplift and basement exhumation between the CFZ and its surrounding areas, such as the Doce River Valley (DRV), are still unresolved. In this study, we aim to investigate the CFZ as a distinctive structure in the tectonic rejuvenation of the passive margin of south-east Brazil. Samples from the CFZ and the DRV were collected for apatite fission-track (AFT) analyses. In the DRV, samples yield AFT central ages from 87 to 97 Ma with mean track lengths (MTL) from 12.6 to 13.3 mu m. In contrast, in the CFZ, AFT central ages from 70 to 83 Ma with MTL values from 13.2 and 13.4 mu m are obtained. The correlation between AFT age and elevation suggests that the tectonic development of these regions was markedly different and uncoupled. The thermal history models from the AFT data further constrain this differential evolution. On the one hand, thermal history modelling for the DRV indicates a slower and protracted cooling since the incipient Atlantic rifting in the Early Cretaceous. On the other hand, the models for CFZ reveal a rapid cooling phase between the Late Cretaceous to the Palaeocene. In the DRV, the observed basement cooling was most probably triggered by erosion of the uplifted rift shoulder generated by Gondwana break-up. The more recent, Late Cretaceous-Palaeocene rock cooling, ...

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