Skip to Main Content
Book Chapter

The pre-Silurian Riachão basin: a new perspective on the basement of the Parnaíba basin, NE Brazil

By
Amanda Porto
Amanda Porto
Department of Geophysics, Observatório Nacional/MCTI, 20921-400, São Cristovão, Rio de Janeiro, Brazil
Search for other works by this author on:
Michael C. Daly
Michael C. Daly
Department of Earth Science, University of Oxford, South Parks Road, Oxford OX1 3AN, UK
Search for other works by this author on:
Emanuele La Terra
Emanuele La Terra
Department of Geophysics, Observatório Nacional/MCTI, 20921-400, São Cristovão, Rio de Janeiro, Brazil
Search for other works by this author on:
Sergio Fontes
Sergio Fontes
Department of Geophysics, Observatório Nacional/MCTI, 20921-400, São Cristovão, Rio de Janeiro, Brazil
Search for other works by this author on:
Published:
January 01, 2018

Abstract

We present a new interpretation of the basement immediately below the pre-Silurian unconformity in the mid-western part of the Parnaíba cratonic basin. Regional seismic reflection data, constrained by well and gravity data, have revealed the remnants of a pre-Silurian basin named the Riachão basin. It has a north–south trend and is about 120 km wide with a minimum area of c. 35 000 km2 and a maximum thickness of 4 km. Seismic interpretation shows the Riachão basin is defined by erosional unconformities at its top (the pre-Silurian unconformity) and base (the top of the pre-Riachão basement). The basin fill is formed of three stratigraphic sequences – Riachão I, II and III – separated by seismic discontinuities and laterally bounded by monoclinal folds and basement uplifts related to thrust faults. Exploration wells show that the Riachão sediments are Ediacaran to Lower Cambrian, clastic and a minimum of 1 km thick, unconformably overlying a heterogeneous metamorphic basement. The mechanism of formation of the basin is unclear. However, our seismic stratigraphic interpretation suggests that Riachão II and III are remnants of marine, clastic, foreland basin sequences of opposed polarity, related to late Neoproterozoic tectonics. The banded, high-amplitude, Riachão I sequence is interpreted as a carbonate platform preceding the main subsidence and clastic input of the Riachão basin.

You do not currently have access to this article.

Figures & Tables

Contents

Cratonic Basin Formation: A Case Study of the Parnaíba Basin of Brazil
CONTAINS OPEN ACCESS

M. C. Daly
M. C. Daly
Search for other works by this author on:
R. A. Fuck
R. A. Fuck
Search for other works by this author on:
J. Julià
J. Julià
Search for other works by this author on:
D.I.M. MacDonald
D.I.M. MacDonald
Search for other works by this author on:
A. B. Watts
A. B. Watts
Search for other works by this author on:
Geological Society of London
Volume
472
ISBN electronic:
9781786204127
Publication date:
January 01, 2018

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal