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Genesis and Geodynamic Significance of Mesoproterozoic and Early Cretaceous Tholeiitic Dyke Swarms from the São Francisco Craton (Brazil).

A. ROSSET
•
DE MIN, ANGELO
•
L. S. MARQUES
altro
P. R. RENNE AND E. M. PICCIRILLO
2007
  • journal article

Periodico
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
Abstract
The eastern border of the Sa ̃o Francisco craton is characterized by widespread Mesoproterozoic (1.0 Ga) tholeiitic dykes and minor analogues of Early Cretaceous age (130 Ma). The Mesoproterozoic dykes (Salvador, Olivenc ̧a, Espinhac ̧o, Diamantina) show large elemental and Sr–Nd isotopic variations that suggest different parental melts related to a small-scale heterogeneous mantle of depleted residua and enriched components (Statistical Upper Mantle Assemblage, SUMA), responsible for plume- and crust-type signatures. The Mesoproterozoic intrusions, compatible with early stages of Rodinia breakup, may represent the initial breakup of the Sa ̃o Francisco– Congo junction. Early Cretaceous dykes (Espinhac ̧o) reveal normal and reversed polarities, indicating two distinct intrusive periods. These intrusions have elemental and Sr–Nd isotopic compositions similar to those of the coeval (132 Ma) high-TiO2 tholeiites from southern Parana ́ Basin (Urubicı ́-type, Brazil) and northern Etendeka (Khumib-type, Namibia). The genesis of these tholeiites requires lithospheric mantle components, as represented by K-alkaline (and carbonatitic) rocks from the Asuncion-Sapucai graben (Paraguay), that highlight the intriguing Pb-isotope relationships involving the Urubicı ́-Khumib tholeiites. The essential role of the Tristan plume is difficult to determine. The spatial distribution of such uncommon high-TiO2 tholeiites reveals that similar lithospheric components may exist in different cratonic blocks and associated mobile belts.
DOI
10.1016/j.jsames.2007.02.002
WOS
WOS:000247856600006
Archivio
http://hdl.handle.net/11368/1693394
info:eu-repo/semantics/altIdentifier/scopus/2-s2.0-34249984356
Diritti
metadata only access
Soggetti
  • Sao Francisco craton

  • Mesoproterozoic_Early...

  • Heterogeneous source ...

  • Lithospheric/plume co...

  • Rodinia breakup

Web of Science© citazioni
26
Data di acquisizione
Mar 9, 2024
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