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The previously missing c. 2.9 Ga high‐K continental crust in West Gondwana revealed in Northeast Brazil
Author(s) -
Ferreira Alanielson C. D.,
Dantas Elton L.,
Fuck Reinhardt A.
Publication year - 2021
Publication title -
terra nova
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.353
H-Index - 89
eISSN - 1365-3121
pISSN - 0954-4879
DOI - 10.1111/ter.12504
Subject(s) - gondwana , archean , geology , continental crust , felsic , proterozoic , magmatism , geochemistry , protolith , crust , earth science , paleontology , mafic , zircon , tectonics , structural basin
Abstract 2.9 Ga is an uncommon magmatic age in Archean evolution worldwide, especially in West Gondwana. We identified so far unknown 2.97–2.92 Ga high‐K calc‐alkaline magmatism in the Borborema Province, northeast Brazil. It appears to indicate that the transition to high‐K magmas occurred before c. 2.7 Ga in Earth's history. The 2.9 Ga protoliths were reworked and progressively changed composition to 2.65 Ga and 2.25 Ga higher‐K granites in early magmatic arcs. Therefore, despite several reworking events from the Archean to Proterozoic times, these rare relicts of K‐rich magmatism indicate that reworking of felsic components was significant for the growth and differentiation of continental crust from c. 2.9 Ga onwards in West Gondwana.