Idades SHRIMP U-Pb do Complexo Sertânia: implicações sobre a evolução tectônica da Zona Transversal, Província Borborema
DOI:
https://doi.org/10.5327/S1519-874x2004000100001Keywords:
Borborema Province, Alto Moxotó Terrane, SHRIMP, Paleoproterozoic, Sertânia ComplexAbstract
The Sertânia complex in the Alto Moxotó Terrane, Zona Transversal of the Borborema Province, Northeast Brazil, is a metasedimentary sequence with a subordinate metavolcanic component, metamorphosed under upper amphibolite facies conditions. Several previous regional geological surveys have included this rock assemblage in an undivided gneissic-migmatitic complex, due to the lack of a tectonostratigraphic model for this unit. This paper presents the first geochronological zircon U-Pb ages (SHRIMP U-Pb ages) and the first Sm-Nd isotopic data for this complex. Field and microscopic research reveals the existence of a volcanoclastic fraction of andesitic and dacitic composition, besides the dominant clastic components in these supracrustals. Furthermore, cathodoluminescence images of zircons show well formed little rounded crystals, thus suggesting reduced sediment transport prior to deposition. The calculated ages means with a 95% confidence level, based on a group of zircons of the same generation plot around 2.0 Ga, representing the episode of primary zircon crystallization. Some observed overgrowths testify to an additional Brasiliano overprint (ca. 0.6 Ga). Geochronological data on the supposed meta-plutonic rocks of the same complex point to the same Paleoproterozoic time interval, thus indicating contemporaneity with the sedimentation of the supracrustals. The obtained Nd model ages and µNd(t) parameters also confirm a contribution of Archean and Paleoproterozoic sources to these supracrustals rocks. These data clearly demonstrate contrast between the supracrustal rock assemblages of the Alto Moxotó Terrane and the supracrustals of other terranes of the Zona Transversal, which display Meso to Neoproterozoic ages, and imply that this crustal segment represents an independent lithotectonic domain.Downloads
Download data is not yet available.
Downloads
Published
2004-04-01
Issue
Section
Articles
License
Authors who publish in this journal shall comply with the following terms:
- Authors keep their copyright and grant to Geologia USP: Série Científica the right of first publication, with the paper under the Creative Commons BY-NC-SA license (summary of the license: https://creativecommons.org/licenses/by-nc-sa/4.0 | full text of the license: https://creativecommons.org/licenses/by-nc-sa/4.0/legalcode) that allows the non-commercial sharing of the paper and granting the proper copyrights of the first publication in this journal.
- Authors are authorized to take additional contracts separately, for non-exclusive distribution of the version of the paper published in this journal (publish in institutional repository or as a book chapter), granting the proper copyrights of first publication in this journal.
- Authors are allowed and encouraged to publish and distribute their paper online (in institutional repositories or their personal page) at any point before or during the editorial process, since this can generate productive changes as well as increase the impact and citation of the published paper (See The effect of Open Access and downloads on citation impact).
How to Cite
Santos, E. J. dos, Nutman, A. P., & Neves, B. B. de B. (2004). Idades SHRIMP U-Pb do Complexo Sertânia: implicações sobre a evolução tectônica da Zona Transversal, Província Borborema . Geologia USP. Série Científica, 4(1), 1-12. https://doi.org/10.5327/S1519-874x2004000100001