A Laurentian affinity for the Embu Terrane, Ribeira Belt (SE Brazil), revealed by zircon provenance statistical analysis

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Ribeiro, Bruno, V ; Faleiros, Frederico M. ; Campanha, Ginaldo A. C. ; Cawood, Peter A. ; Kirkland, Christopher L. ; Barham, Milo ; Martin, Erin L. ; Seraine, Marina ; Cabrita, Dina I. G. ; Yogi, Maria T. A. G. ; Almeida, Vidya V. ; Forero-Ortega, Anny J. A. ; Dantas, Elton L.

• Document type: Journal article
• Source: GEOSCIENCE FRONTIERS; v. 14, n. 1, p. 13-pg., 2023-01-01.

Abstract

New and compiled detrital zircon U-Pb ages from the southern Neoproterozoic-Cambrian Ribeira Belt, SE Brazil, demonstrate Laurentian affinity of the Embu Terrane which is statistically distinct from the adjoining Apial and Sao Roque terranes with cratonic affinity (e.g., Sao Francisco Craton). Zircon provenance results indicate that the type-area of the Embu Terrane is dominated by detrital zircon age modes at ca. 1200 Ma, 1400 Ma, and 1800 Ma, with maximum depositional age of ca. 1000 Ma. In contrast, the Apial and Sao Roque terranes are dominated by Paleoproterozoic detrital zircon ages (ca. 2200- 2000 Ma age dominant component), with maximum depositional ages of ca. 1400 Ma and 1750 Ma, respectively. Multidimensional scaling (MDS) analysis of non-parametric similarity measurements on zircon age populations indicates for the first time that the Embu Terrane encompass two statistically distinct detrital zircon age spectra, which is also reflected in the metamorphic zircon age record. The statistical characterization of the Embu Terrane through populational metrics allow a quantitative comparison with surrounding tectonic domains and rock samples classified such as Embu-type. Our results clearly highlight the distinction between the statistically differentiated Embu Terrane from the Apial and Sao Roque terranes, supporting an allochthonous interpretation. In addition, we demonstrate that rocks samples previously classified as Embu-type are significantly dissimilar to the definition of Embu Terrane, failing to support alternative tectonic models (e.g., intracontinental evolution). Detrital zircon age spectra reveal that the Apial and Sao Roque terranes have similar zircon provenance to domains sourced from the Sao Francisco Craton, whereas detrital zircon populations from the Embu Terrane have greater affinity with SW Laurentia basins (and their inferred sediment sources), consistent with previous findings. Therefore, we interpret the Embu Terrane as a Rodinia descendant developed along the active margin of the SW Laurentia that collided with the Ribeira Belt during early Neoproterozoic (810-760 Ma). (c) 2022 China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/). (AU)

• FAPESP's process: 18/10012-0 - Fluid flow, deformation and tectonic significance of regional shear zones from the southern Ribeira Belt
• Grantee: Frederico Meira Faleiros
• Support Opportunities: Regular Research Grants