Petrochronological constraints and tectonic implications of Tonian metamorphism in the Embu Complex, Ribeira Belt, Brazil

Author(s)

Cabrita, Dina I. G. ^[1] ; Faleiros, Frederico M. ^[1] ; Cawood, Peter A. ^[2] ; Campanha, Ginaldo A. C. ^[1] ; Yogi, Maria T. A. G. ^[3] ; Wainwright, Ashlea N. ^[4] ; Raveggi, Massimo ^[2] ; Almeida, Vidya V. ^[5]

Affiliation

^[1] Univ Sao Paulo, Inst Geociencias, Rua Lago 562, BR-05508080 Sao Paulo, SP - Brazil

^[2] Monash Univ, Sch Earth Atmosphere & Environm, Melbourne, Vic 3800 - Australia

^[3] Carleton Univ, Dept Earth Sci, Ottawa, ON - Canada

^[4] Univ Melbourne, Sch Earth Sci, Parkville, Vic 3800 - Australia

^[5] CPRM Geol Survey Brazil, Rua Costa 55, BR-01304010 Sao Paulo, SP - Brazil

• Document type: Journal article
• Source: Precambrian Research; v. 363, SEP 1 2021.
• Web of Science Citations: 0

Abstract

The Embu Complex of the Ribeira Belt, southeast Brazil, provides records of orogenic processes within the time period between Rodinia break-up and West Gondwana assembly. Recent studies have questioned the accretionary setting for the belt, suggesting an intracontinental setting. In this paper, we present new petrological, U-Pb and Rb-Sr data from metasedimentary rocks of the Embu Complex, discussing the implications for the tectonic evolution from Rodinia to West Gondwana in the Ribeira Belt. Sillimanite, sillimanite-K-feldspar and cordierite zones represent the high-grade metamorphic zones for the metamorphic event identified in the southern portion of the Embu Complex. Petrological and thermodynamic modelling data indicate that the highgrade metamorphic rocks of the complex attained conditions between 750-805 degrees C and 3.6-9.2 kbar. Monazite and zircon U-Pb data indicate that the high-grade metamorphic event occurred between 810-760 Ma, concomitant with igneous activity recorded during this period. In addition, zircon and apatite U-Pb ages, as well as, biotite and muscovite Rb-Sr ages, between 675-550 Ma record a slow cooling rate of 4.4 degrees C/Ma for the period between 675-640 Ma, and a late stage of shear zones development. These results reinforce the accretion of distinct units within the Ribeira Belt during the Neoproterozoic Era. (AU)

• FAPESP's process: 15/26645-3 - Tectonometamorphic evolution of the Embu Terrane and relationships with adjacent terranes in the Southern Ribeira Belt (São Paulo, Brazil)
• Grantee: Dina Isabel Guerreiro Cabrita
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 19/10457-4 - Isotope dating coupled to trace element characteristics in igneous and metamorphic minerals from the Embu Terrane, and their implications for the reconstruction of the Ribeira Belt tectonic evolution
• Grantee: Dina Isabel Guerreiro Cabrita
• Support Opportunities: Scholarships abroad - Research Internship - Doctorate
• 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