Journal
JOURNAL OF STRUCTURAL GEOLOGY
Volume 93, Issue -, Pages 106-130Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.jsg.2016.10.006
Keywords
Polyphase deformation; Strain; Kinematic vorticity; Quartz c-axis fabrics; Exhumation rate; Ribeira Belt
Categories
Funding
- Sao Paulo Research Foundation (FAPESP) [2002/13654-4, 2015/04487-7]
- CPRM-Geological Survey of Brazil (Alto Ribeira II Project) [4077.500, SG.22-X-B-VI]
- National Counsel of Technological and Scientific Development (CNPq) [302884/2015-7]
Ask authors/readers for more resources
The Ribeira Belt (Brazil) is a Neoproterozoic collisional-related feature that was located in a south-central position in West Gondwana. We present quantitative data on finite strain, flow vorticity and deformation temperatures for the Curitiba Terrane, a major segment of the southern Ribeira Belt. Six deformation phases (D-1-D-6) related with crustal thickening and exhumation were recognized. D-1 and D-2-related microstructures are preserved exclusively within porphyroblasts, in part grown during stages of high-pressure (similar to 9-12 kbar) isobaric heating after crustal thickening. D3 phase was active from peak metamorphism attained in contrasting crustal levels (810-400 degrees C), to the early stage of exhumation (500-400 degrees C), as indicated by petrological, microstructural and quartz c-axis fabric evidence. Kinematic vorticity results indicate that the SL3 mylonitic fabric resulted from a simple shear-dominated deformation related with westward thrusting. North-verging overturned D-4 folds with E-W-trending sub horizontal axes derived from a pure shear-dominated deformation. Regional 133 open folds with subvertical axes and NNE-SSW-trending traces were produced by indentation tectonics. D-6 phase comprises retrograde orogen-parallel transcurrent shear zones related with scape tectonics. Geochronological data indicate that D-3-D-6 phases occurred between 584 and 580 Ma, suggesting a fast exhumation rate of similar to 8 mm/year for the deepest rocks from the southern Ribeira Belt. (C) 2016 Elsevier Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available