The orosirian-statherian sequence and transpressive geometry in Santa Maria de Itabira, Minas Gerais

Abstract

The metasedimentary rocks cropping out in the surroundings of the township of Santa Maria de Itabira (MG), comprise Orosirian quartzites herein informally named Pedra Branca Quartzite and the Statherian banded iron formation bearing sequences at the eastern border of the southern Espinhaço Range. They define an allochthonous shear-zone-bound inlier block, between slices of Archean granite-gneissic rocks of Dona Rita Complex, intruded by the 1729±12 Ma old Borrachudos Granite, Neoproterozoic Mafic Rocks (Pedro Lessa Suite) and mesozoic diabase dikes. The structure of the inlier is controlled by three families of folds D1, D2 and D3 nucleated in three deformational phases F1, F2 and F2’ associated to the oblique shear zones development in a transpressive environment during one of the Brasilian Orogenies.

Keywords

• Southern Espinhaço
• Tectonic evolution
• Transpression