Paleoproterozoic banded iron formations from the Quadrilatero Ferrifero, (Iron Quadrangle) in Brazil might be considered a natural "laboratory" to investigate rheology and strain partitioning in quartz and iron oxide rich layers under variable P-T conditions. A microstructural analysis was carried out in banded iron formation samples collected in domains of distinct composition, strain and metamorphic P-T conditions. In the low strain zones and low greenschist facies conditions, magnetite is the dominant mineral phase. Microstructure and texture analyses indicate that the deformation mechanisms in these domains are partitioned between fracturing and pressure solution, in iron oxide rich layers, and crystal plasticity in pure quartz layers. In the intermediate strain zones and mid greenschist facies conditions hematite plates are the dominant phase. A combination of different deformation mechanisms, including dislocation creep, pressure solution and, at less extent, fracturing, contribute to the microfabric development under moderate strain. Magnetite grains are absent at high strain conditions. The intense shearing in the high strain zones and the higher temperatures led to the generation of tectonites showing a remarkably well-defined composition layering, in which bands of hematite plates alternate with layers of large quartz grains. The main deformation mechanisms are, in this case, dislocation creep and pressure solution.