Abstract
This paper presents the results of the geological investigation performed on the Precambrian rocks at the Natividade region (Northern Goias). Archean tonalites, mafic rocks, and supracrustals of ancient evolution not yet reconstituted were modified by strong progressive non- coaxial ductile deformation, with displacement, imbrication shearing recrytallization in high to medium amphibolite facies and some migmatization. These modified rocks grade to granite- greenstone terrain in the eastern part of the area. All these modified rocks and unaffected gneisses are assembled in the Goiano Complex . The mass displacement occurred towards SSE and the mylonitic foliation has 0N30 direction, what is interpreted as related to a not yet located oblique ramp . This important tectonic event is admited to be of Late Archean age. Afterwards, high angle ductile shear zones developed, with 10N20 direction, sinistral movement and recrystallization under green schist facies conditions. This event seems to be of Early Proterozoic age and introduced modifications on the earlier structural geometry. An ensialic basin could be developed and closed in some interval of the, 1.850-450 Ma period; its sedimentary filling, the Natividade Group, accumulated on stable shelf environment was folded with 0N20 trending axis and slightly transformed by low grade metamorphism. Transcurrent 50N60 dextral and 300N315 sinistral faults also could form, cutting this supracrustal sequence and the older Goiano Complex.
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