Abstract
Detailed examination of inclusion trails within garnet and plagioclase poikiloblasts and matrix fabric, from rocks within theCrixás gold mine, Goiás, Brazil, indicate four phases of deformation. D 1 and D 2 are interpreted to be related to early, probably Archean, large-scale isoclinal folding and are limited to S 1 and S 2 fabric in garnet inclusions in the structural lower portion of the mine. D 3, a L-S fabric, the most dominant structural feature of the mine area is interpreted to be related to younger thrusting. D 4 is a crenulation cleavage possibly related to the collapse of the D 3 thrusting event. These four phases correlate to four phases determined from regional mapping. As a consequence of D 3 thrusting, amphibolite facies rocks structurally overlie greenschist facies rocks and are separated by a zone of intense metasomatism and quartz veining. This zone represents the very rich lower ore zone of the Crixás gold mine. The timing of the D 3 is unclear, with Archean to Brasiliano ages possible.
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