Nature and timing of early extensional structures in the Mitakoodi Quartzite, Mount Isa Inlier, northwest Queensland

Dolerite dykes which represent normal and imbricate normal faults are a feature of the Mitakoodi Quartzite on the western limb of the Bulonga Anticline in the central part of the Mount Isa Inlier. The faults and dykes were folded and metamorphosed during subsequent regional compression. Stratigraphic omissions along strike are attributed to low‐angle normal faulting which precedes the compressional folding. The imbricate normal faulting, concurrent dolerite intrusion, and low‐angle regional faulting represent an episode of extension affecting the Mitakoodi Quartzite on the western limb of the Bulonga Anticline. A model of gently dipping faults with several splays cutting up section from sole faults is presented to account for the geometry of this belt of Mitakoodi Quartzite and for smaller scale extensional structures in the same unit.