Nature 304, 493 - 497 (11 August 1983); doi:10.1038/304493a0

Thrusting and duplex formation at Mount Isa, Queensland, Australia

T. H. Bell

Department of Geology, James Cook University, Queensland, Australia 4811

Large-scale repetition of Mount Isa and Haslingden Group rocks in the anticline north of Mount Isa is interpreted as the core of a thrust duplex which has been subsequently folded parallel to the direction of thrusting. Displacement of Mount Isa Group rocks above the duplex is extremely significant to the regional geology and exploration for more Mount Isa style Pb−Zn and Cu orebodies. Interpretation of the geometry of the thrust belt indicates thrusting on different stratigraphical levels below and above the duplex during its formation, horses formed from a heelwards protruding footwall ridge instead of a trough, and the complex effects on stratigraphical cross-sections through duplexes of sloping lateral footwall ramps on horses.

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