Palaeoproterozoic to Mesoproterozoic Geology of North Queensland

Correlating Georgetown and Mt Isa SuccessionsMaximum depositional ages for the Etheridge Group are similar to those ofthe Soldiers Cap and Mt Isa Groups and deformation events appear tocorrelate BUT ……•The provenance of the lower Etheridge Group is very different to any Mt IsaInlier Proterozoic sediments.•The provenance of the upper Etheridge Group is similar to Mount Isa Inlier,but requires an E-W event between ~1660 and 1640 Ma to bring these terranestogether.Other differences between Georgetown and Mt Isa:•Normal geothermal gradient (clockwise P-T-t with superimposed high templowpressure event) vs dominantly high geothermal gradient (anti-clockwiseP-T-t) (e.g. Boger & Hansen, 2004; Cihan et al., 2006; Rubenach 1992)•Intensity of N-S folding decreases westwards towards Mt Isa•E-W vs N-S directed structural grain (e.g. O’Dea et al., 1997)•S-type vs I- and A-type magmatism at ~1555 Ma (e.g. Black & McCulloch, 1990;Wyborn et al., 1992)•Any rigorous geodynamic model needs to take these differences intoaccount