The Delamerian Orogen: exposing an undercover arc

Short abstract: The Delamerian Orogen is spatially and temporally extensive, covering five states in central and eastern Australia. The orogen records the transition from Proterozoic Australia to the Phanerozoic Tasmanides, starting with rifting of the Rodinian supercontinent and transition to a passive margin from ca. 830 to 530 Ma, then developing as a convergent eastern Gondwanan margin from ca. 530 Ma that was terminated by the mid-to-late Cambrian Delamerian Orogeny. The orogen was later impacted by younger geodynamic events, particularly in the Ordovician-Silurian-Devonian. Due to the paucity of exposure, in particular in its central segment, and the complex cover sequences, significant parts of the Delamerian Orogen remain poorly documented. The orogen is also underexplored for resources despite demonstrated potential for magmatic-hydrothermal and other mineral systems. As part of the Exploring for the Future program, the Darling-Curnamona-Delamerian project is working to improve geodynamic framework and mineral systems knowledge through a range of activities including; analysis of legacy drill core, new stratigraphic drilling and major geophysical data acquisition campaigns (airborne electromagnetic, deep crustal seismic reflection, magnetotelluric). Significant first results reveal the existence of a corridor of Siluro-Devonian igneous rocks flanked by Cambrian igneous rocks within the Loch Lilly-Kars Belt, possibly related to an episode of rifting or extension, with potential for rift-related and magmatic-hydrothermal mineral systems of that age. Citation: Gilmore P.J., Roach I.C., Doublier M.P., Mole D.R., Cheng Y., Clark A.D. & Pitt L., 2023. From The Delamerian Orogen: exposing an undercover arc. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://dx.doi.org/10.26186/148679