Towards coupled geodynamic and hydrothermal numerical rift models of sediment-hosted Copper and Zinc deposits

Many large sediment-hosted base metal deposits occur in failed continental rifts and the passive margins of successful rifts, e.g., in the MacArthur Basin, Australia, and the Selwyn Basin in Canada. Continental rifts and their margins provide a specific mix of elevated temperatures and heat flows, fault networks to facilitate fluid flow, sediment supply from the rift shoulders, and ocean water contributing pelagic sediments and sulfate. The large-scale geodynamics thus provide the necessary ingredients for metal leaching and deposition to occur on a variety of spatial and temporal scales. To understand the geodynamic controls on ore formation, we are therefore coupling the geodynamic code ASPECT1,2 (coupled to the landscape evolution model FastScape3,4) with the hydrothermal fluid flow code CSMP++5,6 to include realistic pressure, temperature, and heat flow conditions, as well as permeability and sediment distributions, for fluid flow and metal leaching/deposition. This coupled workflow crosses temporal scales of millions of years to years and spatial scales of hundreds of kilometers to meters. We present preliminary results from geodynamic modelling of large-scale continental rifting and hydrothermal simulations at specific snapshots of the upper 10 km of crust of this large-scale geodynamic evolution, showing the effect of rift duration, adjacent craton thickness, and erosion efficiency on sediment-hosted Cu and Zn deposits.

1Kronbichler et al. (2012). GJI191(1), 12–29.

2Heister et al. (2017). GJI, 210(2), 833–851.

3Neuharth et al. (2022). Geology, 50(3), 361–365.

4Braun & Willett (2013). Geomorphology, 180-181, 170-179.

5Weis et al. (2014). Geofluids, 14(3), 347–371.

6Rodríguez et al. (2021). GCubed, 22(6).