class: center, middle, inverse, title-slide # role of active tectonics gab, australia ## groundwater geodynamics ### Mike Sandiford¹, Ken Lawrie², Ross Brodie² ### ¹University of Melbourne, ²Geoscience Australia ### 2019-08-06 (updated: 2019-10-19) --- ```          ### Take home messages * Derangement of surface drainage systems testify to subtle tectonic modification of the landscape on the million-year timescale relevant to groundwater residence in the Great Artesian Basin. * Changes in channel form and offsets are attributed to an active north to northwest-trending fault system that correlates with a distinct potentiometric anomaly in deep aquifers in the central part of the GAB. * Correlations with changes in lithospheric thickness suggest faulting reflects in part stress sourced from sub-lithospheric mantle flow beneath the GAB. * The observations have implications for hydrogeological interpretations and groundwater process understanding, inclduing water balance studies and the distribution of pressure within GAB aquifers. --- .center[ ] - Figure 1. Key surface catchment systems in heavy blacklines. Grey shade shows the mapped distribution of the Cadna-owie Formation and equivalents in within the Eromanga Basin. --- channel country, central Lake Eyre Basin .center[ ] --- lithopsheric thickness - Nick Rawlinson .center[] --- earthquake epicentres - Gary Gibson .center[] --- Eromanga Basin, Cadna-owie Fm - Geoscience Autralia .center[] --- potentiometric head, Cadna-owie aquifer - Geoscience Autralia .center[] --- gradient in potentiometric head, Cadna-owie aquifer .center[] --- artesian head, Cadna-owie aquifer - Geoscience Autralia .center[] --- planform curvature in potentiometric head, Cadna-owie aquifer .center[] --- 1° smoothed topography, Lake Eyre Basin .center[] --- channel country, central Lake Eyre Basin .center[] --- innamincka domes .center[]