Oral Presentation NCGRT/IAH Australasian Groundwater Conference 2019

Hydrogeological implications of active tectonics in the Great Artesian Basin (97)

Mike Sandiford 1 , Ken Lawrie 2 , Ross S. Brodie 2
  1. School of Earth Science, University of Melbourne, VIC, Australia
  2. Groundwater branch, Geoscience Australia, Canberra, ACT, Australia

The surface drainage systems across central and eastern Australia testify to a diverse range of tectonic processes that continue to modify the landscape in subtle ways. The distribution of channel forms and offsets in the drainage catchments in the Lake Eyre Basin points to the existence of a tectonically active north to northwest-trending fault system that correlates with a distinct potentiometric anomaly in deep aquifers in the central part of the Great Artesian Basin (GAB). Correlations in the distribution of seismic activity and drainage form with changes in lithospheric thickness suggest faulting reflects in part stress sourced from sub-lithospheric mantle flow beneath the GAB, while geometry implies fault activity dates to the late Miocene. These observations have implications for hydrogeological interpretations and groundwater process understanding, while also providing constraints on water balance studies. Recognition of tectonic control on pressures within key aquifers also has groundwater management and monitoring implications, and more general utility for unconventional energy development and monitoring.