Loupe TEM Surveys in an Area Affected by Dryland Salinity

Of all the parameters measured in geophysics it is conductivity that has the broadest range with materials spanning at least six orders of magnitude. It is therefore an effective way to measure difference in the near surface weathering layers. The south-west of Western Australia has undergone sub-aerial weathering since the Permian. In this period the landscape and climate have changed significantly. From a sub-tropical well-drained terrain incised by deep river systems, the area has become more arid and poorly drained with rivers filled with sediments combined with deep, lateritic weathering of the crystalline basement. The result has been a gradual accumulation of salt coming from rainfall in the regolith. These changes and other effects are reflected in conductivity data. The Loupe TEM system was used to map a farm in this area to better understand the processes that result in the salt becoming mobilised and causing scalding of vegetation at the surface. In this case the Loupe system was mounted on a sled and towed behind a vehicle. The results can be interpreted to unravel the geological history of the area and better understand how to manage the landscape.