Biogenesis of landscapes: insights from new isotope techniques and paleo-soils from WA

Has life engineered its environment? Testing the biogenesis hypothesis for the formation of soils.

Isotope Weathering Profile

Characteristic zonation of the weathering profile (regolith) developed on Archean granitic bedrock in WA, showing a resistant lateritic duricrust, clay-rich pallid zone, saprolite, and the local granitic bedrock (Image Anand and Paine, 2002). View larger image.

The landscape of Western Australia (WA) represents unique palaeo-soil systems whose origin and ages are poorly constrained. It is generally assumed that the local soil-plant system has adapted to a local climate and hostile and nutrient-poor regolith developed on the Archean granitic bedrock.

However, a new theory – the Phytotarium concept – might suggest an alternative explanation for the landscape evolution. The idea is that the landscape in the southwest regions of WA (i.e., plateau-like hill tops made of a resistant lateritic duricrust with an underlying clay-rich saprolite/pallid zone, see Figure) rather represents the product of biological processes mediated by plants and microbes that have ‘engineered’ the soils to suit their needs.

Hence, biota may have a direct influence on the underlying geological features and the formation of local landscapes, and this “biogenesis” hypothesis will be put to the test in this project. Specifically, the project will use new and established analytical techniques such as (i) laser-based RbSr dating of soil clays (illites, micas), (ii) ICP MS concentration analysis of local soils and granite bedrock, and also (iii) quantitative element mass balance modelling.

These multiple approaches will be used to constrain the ages of local regolith/palaeo-soils, as well as sources and internal cycling of selected elements in a weathering profile in Avon River catchment at the UWA’s Research Station near Pingelly Farm Brookton in Western Australia. 


Dr Juraj Farkas

Supervisors

Dr Juraj Farkas, Professor David Chittleborough and Associate Professor Matthias Leopold

Research area: Mineral and energy systems, Tectonics and solid earth processes, Palaeoclimatology, Palaeontology and palaeoenvironments, Environmental geochemistry

Recommended honours enrolment: Honours in Geology

Tagged in Honours projects - Geology, Honours Projects - Juraj Farkas, Honours projects - David Chittleborough