Anthropogenic geomorphic change as a potential generator of renewable geologic resources in the humid Pampa of Argentina

- Recent lake sediments have similar or better quality than soils used by the industry.
- Existing sediment resources are enough to supply industry needs during decades-centuries.
- There is at least a tenfold increase of sedimentation rates in lakes during the Anthropocene.
- Present sedimentation rate in lakes is roughly equivalent to consumption.
- Use of lake sediments could considerably mitigate impacts of soil mining.

The nature and amount of sediments in various lakes, intermittent swampy areas and river sectors in the humid Pampa (Buenos Aires Province, Argentina) were analysed. The aim was to determine whether recent sediments in such environments could serve as an alternative resource to the brick industry, for minimising the current, high environmental impact of soil mining. Sediment sequences were obtained, and the thicknesses of the upper sediment layers, corresponding to the suballuvial (approx. 1400-700 years BP) and alluvial (approx. 250 years BP to present) were determined. Sediment samples were collected and analysed for grain size and Atterberg limits. Suitable sediments were then selected to determine the optimal brick materials and their technical properties. Similarly, control bricks were prepared with ceramic pastes of local industries. The results show that the quality of the former is similar or superior to that of the latter. The initial estimates of the available resource indicate a long-term supply for the industry. Estimates of the current sedimentation rates indicate that resource renewal might occur at a rate comparable to current consumption. The sedimentation rates have increased significantly in the past two centuries - more so in the past few decades (the Anthropocene?) - with increasing human modification of geomorphic processes. If the results presented here are confirmed, a highly sustainable model can be implemented in the brick industry.