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

Abstract

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 centuriesmore 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.

Denudation and geomorphic change in the Anthropocene; a global overview.

“…Even though such areas represent a small proportion of the study areas analysed by Rivas et al (2006), their contribution to total sediment generation was estimated to be at least equivalent to (probably greater than) that of "natural" denudation in undisturbed areas, the latter also affected by farming and forestry activities. In a further analysis of sediment accumulation in lakes of the humid Pampa of Argentina, Forte et al (2016) indicated that since the beginning of the 20th century, regional erosion and lake sedimentation rates are 1-2 orders of magnitude greater than those prior to European settlement in the region (around 250 years ago). Similar examples are found in river and lake records globally.…”