BACKGROUND OF U AND Th IN SEDIMENTS OF BEDROCK RIVERS

The Miño River is a good example of bedrock rivers, where sediment geochemistry scarcely studied. Its urban reach when passing through the city Ourense gathers some characteristics that provide interest to its sediments, like scarcity fine sediments accumulation and impact several human activities. Sediments trapped by potholes other rock cavities were considered. In order evaluate society-nature interactions composition it critical determine compositional background (in absence alterations), particularly working with trace elements. This work presents an exploratory assay in from rivers using two uncommon elements, uranium (U) thorium (Th). To their different statistical techniques applied set value calculate possible enrichments. Background was calculated simple least squares lineal regression Al as independent variable (reference element) resulting 8.7 mgU kg-1 5.6 mgTh kg-1. Enrichments found particular samples can be attributed intrinsic microenvironment complexities inside cavities.