Stream sediment analysis for Lithium (Li) exploration in the Douro region (Portugal): A comparative study of the spatial interpolation and catchment basin approaches

Lithium (Li) was recently added to the list of critical raw materials by European Union due its significance for green energy transition. Thus, development new toolchains make Li exploration more economic and effective is needed. Stream sediment analysis can play an important part in these tool chains. In this work, two historical stream datasets covering parts Fregeneda-Almendra pegmatite field Douro region (Portugal) were reprocessed considering distinct approaches: spatial interpolation through inverse distance weighting (IDW) catchment basin approach using concentration area (C-A) fractal analysis. The following objectives delineated: (i) determine pathfinder elements Li, relevant associations mineralization sources; (ii) compare performance both approaches; (iii) identify target areas Li. case interpolation, highest values associated granites although use key allowed lithological discrimination delineation areas. approach, proved be decreasing number interest with high accuracy (>75%) when previously mapped Li-pegmatites. One limitations identified anomalous basins related granites, despite allowing discriminating granite- from pegmatite-related anomalies. Comparing approaches, method adequate early stages (reconnaissance), while suited prospect-scale exploration. Field validation results one containing three others favorable signs region.