This dataset contains LA-ICP-MS trace element concentrations from a greenish siltstone interval at 102.6 m depth in the Los Lagares-1 borehole (Pedroche Formation, Córdoba, Spain). The data include major, minor, and trace elements, including rare earth elements (REE), measured in siliciclastic matrix and associated mineral phases. The dataset provides information on geochemical variability, sediment provenance, and early diagenetic processes. These data contribute to understanding paleoenvironmental conditions and facies transitions between phosphoritic and siliciclastic deposits in the Lower Cambrian.