This dataset contains geochemistry measurements and fossil diatom data from a sediment core retrieved from Isla Hornos, in the Cape Horn Archipelago (''''IHL'''''', -55.97 S, -67.28 W, 156 m asl). The dataset consists of diatom relative frequencies, ITRAX scanning XRF counts, ICP-MS and ICP-OES elemental composition, C percent, N percent, S percent, TEX-86-based lakewater temperature reconstructions and magnetic susceptibility measurements. Ages of the sediment samples were assigned based on an age depth model derived from 14C measurements and span the last c. 11,000 years. Funding: This project was funded by UK Natural Environment Research Council Grant NE/K004514/1 to DAH. The research was carried out under permits from Corporacion Nacional Forestal Region de Magallanes y Antartica Chilena and Ministerio de Relaciones Exteriores Direccion de Fronteras y Limites del Estado.

This dataset contains geochemistry measurements and fossil diatom counts made on a sediment core from La Grange Cop lake, Marion Island (46deg94S, 37deg60E, 60 m above sea level). The dataset consists of diatom relative frequencies, diatom principal components analysis (PCA), and diatom-inferred conductivity, ITRAX scanning XRF elemental percentages and XRF PCA, C%, N%, and delta13C measurements, and magnetic susceptibility measurements. Ages of the sediment samples were assigned based on an age depth model derived from 210Pb, 137Cs, and 14C measurements and span the last c. 700 years. This project was funded by UK Natural Environment Research Council Grant NE/K004514/1 to Dominic A Hodgson and a Research Foundation-Flanders travel bursary to Elie Verleyen.