Loan IDA number IDA271576. Microbial DNA concentrations from DNA extraction using Qiagen PowerSoil Pro DNA Extraction kit and subsequent PCR from shale and sandstone core samples collected and preserved for microbiology (shale SSK111456 and sandstone SSK111457) from UKGEOS Glasgow Observatory, borehole GGC01. DNA extractions and subsequent amplification using PCR indicate levels of microbial DNA below detection limits. Samples and data are derived from the UK Geoenergy Observatories Programme funded by the UKRI Natural Environment Research Council and delivered by the British Geological Survey.