Metagenomes from basal ice cores at Camp Century Greenland

Metagenomic sequencing data from Camp Century ice core and basal ice samples (Greenland) This dataset contains paired-end metagenomic sequencing reads generated from glacial ice and basal debris-rich ice samples collected at Camp Century, Greenland. Fourteen ice samples and four blank controls (frozen Milli-Q water from ULB and IGE) were processed under ultra-clean conditions at the IGE ice core facility (Institut des Géosciences et de l'Environnement, Grenoble). Samples were melted at room temperature and sequentially filtered through 0.2 µm and 0.1 µm polycarbonate filters; DNA was extracted from filters using the PowerWater kit (Qiagen). Two macroscopic debris inclusions (>0.5 cm diameter) from debris-rich ice at 6 m and 0.25 m depth above the ice–bed interface (samples INC 9 and INC 12) were isolated and extracted separately using the same protocol. Metagenomic libraries were prepared with the Illumina DNA Prep Kit, including enzymatic fragmentation (37°C, 15 min), ligation with IDT for Illumina UD Indexes, and size selection (left-hand selection, 80 bp cutoff to remove primer dimers). Libraries were PCR-amplified (20 cycles), purified, and validated by Agilent 4200 Bioanalyser (High Sensitivity D1000 assay). Sequencing was performed on an Illumina NextSeq 1000/2000 platform using P3 600-cycle reagent kits in paired-end 2 × 300 bp configuration, generating approximately 400–500 million reads per run. The dataset includes raw FASTQ files for all ice samples, debris inclusion extracts, and blank controls.