Fig. 4
From: Timing and origin of natural gas accumulation in the Siljan impact structure, Sweden
δ13Ccalcite vs depth. a Closely spaced boreholes VM2, 01–10C and 01–11C (samples from the latter two have been depth-normalized to the sedimentary-crystalline rock interface in VM-2 in order to plot them in the same graph), (b) VM1, (c) CC1, and (d) Solberga-1, with Solberga quarry samples collected at close to ground surface, ~400 m south of Solberga-1 drill site. Each data point represents one SIMS analysis. Fractures with gas occurrences observed during drilling are marked with “x” (including a seep oil observation from borehole 01–10C/VM3, marked “−“) on the right-hand side of the graphs and the depth of the sedimentary-crystalline bedrock interface is also indicated. Errors (2σ) are within the size of the symbols. All plots have the same range on the axes for comparison
