Fig. 4: Stable isotope composition of calcite. | Nature Communications

Fig. 4: Stable isotope composition of calcite.

From: Deep microbial colonization during impact-generated hydrothermal circulation at the Lappajärvi impact structure, Finland

Fig. 4: Stable isotope composition of calcite.The alternative text for this image may have been generated using AI.

a δ13Ccalcite vs. δ18Ocalcite plot for SIMS analyses of calcite from impact melt rock (orange squares), impact melt-bearing breccia (blue circles) and lithic impact breccia (yellow triangles). Fields for isotopic signatures representing different groups (and processes) are highlighted (i, ii, iii, y, yy). Yellow arrows indicate petrographically identified chronological (as documented by CL, BSE and/or indicated by SIMS data) order from older to younger calcite. b–e SEM images of polished calcite crystal cross-sections with spot locations for SIMS analyses, corresponding SIMS C and O isotope data. b 13C-enriched calcite from impact melt rock sample LA1;137, plotted in group “i” in (a). c 13C-enriched calcite from impact melt rock sample LA1;137, group “ii”. d 13C-enriched calcite from impact melt rock sample LA1;30, group “iii”. e 13C-depleted calcite from impact melt-bearing breccia sample LA4;152. In the δ13Ccalcite vs. δ18Ocalcite plot in (a), spots 1–4 plots in group “y”, whereas spots 5–6 are plotted in group “yy”. Each spot represents one SIMS analysis, with errors (1σ) within the size of the symbols.

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