Table 1.
SIMS-determined carbon isotope values of the five taxa of Apex microfossils discussed here
| Taxon (specimen) | Figures | Number of measurements | δ13C‰ VPDB* |
| Unnamed unicell | |||
| (Clast #12) | Figs. 1N, 2 U and V, and 3 I and J | 1 | −30.9 |
| Avg. | (n = 1) | −30.9 | |
| P. minutum | |||
| (Clast #9) | Figs. 1K, 2 O and P, and 3 E and F | 1 | −34.1† |
| (Small clast #2) | Figs. 1F, 2 Q and R, and 3 S and T | 1 | −30.9 |
| (Small clast #3) | Figs. 1G, 2 S and T, and 3 U and V | 1 | −29.8 |
| Avg. | (n = 3) | −31.6 | |
| P. delicatulum | |||
| (Clast #4) | Figs. 1L, 2 E and F, and 3 A and B | 1 | −32.7 |
| (Clast #5) | Figs. 1M, 2 G and H, and 3 C and D | 1 | −38.2 |
| (Clast #6) | Figs. 1J, 2 K and L, and 3 C and D | 1 | −36.9 |
| (Clast #11) | Figs. 1I, 2 M and N, and 3 G and H | 1 | −33.6 |
| Avg. | (n = 4) | −35.4 | |
| A. disciformis | |||
| (Specimen #F) | Figs. 1C, 2 A and B, and 3 K and L | 1 | −41.7 |
| (Specimen #F) | Figs. 1C, 2 A and B, and 3 K and L | 1 | −44.1‡ |
| (Specimen #G, Session-1) | Figs. 1B, 2 C and D, and 3 M and N | 1 | −32.6† |
| (Specimen #G, Session-2) | Figs. 1B, 2 C and D, and 3 M and N | 1 | −38.5§ |
| Avg. | (n = 4) | −39.2 | |
| P. amoenum | |||
| (Specimen #H) | Figs. 1D, 2 I and J, and 3 Q and R | 1 | −39.4 |
| Avg. | (n = 4) | −39.4 |
For detailed summaries of the data, see Supporting Information.
*
Calibrated vs. VPDB, the “Vienna PDB” standard.
†
Marginal 12C-yield spots (see SIMS).
‡
Repeat analysis.
§
Excluding high-δ13C outlier (−9.7‰).