Table 1 Magnesium and strontium contents for echinoderms and coal ball calcite.
From: A marine origin of coal balls in the Midland and Illinois basins, USA
Sample type/locality | Age (# localities for marine echinoderms) | Analyses | mole% MgCO3 Average (range) | Mg/Casw ratio seawater (mol/mol) Average (range) | Sr/Cac ratio carbonate (mmol/mol) Average (range) |
|---|---|---|---|---|---|
Echinoderms in marine facies, N. Am. Midcontinent shelf* | Desmoinesian (1) | 1 ossicle, 10 spots | 12.5 (N.A.) | 3.7† 5.2§ | N.A. |
Echinoderms in marine facies, N. Am. Midcontinent shelf* | Virgilian (3) | 9 ossicles, 81 spots | 10.8 (9.9–11.6) | 3.1 (2.8–3.6)† 4.2 (3.5–4.9)§ | N.A. |
Echinoderms in marine facies, N. Am. Midcontinent shelf* | Desmoinesian-Virgilian (4) | 10 ossicles, 91 spots | 11.0 (9.9–12.5) | 3.3 (2.8–3.7)† 4.3 (3.5–5.2)§ | N.A. |
Echinoderms in echinoderm-plant coal ball, Dalton coal | mid-Missourian | 12 ossicles, 85 spots | 10.2 (9.4–11.9) | 3.0 (2.8–3.6)† 3.3 (2.9–4.2)§ | 1.34 (0.99–1.85) |
Early HMC cement, echinoderm-plant coal ball, Dalton coal | mid-Missourian | 6 plant fossils, 33 spots | 11.9 (10.9–12.3) | 3.2 (2.8–3.3)# | 0.70 (0.58–0.88) |
Early HMC cement plant-only coal ball, Dalton coal | mid-Missourian | 12 plant fossils, 55 spots | 10.5 (8.8–12.0) | 2.7 (2.1–3.1)# | 0.84 (0.70–1.04) |
LMC cement in echinoderms, Dalton coal | mid-Missourian | 7 ossicles, 14 spots | 2.4 (2.0–3.5) | N.A. | 0.74 (0.54–0.88) |
LMC cement in plant debris plant-echinoderm coal ball, Dalton | mid-Missourian | 7 plant fossils, 37 spots | 2.1 (1.5–2.5) | N.A. | 2.89 (0.60–4.98) |
LMC cement in plant fossil plant-only echinoderm ball, Dalton | mid-Missourian | 10 plant fossils, 31 spots | 1.7 (1.2–2.2) | N.A. | 0.66 (0.38–1.00) |
Echinoderm in echinoderm-plant coal ball, Calhoun Coal | latest Missourian | 14 ossicles, 90 spots | 12.5 (11.2–13.2) | 3.7 (3.3–4.0)† 4.5 (3.8–5.1)§ | 1.54 (1.28–1.97) |
Early HMC cement, echinoderm-plant coal ball, Calhoun Coal | latest Missourian | 6 plant fossils, 13 spots | 14.8 (12.6–17.5) | 4.2 (3.4–5.2)# | 0.97 (0.54–1.23) |
Early HMC cement, plant-only coal ball, Calhoun Coal | latest Missourian | 10 plant fossils, 44 spots | 15.8 (13.1–17.8) | 4.5 (3.5–5.3)# | 0.70 (0.49–1.19) |
LMC cement in echinoderms Calhoun Coal | latest Missourian | 13 ossicles, 43 spots | 2.3 (1.0–4.0) | N.A. | 1.11 (0.33–1.74) |
LMC cement in plant debris plant-echinoderm coal ball, Calhoun | latest Missourian | 8 plant fossils, 19 spots | 2.8 (1.9–4.1) | N.A. | 1.55 (0.92–2.14) |
LMC cement in plant fossil plant-only coal ball, Calhoun | latest Missourian | 7 plant fossils, 11 spots | 1.6 (0.7–2.1) | N.A. | 0.24 (0.00–0.24) |
