Table 4 Extrapolations of global CaCO3 deposits applying the parameters of this study (Table 3) but using the broad range of past global reef area estimates shown in Table 5.
From: New constraints on the postglacial shallow-water carbonate accumulation in the Great Barrier Reef
Calculation | Total postglacial reefal (and Halimeda) CaCO3, including pre-Holocene drowned reefs | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Features | Extrapolation of global Holocene + shelf-edge (average of mass and area adjustment factors) + Halimeda mounds (mass factor) | |||||||||||
Timing (ka BP) | 19 to 0 | |||||||||||
Average reef thickness (m) | 8–15 | |||||||||||
Porosity (%) | 35–50 | |||||||||||
Density (kg m−3) | 2930 | |||||||||||
Study | Preferred area estimate Spalding et al.56 | De Vooys64 | Newell73—minimum | Spalding and Grenfell16 | Vecsei61 | Ryan et al15—minimum | Kleypas58—minimum | Smith28 | Kleypas58—maximum | Milliman74 | Newell73—maximum | Copper65 |
Reef area (km2) | 398,095 | 156,995 | 210,261 | 357,445 | 483,601 | 700,872 | 818,618 | 864,876 | 1,045,700 | 2,018,510 | 2,102,615 | 2,102,615 |
Total volume > 130 mbsl (km3) | 5593 | 2206 | 2954 | 5022 | 6795 | 9847 | 11,502 | 12,152 | 14,692 | 28,360 | 29,542 | 29,542 |
Net CaCO3 volume (km3) | 3525 | 1390 | 1862 | 3165 | 4282 | 6206 | 7248 | 7658 | 9259 | 17,873 | 18,618 | 18,618 |
Net CaCO3 mass (Gt CaCO3) | 10,328 | 4073 | 5455 | 9273 | 12,546 | 18,183 | 21,238 | 22,438 | 27,129 | 52,368 | 54,550 | 54,550 |
Net CaCO3 accumulation rate (Gt CaCO3 y−1) | 0.6 | 0.2 | 0.3 | 0.5 | 0.7 | 1.1 | 1.2 | 1.3 | 1.6 | 3.1 | 3.2 | 3.2 |
Mass areal accumulation (kg m−2) | 25,944 | 25,944 | 25,944 | 25,944 | 25,944 | 25,944 | 25,944 | 25,944 | 25,944 | 25,944 | 25,944 | 25,944 |
