Scientific Reports

Table 2 Deposits at the control zones of Hydrographer’s and Noggin Passages: total area, CaCO₃ volume, CaCO₃ mass and mass areal accumulation for different geomorphic zones⁴⁷.

From: New constraints on the postglacial shallow-water carbonate accumulation in the Great Barrier Reef

Study area		Hydrographers Passage
Stratigraphic unit		Unit 1 (postglacial)
Geomorphic zone		Entire study area			Inner barrier			Outer barrier
Velocity scenario		Min	Best est	Max	Min	Best est	Max	Min	Best est	Max
Area (km²)	Polygons digitized on geomorphic maps	422	422	422	42	42	42	29	29	29
Total volume (km³)	Calculations above 130 mbsl	2.71	3.18	3.64	0.41	0.57	0.74	0.31	0.42	0.53
Net carbonate volume (km³)	Porosity = 35%	1.76	2.07	2.36	0.27	0.37	0.48	0.20	0.27	0.35
Net carbonate mass (Gt CaCO₃)	Density = 2930 kg m⁻³	5.16	6.06	6.93	0.78	1.09	1.40	0.59	0.80	1.02
Mass areal accumulation (kg m⁻²)	Area as indicated	12,235	14,370	16,414	18,682	26,028	33,419	20,393	27,648	35,003
Reef area cover		18.8%

Study area		Hydrographers Passage
Stratigraphic unit		Unit 1 (postglacial)
Geomorphic zone		Inner + outer platform			Terrace + shelf-break			All barrier (inner + outer)
Velocity scenario		Min	Best est	Max	Min	Best est	Max	Min	Best est	Max
Area (km²)	Polygons digitized on geomorphic maps	240	240	240	111	111	111	71	71	71
Total volume (km³)	calculations above 130 mbsl	0.98	1.02	1.06	1.01	1.17	1.31	0.72	1.00	1.27
Net carbonate volume (km³)	Porosity = 35%	0.64	0.66	0.69	0.66	0.76	0.85	0.47	0.65	0.83
Net carbonate mass (Gt CaCO₃)	Density = 2930 kg m⁻3	1.86	1.94	2.02	1.92	2.23	2.49	1.38	1.89	2.42
Mass areal accumulation (kg m⁻²)	Area as indicated	7767	8092	8406	17,325	20,062	22,438	19,381	26,690	34,066
Reef area cover		18.8%

Study area		Noggin Passage
Stratigraphic unit		Unit 1 (postglacial)
Geomorphic zone		Entire study area			Inner barrier			Outer barrier
Velocity scenario		Min	Best est	Max	Min	Best est	Max	Min	Best est	Max
Area (km²)	Polygons digitized on geomorphic maps	85	85	85	10	10	10	18	18	18
Total volume (km³)	Calculations above 130 mbsl	0.49	0.54	0.58	0.07	0.08	0.10	0.14	0.16	0.18
Net carbonate volume (km³)	Porosity = 35%	0.32	0.35	0.38	0.05	0.06	0.06	0.09	0.10	0.12
Net carbonate mass (Gt CaCO₃)	Density = 2930 kg m⁻³	0.93	1.02	1.11	0.13	0.16	0.19	0.26	0.31	0.35
Mass areal accumulation (kg m⁻²)	Area as indicated	10,956	11,987	13,086	13,222	16,087	18,972	14,726	17,134	19,586
Reef area cover		17.8%
Average mass areal accumulation [kg m⁻²]	Barriers and shelf break	20,245

Study area		Noggin Passage
Stratigraphic unit		Unit 1 (postglacial)
Geomorphic zone		Inner + outer platform			Terrace + shelf-break			All barrier (inner + outer)
Velocity scenario		Min	Best est	Max	Min	Best est	Max	Min	Best est	Max
Area (km²)	Polygons digitized on geomorphic maps	26	26	26	31	31	31	28	28	28
Total volume (km³)	Calculations above 130 mbsl	0.05	0.06	0.06	0.23	0.23	0.24	0.21	0.25	0.28
Net carbonate volume (km³)	Porosity = 35%	0.03	0.04	0.04	0.15	0.15	0.16	0.14	0.16	0.18
Net carbonate mass (Gt CaCO₃)	Density = 2930 kg m⁻³	0.10	0.11	0.11	0.44	0.45	0.46	0.40	0.47	0.54
Mass areal accumulation (kg m⁻²)	Area as indicated	3817	3996	4342	14,146	14,509	14,886	14,186	16,758	19,365
Reef area cover		17.8%
Average mass areal accumulation [kg m⁻²]	Barriers and shelf break	20,245

Reef area ratio in the area comprised between the outer GBR fore-reef and the 130-m contour is similar in both sites. These figures are based on seismic three-dimensional reconstructions, geomorphic interpretations and core data^30,34,40,47.

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