Sediment accumulation and Holocene - OzCoasts

More documents

Recommendations

Info

Sediment accumulation and Holocene evolution of the Fitzroy River lower floodplain Figure 21: Graph to show the correlation between flood events and Surat and Bowen Basin sediment contribution to Crescent Lagoon core FK406B. 44
Sediment accumulation and Holocene evolution of the Fitzroy River lower floodplain Geochronology Depth profile radionuclide activities are shown in Table 14 (Crescent lagoon) and Table 16 (Frogmore lagoon). Three OSL dates were also determined on the Crescent lagoon sediment (Table 15). The detection of 137 Cs in the 56–60 cm depth section indicates a post-1958 age. The maximum 137 Cs activity occurs in the 52–56 cm interval, and may correspond to the years of peak 137 Cs fallout In Australia (1963–1965), although a direct correlation between fallout and sediment activity cannot be assumed. This is due to fact that 137 Cs fluxes to the lagoon are likely controlled not just by direct fallout into the lagoon, but also by the transport of 137 Cs-labelled sediment from the Fitzroy catchment. The transport of this sediment will, in turn, be controlled by the erosion processes and have a finite delay time. Table 14: Gamma spectrometry data for Crescent Lagoon core FK406B. CRS – Constant rate of supply. Depth (m) 137 Cs 226 Ra 210 Pb Excess 210 Pb CRS 0.00–0.02 1.9 ± 0.25 23.4 ± 0.4 49.0 ± 4.7 25.5 ± 4.8 0.0 ± 0.0 0.08–0.11 1.0 ± 0.24 22.7 ± 0.4 50.7 ± 2.3 28.0 ± 2.3 3.2 ± 0.5 0.24–0.28 2.6 ± 0.17 26.6 ± 0.4 52.1 ± 2.3 25.5 ± 2.4 13.0 ± 1.3 0.36–0.40 3.4 ± 0.17 24.1 ± 0.3 47.2 ± 2.1 23.1 ± 2.1 24.0 ± 2.1 0.48–0.52 4.8 ± 0.26 26.4 ± 0.4 34.7 ± 2.1 8.3 ± 2.1 35.9 ± 2.4 0.52–0.56 7.5 ± 0.33 25.1 ± 0.5 36.0 ± 3.1 10.9 ± 3.1 37.7 ± 2.4 0.56–0.60 5.2 ± 0.42 23.5 ± 0.6 39.7 ± 3.6 16.2 ± 3.7 40.0 ± 2.3 0.60–0.64 0.3 ± 0.17 25.7 ± 0.3 28.7 ± 1.9 3.0± 1.9 45.1 ± 2.0 0.64–0.68 -0.1 ± 0.18 29.9 ± 0.4 32.5 ± 1.4 2.6 ± 1.5 0.72–0.76 -0.2 ± 0.17 28.8 ± 0.3 31.6 ± 1.8 2.8 ± 1.8 0.80–0.84 -0.1 ± 0.17 27.2 ± 0.3 27.1 ± 1.5 -0.1 ± 1.5 0.96–1.00 -0.2 ± 0.18 26.4 ± 0.3 29.4 ± 1.4 3.0 ± 1.4 1.12–1.16 -0.1 ± 0.17 25.6 ± 0.3 28.2 ± 1.4 2.6 ± 1.4 1.185–1.225 0 ± 0.18 27.9 ± 0.3 25.2 ± 1.5 -2.7 ± 1.5 1.24–1.25 0 ± 0.23 26.5 ± 0.5 30.5 ± 2.5 4.0 ± 2.5 1.25–1.31 0.1 ± 0.16 25.6 ± 0.2 37.5 ± 1.0 11.9 ± 1.1 The excess 210 Pb profile in the upper 60 cm provides some chronological information, especially when considered in association with the 137 Cs profile, but the lack of detectable excess 210 Pb in the 60–125 cm interval does not provide a 45
Page 3 and 4:
Sediment accumulation and Holocene
Page 5 and 6: Sediment accumulation and Holocene
Page 55: Sediment accumulation and Holocene
show all

Sediment accumulation and Holocene - OzCoasts

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?