Patterns of sedimentation in the macrotidal Fly River delta, Papua New Guinea
Baker, E.K.; Harris, P.T.; Keene, J.B.; Short, S.A. (1995). Patterns of sedimentation in the macrotidal Fly River delta, Papua New Guinea, in: Flemming, B.W. et al. (Ed.) Tidal Signatures in Modern and Ancient Sediments. Special Publication of the International Association of Sedimentologists, 24: pp. 193-211
In: Flemming, B.W.; Bartholomä, A. (Ed.) (1995). Tidal Signatures in Modern and Ancient Sediments. Special Publication of the International Association of Sedimentologists, 24. Blackwell Science: Oxford. ISBN 0-86542-978-2. 358 pp., more
In: Special Publication of the International Association of Sedimentologists. Blackwell: Oxford. ISSN 0141-3600; e-ISSN 2054-6610, more
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| Authors | | Top |
- Baker, E.K.
- Harris, P.T.
- Keene, J.B.
- Short, S.A.
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| Abstract |
Cores and grab samples provide preliminary information on the character of sedimentary deposits in the macrotidal F1y River delta of southern Papua New Guinea. 210Pb activities in the cores and surface sediments show a wide variability, suggesting differences in the initial specific activity (dpm g- 1) of the sediments being deposited. As a consequence, estimates of sediment accumulation rate using the 210Pb technique are not always possible. The available data suggest sediment accumulation rates in one part of the study area of about 8-10 cm yr-1 The sediments consist of laminated, very well sorted, heavy mineral rich sands and poorly sorted silts with generally less than 30% clay. Biological activity is restricted by the extreme current speeds (up to 2.4 m s-1), high suspended sediment load (near bed turbidity levels reach 40g1- 1) and low salinities ( <5%0). The distributary channel deposits are sheltered by islands from the large swell waves that propagate landwards from the Coral Sea. This and the paucity of organisms contribute to the preservation of ubiquitous sand/mud laminations. The laminae do not exhibit direct evidence of tidal cyclicity (tidal bundles). Deposition of mud-sand couplets is interpreted as occurring during neap tides, possibly coinciding with times of relatively low surface swell wave energy. This is based on an average couplet thickness of 4.2 mm and an accumulation rate of around 8-10 cm yr- 1 derived from 210Pb analysis. |
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