Quaternary sedimentation of the North Taieri Bight, Otago continental shelf.
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An area of the east Otago continental shelf, south of Otago Peninsula was investigated using dredged sediment samples and, to a lesser extent, seismic profiles, sidsescan sono-graphs and piston cores.
Relict and reworked gravels and sands cover the middle and outer shelf. Associated with these are relict faunas and relict topography (a drowned barrier system). Inshore of the gravels, two bands of modern sediment are moving northwards over the inner shelf. The innermost band is derived from the Otago schists via the Clutha (and Taieri) River while the outer band is derived from Tuhuan plutonic rocks further south. Offshore of the relict sediment modern bioclastic sands and gravels (Mollusca and Bryozoa) cover the outer shelf. Heavy and light mineral traces are useful in distinguishing sediment of contrasting provenance.
The response of sediment to the modern hydrodynamic regime is evaluated and the origin of the midshelf relict topography discussed.
Evidence for former stands of sea level at midshelf depths is considered and some modification to local sea level curves is suggested.
Relict and reworked gravels and sands cover the middle and outer shelf. Associated with these are relict faunas and relict topography (a drowned barrier system). Inshore of the gravels, two bands of modern sediment are moving northwards over the inner shelf. The innermost band is derived from the Otago schists via the Clutha (and Taieri) River while the outer band is derived from Tuhuan plutonic rocks further south. Offshore of the relict sediment modern bioclastic sands and gravels (Mollusca and Bryozoa) cover the outer shelf. Heavy and light mineral traces are useful in distinguishing sediment of contrasting provenance.
The response of sediment to the modern hydrodynamic regime is evaluated and the origin of the midshelf relict topography discussed.
Evidence for former stands of sea level at midshelf depths is considered and some modification to local sea level curves is suggested.
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108 leaves : 2 transparencies (in pocket), illus. (part col.) ; 30 cm.
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1979Williams
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Williams, Julia Jane., “Quaternary sedimentation of the North Taieri Bight, Otago continental shelf.,” Otago Geology Theses, accessed April 23, 2025, https://theses.otagogeology.org.nz/items/show/127.