Glacial^interglacial (MIS 1^10) migrations of the Subtropical Front across ODP Site 1119, Canterbury Bight, Southwest Paci¢c Ocean
Ocean Drilling Program (ODP) Site 1119 is located at water depth 395 m near the subtropical front (STF; here represented by the Southland Front), just downslope from the shelf edge of eastern South Island, New Zealand. The upper 86.19 metres composite depth (mcd) of Site 1119 sediment was deposited...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.649.5228 http://members.iinet.net.au/~glrmc/Carter R. et al. Marine Geology 04.pdf |
| Summary: | Ocean Drilling Program (ODP) Site 1119 is located at water depth 395 m near the subtropical front (STF; here represented by the Southland Front), just downslope from the shelf edge of eastern South Island, New Zealand. The upper 86.19 metres composite depth (mcd) of Site 1119 sediment was deposited at an average sedimentation rate of 34 cm/kyr during Marine Isotope Stages (MIS) 1^8 (0^252 ka), and is underlain across a V25 kyr intra-MIS 8 unconformity by MIS 8.5^11 (277^367 ka) and older sediment deposited at V14 cm/kyr. A time scale is assigned to Site 1119 using radiocarbon dates for the period back toV39 ka, and, prior to then, by matching its climatic record with that of the Vostok ice core, which it closely resembles. Four palaeoceanographic proxy measures for surface water masses vary together with the sandy-muddy, glacial^interglacial (G/I) cyclicity at the site. Interglacial intervals are characterised by heavy N13C, high colour reflectance (a proxy for carbonate content), low Q-ray (a proxy for clay content) and light N18O; conversely, glacial intervals exhibit light N13C, low reflectance, high Q-ray and heavy N18O signatures. Early interglacial intervals are represented by silty clays with 10^105-cm-thick beds of sharp-based (Chondrites-burrowed), shelly, graded, fine sand. The sands are rich in foraminifera, and were deposited distant from the shoreline under the influence of longitudinal flow in relatively deep water. Glacial intervals comprise mostly micaceous silty clay, though with some thin (2^10 cm thick) sands present also at peak cold periods, and contain the |
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