Abstract:
The main inflow of deep water to the Pacific is via a deep western boundary current. As the current passes along the continental margin off eastern New Zealand, it receives much terrigenous sediment, which, together with the biogenic pelagic supply, has been reworked into a suite of large drifts. Ocean Drilling Program Site 1123 on the North Chatham Drift and Site 1124 on the Rekohu Drift have yielded high-resolution and well- dated records of carbonate and terrigenous fluxes for the past 3 m.y. Deposition at both drifts was affected by a deep western boundary current background sediment flux and by glacial-interglacial cycles. In addition, drifts received site-specific flux pulses caused by (1) sediment remobilization under a vigorous Antarctic Circumpolar Current, (2) increased oceanic productivity, (3) overspill of sediment from the newly formed Hikurangi Channel, and (4) generally increased discharge from the Hikurangi Channel under intensified Quaternary uplift and paleoclimatic oscillations.