Venti, Nicholas L.; Billups, Katharina (2012): Stable-isotope stratigraphy of the Pliocene-Pleistocene climate transition in the northwestern subtropical Pacific. Elsevier, Amsterdam, Netherlands, Palaeogeography, Palaeoclimatology, Palaeoecology, 326-328, 54-65, georefid:2012-056453

Abstract:
From Ocean Drilling Program (ODP) Site 1208 on Shatsky Rise below the Kuroshio Current Extension, we present the North Pacific's first orbital-scale benthic-foraminiferal delta (super 18) O and delta (super 13) C time series to span the Pliocene-Pleistocene climate transition. Excellent agreement between the Site 1208 delta (super 18) O record and the global delta (super 18) O stack of Lisiecki and Raymo (2005) provides orbital-scale age control and confirms continuous stratigraphy from 3.7 to 1.8 Ma at the single-hole site. Cross-spectral analysis of the delta (super 18) O and delta (super 13) C time series reveals that these are coherent to 80% confidence at the 41-kyr obliquity band prior to 3.3 Ma (glacial isotope stage M2) and increase to the 95% level thereafter. Throughout, delta (super 18) O cycles consistently lead delta (super 13) C cycles by approximately 3 kyr. This suggests that global-ocean delta (super 13) C variations, as produced by terrestrial-marine (super 12) C transfers, were responsive to obliquity-induced climate changes before the Northern Hemisphere glaciations (NHG) reached mid latitudes at 2.7 Ma. In contrast, 41-kyr carbonate sedimentation (as derived from sediment reflectance) cycles, maxima tightly coupled to (>95% confidence) and in phase with minima in the delta (super 18) O record, do not emerge until 2.7 Ma. Foraminiferal fragmentation counts indicate that carbonate preservation is not the primary process behind enhanced carbonate deposition during interglacials. Thus, we surmise that hydrography-related changes in biogenic opal and carbonate production in surface water best explain glacial-interglacial carbonate cycles beginning with significant NHG. Firm establishment of orbital-scale age control on the stratigraphically complete Site 1208 section now provides a platform for high-resolution paleoceanographic reconstruction of the relatively understudied North Pacific. Abstract Copyright (2012) Elsevier, B.V.
Coverage:
West: 158.1200 East: 158.1200 North: 36.0800 South: 36.0800
Relations:
Expedition: 198
Site: 198-1208
Data access:
Provider: SEDIS Publication Catalogue
Data set link: http://sedis.iodp.org/pub-catalogue/index.php?id=10.1016/j.palaeo.2012.02.001 (c.f. for more detailed metadata)
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