Venz, Kathryn A; Hodell, David A (2002): Plio-Pleistocene age-depth points and occurrence of hiatuses in ODP sites of the Southern Ocean [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.696106, Supplement to: Venz, KA; Hodell, DA (2002): New evidence for changes in Plio-Pleistocene deep water circulation from Southern Ocean ODP Leg 177 Site 1090. Palaeogeography, Palaeoclimatology, Palaeoecology, 182(3-4), 197-220, https://doi.org/10.1016/S0031-0182(01)00496-5
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Abstract:
Changes in Atlantic deep water circulation were reconstructed by comparing the benthic foraminiferal delta13C record at ODP Site 1090 in the South Atlantic with similar records from the North Atlantic (Sites 982, 607, 925, 929) and deep Pacific (Site 849) oceans. Important deep water circulation changes occurred in the early Pleistocene at 1.55 Myr and during the Mid-Pleistocene Transition at 0.9 Myr. At 1.55 Myr, glacial delta13C values in the Southern Ocean became significantly lower than those in the deep Pacific, establishing a pattern that persisted throughout the late Pleistocene. We propose that the lowering of delta13C values of Southern Component Water (SCW) at this time resulted from expansion of sea ice and reduced ventilation of deep water during glacial periods after marine isotope stage 52. Accompanying this change in Southern Ocean deep water circulation was enhanced interhemispheric coupling between the North and South Atlantic after 1.55 Myr. At ~0.9 Myr, the magnitude of glacial-to-interglacial variabilityin delta13C increased and shifted to a longer frequency (100 kyr) along with oceanic delta18O (ice volume). Calculation of percent Northern Component Water (NCW) using Site 1090 as the SCW end member yielded 20-30% less reduction of NCW during glacial periods of the late Pleistocene. Also, a trend toward reduced glacial suppression of NCW during the past 400 kyr is not evident. The apparent decoupling of ice volume and deep water circulation reported previously maybe an artifact of using a Pacific, rather than a Southern Ocean, carbon isotopic record to calculate past mixing ratios of NCW and SCW.
Project(s):
Ocean Drilling Program (ODP)
Coverage:
Median Latitude: 7.299525 * Median Longitude: -3.477183 * South-bound Latitude: -42.913617 * West-bound Longitude: -15.854183 * North-bound Latitude: 57.512667 * East-bound Longitude: 8.899817
Date/Time Start: 1995-07-15T00:00:00 * Date/Time End: 1997-12-25T00:00:00
Event(s):
162-982 * Latitude: 57.512667 * Longitude: -15.854183 * Date/Time Start: 1995-07-15T00:00:00 * Date/Time End: 1995-07-19T00:00:00 * Elevation: -1134.2 m * Penetration: 1143.9 m * Recovery: 1008 m * Location: South Atlantic Ocean * Campaign: Leg162 * Basis: Joides Resolution * Method/Device: Composite Core (COMPCORE) * Comment: 120 cores; 1123.9 m cored; 0 m drilled; 89.7% recovery
177-1090 * Latitude: -42.913617 * Longitude: 8.899817 * Date/Time: 1997-12-25T00:00:00 * Elevation: -3701.6 m * Penetration: 936.4 m * Recovery: 874.9 m * Location: South Atlantic Ocean * Campaign: Leg177 * Basis: Joides Resolution * Method/Device: Composite Core (COMPCORE) * Comment: 101 cores; 936.4 m cored; 0 m drilled; 93.4% recovery
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
4 datasets
Download Data
Datasets listed in this publication series
- Venz, KA; Hodell, DA (2002): (Table 3) Plio-Pleistocene age-depth points of ODP Site 162-982 in the Southern Ocean. https://doi.org/10.1594/PANGAEA.696101
- Venz, KA; Hodell, DA (2002): Stable carbon and oxygen isotope record of Cibicidoides wuellerstorfi of ODP Hole 162-982. https://doi.org/10.1594/PANGAEA.774880
- Venz, KA; Hodell, DA (2002): (Table 3) Plio-Pleistocene age-depth points of ODP Site 177-1090 in the Southern Ocean. https://doi.org/10.1594/PANGAEA.696102
- Venz, KA; Hodell, DA (2002): (Table 4) Occurrences of hiatuses in the Plio-Pleistocene of ODP Site 177-1090 in the Southern Ocean. https://doi.org/10.1594/PANGAEA.696103