Abstract
The first high resolution record of dinoflagellate cysts ∼110–155 kyr over Termination II and the Last Interglacial in the Santa Barbara Basin, California from ODP Hole 893A details a complex paleoceanographic history. Variation in cyst relative abundances, concentrations, and diversity reflects climatic and ocean circulation changes, and the assemblages are used to make qualitative reconstructions of sea surface temperature (SST) and annual primary productivity. The dominance of heterotrophic Brigantedinium spp. throughout the section indicates an important influence of coastal upwelling on the basin. Based on the dinoflagellate cyst assemblages, five zones are identified, which approximately correspond to the marine isotope stage boundaries and their associated changes in SST and sea level. Cooler intervals, MIS 6 and MIS 5d, are characterized by cold-water indicator species Selenopemphix undulata whereas thermophilic taxon Spiniferites mirabilis characterizes a warm MIS 5e. In contrast to other studies in the Pacific, the data exhibits a one to two-thousand-year cooling event ∼129 kyr that correlates to the Termination II sea level still-stand of the two-step deglaciation. A significant increase in cyst concentrations in the latest MIS 5e implies enhanced primary production due to increased seasonal upwelling and the warm, nutrient rich waters entering the basin after sea level stabilizes near modern levels. The hydrological evolution and cyst signal of the Last Interglacial is similar to the development of the Holocene in the Santa Barbara Basin, but the sustained presence of Spiniferites mirabilis across MIS 5e indicates SSTs were higher than modern conditions.
| Original language | English (US) |
|---|---|
| Article number | 110875 |
| Journal | Palaeogeography, Palaeoclimatology, Palaeoecology |
| Volume | 591 |
| DOIs | |
| State | Published - Apr 1 2022 |
| Externally published | Yes |
Bibliographical note
Funding Information:Sediment samples were provided by the Integrated Ocean Drilling Program (IODP). We thank C. Broyles and P. Rumford for their assistance in subsampling the sediments. Funding for this research was provided by the Natural Science and Engineering Research Council of Canada (NSERC) to V.P. (Grant RGPIN/6388-2015 ). Graduate research of J.R.O was supported by the University of Victoria and the Arne Lane Graduate Fellowships. We are grateful to the Editor (Dr. Alex Dickson) and two anonymous reviewers for constructive suggestions which improved this manuscript.
Funding Information:
Sediment samples were provided by the Integrated Ocean Drilling Program (IODP). We thank C. Broyles and P. Rumford for their assistance in subsampling the sediments. Funding for this research was provided by the Natural Science and Engineering Research Council of Canada (NSERC) to V.P. (Grant RGPIN/6388-2015). Graduate research of J.R.O was supported by the University of Victoria and the Arne Lane Graduate Fellowships. We are grateful to the Editor (Dr. Alex Dickson) and two anonymous reviewers for constructive suggestions which improved this manuscript.
Publisher Copyright:
© 2022 Elsevier B.V.
Keywords
- Dinoflagellate cysts
- Last Interglacial
- Marine isotope stages 6-5d
- Marine primary productivity
- ODP Hole 893A
- Paleo-climate
- Santa Barbara Basin
- Sea-surface temperature
