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| Formato: | Dataset Open Access |
| Lenguaje: | en |
| Publicado: |
PANGAEA
2004
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| Materias: | |
| Acceso en línea: | https://doi.org/10.1594/PANGAEA.742605 |
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| _version_ | 1867171772235776000 |
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| author | Stickley, Catherine E Brinkhuis, Henk Schellenberg, Stephen A Sluijs, Appy Röhl, Ursula Fuller, Michael D Grauert, M Huber, Matthew Warnaar, Jeroen Wiliams, Graham L |
| author_facet | Stickley, Catherine E Brinkhuis, Henk Schellenberg, Stephen A Sluijs, Appy Röhl, Ursula Fuller, Michael D Grauert, M Huber, Matthew Warnaar, Jeroen Wiliams, Graham L |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Tectonic changes that produced a deep Tasmanian Gateway between Australia and Antarctica are widely invoked as the major mechanism for Antarctic cryosphere growth and Antarctic Circumpolar Current (ACC) development during the Eocene/Oligocene (E/O) transition (34-33 Ma). Ocean Drilling Program (ODP) Leg 189 recovered near-continuous marine sedimentary records across the E/O transition interval at four sites around Tasmania. These records are largely barren of calcareous microfossils but contain a rich record of siliceous- and organic-walled marine microfossils. In this study we integrate micropaleontological, sedimentological, geochemical, and paleomagnetic data from Site 1172 (East Tasman Plateau) to identify four distinct phases (A-D) in the E/O Tasmanian Gateway deepening that are correlative among ODP Leg 189 sites. Phase A, prior to 35.5 Ma: minor initial deepening characterized by a shallow marine prodeltaic setting with initial condensation episodes. Phase B, 35.5-33.5 Ma: increased deepening marked by the onset of major glauconitic deposition and inception of energetic bottom-water currents. Phase C, 33.5-30.2 Ma: further deepening to bathyal depths, with episodic erosion by increasingly energetic bottom-water currents. Phase D, <30.2 Ma: establishment of stable, open-ocean, warm-temperate, oligotrophic settings characterized by siliceous-carbonate ooze deposition. Our combined evidence indicates that this early Oligocene Tasmanian Gateway deepening initially produced an eastward flow of relatively warm surface waters from the Australo-Antarctic Gulf into the southwestern Pacific Ocean. This "proto-Leeuwin" current fundamentally differs from previous regional reconstructions of eastward flowing cool water (e.g., a "proto-ACC") during the early Oligocene and thereby represents an important new constraint for reconstructing regional- to global-scale dynamics for this major global change event. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_742605 |
| institution | PANGAEA |
| language | en |
| publishDate | 2004 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Geochemical measurements of the Tasmanian Gateway from ODP Hole 189-1172A Stickley, Catherine E Brinkhuis, Henk Schellenberg, Stephen A Sluijs, Appy Röhl, Ursula Fuller, Michael D Grauert, M Huber, Matthew Warnaar, Jeroen Wiliams, Graham L 189-1172A; Carbon, organic, total; Carbonates; Coulometry; DEPTH, sediment/rock; DRILL; Drilling/drill rig; Grain size, mean; Isotope ratio mass spectrometry; Joides Resolution; Leg189; Ocean Drilling Program; ODP; Tasman Sea; δ13C, carbonate; δ18O, carbonate Tectonic changes that produced a deep Tasmanian Gateway between Australia and Antarctica are widely invoked as the major mechanism for Antarctic cryosphere growth and Antarctic Circumpolar Current (ACC) development during the Eocene/Oligocene (E/O) transition (34-33 Ma). Ocean Drilling Program (ODP) Leg 189 recovered near-continuous marine sedimentary records across the E/O transition interval at four sites around Tasmania. These records are largely barren of calcareous microfossils but contain a rich record of siliceous- and organic-walled marine microfossils. In this study we integrate micropaleontological, sedimentological, geochemical, and paleomagnetic data from Site 1172 (East Tasman Plateau) to identify four distinct phases (A-D) in the E/O Tasmanian Gateway deepening that are correlative among ODP Leg 189 sites. Phase A, prior to 35.5 Ma: minor initial deepening characterized by a shallow marine prodeltaic setting with initial condensation episodes. Phase B, 35.5-33.5 Ma: increased deepening marked by the onset of major glauconitic deposition and inception of energetic bottom-water currents. Phase C, 33.5-30.2 Ma: further deepening to bathyal depths, with episodic erosion by increasingly energetic bottom-water currents. Phase D, <30.2 Ma: establishment of stable, open-ocean, warm-temperate, oligotrophic settings characterized by siliceous-carbonate ooze deposition. Our combined evidence indicates that this early Oligocene Tasmanian Gateway deepening initially produced an eastward flow of relatively warm surface waters from the Australo-Antarctic Gulf into the southwestern Pacific Ocean. This "proto-Leeuwin" current fundamentally differs from previous regional reconstructions of eastward flowing cool water (e.g., a "proto-ACC") during the early Oligocene and thereby represents an important new constraint for reconstructing regional- to global-scale dynamics for this major global change event. |
| title | Geochemical measurements of the Tasmanian Gateway from ODP Hole 189-1172A |
| topic | 189-1172A; Carbon, organic, total; Carbonates; Coulometry; DEPTH, sediment/rock; DRILL; Drilling/drill rig; Grain size, mean; Isotope ratio mass spectrometry; Joides Resolution; Leg189; Ocean Drilling Program; ODP; Tasman Sea; δ13C, carbonate; δ18O, carbonate |
| url | https://doi.org/10.1594/PANGAEA.742605 |