Planktonic Foraminiferal Biostratigraphy in the Central North Pacific Ocean

Douglas, Robert G.

doi:10.2973/dsdp.proc.17.122.1973

Cited by 34 publications

(37 citation statements)

References 4 publications

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“…Tertiary deep-sea benthic foraminifera have been the subject of several recent papers that delineate the taxonomy, biostratigraphy, paleobiogeography, and paleoecology of this hitherto poorly-known group Douglas, 1973;Schnitker, 1979;. These studies have concentrated on bathyal and abyssal benthic foraminifera recovered by the DSDP.…”

Section: Previous Workmentioning

confidence: 99%

Late Paleogene (Eocene to Oligocene) paleoceanography of the northern North Atlantic

Miller¹

1982

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Seismic stratigraphic evidence from the western and northern North Atlantic indicates that a major change in abyssal circulation occurred in the latest Eocene to earliest Oligocene. In the northern North Atlantic, the widely-distributed reflector R4 correlates with an unconformity that can be traced to its correlative conformity near the top of the Eocene. This horizon reflects a change from weakly circulating (Eocene) to vigorously circulating bottom water (early Oligocene). Sediment distribution patterns provide evidence for strong contour-following bottom water flow beginning at reflector R4 time; this suggests a northern source for this bottom water, probably from the Arctic via the Norwegian-Greenland Sea and Faeroe-Shetland Channel. Erosion and current-controlled sedimentation continued through the Oligocene; however, above reflector R3 (middle to upper Oligocene), the intensity of abyssal currents decreased. Above reflector R2 (upper lower Miocene) current-controlled sedimentation became more coherent and a major phase of sedimentary drift development began. This resulted from further reduction in speeds and stabilization of abyssal currents.Paleontological and stable isotopic data support these interpretations. In the Bay of Biscay/Goban Spur regions, a major 6180 increase began at -38 Ma (late Eocene), culminating in a rapid (< 0.5 my) increase in 6180 just above the Eocene/Oligocene boundary (~ 36.5 Ma). A rapid 6 13 C increase also occurs at -36.5 Ma in these sites. Major changes in benthic foraminiferal assemblages also occurred between the middle Eocene and the earliest Oligocene: 1) In the Labrador Sea, a predominantly agglutinated assemblage was replaced by a calcareous assemblage between the middle Eocene and early Oligocene; 2) In the abyssal (> 3km) Bay of Biscay, an indigenous Eocene calcareous fauna including Nuttallides truempyi, Clinapertina spp., Abyssammina spp., Aragonia spp., and Alabamina dissonata became extinct between the middle Eocene and earliest Ollgocene; 3) In shallower sites (< 3km paleodepth) throughout the Atlantic, a Nuttallides truempyi-dominated assemblage was replaced by a Globocassidulina subglobosa-yroidinoides-Cibicidoides ungerianus-Oridorsalis assemblage in the early late Eoce (~ 40-3 5 ma). These Taunal and isotopic changes represent the transition from warm, old, corrosive Eocene bottom waters to colder, younger (lower C02 and higher pH, hence less corrosive) early Oligocene bottom waters.

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Section: Previous Workmentioning

confidence: 99%

Late Paleogene (Eocene to Oligocene) paleoceanography of the northern North Atlantic

Miller¹

1982

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“…Cibicidoides laurisae first occurs in Section 574C-32,CC. O. mexicana is, according to Douglas (1973), limited to the Eocene in the Pacific. A. dissonata was used as an Eocene marker species by Douglas (1973), Proto Decima and Bolli (1978), and Schnitker (1979).…”

Section: Benthic Foraminifersmentioning

confidence: 99%

“…O. mexicana is, according to Douglas (1973), limited to the Eocene in the Pacific. A. dissonata was used as an Eocene marker species by Douglas (1973), Proto Decima and Bolli (1978), and Schnitker (1979). However, Miller and Curry (1982), Miller et al (1985), and Tjalsma and Lohmann (1982) state that N. truempyi is the most reliable marker of the Eocene/Oligocene boundary.…”

Section: Benthic Foraminifersmentioning

confidence: 99%

Site 574

1985

Initial Reports of the Deep Sea Drilling Project

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Total core recovered (m): 574-208.93 574A-180.74 574B-9.45 574C-197.35 Core recovery (%): 574-101 574A-100 574B-50 574C-58 Oldest sediment cored:Depth sub-bottom (m): 517. of flat, acoustically well stratified sediments. The site is just north of the crest of the sediment bulge in the equatorial high-productivity belt, and it is the second of a three-site latitudinal transect along 133°W. The site was drilled to provide detailed documentation of the area's migration across the equator and of Tertiary equatorial Pacific paleoceanography. To this end two holes were drilled with the hydraulic piston corer (HPC) to approximately the same depth (574, 0 to 206.5 m; 574A, 0 to 180.2 m), and two holes were rotary drilled (574B, 185 to 194.5 m; 574C, 194.5 to 525.5 m, i.e., to basement).The oldest sediments in the sequence recovered are uppermost Eocene (520 m sub-bottom). Except for minor hiatuses, the sequence is continuous from this age through the Quaternary. The bottom cores contain about 60 cm of basalt, placing basement at 520 m sub-bottom. The sedimentary sequence is divided into a basal metalliferous calcareous unit (502.5 to 520.0 m), a calcareous ooze chalk unit in the middle (84.1 to 502.5 m), and a cyclic siliceous calcareous ooze unit at the top (0 to 84.1 m).All major planktonic microfossils are represented, although the dissolution of the planktonic foraminifers limits their stratigraphic usefulness. Initial data from the foraminifers, diatoms, calcareous nannofossils, and radiolarians indicate that a remarkably complete uppermost Eocene to lowest Oligocene transition was collected near the bottom of Hole 574C (within the metalliferous calcareous sedimentary unit above basement).The sediment accumulation rate is variable, ranging between 5 and 35 m/m.y.; it is low between 0 and 12 Ma, high between 12 and 23 Ma, and low again between 23 and 34 Ma. The mass accumulation rates are highest (about 3 g/cm 2 per 1000 yr.) in the lower Oligocene and at about 12.5 Ma, with a low of 0.28 g/cm 2 per 1000 yr. occurring between 0 and 5 Ma.The records of calcium carbonate content and the sediment's physical properties show major fluctuations in the last 12 m.y. They are more uniform in the older part of the section. Natural remanent magnetization (NRM) intensity is broadly correlative to lithology; magnetization is strongest in the upper cyclic siliceouscalcareous unit and the basal metalliferous unit and extremely weak throughout most of the middle, calcareous unit. The analysis of inorganic geochemistry suggests the presence of a diffusional control in the section^ upper 150 m and of diagenetic reactions in its lower portion.

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“…The seemingly straightforward explanation of water depth as a controlling factor has been questioned in recent years (Streeter, 1973;Douglas, 1973). Thus, one of the purposes of this study is to document faunal changes at this site with accompanying temperature fluctuations determined from oxygen isotope ratios.…”

Section: Introductionmentioning

confidence: 99%

“…Notable exceptions are the works of Berggren (1972Berggren ( , 1975, Douglas (1973), and Vincent et al (1974) on samples taken by the Deep Sea Drilling Project. Older works, providing the reference faunas for these deeper, open marine sections include Beckmann (1953), Bandy (1970), Cushman and Renz (1948), Cushman and Stainforth (1945), Palmer (1940), AGIP (1959), and Bermudez (1949): see Berggren and Phillips (1971) for a more extensive bibliography.…”

Section: Introductionmentioning

confidence: 99%

Eocene to Early Miocene Benthic Foraminifera DSDP Leg 39, South Atlantic

Boersma¹

1977

Initial Reports of the Deep Sea Drilling Project

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Planktonic Foraminiferal Biostratigraphy in the Central North Pacific Ocean

Cited by 34 publications

References 4 publications

Late Paleogene (Eocene to Oligocene) paleoceanography of the northern North Atlantic

Late Paleogene (Eocene to Oligocene) paleoceanography of the northern North Atlantic

Site 574

Eocene to Early Miocene Benthic Foraminifera DSDP Leg 39, South Atlantic

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