Accumulation Rates in Leg 74 Sediments

Shackleton, N.J.

doi:10.2973/dsdp.proc.74.117.1984

Cited by 34 publications

(41 citation statements)

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“…A numerical age determined for the Cretaceous/Tertiary boundary horizon by interpolation from the magnetic C-29R boundaries and by extrapolation downward using the C-29N and upward using the C-30N boundary varies between about 66.3 and 66.5 m.y. This is in complete agreement with other recent estimates based on the same time scale (Berggren et al, in press;Shackleton et al, 1984).…”

Section: Site 577supporting

confidence: 94%

“…In both holes the boundary is located within the interval of reversed polarity that separates the marine magnetic Anomalies 29 and 30, denoted as the C-29R subchron in the presently used nomenclature. Worldwide, the same result was obtained from analyses of various marine sections (Alvarez et al, 1977;Alvarez and Lowrie, 1978;Hsü et al, 1982;Shackleton et al, 1984;Thierstein, 1982 and references therein). As pointed out by Thierstein (1982), the relative position of the paleontological boundary within the magnetic C-29R subchron is highly variable in different pelagic sequences, indicating major changes in sedimentation rate and/or the possible presence of hiatuses.…”

Section: Site 577supporting

confidence: 71%

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The Magnetostratigraphy of Northwest Pacific Sediments, Deep Sea Drilling Project Leg 86

Bleil¹

1985

Initial Reports of the Deep Sea Drilling Project

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Results of paleomagnetic analyses of pelagic sediment sequences recovered in the Northwest Pacific during Deep Sea Drilling Project Leg 86 are presented. On the basis of these data, almost complete late Cenozoic magnetostratigraphies are established for each drill site.At Site 577, on the Shatsky Rise, a stratigraphic duplication of Late Cretaceous to middle Eocene sequences was achieved using the hydraulic piston coring technique. For the first time, a detailed paleomagnetic study of this period using largely undisturbed and complete sedimentary columns from the Pacific region was possible. Available biostratigraphy and stable isotope stratigraphy data allowed a positive correlation of the downhole magnetic reversal patterns with a calibrated geomagnetic polarity time scale. In general, the results obtained are in remarkable agreement with other recently published magnetostratigraphies from various parts of the world. Therefore, they represent a high quality framework for an early Tertiary magnetobiochronology including the Cretaceous/Tertiary boundary interval.

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Section: Site 577supporting

confidence: 94%

Section: Site 577supporting

confidence: 71%

The Magnetostratigraphy of Northwest Pacific Sediments, Deep Sea Drilling Project Leg 86

Bleil¹

1985

Initial Reports of the Deep Sea Drilling Project

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“…Continuous deterioration of Neogene climate in the high latitudes and the expansion of the Antarctic surface water mass essentially drove out calcareous nannoplankton. However, a few early-middle Pleistocene species of calcareous nannofossils were found on Berggren et al (1985); d ; e Shackleton et al (1984); f Monechi and Thierstein (1985).…”

Section: Reticu Zygrhimentioning

confidence: 99%

Upper Cretaceous and Cenozoic Calcareous Nannofossils of the Kerguelen Plateau (Southern Indian Ocean) and Prydz Bay (East Antarctica)

Wei¹,

Thierstein²

1991

Proceedings of the Ocean Drilling Program

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“…The ages of several of the key lower Eocene nannofossil datums used here resulted from a study of DSDP Leg 74 cores (taken in the South Atlantic) (Shackleton, 1984) that employed the new magnetic-anomaly time scale of . At Sites 527 and 528, the percent of core recovery and the position of magnetic anomalies in relation to the recovered section suggest that the identification of Anomalies 21, 22, and 23 are correct.…”

Section: Ages Of Nannofossil Datums; Sediment Accumulation Ratesmentioning

confidence: 99%

“…At Sites 527 and 528, the percent of core recovery and the position of magnetic anomalies in relation to the recovered section suggest that the identification of Anomalies 21, 22, and 23 are correct. Within this interval, the following nannofossil datums and their ages were determined (Shackleton, 1984): the first occurrences of Nannotetrina fulgens (= N. quadrata) at 49.5 Ma and Discoaster sublodoensis at 51.7 Ma; and the last occurrence of Tribrachiatus orthostylus at 54.0 Ma. Below Anomaly 23, and especially in the reversed interval between Anomalies 23 and 24, the dating of events is less certain, owing to changes in sedimentation rate, to low magnetic inclinations, and to lack of data.…”

Section: Ages Of Nannofossil Datums; Sediment Accumulation Ratesmentioning

confidence: 99%

Lower Eocene Calcareous Nannofossil Biostratigraphy Beneath the Atlantic Slope and Upper Rise off New JerseyNew Zonation Based on Deep Sea Drilling Project Sites 612 and 613

Valentine¹

1987

Initial Reports of the Deep Sea Drilling Project

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Lower Eocene calcareous nannofossil limestone cored at DSDP Site 612 on the middle slope off New Jersey represents an almost complete biostratigraphic sequence; only the lowest biozone (CP9a; NP10*) was not recovered. The thickness of the strata (198 m), the good preservation of the nannofossils, and the lack of long hiatuses justify the acceptance of this section as a lower Eocene reference for the western North Atlantic margin. The widely recognized and very similar nannofossil zonations of Martini (NP zones) and Bukry-Okada (CP zones) are emended slightly to make their lower Eocene biozones coeval; in addition, five new subzones are erected that subdivide zones CP10 and CPU (NP12 and NP13). Established biozone names are retained as they are altered little in concept, but alphanumeric code systems are changed somewhat by appending an asterisk (*) to identify zones that are emended. Zone CP10* (NP12*) is divided into two parts, the Lophodolithus nascens Subzone (CP10*a; NP12*a) and the Helicosphaera seminulum Subzone (CP10*b; NP12*b). Zone CPU* (NP13*) is divided into three parts, the Helicosphaera lophota Subzone (CPll*a; NP13*a), the Cyclicargolithuspseudogammation Subzone (CP1 l*b; NP13*b), and the Rhabdosphaera tenuis Subzone (CPll*c; NP13*c). At Site 612, a time-depth curve based on nannofossil datums dated in previous studies reveals a smoothly declining sediment accumulation rate, from 4.9 cm/10 3 yr in CP10* (NP12*) to 2.8 cm/10 3 yr. in CP12* (NP14*). The ages of first-occurrence datums not previously dated are approximated by projection onto this timedepth curve and are as follows: Helicosphaera seminulum, 55.0 Ma; Helicosphaera lophota, 54.5 Ma; Cyclicargolithus pseudogammation, 53.7 Ma; Rhabdosphaera tenuis, 52.6 Ma; and Rhabdosphaera inflata, 50.2 Ma. At nearby Site 613 on the upper rise, strata of similar age, 139 m thick, contain an unconformity representing Subzone CPll*b (NP13*b) and a hiatus of approximately 1.1 m.y. duration. The sediment accumulation rate in the lower part of this section (9.7 cm/10 3 yr.) is twice that observed for equivalent strata at Site 612. The hiatus and the heightened sediment accumulation rate at Site 613 probably represent the effects of episodic mass wasting on the early Eocene continental slope and rise. INTRODUCTIONDuring Deep Sea Drilling Project Leg 95, core holes at Sites 612 and 613 on the continental margin off New Jersey penetrated a thick section of richly fossiliferous Eocene calcareous nannofossil limestone (Fig. 1). Eocene strata are widespread beneath the U.S. Atlantic margin. Beneath the outer shelf and upper slope the section is 400 to 500 m thick, but it thins both to seaward beneath the rise and to landward beneath the coastal plain, where erosional unconformities are evident.The sections at Sites 612 and 613 represent an almost complete sequence of lower Eocene nannofossil biozones. In all, smear slides from 101 samples were examined in a 221-m section from Site 612 on the middle slope (water depth 1404 m) and from 55 samples in a 148-m s...

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Accumulation Rates in Leg 74 Sediments

Cited by 34 publications

References 1 publication

The Magnetostratigraphy of Northwest Pacific Sediments, Deep Sea Drilling Project Leg 86

The Magnetostratigraphy of Northwest Pacific Sediments, Deep Sea Drilling Project Leg 86

Upper Cretaceous and Cenozoic Calcareous Nannofossils of the Kerguelen Plateau (Southern Indian Ocean) and Prydz Bay (East Antarctica)

Lower Eocene Calcareous Nannofossil Biostratigraphy Beneath the Atlantic Slope and Upper Rise off New JerseyNew Zonation Based on Deep Sea Drilling Project Sites 612 and 613

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Accumulation Rates in Leg 74 Sediments

Cited by 34 publications

References 1 publication

The Magnetostratigraphy of Northwest Pacific Sediments, Deep Sea Drilling Project Leg 86

The Magnetostratigraphy of Northwest Pacific Sediments, Deep Sea Drilling Project Leg 86

Upper Cretaceous and Cenozoic Calcareous Nannofossils of the Kerguelen Plateau (Southern Indian Ocean) and Prydz Bay (East Antarctica)

Lower Eocene Calcareous Nannofossil Biostratigraphy Beneath the Atlantic Slope and Upper Rise off New JerseyNew Zonation Based on Deep Sea Drilling Project Sites 612 and 613

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Lower Eocene Calcareous Nannofossil Biostratigraphy Beneath the Atlantic Slope and Upper Rise off New JerseyNew Zonation Based on Deep Sea Drilling Project Sites 612 and 613