A Younger Dryas Ash Bed in Western Norway, and Its Possible Correlations with Tephra in Cores from the Norwegian Sea and the North Atlantic

Mangerud, Jan; Lie, Sven Erik; Furnes, Harald; Kristiansen, I. L.; Lømo, Leif

doi:10.1016/0033-5894(84)90092-9

Cited by 328 publications

(307 citation statements)

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“…An ash layer, found between 350 and 400 cm, has been related to the Vedde tephra level by H. Haflidason (University of Bergen). Dated at 10.6 kyr BP (Mangerud et al, 1984), it corresponds to the climatic cold Younger Dryas event and is well-defined in PC13 in the oxygen isotope record . From 360 to 240 cm (10.1-8.6 kyr), an increase in magnetite concentration and grain-size matches a drop in the smectite/illite ratio (with a minimum at 290 cm, 9.1 kyr; Stoner et al, 1995;Fagel et al, 1997).…”

Section: Methodsmentioning

confidence: 99%

Smectite composition as a tracer of deep circulation: the case of the Northern North Atlantic

et al. 2001

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The link between smectite composition in sediments from the northern North Atlantic and Labrador Sea, and deep circulation is being further investigated through detailed studies of the X-ray pattern of smectites and cation saturations. This allows clear distinction of dominant terrigenous sources associated to the main components of the modern Western Boundary Undercurrent. Time variations of smectite characteristics in two piston cores from the inlet and outlet of the Western Boundary Undercurrent gyre in the Labrador Sea indicate: (1)

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Section: Methodsmentioning

confidence: 99%

Smectite composition as a tracer of deep circulation: the case of the Northern North Atlantic

et al. 2001

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“…Ash of Holocene age, however, including a widespread, 10,600-yr-old, rhyolitic marker horizon (Mangerud et al, 1984), was not recov ered at Site 642. Ash layers of Pleistocene to Miocene age have previously been recovered in the North Atlantic on the Rockall Plateau (DSDP Leg 48, Sites 403-406 and Leg 81, Sites 552-554), on the Reykjanes Ridge (Leg 49, Sites 407-409), and on the Iceland-Faeroe Ridge, the Iceland Plateau, the Jan Mayen Ridge, the Vetoing Plateau, and the Norway Basin (Leg 38, Sites 336-352).…”

Section: Tephra Correlation and Sources In The North Atlantic Regionmentioning

confidence: 96%

Site 642: Norwegian Sea

Eldholm¹,

Thiede²,

Taylor³

1987

Proceedings of the Ocean Drilling Program

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♦REMARKS: Although 110 cores were taken, Cores 104-642E-1W and -642E-2W are wash cores and Core 104-642E-49B is bit samples. They are treated only as samples and excluded in the core-recovery calculation. SITE 642 SUMMARY IntroductionODP Site 642 is located at the outer Vriring Plateau, east of magnetic anomaly 24B and over the inner part of the wedge of the seaward-dipping reflector sequence. Coring at Site 642 re covered a volcanic sequence consisting of two main units below a cover of predominantly pelagic-hemipelagic Neogene and Qua ternary sediments. A total of five holes were drilled at the site. These are:642A. 1 APC core, 1.3-10.8 mbsf, 642B. 25 APC cores, 0-221.1 mbsf, 642C. 24 APC cores, 0-199.6 mbsf, 642D. 18 XCB and 2 NCB cores, 189.9-329.9 mbsf, and 642E. 107 R cores, 322.5-1229.4 mbsf.The results of coring these holes, all of which are located within 450 m of each other, are summarized in a single lithostratigraphic column (Fig. 1 The high recovery and quality of the cores, the microfossil as semblages, and paleomagnetic record make the drilled sequence an excellent late Cenozoic reference section at high latitudes. In addi tion, about 50 discrete ash layers document adjacent North Atlantic (probably Icelandic) volcanism. The pelagic and hemipelagic Neo gene and Quaternary sediments allow us to describe the depositional environment and the properties of surface and bottom-water masses during times of late Cenozoic glacial/interglacial climatic fluctua tions (possibly lasting 4.5 m.y), as well as during the "preglacial" timespan when the Norwegian Sea was filled with temperate to sub polar water masses.Seismic data, as well as physical properties measurements and their correlations, reveal a low seismic velocity, about 1.6 km/s, for the sedimentary section. The major intrasedimentary marker at the plateau appears to be of early or basal Miocene age, indicating that the seismic stratigraphy established by earlier studies may have to be reevaluated.The entire volcanic section contains 137 volcanic flows, 59 volca niclastic sediment layers, and seven units that may be dikes. The se quence can be divided into upper and lower series that are distinctive in the textural, mineralogical, chemical, and structural characteris tics of the flows as well as in the compositions of interlayered volca niclastic sediments. The entire series was deposited under terrestrial conditions. In the seismic record these series are separated by a band of low-frequency reflectors, the first of which is denoted "K." The upper volcanic series composes the seaward-dipping reflector sequence at the outer Wring Plateau. 315-1093 mbsf. Middle(?)/Early EoceneThe upper series consists of 120 tholeiitic basalt flows. Their composition suggests an affinity with the basalts of the North At lantic Paleogene volcanic province. Two varieties of flows, fine-and medium-grained, which differ in quantitative mineral content, gran ularity, internal flow fabric, and average thickness have been ob served. Interlayered volcaniclastic sediments, whi...

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“…What is more revealing is to assess whether a linear age sequence can be theoretically "bioturbated" to produce offsets of over 3000 years, given the observed species abundance changes downcore, and by employing a realistic mixing depth. To determine the characteristic mixing depth for sandsized material in BOFS 5K, we examined the dispersal of coarse fraction sediment from an instantaneously deposited layer, the Vedde Ash [Mangerud et al, 1984]. In Figure 4a, the number of sand-sized rhyolitic shards per gram of total sediment is plotted against depth downcore.…”

Section: Bioturbation: a Simple Modelmentioning

confidence: 99%

“…For correlation purposes, the presence of ash peaks is often considered a means of establishing reliable chronological tie points across a suite of cores. In the northeast Atlantic, the Vedde Ash peak is usually assigned a 14C (atmospheric) age of 10,600 years [Mangerud et al, 1984]. This age has been recently revised to around 10,300 years [Bard et al, 1993b], which corresponds to a calibrated age of 12,152 years.…”

Section: Magnetic Susceptibility and Water Contentmentioning

confidence: 99%

Chronology for climate change: Developing age models for the biogeochemical ocean flux study cores

Manighetti¹,

McCave²,

Maslin³

et al. 1995

Paleoceanography

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Abstract. We construct age models for a suite of cores from the northeast Atlantic Ocean by means of accelerator mass spectrometer dating of a key core, BOFS 5K, and correlation with the rest of the suite. The effects of bioturbation and foraminiferal species abundance gradients upon the age record are modeled using a simple equation. The degree of bioturbation is estimated by comparing modeled profiles with dispersal of the Vedde Ash layer in core 5K, and we find a mixing depth of roughly 8 cm for sand-sized material. Using this value, we estimate that age offsets between unbioturbated sediment and some foraminifera species after mixing may be up to 2500 years, with lesser effect on fine carbonate (< 10 •m) ages. The bioturbation model illustrates problems associated with the dating of "instantaneous" events such as ash layers and the "Heinrich" peaks of ice-rafted detritus. Correlations between core 5K and the other cores from the BOFS suite are made on the basis of similarities in the downcore profiles of oxygen and carbon isotopes, magnetic susceptibility, water and carbonate content, and via marker horizons in X radiographs and ash beds.

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A Younger Dryas Ash Bed in Western Norway, and Its Possible Correlations with Tephra in Cores from the Norwegian Sea and the North Atlantic

Cited by 328 publications

References 31 publications

Smectite composition as a tracer of deep circulation: the case of the Northern North Atlantic

Smectite composition as a tracer of deep circulation: the case of the Northern North Atlantic

Site 642: Norwegian Sea

Chronology for climate change: Developing age models for the biogeochemical ocean flux study cores

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