Latest Pleistocene—Holocene paleoceanographic trends on the continental margin of eastern Canada: Foraminiferal, dinoflagellate and pollen evidence

Scott, David B.; Mudie, Peta J.; Vilks, G; Younger, D. Chloe

doi:10.1016/0377-8398(84)90013-6

Cited by 98 publications

(57 citation statements)

References 40 publications

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“…Whether this change is due to an océanographie effect, such as the incursion of Arctic waters (cf. the Baffin Current or the Inner Labrador Current), as suggested by Osterman (1982), Scott et al (1984) and Vilks et al (1984), or to a change in the preservation potential of arenaceous tests (Vilks and Deonarine, 1988) which actually may accompany environmental changes, is not clear. However, the very wide regional occurrence of the arenaceous zone does suggest paleoceanographic control .…”

Section: Interpretation Of Paleoenvironmentsmentioning

confidence: 99%

“…Samples of till from other marine studies are either barren of foraminifera (e.g. Scott et al, 1984;MacLean ef al., 1989) or contain mixed assemblages of foraminifera, such as mixed arctic and boreal assemblages (e.g. HaId and Vorren, 1987;Sejrup ef a/., 1987).…”

Section: Interpretation Of Paleoenvironmentsmentioning

confidence: 99%

“…This interpretation is based on the higher diversity of the assemblage, on the increasing percentages of Fursenkoina fusiformis, and on the introduction of lslandiella norcrossi into the assemblage. Based on the modern habitat preferences of the fauna, the bottom water in both the extreme ice proximal and the ice proximal environments was probably cold and turbid, with reduced salinities and, possibly, low oxygen content Scott et al, 1984;Schafer and Cole, 1986;HaId and Vorren, 1987;Vilks et al, 1989). Osterman (1982; suggested that ice distal sediments in Frobisher Bay are characterized by a Cassidulina reniforme-lslandiella helenae Zone.…”

Section: Interpretation Of Paleoenvironmentsmentioning

confidence: 99%

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The Quaternary History of Cumberland Sound, Southeastern Baffin Island: The Marine Evidence

Jennings¹

2007

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ABSTRACTAcoustic and core data from Cumberland Sound show that glacial ice derived from the Foxe Sector (Amadjuak Dome) of the Laurentide Ice Sheet advanced to the continental shelf at the mouth of the sound during a late phase of the Foxe Glaciation. The basal lithofacies/acoustic unit (Ai/BUD) in the sound is a massive, black diamicton. On the basis of strati-graphic, acoustic, lithologie and faunal evidence, this unit is interpreted as till. The till is overlain by an ice proximal to ice distal glacial-marine sediment sequence termed the Davis Strait Silt (DSS). The influence of ice retreat is reflected in the foraminiferal assemblages of the DSS. Rapid sedimentation rates in the sound prevailed during deposition of the DSS as shown by the conformable geometry of the DSS. Accelerator Mass Spectrometry dates on molluscs and foraminifera and a single conventional 14C date on disseminated organic material from ice proximal sediment of the DSS (lithofacies B and lower lithofacies C) indicate that the ice retreated rapidly from its probable maximum position on the shelf no earlier than ca. 13,400 BP and into the fiords along the coast of the sound by ca. 8900 BP. Deposition of ice-distal glacial marine sediments (lower lithofacies D) continued in the sound until ca. 7600 BP as the ice margin rapidly retreated into the fiords. Between ca. 8900 BP and ca. 8000 BP, the foraminiferal fauna show that the influence of glacial ice is remote and that "Atlantic Water" impinges on the seafloor. Postglacial sedimentation began in the sound at ca. 7600 BP. Retreat of the ice margin onto land made the fiord basins available as sediment catchments. The reduced sedimentation rates in the sound during this interval are indicated by the change to onlapping basin fill geometry of the Tiniktartuq Silt and Clay (TS&C). Calcareous foraminifera disappear from the sediments by ca. 6300 BP and are replaced by agglutinated foraminifera reflecting "Arctic Water" conditions at the seafloor. The TS&C is presently being deposited in the sound.

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Section: Interpretation Of Paleoenvironmentsmentioning

confidence: 99%

Section: Interpretation Of Paleoenvironmentsmentioning

confidence: 99%

Section: Interpretation Of Paleoenvironmentsmentioning

confidence: 99%

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The Quaternary History of Cumberland Sound, Southeastern Baffin Island: The Marine Evidence

Jennings¹

2007

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“…Glacial marine late Pleistocene deposits in and off eastern Canada rarely contain any temperate species {e.g., Guilbault, 1993;Rodrigues era/., 1993;Scott et al, 1984Scott et al, , 1989Vilks, 1980Vilks, , 1981Vilks and Mudie, 1983;Vilks and Rashid, 1976). Two factors may explain the presence of a background level of exclusively temperate species even during cold water intervals: (1) any glacial advance between 12,000 and 9000 years BP was within the fjords, quite far away from the core depositional site (Lutemauer et al, 1989b); and (2) hydrographie conditions relating to the California Undercurrent may have brought warmer water through deep troughs up to the core site (see Paleoceanography subsection of Discussion), resulting in the presence of significant proportions of species such as Nonionella Stella and Epistominella pacifica.…”

Section: Recognition Of Arctic and Temperate Foraminifer Indicator Spmentioning

confidence: 99%

Foraminiferal Evidence of Younger Dryas Age Cooling on the British Columbia Shelf

Patterson¹,

Guilbault²,

Thomson³

et al. 2007

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Cluster analysis of foraminifera from a ~12,000-9000 radiocarbon year old piston core from Goose Island Trough, Queen Charlotte Sound, indicates that a cold interval correlative with the Younger Dryas stadial occurred during a shallow water phase. The reduction in depth was caused by the passage across the area, between 11,500 and 10,000 years BP, of a glacial forebulge associated with the retreat of the Late Wisconsinian ice sheets. Published sedimentological evidence indicate that water depths decreased to ~75-90 m, placing the site above the permanent North Pacific pycnocline (100 m). Low salinity-near glacial conditions, at these depths, between -11,100 and 10,000 years BP were recognized by abundant populations of Cassidulina reniforme and lslandiella helenae. This cold interval has also been recognized in cores from elsewhere in Queen Charlotte Sound. The depressed salinity and temperature may have resulted from a modification of regional weather patterns. Decreased mean continental summer temperatures could have reduced the seasonal influence of the North Pacific High and lengthened that of the Aleutian Low. This would have resulted in a near continuous onshore surface Ekman transport and enhanced coastal runoff, effectively blocking the movement onto the shelf of deep, saline, warm water of the California Undercurrent. The resultant isolated inshore basin comprised of present-day Hecate Strait and Queen Charlotte Sound is tentatively named the "Hecate Sea". By ~10,000 years BP, weather and ocean circulation had returned to near modern patterns as indicated by the disappearance of lslandiella helenae and by the development of an Epistominella vitrea - dominated biofacies.L'analyse des groupements effectuée sur des populations de foraminifères d'une carotte à piston couvrant la période de 12 000 à 9000 ans BP, provenant du Goose Island Trough, dans le bassin de la Reine-Charlotte, démontre l'existence d'un intervalle froid contemporain du Dryas récent. Il coïncide avec une phase à bathymétrie réduite qui résulte du déplacement vers l'est, entre 11 500 et 10 000 ans BP, du bombement isostatique associé à l'Inlandsis de la Cordillière à la suite de son retrait. Des données sédimentologiques publiées montrent que la profondeur a diminué jusqu'à ~75-90 m, amenant le site étudié au-dessus de la pycnocline permanente du Pacifique Nord (100 m). L'existence de conditions hyposalines de type glaciaire, à ces profondeurs, entre 11 100 et 10 000 ans BP ont été reconnues grâce à la présence d'assemblages à Cassidulina reniforme et lslandiella helenae. Cet intervalle froid a également été reconnu ailleurs dans le bassin de la Reine-Charlotte. Les salinités et les températures réduites sont peut-être le résultat d'un changement dans les configurations météorologiques régionales. Des températures estivales plus basses sur le continent auraient réduit l'influence saisonnière de l'anticyclone du Pacifique Nord et rallongé celle de la dépression des Aloutiennes. Ceci aurait engendré un transport d'Ekman de surface quasi perm...

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“…again reveals the penetration of North Atlantic water masses into the Labrador Sea shortly after 10,400 BP. However, the noticeable occurrence of Multispinula minuta and of Cyst P (Mudie, in SCOTT et al, 1984) at the base of the zone (Dllla) constitutes an Arctic component that probably resulted from meltwater transit through the Greenland current.…”

Section: Palynostratigraphymentioning

confidence: 99%

Paleoenvironments along the Eastern Laurentide Ice Sheet Margin and Timing of the Last Ice Maximum and Retreat

Vernal¹,

Hillaire‐Marcel²

2008

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Palynological and isotopic analysis in a few deep-sea cores from the Labrador Sea reveals strong environmental changes related to the Late Pleistocene glacial fluctuations over eastern Canada. On the whole, the Labrador Sea was characterized by strong exchanges between North Atlantic water masses, Arctic outflows, and meltwater discharges from Laurentide, Greenland and lnuitian ice sheets. The penetration of temperate Atlantic waters persisted throughout most of the Late Pleistocene, with a brief interruption during the Late Wisconsinan. During this glacial substage, a slight but continuous meltwater runoff from the Laurentide ice margins grounded on the northern Labrador Shelf is indicated by relatively low 18O values and low-salinity (< 30‰) dinocyst assemblages. The calving of the ice margin, the melwater outflow and the subsequent dilution of surface waters offshore Labrador probably contributed to the dispersal of floating ice and, consequently, to a southward displacement of the polar front restraining the penetration of North Atlantic waters into the Labrador Sea. The advection of southern air masses along the Laurentide ice margins, shown by pollen assemblages, was favourable to abundant precipitation and therefore, high ice accumulation rates, especially over northern Labrador during the Late Wisconsinan. The déglaciation is marked by a brief, but significant, melting event of northern Laurentide ice shortly after 17 ka. The main glacial retreat occurred after ca. 11 ka. It allowed restoration of WSW-ENE atmospheric trajectories, increased phytoplanktonic productivity, and penetration of North Atlantic water masses into the Labrador Sea.L'analyse palynologique et isotopique de forages de la mer du Labrador révèle des changements des paléo-milieux du Pleistocene supérieur, en relation étroite avec les glaciations de l'est du Canada. De façon générale, la mer du Labrador a connu des échanges importants entre les masses d'eaux nord-atlantiques, celles des bassins septentrionaux de l'est du Canada et celles d'apports d'eaux de fonte des grandes calottes de l'hémisphère nord (laurentidienne, groenlandaise et inuitienne). La mer du Labrador fut influencée par la pénétration des masses d'eaux tempérées de l'Atlantique Nord au cours de la majeure partie du Pleistocene supérieur, à l'exception du Wisconsinien supérieur. Pendant cet épisode, des apports discrets mais continus d'eaux de fonte le long des marges glaciaires immergées dans le secteur ouest de la mer du Labrador sont indiqués par de faibles teneurs en 18O et par les assemblages de dinokystes associés à de faibles salinités (< 30‰). Le vêlage le long des marges glaciaires, l'évacuation des eaux de fonte et la dilution subséquente des masses d'eaux superficielles ont sans doute favorisé une dispersion méridionale des glaces flottantes pendant le Wisconsinien supérieur, provoquant ainsi une descente latitudinale du front polaire et limitant la pénétration de la dérive nord-atlantique dans la mer du Labrador. Par ailleurs, l'advection de masses d'air d'ori...

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Latest Pleistocene—Holocene paleoceanographic trends on the continental margin of eastern Canada: Foraminiferal, dinoflagellate and pollen evidence

Cited by 98 publications

References 40 publications

The Quaternary History of Cumberland Sound, Southeastern Baffin Island: The Marine Evidence

The Quaternary History of Cumberland Sound, Southeastern Baffin Island: The Marine Evidence

Foraminiferal Evidence of Younger Dryas Age Cooling on the British Columbia Shelf

Paleoenvironments along the Eastern Laurentide Ice Sheet Margin and Timing of the Last Ice Maximum and Retreat

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