Holocene History of a Portion of Northernmost Ellesmere Island

Lyons, John B.; Mielke, James E.

doi:10.14430/arctic2930

Cited by 42 publications

(34 citation statements)

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“…Meanwhile, foraminiferal abundances increased sharply; their significant correlation with pigment concentrations (r = 0.76, P < 0.001) suggested that they were responding to greater phytoplankton food supply. δ 13 C ORG also differed significantly (P = 0.05) between marine and epishelf stages, with higher δ 13 C ORG values after ∼4 cal ka BP reflective of the accumulation of 13 C-rich meltwater behind the ice shelf (10). One Disraeli Fiord driftwood sample had a 14 C range that fell after the sediment-inferred date of ice-shelf formation (12) (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…These studies suggested ice-shelf absence after deglaciation at ∼9.5 calibrated (cal) ka BP and produced a range of WHIS age estimates between 3.0 and 5.5 cal ka BP (12)(13)(14)(15)(16). Although the presence of ice shelves precludes driftwood emplacement, it is difficult to ascertain whether periods of driftwood absence may have been caused by ice shelves or by past variability in delivery mechanisms such as ocean currents or ice conditions, changes in terrestrial vegetation, or potential disturbance after deposition (17,18); driftwood-based dates are consequently recognized as providing only upper limits to ice-shelf ages (12,18,19).…”

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confidence: 97%

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Holocene dynamics of the Arctic's largest ice shelf

Antoniades

Francus

Pienitz

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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Ice shelves in the Arctic lost more than 90% of their total surface area during the 20th century and are continuing to disintegrate rapidly. The significance of these changes, however, is obscured by the poorly constrained ontogeny of Arctic ice shelves. Here we use the sedimentary record behind the largest remaining ice shelf in the Arctic, the Ward Hunt Ice Shelf (Ellesmere Island, Canada), to establish a long-term context in which to evaluate recent ice-shelf deterioration. Multiproxy analysis of sediment cores revealed pronounced biological and geochemical changes in Disraeli Fiord in response to the formation of the Ward Hunt Ice Shelf and its fluctuations through time. Our results show that the ice shelf was absent during the early Holocene and formed 4,000 years ago in response to climate cooling. Paleoecological data then indicate that the Ward Hunt Ice Shelf remained stable for almost three millennia before a major fracturing event that occurred ∼1,400 years ago. After reformation ∼800 years ago, freshwater was a constant feature of Disraeli Fiord until the catastrophic drainage of its epishelf lake in the early 21st century.climate change | glaciology | paleoceanography | geochemistry

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Section: Discussionmentioning

confidence: 99%

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confidence: 97%

Holocene dynamics of the Arctic's largest ice shelf

Antoniades

Francus

Pienitz

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

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“…The youngest wood landward of the ice shelves is 3 -4 ka old ( Fig. 4; Crary, 1960;Lyons and Meilke, 1973;Lemmen et al, 1988). The aggregate distribution of driftwood dates from the Arctic Ocean coast of Ellesmere Island resembles that for the Baffin Bay region (cf.…”

Section: Region Not Accessible From Baffin Baymentioning

confidence: 99%

Changes in Driftwood Delivery to the Canadian Arctic Archipelago: The Hypothesis of Postglacial Oscillations of the Transpolar Drift

Dyke¹,

England²,

Reimnitz³

et al. 1997

ARCTIC

125

106

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ABSTRACT. Driftwood appears to be absent in the Beaufort Gyre but abundant in parts of the Transpolar Drift (TPD), which crosses the Arctic Ocean from the Chukchi Sea to the vicinity of northeastern Greenland. Nearly 300 radiocarbon dates on Holocene driftwood from the Canadian Arctic Archipelago reveal two regions with contrasting histories of driftwood incursion: the region accessible to wood brought into Baffin Bay by the West Greenland Current and the rest of the archipelago, which receives wood from the Arctic Ocean. We hypothesize that when the TPD was deflected westward along northern Greenland, wood was delivered widely to the Canadian Arctic Archipelago; when the TPD exited entirely through Fram Strait via the East Greenland Current, little or no wood was delivered to most of the archipelago, but some continued into Baffin Bay via the West Greenland Current. A split TPD delivered wood to both regions. The regional driftwood incursion histories exhibit multiple maxima and minima that can be explained by this hypothesis. The Larix to Picea ratio of wood arriving in the Canadian Arctic Archipelago has also changed through time. This may indicate varying contributions from Russian versus North American sources, which in turn may indicate variable mixing of wood en route. The inferred discharge paths of the TPD were apparently stable for intervals ranging from several millennia to centuries or perhaps only decades. The last major switch broadly correlates with the onset of Neoglaciation. Variations in the path and strength of the TPD may have important oceanographic and climatic consequences downstream in the North Atlantic Ocean.Key words: driftwood, Transpolar Drift, Beaufort Gyre, sea ice, ocean currents RÉSUMÉ. Il semble qu'il n'y ait pas de bois flotté dans la circulation de Beaufort mais qu'on en trouve en abondance dans certaines parties du courant d'impulsion transpolaire, qui traverse l'océan Atlantique depuis la mer des Tchouktches jusqu'au voisinage du nord-est du Groenland. Près de 300 datations au carbone 14 effectuées sur du bois flotté datant de l'holocène et provenant de l'archipel Arctique canadien mettent en évidence deux régions qui possèdent un passé divergent quant à l'incursion de bois flotté: la région que peut atteindre le bois transporté dans la baie de Baffin par le courant groenlandais oriental, et le reste de l'archipel, qui reçoit le bois en provenance de l'océan Arctique. Nous avançons l'hypothèse que, quand le courant transpolaire était défléchi vers l'ouest le long de la partie septentrionale du Groenland, il y avait un fort apport de bois dans l'archipel Arctique canadien; quand le courant transpolaire passait en sa totalité par le détroit de Fram pour rejoindre le courant groenlandais oriental, peu de bois, sinon aucun, atteignait la plupart de l'archipel, un peu étant cependant acheminé dans la baie de Baffin via le courant groenlandais occidental. Un courant transpolaire divisé amenait du bois aux deux régions. L'historique des incursions régionales de bois flotté révèle l...

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“…Ice shelves created by the accretion of land-fast sea ice are well documented from northernmost Ellesmere Island (cf. the Ward Hunt Ice Shelf; Koenig and others, 1952;Hattersley-Smith and others, 1955 ;Crary, 1960;Lyons and Mielke, 1973). Radiometric dates on the youngest driftwood trapped behind the Ward Hunt Ice Shelf and on organic debris incorporated within it suggest initial formation c. 3000-4000 B. P., hence, following the Holocene Climatic Optimum (Crary, 1960 ;HattersleySmith, 1969;Lyons and Mielke, 1973).…”

Section: Introductionmentioning

confidence: 99%

“…the Ward Hunt Ice Shelf; Koenig and others, 1952;Hattersley-Smith and others, 1955 ;Crary, 1960;Lyons and Mielke, 1973). Radiometric dates on the youngest driftwood trapped behind the Ward Hunt Ice Shelf and on organic debris incorporated within it suggest initial formation c. 3000-4000 B. P., hence, following the Holocene Climatic Optimum (Crary, 1960 ;HattersleySmith, 1969;Lyons and Mielke, 1973). The build-up ofland-fast sea ice is due to the freezing of low-salinity sea-water at its base and, to a lesser extent, to the periodic surface accumulation of iced firn (Marshall, 1955).…”

Section: Introductionmentioning

confidence: 99%

Former Ice Shelves in the Canadian High Arctic

1978

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ABSTRACT. Moraines depos ited by the outermos t ice ad vance across Judge Daly Promontory, northeas tern Elles m e re I sland , reRect thin , topographically controlled ice lobes extending to sea-level. The termini of two ice lobes were in vestiga ted a nd both produced ice shelves where they Rowed into isostatically depressed e mbayme nts along wes te rn K ennedy Channel. M orphological evide nce for these ice shelves occurs at the e ntrance to these valleys whe re steeply descending la teral moraines become a bruptly horizontal for 2 km. In addition, both the h o rizontal moraines a nd associated pro-glacial terraces are fossiliferous downva lley from the a pparent grounding line. Based o n the differences in elevation between the h orizonta l moraines a nd the valley bottoms, the two ice shelves had es timated thicknesses of c. 110 a nd 150 m . A proglacial outwash terrace at 175 m a .s.l. is conside red to re present the a pproximate rel a tive sea-level during the formation a nd break-up of the ice shelves. This rela tive sea-level is consistent with the water depths required to Roa t the calcula ted ice thicknesses in b o th valleys. Associated with these ice margins are finite HC dates Of28 000-30000 B.P. a nd a mino-acid age es timates of > 35000 B.P. The importa nce and likelihood of additional past ice shelves in the Ca nadia n High Arcti c is discussed. R EsuME. Ancims glaciers dans le Grand N ord Canadien. D es moraines deposees par l' avance extreme de la gl ace a trave rs le Judge Da ly Promontory, au Nord-Est d e 1' lle d'Elles m e re, sont I'indi ce d e lobes de glace peu epa is contro les par la topog raphie et s'etendantjusqu' au niveau d e la m er. On a exa mine les extremites de deux lobes d e glace et tous d e ux ont engendre d es platformes de glace lo rsqu'elles fl ottaient d a ns d es baies rendues plus profo ndes pa r I' isostas ie le long de K ennedy Cha nnel occide nta l. Des preuves m o rphologiques de l'existence d e ces platformes subsistent a l'entree d e ces vallt!es lorsque les moraines la te rales jusque la en pente prononcee d eviennent brusquement horizon ta les sur 2 km. De plus, les morain es ho~izontales et les terrasses pro-glacia ires associees sont fossiliferes a l'aval d e la ligne d e rivage apparente. En se basant sur la difference d' a ltitude entre les mora ines horizon ta les e t les fonds d e la vallee, les deux glaciers avaient des epaisseurs es timees a ltO et 150 m . U ne terrasse pro-glaciaire alluvial e a 175 m au-dessus du niveau de la mer est conside ree comme representa nt le niveau rela tif a pproximatif d e la mer penda nt la fo rma tion et la dispa rition d es glaciers. Ce niveau d e la mer est coh e re nt a vec les epaisseurs d 'eau requises pour permettre que Rotte l'e paisseur de glace calculee dans les deux vall ees. A ces form a tions periglacia ires sont associees des da tations a u carbone 14 de 28000 a 30 000 ans ava nt le present e t d es a mino-acides ages d e 35 000 ans.L ' importa nce e t la vrai sembl a n ce d e l'existence d e glaciers sup...

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Holocene History of a Portion of Northernmost Ellesmere Island

Cited by 42 publications

References 16 publications

Holocene dynamics of the Arctic's largest ice shelf

Holocene dynamics of the Arctic's largest ice shelf

Changes in Driftwood Delivery to the Canadian Arctic Archipelago: The Hypothesis of Postglacial Oscillations of the Transpolar Drift

Former Ice Shelves in the Canadian High Arctic

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