Holocene Diatom Stratigraphy and Paleoceanography of the
Eurasian Arctic Seas
Y. Polyakova
Geographical Department, Moscow State University, 119899 Moscow, Russia
Recei ved II March 1997 and accepted in revised fonn 3 May 1998
Abstract - Five ecological zones were established on the basis of changes in relative
abundance of diatom valves, ecological and biogeographical composition of diatom
assemblages from the Holocene sediments of the Eurasian Arctic seas, These diatom
ecozones reflecting the main stages of paleoceanological evolution of the Arctic Seas during
the Holocene may be used as stratigraphical markers for subdivision of the sediment
sequences. It was revealed that in the eastern part of the Eurasian Arctic shelf the most
significant paleoceanological changes took place about 12-11 Ka, caused by the opening of
the Bering Strait and supply of wann highly productive Bering Sea waters into the Chukchi
Sea. In the western part of the Arctic shelf this event was connected with intensifying of
the the North Atlantic current about 9-8 Ka. During the Holocene in all Arctic Seas the
most favourable hydrobiological conditions for the arctic phytocoenoses development
("hydrobiological or marine optimum") corresponding to the Ecozone III existed at the end
of Atlantic to the beginning of Subboreal periods.
Introduction
The Holocene paleoceanography of the Arctic Ocean s still poorly known, yet it becomes
increasingly clear that this very sensitive region played a key role in short- and long-term
changes of global ocean circulation and climate formation. While much progress has been made
toward reconstruction of the Late Pleistocene and Holocene paleoclimatic changes and their
regional manifestations in the high latitudinal continental regions of the Northern hemisphere,
paleoceanological fluctuations of the Arctic basin and marginal shelf seas are still not clearly
understood. By now such important paleogeographical problems as correlation of
paleoenvironmental changes in the Arctic Ocean (especially in shelf and adjacent land areas) and
reconstructions of their inter-relations are still far from being solved. The Eurasian Arctic shelf
comprising about 1/3 of the total area of the Arctic Ocean exhibits the most promise for solution
of these problems. The Eurasian Arctic shelf stretching from the Atlantic to Pacific Oceans and
fringed by the Arctic basin is a critical area for the flux of fresh water and sea ice formation
that modulate the Earth's climate.
The data obtained to date give evidence for considerable paleoceanological fluctuations in the
Arctic Ocean during the Late Pleistocene and Holocene, thus allowing us to draw the most
general conclusions about the main paleoenvironmental changes during this period. The
available core data from the deep Arctic basins relate faunal and sedimentological variables
caused by changing paleoenvironmental conditions during theLatest Quaternary and Holocene.
Some aspects have been emphasized in those studies: (i) two peak deglacial meltwater episodes
in the Arctic Ocean at 14-12 Ka (Termination Ia) and 10-8 Ka (Termination Ib); (ii) high
organic productivity during Termination I following the abundance minimum in last glacial
stage associated with a strong inflowing of warm North Atlantic water (Cronin et aI., 1994);
(iii) the major abundance maxima of planktic and benthic foraminifers ascribed to mid- to late
Holocene (Norgaard-Pedersen, 1996) and several mid-Holocene key faunal events indicating a
period of warming and/or enhanced flow between the Canadian and Eurasian Basins (Cronin et
aI., 1994); (iiii) the seasonally open water in the central Arctic Ocean during the Holocene on
In: Kassens, H .. H.A. Bauch, l. Dmitrenko, H. Eicken, H.-W. Hubberten, M. Melles, J. Thiede and L. Timokhov (eds.)
Land-Ocean Systems in the Siberian Arctic: Dynamics and History. Springer-Verlag, Berlin, 1999,615-634.
Eurasian Arctic Seas
Y. Polyakova
Geographical Department, Moscow State University, 119899 Moscow, Russia
Recei ved II March 1997 and accepted in revised fonn 3 May 1998
Abstract - Five ecological zones were established on the basis of changes in relative
abundance of diatom valves, ecological and biogeographical composition of diatom
assemblages from the Holocene sediments of the Eurasian Arctic seas, These diatom
ecozones reflecting the main stages of paleoceanological evolution of the Arctic Seas during
the Holocene may be used as stratigraphical markers for subdivision of the sediment
sequences. It was revealed that in the eastern part of the Eurasian Arctic shelf the most
significant paleoceanological changes took place about 12-11 Ka, caused by the opening of
the Bering Strait and supply of wann highly productive Bering Sea waters into the Chukchi
Sea. In the western part of the Arctic shelf this event was connected with intensifying of
the the North Atlantic current about 9-8 Ka. During the Holocene in all Arctic Seas the
most favourable hydrobiological conditions for the arctic phytocoenoses development
("hydrobiological or marine optimum") corresponding to the Ecozone III existed at the end
of Atlantic to the beginning of Subboreal periods.
Introduction
The Holocene paleoceanography of the Arctic Ocean s still poorly known, yet it becomes
increasingly clear that this very sensitive region played a key role in short- and long-term
changes of global ocean circulation and climate formation. While much progress has been made
toward reconstruction of the Late Pleistocene and Holocene paleoclimatic changes and their
regional manifestations in the high latitudinal continental regions of the Northern hemisphere,
paleoceanological fluctuations of the Arctic basin and marginal shelf seas are still not clearly
understood. By now such important paleogeographical problems as correlation of
paleoenvironmental changes in the Arctic Ocean (especially in shelf and adjacent land areas) and
reconstructions of their inter-relations are still far from being solved. The Eurasian Arctic shelf
comprising about 1/3 of the total area of the Arctic Ocean exhibits the most promise for solution
of these problems. The Eurasian Arctic shelf stretching from the Atlantic to Pacific Oceans and
fringed by the Arctic basin is a critical area for the flux of fresh water and sea ice formation
that modulate the Earth's climate.
The data obtained to date give evidence for considerable paleoceanological fluctuations in the
Arctic Ocean during the Late Pleistocene and Holocene, thus allowing us to draw the most
general conclusions about the main paleoenvironmental changes during this period. The
available core data from the deep Arctic basins relate faunal and sedimentological variables
caused by changing paleoenvironmental conditions during theLatest Quaternary and Holocene.
Some aspects have been emphasized in those studies: (i) two peak deglacial meltwater episodes
in the Arctic Ocean at 14-12 Ka (Termination Ia) and 10-8 Ka (Termination Ib); (ii) high
organic productivity during Termination I following the abundance minimum in last glacial
stage associated with a strong inflowing of warm North Atlantic water (Cronin et aI., 1994);
(iii) the major abundance maxima of planktic and benthic foraminifers ascribed to mid- to late
Holocene (Norgaard-Pedersen, 1996) and several mid-Holocene key faunal events indicating a
period of warming and/or enhanced flow between the Canadian and Eurasian Basins (Cronin et
aI., 1994); (iiii) the seasonally open water in the central Arctic Ocean during the Holocene on
In: Kassens, H .. H.A. Bauch, l. Dmitrenko, H. Eicken, H.-W. Hubberten, M. Melles, J. Thiede and L. Timokhov (eds.)
Land-Ocean Systems in the Siberian Arctic: Dynamics and History. Springer-Verlag, Berlin, 1999,615-634.