Late Pleistocene History of the North Pacific: Evidence from a Quantitative Study of Radiolaria in Core V21-173

1973 ◽  
Vol 3 (1) ◽  
pp. 89-98 ◽  
Author(s):  
Harvey Maurice Sachs
Keyword(s):  
Late Pleistocene ◽  
North Pacific ◽  
Transfer Functions ◽  
Near Surface ◽  
The Past ◽  
The North ◽  
History Of ◽  
The North Pacific ◽  
Oceanographic Conditions ◽  
Radiolarian Assemblages

AbstractObjective quantitative estimates of paleo-oceanographic conditions in the North Pacific can be made by analyses of radiolarian assemblages. With appropriate computation, transfer functions developed in a study of surface sediments can be used to estimate oceanographic conditions in cores containing late Pleistocene radiolarian faunas. Analysis of core V21-173 indicates that conditions as warm as the Holocene were rare during the past 800,000 yr, and that the region experienced marked near-surface temperature drops correlative with Caribbean and continental records for the past 250,000 yr. A major world-wide warm event at about 400,000 yr is also indicated.

North Pacific Radiolarian Assemblages and their Relationship to Oceanographic Parameters

1973 ◽  
Vol 3 (1) ◽  
pp. 73-88 ◽  
Author(s):  
Harvey Maurice Sachs
Keyword(s):  
North Pacific ◽  
Surface Sediments ◽  
Transfer Functions ◽  
Abundant Species ◽  
Near Surface ◽  
The North ◽  
The Relationship ◽  
The North Pacific ◽  
Oceanographic Conditions ◽  
Radiolarian Assemblages

AbstractA quantitative study of the distribution of Radiolaria in surface sediments of the North Pacific has demonstrated the feasibility of utilizing complete radiolarian thanatocoenoses as indicators of past oceanographic conditions.In samples from 36 core tops from the region 33° N-54° N, 148° E-140° W, 87–96% of all radiolarians encountered could be assigned to one of 120 taxa recognized. Q-mode factor analysis of distributional data for the 57 most abundant species yields four independent assemblages. Three of these reflect near-surface oceanographic conditions, and the fourth responds to bottom conditions. Regression-developed transfer functions describe the relationship between the assemblages and oceanographic parameters.

The near-surface circulation of the North Pacific using satellite tracked drifting buoys

1983 ◽  
Vol 88 (C12) ◽  
pp. 7507 ◽  
Author(s):  
Gerard J. McNally ◽  
William C. Patzert ◽  
A. D. Kirwan ◽  
Andrew C. Vastano
Keyword(s):  
North Pacific ◽  
Near Surface ◽  
The North ◽  
Surface Circulation ◽  
The North Pacific ◽  
Drifting Buoys

Did a Beringian ice sheet once exist?

2020 ◽  
Author(s):  
Zhongshi Zhang ◽  
Qing Yan ◽  
Ran Zhang ◽  
Florence Colleoni ◽  
Gilles Ramstein ◽  
...  
Keyword(s):  
North Pacific ◽  
Ice Sheets ◽  
Ice Sheet ◽  
Climate Modelling ◽  
Mountain Glaciers ◽  
The Past ◽  
The North ◽  
Paleoclimate Records ◽  
Glacial Landforms ◽  
The North Pacific

<p>Did a Beringian ice sheet once exist? This question was hotly debated decades ago until compelling evidence for an ice-free Wrangel Island excluded the possibility of an ice sheet forming over NE Siberia-Beringia during the Last Glacial Maximum (LGM). Today, it is widely believed that during most Northern Hemisphere glaciations only the Laurentide-Eurasian ice sheets across North America and Northwest Eurasia became expansive, while Northeast Siberia-Beringia remained ice-sheet-free. However, recent recognition of glacial landforms and deposits on Northeast Siberia-Beringia and off the Siberian continental shelf has triggered a new round of debate.These local glacial features, though often interpreted as local activities of ice domes on continental shelves and mountain glaciers on continents,   could be explained as an ice sheet over NE Siberia-Beringia. Only based on the direct glacial evidence, the debate can not be resolved. Here, we combine climate and ice sheet modelling with well-dated paleoclimate records from the mid-to-high latitude North Pacific to readdress the debate. Our simulations show that the paleoclimate records are not reconcilable with the established concept of Laurentide-Eurasia-only ice sheets. On the contrary, a Beringian ice sheet over Northeast Siberia-Beringia causes feedbacks between atmosphere and ocean, the result of which well explains the climate records from around the North Pacific during the past four glacial-interglacial cycles. Our ice-climate modelling and synthesis of paleoclimate records from around the North Pacific argue that the Beringian ice sheet waxed and waned rapidly in the past four glacial-interglacial cycles and accounted for ~10-25 m ice-equivalent sea-level change during its peak glacials. The simulated Beringian ice sheet agrees reasonably with the direct glacial and climate evidence from Northeast Siberia-Beringia, and reconciles the paleoclimate records from around the North Pacific. With the Beringian ice sheet involved, the pattern of past NH ice sheet evolution is more complex than previously thought, in particular prior to the LGM.</p>

Sign in / Sign up

Export Citation Format

Share Document