scholarly journals Pre-Late Wisconsinan Paleoenvironments in Atlantic Canada

2007 ◽  
Vol 39 (3) ◽  
pp. 239-254 ◽  
Author(s):  
Robert J. Mott ◽  
Douglas R. Grant
Keyword(s):  
Deep Sea ◽  
Coniferous Forests ◽  
Atlantic Canada ◽  
White Pine ◽  
Previous Cycle ◽  
Oxygen Isotope Record ◽  
Isotope Record ◽  
Late Wisconsinan ◽  
Organic Deposits ◽  
Palynological Records

ABSTRACT Numerous Quaternary organic deposits of various lithologies beneath one or more till units of Wisconsinan age have been discovered in boreholes and exposures in coastal bluffs, quarries and river banks at widespread localities throughout Atlantic Canada. Ongoing palynological and macro-fossil studies, still in a preliminary stage at many sites, reveal a variety of environments from forests dominated by thermophilous hardwood genera and white pine, to mixed temperate hardwood and conifer forests, to boreal coniferous forests of spruce and balsam fir, and forest tundra and tundra communities characterized by spruce, shrubs and herbs. Lithologie and pollen stratigraphie relationships and radiocarbon, amino acid and Thorium/Uranium dating allow a tentative assignment to the Sangamonian Stage and possibly to Early and Middle Wisconsinan time. Three intervals of organic accumulation are apparent: an early interval, when climate became warmer than the present; a second interval, when climate was similar to the present; and a third interval, with cooler climate. The latter interval is characterized by at least three climatic cycles, each one cooler than the previous cycle. Tentative correlations with the deep-sea oxygen isotope record and continental palynological records are presented.

scholarly journals Sangamonian Forest History and Climate in Atlantic Canada

2007 ◽  
Vol 44 (3) ◽  
pp. 257-270 ◽  
Author(s):  
Robert J. Mott
Keyword(s):  
Atlantic Canada ◽  
Last Interglacial ◽  
Cape Breton Island ◽  
Green Point ◽  
Sequence Of Events ◽  
Cape Breton ◽  
Oxygen Isotope Record ◽  
Isotope Record ◽  
Climatic Optimum ◽  
Organic Deposits

ABSTRACT Seven of the more than twenty five buried organic deposits in Atlantic Canada assigned to pre-Wisconsinan non-glacial intervals possibly relate to the climatic optimum of the Sangamon Interglaciation, that is substage 5e of the deep-sea oxygen isotope record. These sites are East Bay and Green Point on Cape Breton Island. Addington Forks and East Milford in mainland Nova Scotia. Le Bassin and Portage-du-Cap on the Iles de la Madeleine, Québec, and Woody Cove, Newfoundland. Except for Woody Cove, none of the sites records a complete climatic cycle, and the sequence of events must be pieced together from their disparate records. The spectra, characterized by significant amounts of thermophilous taxa that are not as abundant or present in the region today, are similar in general to Holocene spectra at sites immediately south of the lower Great Lakes. Comparison of the fossil spectra from five sites with modern surface spectra from eastern North America yields modern analogs which, if valid, indicate that the climate in Atlantic Canada during the climatic optimum of the last interglacial interval was more continental in character and considerably warmer than present.

scholarly journals Paleoecology of Organic Deposits of Probable Last Interglacial Age in Northern Ontario

2007 ◽  
Vol 44 (3) ◽  
pp. 309-318 ◽  
Author(s):  
Robert J. Mott ◽  
Ronald N. W. DiLabio
Keyword(s):  
Deep Sea ◽  
Hudson Bay ◽  
Last Interglacial ◽  
Northern Ontario ◽  
Hudson Bay Lowlands ◽  
Organic Sediment ◽  
Oxygen Isotope Record ◽  
Isotope Record ◽  
Organic Deposits ◽  
River Valleys

ABSTRACT Nonglacial deposits in northern Ontario that may date to the last interglacial interval are well known from the Hudson Bay Lowlands where they have been described in sections along several river valleys. Soil horizons, peat beds and other organic sediment sequences comprise the Missinaibi Formation of the Moose River Basin studied for pollen and macrofossils. Results suggest that the climate was as warm or warmer than present, and spruce woodlands prevailed among broad expanses of bog and fen. The Beaver River peat records conditions similar to the present in the Fort Severn area with open spruce woodlands dispersed in peatlands. South of the Lowlands in the Timmins area, a widespread organic-silt horizon termed the Owl Creek beds is stratigraphically equivalent to the Missinaibi Formation. The waning phase of a warm interval is represented, with early climate possibly similar to the present and the later climate much cooler. Correlation of the Missinaibi Formation with substage 5e of the deep-sea oxygen isotope record is corroborated by amino acid results on marine shells from some associated units. Analysis of shells from beneath the Beaver River peat bed indicate that this interval may be considerably younger, possibly substage 5c or, more likely, 5a. The Owl Creek beds may relate to sub-stage 5e, or to one of the younger intervals, 5c or 5a.

Speleothems, Travertines, and Paleoclimates

1983 ◽  
Vol 20 (1) ◽  
pp. 1-29 ◽  
Author(s):  
G. J. Hennig ◽  
R. Grün ◽  
K. Brunnacker
Keyword(s):  
Oxygen Isotope ◽  
Deep Sea ◽  
Clear Relationship ◽  
Sufficient Data ◽  
Geographic Position ◽  
Oxygen Isotope Record ◽  
Isotope Record ◽  
Age Range ◽  
Stimulation Of ◽  
Frequency Curves

AbstractAge data for about 660 speleothems and about 140 spring-deposited travertines were collected, including many unpublished results. These data were plotted as histograms and also as error-weighted frequency curves on a 350,000-yr scale. These plots clearly show periods of increased speleothem/travertine growth as well as times of cessation. The periods of most frequent speleothem growth were between approximately 130,000 and 90,000 yr ago and since about 15,000 yr ago. Such periods before 150,000 yr ago, however, cannot be yet recognized because of a lack of sufficient data and the associated uncertainties of dates in this age range. A comparison with the oxygen-isotope record of deep-sea core V28–:238 shows a clear relationship, indicating that terrestrial calcite formation is controlled by paleoclimatic fluctuations. The evident climatic stimulation of Quaternary calcite formation is readily explained geochemically and is substantiated by the obvious difference in speleothem/travertine growth as a function of geographic position.

The Holstein Interglaciation: Time-Stratigraphic Position and Correlation to Stable-Isotope Stratigraphy of Deep-Sea Sediments

1986 ◽  
Vol 26 (3) ◽  
pp. 283-298 ◽  
Author(s):  
Michael Sarnthein ◽  
Helmut E. Stremme ◽  
Augusto Mangini
Keyword(s):  
Oxygen Isotope ◽  
Deep Sea ◽  
Significant Proportion ◽  
Soil Formation ◽  
Oxygen Isotope Record ◽  
Isotope Record ◽  
Stratigraphic Position ◽  
Isotope Stratigraphy ◽  
Global Sea Level ◽  
Central Atlantic

Marine molluscan shells from para-type and other localities of the Holsteinian interglaciation were dated by Th/U and the electron spin resonance (ESR) method to more than 350,000 and 370,000 yr B.P., beyond the limit of Th/U dating. The high age estimate is corroborated by a K/Ar age of 420,000 yr B.P. determined from volcanic ash near the base of the Ariendorf paleosol in the Middle Rhine valley believed to be a pedostratigraphic equivalent of the Holsteinian. Shells from the Herzeele marine unit III, an equivalent of the Wacken (Dömnitz) warm stage in northern France and subsequent to the Holsteinian, revealed ages between 300,000 and 350,000 yr B.P. A correlation of these two warm stages with marine oxygen-isotope stages 11 and 9 on the SPECMAP and CARTUNE time scales is suggested. From the benthic oxygen-isotope record one may infer that no exceptionally high global sea-level rise corresponds to the large transgressions of the Holstein Sea in northern Germany. Therefore, a significant proportion of the transgression was probably the result of an unusually large local glacial-isostatic depression caused by the extreme buildup of ice during the preceding Elster glaciation (stage 12). According to the deep-sea record, it lasted approximately 50% longer than the subsequent cold stage 10. The outstanding soil formation with Braunlehm and the well-developed thermal optimum of the Holsteinian are tentatively related to a phase of minimum sea-ice cover in the Norwegian-Greenland Sea, as deduced from long benthic carbon-isotope records from the central Atlantic.

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