scholarly journals Klima-Änderungen im Pleistozän: Isotopenuntersuchungen an fossilen Seesedimenten aus dem Holstein-Interglazial Ost-Polens

1999 ◽  
Vol 49 (1) ◽  
pp. 21-34
Author(s):  
Jerzy Nitychoruk ◽  
Jochen Hoefs ◽  
Jürgen Schneider
Keyword(s):  
Pollen Zone

Abstract. In Ost-Polen erbohrte Seesedimente mit einer Mächtigkeit bis zu 55 m (Ossówka-See) dokumentieren das ganze Holstein-Interglazial und die Anfangsperiode der Saale-Eiszeit. An ausgewählten Bohrkernen der Seen von Ossówka und Wilczyn wurden palaeobiologische (Malakofauna, Palynologie und Pflanzen-Makroreste) und Isotopen-Untersuchungen durchgeführt. Die für den längsten (55 m) und vollständigsten Bohrkern nahe der Ortschaft Ossówka bestimmten C- und O-Isotopenwerte betragen: δ13C: Minimalwerte bis -6,4 ‰ für Ablagerungen am Beginn des Interglazials, Maximalwerte bis +10,0‰ für Ablagerungen aus der kalten Frühglazialperiode; δ18O: Maximalwerte bis -3,6 ‰ für Ablagerungen aus dem ersten Abschnitt des Interglazial-Optimums, Minimalwerte bis -10,1 ‰ für Ablagerungen aus der kältesten Periode unmittelbar vor der nächsten Vereisung. Generell gibt der Kurvenverlauf der O-Isotopenwerte gut die palynologisch dokumentierten Klimaveränderungen wieder. Im Profil sind jedoch zwei Perioden zu beobachten, in denen das Isotopenbild nicht mit der palynologischen Aussage übereinstimmt, einmal im klimatischen Interglazial-Optimum und zum anderen im jüngeren Teil des frühen Saale-Glazials. 1. Während des klimatischen Optimums des Holstein-interglazials (Pollen-Zone G und H) sprechen die Isotopenkurven der Seesedimente für relativ kühle Klimaverhältnisse. Dies kann durch eine Zunahme der Niederschlagsmenge, die zu einer Seespiegel-Erhöhung führte und/oder durch den Einfluß von isotopisch leichten Zuflüssen erklärt werden. 2. Im oberen Teil des Profils, der eine kühle, der Vereisung vorangehende Phase darstellt, erreichen die δ13C-und δ18O-Isotope unerwartet hohe Werte, was möglicherweise auf die Redeposition von "warmen" interglazialen Ablagerungen und/oder auf eine Zunahme der Evaporation unter trockenen Steppenklima-Bedingungen mit Seespiegel-Tiefständen zurückzuführen ist. Abkühlungsphasen fallen mit der Verschiebung der Sauerstoffisotopenverhältnisse in Richtung einer 18O- Verarmung zusammen.

scholarly journals Atmospheric Radiocarbon at the End of the Last Glacial: An Estimate Based on AMS Radiocarbon Dates on Terrestrial Macrofossils From Lake Sediments

Radiocarbon ◽  
1989 ◽  
Vol 31 (03) ◽  
pp. 795-804 ◽  
Author(s):  
Hugo Zbinden ◽  
Michael Andree ◽  
Hans Oeschger ◽  
Brigitta Ammann ◽  
Andre Lotter ◽  
...  
Keyword(s):  
Mass Spectroscopy ◽  
Calibration Curve ◽  
Hard Water ◽  
Sedimentation Rates ◽  
Local Effects ◽  
Data Set ◽  
Radiocarbon Dates ◽  
Pollen Zone ◽  
Plant Remains ◽  
The Last Glacial

The main purpose of this work is to reconstruct the atmospheric Δ 14C in the glacial-postglacial transition, 14,000 – 10,000 BP, a range not covered by the tree-ring calibration curve. We measured 14C/12C ratios on series of terrestrial macrofossils from sediments of two Swiss lakes. We selected exclusively plant remains of recognizable terrestrial origin that are not affected by hard water and thus reflect atmospheric 14C concentration. Due to the scarcity of such material, we used accelerator mass spectroscopy. Cores of two lakes were measured to eliminate local effects and to check the reproducibility of results. This required a reliable, 14C-independent correlation of the cores, obtained through local pollen zone boundaries 14C ages were obtained as a function of the depth in the cores. If sedimentation rates are known ages can be converted into Δ 14C values. We also attempted estimating sedimentation rates; calculations are based on the Swedish varve chronology. Results were combined to form an entire data set. The Δ 14C curve shows an increase with time during the Allerød and decreases during Preboreal and Bølling periods. Probabilities for these 14C variations are discussed.

Lake Sediments as Continental δ18O Records from the Glacial/Post-Glacial Transition

1984 ◽  
Vol 5 ◽  
pp. 149-152 ◽  
Author(s):  
U. Siegenthaler ◽  
U. Eicher ◽  
H. Oeschger ◽  
W. Dansgaard
Keyword(s):  
Lake Sediments ◽  
North Atlantic Ocean ◽  
Ice Cores ◽  
Late Glacial ◽  
Climatic Changes ◽  
Striking Similarity ◽  
Carbonate Sediments ◽  
Polar Ice ◽  
Pollen Zone ◽  
First Results

As in polar ice, 18O variations of precipitation are recorded in carbonate sediments formed in lakes (lake marl). We have analyzed many late-glacial profiles from Europe, There are strong l8O variations which coincide with well-known pollen zone boundaries and which indicate that abrupt, drastic climatic changes occurred in the late glacial period. These events are a major warming around 13 ka BP (pollen zone boundary Oldest Dryas/Bölling) and a marked cold phase between about 10.8 and 10 ka BP (Younger Dryas). Comparison of the δ18O records of European lake sediments and of Greenland ice cores reveal a striking similarity which indicates that climatic changes in the late glacial and early postglacial were parallel in Greenland and in Europe. First results from North American lake-sediment profiles do not exhibit similar δ18O variations. This pattern of climatic changes was probably caused by retreating and readvancing polar water in the high-latitude North Atlantic Ocean, as discussed by Ruddiman and McIntyre (1981).

Problems of inertia and threshold related to post-Glacial habitat changes

1965 ◽  
Vol 161 (984) ◽  
pp. 331-342 ◽  
Keyword(s):  
Late Quaternary ◽  
Great Distance ◽  
Radiocarbon Age ◽  
Habitat Changes ◽  
Pollen Zone ◽  
Relative Chronology ◽  
Pollen Diagrams ◽  
Circular Argument ◽  
History Of

Most of the major late-Quaternary vegetational changes deduced from the study of pollen diagrams have generally been supposed to have been brought about by climatic change. The assumption has also been made that widespread climatically controlled vegetational changes are likely to have been broadly synchronous (cf. for instance Godwin 1956, p. 57). Recently, however, it has become clear that differences of migration rate and the rates of pedogenesis should be given more attention; Faegri, in particular, has made this point very strongly with reference to the history of the Scandinavian flora (Faegri 1963). In addition, it is appropriate to note that Iversen (1960, p. 9) has questioned whether we can attach any climatic significance to the pollen zone transitions up to the beginning of the Atlantic period and whether they will prove to be synchronous over any great distance. Nevertheless, the assumption that the well-marked vegetational changes in a small area such as the British Isles are likely to have been synchronous has sufficed to allow the establishment of a useful relative chronology for archaeological and other purposes. While the radiocarbon age estimations so far obtained do not on the whole confute the assumptions, there are a number of exceptions (cf. Godwin 1960; Godwin & Willis 1959, 1962; McAulay & Watts 1961, etc.). For phytogeographical purposes, however, it is clearly to argue in a circle to use a chronology based on vegetational evidence; we must equally be on our guard against the circular argument in discussing the role of habitat changes in palaeoecology.

Late Wisconsinan glacitectonic structures and evidence of postglacial permafrost in north-central Newfoundland

1977 ◽  
Vol 14 (12) ◽  
pp. 2797-2806 ◽  
Author(s):  
N. Eyles
Keyword(s):  
High Rate ◽  
The West ◽  
North Central ◽  
Deformation Structures ◽  
Pollen Zone ◽  
Air Temperatures ◽  
Ground Collapse ◽  
Glacier Ice ◽  
Ice Wedge ◽  
Late Wisconsinan

Rhythmically-bedded glaciofluvial sediments deposited subaqueously and now exposed on an emerged coastal foreland in north-central Newfoundland, exhibit postdepositional deformation structures such as synclinal folds and faulted zones of ground collapse, the result of melting of underlying buried glacier ice. A high rate of glaciofluvial deposition is indicated. The development of fault systems in those sediments overlying decaying glacier ice can be compared with laboratory simulations of vertical foundering in sedimentary rocks. Ice-wedge casts transecting folded and faulted sections in the area are indisputable evidence of subsequent permafrost conditions, i.e. a period when mean annual air temperatures lay below −6 °C. A rise of at least 10.4 °C in mean annual air temperature is indicated since that time. A severe periglacial climate is considered to have existed in the area from 12 000 to 10 000 years BP and ice wedges developed with a minimum growth rate of 1.25 mm/year. Comparison with reports of ice-wedge casts in Nova Scotia and the west coast of Newfoundland indicate that the period which they formed in north-central Newfoundland may be correlated with the tundra pollen zone L-3 of Livingstone and Livingstone, the Greatlakian substage of the Lake Wisconsinan in Midcontinental North America.

Changes of Water Level in the Eemian Palaeolake at Imbramowice (SW Poland) Based on Isotopic and Cladoceran Data

2010 ◽  
Vol 73 (1) ◽  
pp. 143-150 ◽  
Author(s):  
Joanna Mirosław-Grabowska ◽  
Michał Gąsiorowski
Keyword(s):  
Water Level ◽  
Initial Phase ◽  
Trophic Status ◽  
Positive Trend ◽  
Phytoplankton Productivity ◽  
Lake Evolution ◽  
Pollen Zone ◽  
Sw Poland ◽  
Mis 5E ◽  
Isotope Analyses

Isotopic and cladoceran investigations of Eemian (MIS 5e) lake sediments from Imbramowice, SW Poland, allow us to reconstruct the environmental conditions, especially changes of water level and trophic status, during the early and middle Eemian Interglaciation. We analyzed the sediments from 6.5 to 11.0 m depth in a core provided by Mamakowa (1989). The upper 6.5 m had insufficient carbonates and cladoceran contents for analyses. The analyzed section consists of sandy and organic silts at the bottom, followed by gyttja characterized by increasing CaCO3 content. Measured δ18O values oscillate from ca. -9 to -4‰ and δ13C from -3.5 to above + 6‰. Based on stable isotope analyses of carbonates, we define and characterize eight isotopic horizons (Is). We identify 26 taxa of subfossil Cladocera and seven zones (CLZ) of faunal development. Probably the greatest depth of the lake occurred with pollen zone E2; shallowing then took place. During pollen zones E2-E3, gradual warming is observed and expressed through a positive trend in both δ18O and δ13C values. Pollen zone E4 is characterized by frequent changes of water level. During the Eemian Interglaciation, excluding the initial phase of lake evolution, the lake was meso-eutrophic and eutrophic with high phytoplankton productivity.

scholarly journals 14C Dating of Plant Macrofossils in Lake Sediment

Radiocarbon ◽  
1986 ◽  
Vol 28 (2A) ◽  
pp. 411-416 ◽  
Author(s):  
Michael Andree ◽  
Hans Oeschger ◽  
Ulrich Siegenthaler ◽  
Trudi Riesen ◽  
Markus Moell ◽  
...  
Keyword(s):  
Aquatic Plant ◽  
Hard Water ◽  
Late Glacial ◽  
Plant Macrofossils ◽  
Water Effect ◽  
Terrestrial Plants ◽  
14C Dating ◽  
Pollen Zone ◽  
Swiss Plateau ◽  
Terrestrial Material

Macrofossils of terrestrial plants have been picked from a sediment core taken in Lake Lobsigen, a small lake on the Western Swiss Plateau. The sediments were previously analyzed for pollen composition, plant and animal macrofossils, and stable isotopes. Plant macrofossils were selected near pollen zone boundaries in Late Glacial and early Postglacial sediment for 14C dating by AMS. In the same lake carbonate and gyttja (aquatic plant) samples were dated by decay counting. The dates on terrestrial material are generally younger than those on carbonate and gyttja, ie, material reflecting the 14C/C ratio of dissolved bicarbonate in lake water. This is probably due to a contribution of dissolved limestone carbonate and thus a somewhat reduced 14C/C ratio in the lake's water (hard water effect).

Excavations in Zone VII Peat at Storrs Moss, Lancashire, England, 1965–67

1971 ◽  
Vol 37 (1) ◽  
pp. 112-137 ◽  
Author(s):  
T. G. E. Powell ◽  
Frank Oldfield ◽  
J. X. W. P. Corcoran
Keyword(s):  
Lake Sediments ◽  
Wide Distribution ◽  
Anthropogenic Change ◽  
Raised Bog ◽  
The West ◽  
Group Vi ◽  
Archaeological Evidence ◽  
Pollen Zone ◽  
Analytical Studies ◽  
North Western

Within recent years pollen-analytical studies carried out in lake sediments and raised bog peats around the head of Morecambe Bay, Lancashire, have disclosed extensive evidence for anthropogenic change at the British Pollen Zone VIIa–VIIb (Atlantic–Sub-Boreal) boundary, including characteristic ‘Ulmus Decline’, and Landnam phenomena (summarized by Oldfield, 1963). The question immediately arose as to the archaeological identity of the prehistoric communities responsible. The beginnings of Neolithic settlement in north-western England were quite obscure, and have largely so remained. The principal archaeological evidence for any Neolithic penetration of the region derives from the accidental discovery, nearly a century ago, of a bog-site at Ehenside Tarn, close to the west Cumberland coast (Piggott, 1954, 295–9; Walker, 1966), and to the presence of numerous stone axes occurring as stray finds throughout the region. More recently, the discovery of ‘stone axe factories’ on the high screes of Great Langdale and Scafell, and the wide distribution of Group VI axes therefrom, have emphasized the potentialities for further investigation (Fell, 1966, and refs. therein).

Stratigraphy, Pollen Analysis, and Paleoclimatic Interpretation of Pulbeena Swamp, Northwestern Tasmania

1982 ◽  
Vol 18 (1) ◽  
pp. 108-126 ◽  
Author(s):  
E. A. Colhoun ◽  
G. van de Geer ◽  
W. G. Mook
Keyword(s):  
Pollen Analysis ◽  
Climatic Conditions ◽  
Major Phase ◽  
The Holocene ◽  
Last Glacial ◽  
Pollen Zone ◽  
Peat Deposits ◽  
Glacial Stage ◽  
The Last Glacial

AbstractSedimentary, palynologic, and 14C analysis of 480 cm of freshwater marl and swamp-peat deposits, formed under the influence of fluctuating artesian springs, provides a paleoenvironmental and paleoclimatic record of approximately 65,000 yr for northwestern Tasmania.The Holocene (Pollen Zone 1, 11,000-0 yr B.P.) climate was warm and moist, and forest vegetation was dominant throughout the area. During the later part of the last glacial stage (Pollen Zone 2, 35,000–11,000 yr B.P.) the climate was generally drier, and grassy open environments were widespread. The driest part of this period occurred between 25,000 to 11,000 yr B.P., when temperatures in western Tasmania were markedly reduced during the last major phase of glaciation. Prior to 35,000 yr B.P. (Pollen Zones 3–9) a long “interstadial complex” dating to the middle of the last glacial stage is recognized. During this period the climate was generally moist, and forest and scrub communities were more important than during the later part of the last glacial stage, except during Pollen Zone 5 when high Gramineae plus Compositae values suggest drier conditions. High Gramineae and Compositae values also occur in Pollen Zone 10 at the base of the diagram. They suggest that a phase of drier and cooler climatic conditions occurred during the early part of the last glacial stage.

On Post-Glacial Pelicans in Britain

1958 ◽  
Vol 95 (2) ◽  
pp. 153-160 ◽  
Author(s):  
C. L. Forbes ◽  
K. A. Joysey ◽  
R. G. West
Keyword(s):  
Iron Age ◽  
Fossil Record ◽  
East Anglia ◽  
North West ◽  
Pollen Zone

AbstractA bone found in the peat near King's Lynn, Norfolk, has been identified as belonging to a pelican. This is the fifth fossil record from East Anglia but it is the first to be accurately dated, and it can be correlated with Godwin's pollen zone VII–VIII (Iron Age). Other fossil pelican bones from East Anglia and Somerset are identified as those of the Dalmatian Pelican rather than the White Pelican which now visits parts of north-west Europe.

Stratigraphic Evidence of a Pre-Wisconsinan Interglaciation in the Adirondack Mountains, New York

1993 ◽  
Vol 40 (2) ◽  
pp. 163-168 ◽  
Author(s):  
Ernest H. Muller ◽  
Les Sirkin ◽  
Jesse L. Craft
Keyword(s):  
New York ◽  
Lake Sediments ◽  
Open Pit ◽  
Open Pit Mining ◽  
Adirondack Mountains ◽  
Warm Climate ◽  
Pollen Zone ◽  
Hardwood Species ◽  
Oak Pollen ◽  
Brown Clay

AbstractMultiple tills separated by interbedded lake sediments were temporarily exposed during open-pit mining at Sanford Hill, near Newcomb, in the central Adirondack Mountains of northeastern New York. Radiocarbon ages of wood fragments from brown clay between two tills at that site indicate an age older than 55,000 yr B.P. A pollen profile in the brown pond clay (Tahawus clay) records a transition from initial domination by pine, spruce, and birch to an oak pollen zone. The upward disappearance of spruce and decrease of pine and birch are accompanied by diversification and increase in hardwood pollen. This assemblage includes several warm-climate hardwood species that are not represented in the postglacial flora of the region, suggesting that the biota existed during an interglacial or interstadial interval that was warmer and/or longer than postglacial time. Accordingly, the Tahawus clay is tentatively assigned to the Sangamon interglaciation, and probably to marine oxygen isotope substage 5e. Truncation of the Tahawus clay by glacial erosion may account for the absence of a Sangamon paleosol.

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