scholarly journals Revisions and Extension of the Hohenheim Oak and Pine Chronologies: New Evidence About the Timing of the Younger Dryas/Preboreal Transition

Radiocarbon ◽  
1998 ◽  
Vol 40 (3) ◽  
pp. 1107-1116 ◽  
Author(s):  
Marco Spurk ◽  
Michael Friedrich ◽  
Jutta Hofmann ◽  
Sabine Remmele ◽  
Burkhard Frenzel ◽  
...  
Keyword(s):  
Calibration Curve ◽  
Younger Dryas ◽  
Ice Cores ◽  
Early Holocene ◽  
Proxy Data ◽  
The Past ◽  
Varve Chronology ◽  
New Evidence ◽  
Radiocarbon Calibration

Oak and pine samples housed at the Institute of Botany, University of Hohenheim, are the backbone of the early Holocene part of the radiocarbon calibration curve, published in 1993 (Becker 1993; Kromer and Becker 1993; Stuiver and Becker 1993; Vogel et al. 1993). Since then the chronologies have been revised. The revisions include 1) the discovery of 41 missing years in the oak chronology and 2) a shift of 54 yr for the oldest part back into the past. The oak chronology was also extended with new samples as far back as 10,429 BP (8480 BC). In addition, the formerly tentatively dated pine chronology (Becker 1993) has been rebuilt and shifted to an earlier date. It is now positioned by 14C matching at 11,871-9900 BP (9922–7951 BC) with an uncertainty of ±20 yr (Kromer and Spurk 1998). With these new chronologies the 14C calibration curve can now be corrected, eliminating the discrepancy in the dating of the Younger Dryas/Preboreal transition between the proxy data of the GRIP and GISP ice cores (Johnsen et al. 1992; Taylor et al. 1993), the varve chronology of Lake Gościąż (Goslar et al. 1995) and the pine chronology (Becker, Kromer and Trimborn 1991).

scholarly journals How dry was the Younger Dryas? Evidence from a coupled <i>δ</i><sup>2</sup>H–<i>δ</i><sup>18</sup>O biomarker paleohygrometer applied to the Gemündener Maar sediments, Western Eifel, Germany

2019 ◽  
Vol 15 (2) ◽  
pp. 713-733 ◽  
Author(s):  
Johannes Hepp ◽  
Lorenz Wüthrich ◽  
Tobias Bromm ◽  
Marcel Bliedtner ◽  
Imke Kathrin Schäfer ◽  
...  
Keyword(s):  
Isotope Composition ◽  
Younger Dryas ◽  
Late Glacial ◽  
Climatic Conditions ◽  
Leaf Water ◽  
Early Holocene ◽  
Unexpected Finding ◽  
Temperature Dependent ◽  
The Past ◽  
Natural Climate

Abstract. Causes of the Late Glacial to Early Holocene transition phase and particularly the Younger Dryas period, i.e. the major last cold spell in central Europe during the Late Glacial, are considered to be keys for understanding rapid natural climate change in the past. The sediments from maar lakes in the Eifel, Germany, have turned out to be valuable archives for recording such paleoenvironmental changes. For this study, we investigated a Late Glacial to Early Holocene sediment core that was retrieved from the Gemündener Maar in the Western Eifel, Germany. We analysed the hydrogen (δ2H) and oxygen (δ18O) stable isotope composition of leaf-wax-derived lipid biomarkers (n-alkanes C27 and C29) and a hemicellulose-derived sugar biomarker (arabinose), respectively. Both δ2Hn-alkane and δ18Osugar are suggested to reflect mainly leaf water of vegetation growing in the catchment of the Gemündener Maar. Leaf water reflects δ2H and δ18O of precipitation (primarily temperature-dependent) modified by evapotranspirative enrichment of leaf water due to transpiration. Based on the notion that the evapotranspirative enrichment depends primarily on relative humidity (RH), we apply a previously introduced “coupled δ2Hn-alkane–δ18Osugar paleohygrometer approach” to reconstruct the deuterium excess of leaf water and in turn Late Glacial–Early Holocene RH changes from our Gemündener Maar record. Our results do not provide evidence for overall markedly dry climatic conditions having prevailed during the Younger Dryas. Rather, a two-phasing of the Younger Dryas is supported, with moderate wet conditions at the Allerød level during the first half and drier conditions during the second half of the Younger Dryas. Moreover, our results suggest that the amplitude of RH changes during the Early Holocene was more pronounced than during the Younger Dryas. This included the occurrence of a “Preboreal Humid Phase”. One possible explanation for this unexpected finding could be that solar activity is a hitherto underestimated driver of central European RH changes in the past.

Revised ‘absolute’ dating of the early Mesolithic site of Star Carr, North Yorkshire, in the light of changes in the early Holocene tree-ring chronology

Antiquity ◽  
2000 ◽  
Vol 74 (284) ◽  
pp. 304-307 ◽  
Author(s):  
Petra Dark
Keyword(s):  
Environmental Change ◽  
Tree Ring ◽  
Calibration Curve ◽  
Early Holocene ◽  
Tree Ring Chronology ◽  
Absolute Dating ◽  
The Absolute ◽  
Holocene Environmental Change ◽  
Radiocarbon Calibration

Recent revision of the radiocarbon calibration curve for the early Holocene has implications for the ‘absolute’ date of Mesolithic sites such as Star Carr, and for their relationship to the timescale of early Holocene environmental change.

scholarly journals River of Change: a Model for the Development of Terraces Along the Bow River, Alberta

2004 ◽  
Vol 56 (2-3) ◽  
pp. 155-169 ◽  
Author(s):  
Gerald A. Oetelaar
Keyword(s):  
Late Pleistocene ◽  
Rocky Mountains ◽  
Sediment Load ◽  
Younger Dryas ◽  
Early Holocene ◽  
Stream Power ◽  
Independent Variables ◽  
The Past ◽  
Initial Episode ◽  
Alluvial Terraces

Abstract Researchers working in the Bow River valley have identified a minimum of four alluvial terraces, the upper two of which have been designated as paired terraces. Over the past 35 years, they have attempted to correlate these alluvial landforms and to generate models for the development of the terraces along the section of the Bow River between Calgary and the Rocky Mountains. In this study, Mazama ash and an early Holocene paleosol are used to correlate the terrace suites examined by previous researchers and to generate a model which accounts for the development of the upper two sets of paired terraces. These paired terraces reflect major episodes of aggradation and degradation that result from changes in independent variables such as climate and uplift. The initial episode of aggradation, dating from the late Pleistocene, is the result of paraglacial processes in a sparsely vegetated, yet saturated environment. Following a brief episode of degradation at the end of the Younger Dryas, the second episode of aggradation, dating from 9000 to 5000 BP, is caused by increased sediment load and lowered stream power during the Hypsithermal.

scholarly journals A paleoclimatic perspective on the 21st-century glacier loss on Kilimanjaro, Tanzania

2011 ◽  
Vol 52 (59) ◽  
pp. 60-68 ◽  
Author(s):  
Lonnie G. Thompson ◽  
Ellen Mosley-Thompson ◽  
Mary E. Davis ◽  
Keith Mountain
Keyword(s):  
Ice Core ◽  
Ice Cores ◽  
Temporal Perspective ◽  
The Past ◽  
Direct Measurements ◽  
Ice Retreat ◽  
Ice Field ◽  
Paleoclimate Records ◽  
New Evidence ◽  
Made In

AbstractAssessing the significance of current glacier loss on Kilimanjaro, Tanzania, demands a well-constrained temporal perspective. That context is provided by direct measurements, ancillary observations of the ice fields and the analyses of the ice cores collected from them. Ice retreat mechanisms observed there today are consistent with the preservation of the oldest ice, ~11.7 ka, in the central deepest part of the Northern Ice Field (NIF). This ice-core derived paleoclimate history published by Thompson and others (2002) is further confirmed by more recent paleoclimate records from tropical East Africa. Mounting evidence suggests that the (anticipated) loss of the entire NIF will be unprecedented within the past 10 000 years. New evidence bears directly on the mechanisms driving the current ice loss. Measurements made in 2000 on the NIF document that air temperature at 0.5 and 1.5 m above the surface remained below 5°C, while a surface temperature of 0.0°C was sustained for up to 8 hours d-1 under clear conditions, consistent with observations of melting on all Kilimanjaro summit ice fields. The linear relationship between oxygen and hydrogen isotopic ratios for all six ice cores drilled in 2000 lies very close to the global meteoric waterline and does not support sublimation (evaporation) as a major driver of ice loss today or in the past on Kilimanjaro.

scholarly journals Illuminating Intcal During the Younger Dryas

Radiocarbon ◽  
2020 ◽  
Vol 62 (4) ◽  
pp. 883-889 ◽  
Author(s):  
Frederick Reinig ◽  
Adam Sookdeo ◽  
Jan Esper ◽  
Michael Friedrich ◽  
Giulia Guidobaldi ◽  
...  
Keyword(s):  
Environmental Change ◽  
Calibration Curve ◽  
Younger Dryas ◽  
Late Glacial ◽  
Precision Data ◽  
The Past ◽  
Climate And Environmental Change ◽  
Absolute Dating ◽  
High Precision Data ◽  
Geochronological Dating

ABSTRACTAs the worldwide standard for radiocarbon (14C) dating over the past ca. 50,000 years, the International Calibration Curve (IntCal) is continuously improving towards higher resolution and replication. Tree-ring-based 14C measurements provide absolute dating throughout most of the Holocene, although high-precision data are limited for the Younger Dryas interval and farther back in time. Here, we describe the dendrochronological characteristics of 1448 new 14C dates, between ~11,950 and 13,160 cal BP, from 13 pines that were growing in Switzerland. Significantly enhancing the ongoing IntCal update (IntCal20), this Late Glacial (LG) compilation contains more annually precise 14C dates than any other contribution during any other period of time. Thus, our results now provide unique geochronological dating into the Younger Dryas, a pivotal period of climate and environmental change at the transition from LG into Early Holocene conditions.

scholarly journals Radiocarbon Calibration by Means of Varves Versus 14C Ages of Terrestrial Macrofossils from Lake Gościąż and Lake Perespilno, Poland

Radiocarbon ◽  
2000 ◽  
Vol 42 (3) ◽  
pp. 335-348 ◽  
Author(s):  
Tomasz Goslar ◽  
Maurice Arnold ◽  
Nadine Tisnerat-Laborde ◽  
Christine Hatté ◽  
Martine Paterne ◽  
...  
Keyword(s):  
Calibration Curve ◽  
Younger Dryas ◽  
Late Glacial ◽  
Cariaco Basin ◽  
Rapid Decline ◽  
Radiocarbon Dates ◽  
Radiocarbon Calibration

This paper presents radiocarbon dates of terrestrial macrofossils from Lakes Gościąż and Perespilno, Poland. These data agree very well with most of the German pine calibration curve. In the Late Glacial, they generally agree with the data from Lake Suigetsu, Japan, and indicate constant or even increasing 14C age between 12.9 and 12.7 ka BP, rapid decline of 14C age around 12.6 ka BP, and a long plateau 10,400 14C BP around 12 ka BP. Correlation with corals and data from the Cariaco basin seems to support the concept of site-speficic, constant values of reservoir correction, in contradiction to those introduced in the INTCAL98 calibration. Around the Allerød/Younger Dryas boundary our data strongly disagree with those from the Cariaco basin, which reflects large discrepancy between calendar chronologies at that period. The older sequence from Lake Perespilno indicates two periods of rapid decline in 14C age, around 14.2 and 13.9 ka BP.

scholarly journals SHCal13 Southern Hemisphere Calibration, 0–50,000 Years cal BP

Radiocarbon ◽  
2013 ◽  
Vol 55 (4) ◽  
pp. 1889-1903 ◽  
Author(s):  
Alan G Hogg ◽  
Quan Hua ◽  
Paul G Blackwell ◽  
Mu Niu ◽  
Caitlin E Buck ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Calibration Curve ◽  
Younger Dryas ◽  
Autoregressive Process ◽  
Measured Data ◽  
Data Sets ◽  
Short Term ◽  
Data Set ◽  
Radiocarbon Calibration

The Southern Hemisphere SHCal04 radiocarbon calibration curve has been updated with the addition of new data sets extending measurements to 2145 cal BP and including the ANSTO Younger Dryas Huon pine data set. Outside the range of measured data, the curve is based upon the ern Hemisphere data sets as presented in IntCal13, with an interhemispheric offset averaging 43 ± 23 yr modeled by an autoregressive process to represent the short-term correlations in the offset.

scholarly journals Extended dilation of the radiocarbon time scale between 40,000 and 48,000 y BP and the overlap between Neanderthals andHomo sapiens

2020 ◽  
Vol 117 (35) ◽  
pp. 21005-21007 ◽  
Author(s):  
Edouard Bard ◽  
Timothy J. Heaton ◽  
Sahra Talamo ◽  
Bernd Kromer ◽  
Ron W. Reimer ◽  
...  
Keyword(s):  
Calibration Curve ◽  
Time Scale ◽  
Homo Sapiens ◽  
Time Range ◽  
Scientific Communities ◽  
Geomagnetic Excursion ◽  
The Past ◽  
New Feature ◽  
The Relationship ◽  
Radiocarbon Calibration

The new radiocarbon calibration curve (IntCal20) allows us to calculate the gradient of the relationship between14C age and calendar age over the past 55 millennia before the present (55 ka BP). The new gradient curve exhibits a prolonged and prominent maximum between 48 and 40 ka BP during which the radiocarbon clock runs almost twice as fast as it should. This radiocarbon time dilation is due to the increase in the atmospheric14C/12C ratio caused by the14C production rise linked to the transition into the Laschamp geomagnetic excursion centered around 41 ka BP. The major maximum in the gradient from 48 to 40 ka BP is a new feature of the IntCal20 calibration curve, with far-reaching impacts for scientific communities, such as prehistory and paleoclimatology, relying on accurate ages in this time range. To illustrate, we consider the duration of the overlap between Neanderthals andHomo sapiensin Eurasia.

scholarly journals Testing the Fidelity of Methods Used in Proxy-Based Reconstructions of Past Climate

2005 ◽  
Vol 18 (20) ◽  
pp. 4097-4107 ◽  
Author(s):  
Michael E. Mann ◽  
Scott Rutherford ◽  
Eugene Wahl ◽  
Caspar Ammann
Keyword(s):  
Tree Rings ◽  
Climate Changes ◽  
Ice Cores ◽  
Data Networks ◽  
Proxy Data ◽  
Climate History ◽  
Past Climate ◽  
Climate Proxy ◽  
The Past ◽  
Statistical Approaches

Abstract Two widely used statistical approaches to reconstructing past climate histories from climate “proxy” data such as tree rings, corals, and ice cores are investigated using synthetic “pseudoproxy” data derived from a simulation of forced climate changes over the past 1200 yr. These experiments suggest that both statistical approaches should yield reliable reconstructions of the true climate history within estimated uncertainties, given estimates of the signal and noise attributes of actual proxy data networks.

Successive Oceanic and Solar Forcing Indicated by Younger Dryas and Early Holocene Climatic Oscillations in the Jura

1995 ◽  
Vol 43 (3) ◽  
pp. 279-285 ◽  
Author(s):  
Michel Magny
Keyword(s):  
Lake Level ◽  
Younger Dryas ◽  
Early Holocene ◽  
Solar Forcing ◽  
Proxy Data ◽  
Climatic Oscillations ◽  
Middle Latitudes ◽  
The Alps ◽  
Second Period ◽  
Recent Extension

AbstractThe recent extension of (1) the residual Δ14C curve back to 11,400 cal yr B.P. and (2) the lake-level reconstruction in the Jura back to ca. 13,500 cal yr B.P. offers the opportunity of testing by proxy data the relationships between climate, atmospheric 14C, the sun, and the ocean recently suggested from the atmospheric 14C record. The climatic significance of the Jura record is supported by correlations with climatic oscillations reconstructed in the Alps from glaciers and timberline movements. Correspondence between the 14C and paleoclimatic record from the Jura suggests a working hypothesis: two intervals within the Holocene can be distinguished in the middle latitudes of western and central Europe. An early Holocene period shows abrupt climatic oscillations linked to ocean forcing. Major colder climate phases developed between ca. 9000 and 8800, and between ca. 8000 and 7000 cal yr B.C. that coincide with higher Δ14C values. After 6000 cal yr B.C., a second period is characterized by smoother multicentury climatic oscillations linked to solar forcing.

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