Hans Oeschger
Biographic Data
| ID | 5597034 |
|---|---|
| NAME | Hans Oeschger |
| GIVEN NAMES | Hans |
| FAMILY NAME | Oeschger |
| SIGNATURE | OESCHGER H |
| VERIFIED | No |
| TOTAL WORKS | 18 |
| TOTAL CITATIONS | 66 |
| WORKS AS AUTHOR | 18 |
| WORKS AS EDITOR | 0 |
| FIRST PUBLICATION YEAR | 1980 |
| LATEST PUBLICATION YEAR | 1995 |
| H-INDEX | 5 |
Klimaforschung in der Tiefe der Jahre
Throughout the last few decades, scientists have generated a wealth of information from naturally occurring paleorecords of a wide spectrum of environmental and climate parameters which reflect evolution of Earth systems. A fundamental task of Global Change research is to disentangle human-induced climate change from the natural climatic variability of the past 200 years. A second fundamental task of Global Change research is to describe Earth sy…
The awareness of global climatic and environmental change
Present understanding suggests that a doubling of CO 2 emission will occur in about 50 years and will lead to global warming of 2–4°C. Data from the past supports this. The paper analyses the factors influencing climatic change and the challenges to humanity this presents
Past Global Changes (Pages)
“PAGES” is a Core Project of the International Geosphere-Biosphere Programme (IGBP). Through the organization of coordinated national and international scientific efforts, PAGES seeks to obtain and interpret a variety of paleoclimatic records and to provide the data essential for the validation of predictive climatic models. The PAGES Project is designed to increase our understanding of the natural physical processes which control the Earth's env…
Atmospheric Radiocarbon at the End of the Last Glacial
The main purpose of this work is to reconstruct the atmospheric Δ 14 C in the glacial-postglacial transition, 14,000 – 10,000 BP, a range not covered by the tree-ring calibration curve. We measured 14 C/ 12 C 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 14 C concentration. Due…
C in the Environment of Swiss Nuclear Installations
The results of a 10-year survey of 14 C content in tree leaves from the vicinity of Swiss nuclear installations are reported. The interpretation is based on the results from a reference station showing a systematic decrease from δ 14 C = +350 in 1977 to ca 4–190 in 1987. Excess activities of up to ca 100 are observed in the vicinity of nuclear power plants which are compatible with release rates and dilution calculations. A higher excess of up to…
Can the Greenland Climatic Jumps be Identified in Records from Ocean and Land?
Sharp jumps in climate punctuate the records from borings in the Greenland ice cap during the time interval 60,000 to about 20,000 yr ago. Rapid fluctuations are also seen in foraminifera records for cores from the northern Atlantic and in a pollen record from a core from a bog in the Vosges Mountains in France. In this paper we present a new radiocarbon chronology for northern Atlantic deep-sea core V23-81 which permits comparison with the radio…
Laser Resonance Ionization Mass Spectrometry for Krypton-81 Analysis
A new laser-based analytical technique is described for isotope selective noble gas atom counting. The method has been used to detect 81 Kr atoms in a groundwater sample
AMS Radiocarbon Dates on Foraminifera from Deep Sea Sediments
14 C ages were determined on samples of foraminifera separated from cores from three areas of the tropical Pacific (East Pacific Rise, Oontong Java Plateau, and South China Sea). Analyses were made on four planktonic species and on mixed benthics. The purpose of the multiple analysis on planktonic species is to assess the importance of artifacts resulting from the bioturbation-abundance change couple, from the bioturbation-partial dissolution cou…
C Dating of Plant Macrofossils in Lake Sediment
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 14 C dating by AMS. In the same lake carbonate and gyttja (aquatic plant) samples w…
Dating Polar Ice by 14 C Accelerator Mass Spectrometry
Results of 14 C/ 12 C ratio measurements on CO 2 extracted from air bubbles in polar ice are presented. The samples investigated originate from the Dye 3, South Greenland, deep ice core and span approximately the last 10,000 years. The results are calibrated with tree-ring records. The 14 C ages are compared with information obtained from seasonal variations of ice-core parameters and rheologic model calculation
Radioisotope Dating with the ETHZ-EN-Tandem Accelerator
During the last three years the ETH-EN-tandem accelerator facility has been adapted for the quantitative determination of the rare isotopes 14 C and 10 Be in mg samples. The goal of this project is to routinely achieve a 1% accuracy when measuring 14 C/ 12 C ratios with a minimum expenditure of human resources and beam time. The concept is similar to that proposed by Purser and Henley (1978). The early evolution of this dating facility was descri…
Temporal 10 Be Variations in Ice
10 Be (T 1/2 = 1.5·10 6 y) is mainly produced in the atmosphere by cosmic ray spallation reactions on nitrogen and oxygen. About 70 % of the production takes place in the stratosphere. 10 Be becomes attached to aerosols within a very short time. If 10 Be is produced in the stratosphere some latitudinal mixing occurs. Most of the 10 Be is transferred to the troposphere during spring and early summer when, mainly at median latitudes, large stratosp…
Use of 39 Ar and 14 C for Groundwater Dating
Cosmic-ray produced atmospheric 39 Ar activity (T 1/2 = 269 yr) has been determined at 0.11 ±0.012 dpm/lt argon. Ice samples from two profiles in Greenland bore holes showed conclusively that 39 Ar dating leads to correct ages. Corrections can be made for possible contamination of the samples with ambient air during field extraction and during laboratory processing by measuring 85 Kr in the same samples. The following isotopes: 14 C, 39 Ar, 85 Kr…
Low-Level Gas Proportional Counting in An Underground Laboratory
Results of measurements in an underground laboratory, 70m of water equivalent below surface, are given. Background values of proportional gas counters with volumes between 16cc and 1.5L are lower by a factor of 2—4.5 compared to the values in the previously used laboratory (7m w.e.). High counting gas pressures, up to 5 at CH 4 and up to 36 at P-10, enable the use of relatively small counters with correspondingly small background contributions fr…
Information on the CO 2 Cycle from Ice Core Studies
Information on the history of the atmospheric CO 2 content and the 13 C/ 12 and 14 C/C ratios is recorded in natural ice. Measurements on samples from very cold accumulation regions show that CO 2 is occluded not only in air bubbles, but also in the ice lattice. The two CO 2 components are of similar size. It is very difficult to measure CO 2 in the bubbles and CO 2 in the ice lattice separately. By melting the samples and extracting the evolving…
C and Other Parameters During the Younger Dryas Cold Phase
Pollen analysis as well as 18 O/ 16 O results on lake marl show that the Younger Dryas climatic period, between about 11,000 and 10,300 bp, was the last vigorous cold phase of the Würm Glacial. Detailed 14 C analyses from a peat bog near Wachseldorn (Switzerland) point to a 14 C anomaly in this period. Further indication of a 14 C anomaly is given by the observation that, during the Younger Dryas period, the sedimentation rates in several lakes a…
Low-Level Liquid Scintillation Counting in An Underground Laboratory
A commercial liquid scintillation counter (LSC) was tested for its ability of low level counting (LLC) in two underground laboratories (70m of water equivalent cover). Reduction of total background and background components compared to the normal counting laboratory (5m w.e. cover) up to a factor of 9 depending on the energy range and the shielding of counting cell and laboratory walls were obtained. First experiments with a large volume cell (50…
C Variations Caused by Changes in the Global Carbon Cycle
A box-diffusion model for the carbon cycle is used to estimate the magnitude of 14 C variations caused by changes of reservoir sizes and exchange fluxes in the global carbon system. The influence of changes in atmospheric CO 2 concentration, biomass, CO 2 exchange rate between atmosphere and ocean, and ocean mixing is considered. Steady-state 14 C concentrations as well as the transients are calculated. For changing biomass, atmospheric CO 2 leve…
C Variations Caused by Changes in the Global Carbon Cycle
A box-diffusion model for the carbon cycle is used to estimate the magnitude of 14 C variations caused by changes of reservoir sizes and exchange fluxes in the global carbon system. The influence of changes in atmospheric CO 2 concentration, biomass, CO 2 exchange rate between atmosphere and ocean, and ocean mixing is considered. Steady-state 14 C concentrations as well as the transients are calculated. For changing biomass, atmospheric CO 2 leve…
C Dating of Plant Macrofossils in Lake Sediment
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 14 C dating by AMS. In the same lake carbonate and gyttja (aquatic plant) samples w…
Atmospheric Radiocarbon at the End of the Last Glacial
The main purpose of this work is to reconstruct the atmospheric Δ 14 C in the glacial-postglacial transition, 14,000 – 10,000 BP, a range not covered by the tree-ring calibration curve. We measured 14 C/ 12 C 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 14 C concentration. Due…
Low-Level Gas Proportional Counting in An Underground Laboratory
Results of measurements in an underground laboratory, 70m of water equivalent below surface, are given. Background values of proportional gas counters with volumes between 16cc and 1.5L are lower by a factor of 2—4.5 compared to the values in the previously used laboratory (7m w.e.). High counting gas pressures, up to 5 at CH 4 and up to 36 at P-10, enable the use of relatively small counters with correspondingly small background contributions fr…
C in the Environment of Swiss Nuclear Installations
The results of a 10-year survey of 14 C content in tree leaves from the vicinity of Swiss nuclear installations are reported. The interpretation is based on the results from a reference station showing a systematic decrease from δ 14 C = +350 in 1977 to ca 4–190 in 1987. Excess activities of up to ca 100 are observed in the vicinity of nuclear power plants which are compatible with release rates and dilution calculations. A higher excess of up to…
AMS Radiocarbon Dates on Foraminifera from Deep Sea Sediments
14 C ages were determined on samples of foraminifera separated from cores from three areas of the tropical Pacific (East Pacific Rise, Oontong Java Plateau, and South China Sea). Analyses were made on four planktonic species and on mixed benthics. The purpose of the multiple analysis on planktonic species is to assess the importance of artifacts resulting from the bioturbation-abundance change couple, from the bioturbation-partial dissolution cou…
Temporal 10 Be Variations in Ice
10 Be (T 1/2 = 1.5·10 6 y) is mainly produced in the atmosphere by cosmic ray spallation reactions on nitrogen and oxygen. About 70 % of the production takes place in the stratosphere. 10 Be becomes attached to aerosols within a very short time. If 10 Be is produced in the stratosphere some latitudinal mixing occurs. Most of the 10 Be is transferred to the troposphere during spring and early summer when, mainly at median latitudes, large stratosp…
Information on the CO 2 Cycle from Ice Core Studies
Information on the history of the atmospheric CO 2 content and the 13 C/ 12 and 14 C/C ratios is recorded in natural ice. Measurements on samples from very cold accumulation regions show that CO 2 is occluded not only in air bubbles, but also in the ice lattice. The two CO 2 components are of similar size. It is very difficult to measure CO 2 in the bubbles and CO 2 in the ice lattice separately. By melting the samples and extracting the evolving…
Dating Polar Ice by 14 C Accelerator Mass Spectrometry
Results of 14 C/ 12 C ratio measurements on CO 2 extracted from air bubbles in polar ice are presented. The samples investigated originate from the Dye 3, South Greenland, deep ice core and span approximately the last 10,000 years. The results are calibrated with tree-ring records. The 14 C ages are compared with information obtained from seasonal variations of ice-core parameters and rheologic model calculation
C and Other Parameters During the Younger Dryas Cold Phase
Pollen analysis as well as 18 O/ 16 O results on lake marl show that the Younger Dryas climatic period, between about 11,000 and 10,300 bp, was the last vigorous cold phase of the Würm Glacial. Detailed 14 C analyses from a peat bog near Wachseldorn (Switzerland) point to a 14 C anomaly in this period. Further indication of a 14 C anomaly is given by the observation that, during the Younger Dryas period, the sedimentation rates in several lakes a…
Low-Level Liquid Scintillation Counting in An Underground Laboratory
A commercial liquid scintillation counter (LSC) was tested for its ability of low level counting (LLC) in two underground laboratories (70m of water equivalent cover). Reduction of total background and background components compared to the normal counting laboratory (5m w.e. cover) up to a factor of 9 depending on the energy range and the shielding of counting cell and laboratory walls were obtained. First experiments with a large volume cell (50…
Use of 39 Ar and 14 C for Groundwater Dating
Cosmic-ray produced atmospheric 39 Ar activity (T 1/2 = 269 yr) has been determined at 0.11 ±0.012 dpm/lt argon. Ice samples from two profiles in Greenland bore holes showed conclusively that 39 Ar dating leads to correct ages. Corrections can be made for possible contamination of the samples with ambient air during field extraction and during laboratory processing by measuring 85 Kr in the same samples. The following isotopes: 14 C, 39 Ar, 85 Kr…
Use of 39 Ar and 14 C for Groundwater Dating
Cosmic-ray produced atmospheric 39 Ar activity (T 1/2 = 269 yr) has been determined at 0.11 ±0.012 dpm/lt argon. Ice samples from two profiles in Greenland bore holes showed conclusively that 39 Ar dating leads to correct ages. Corrections can be made for possible contamination of the samples with ambient air during field extraction and during laboratory processing by measuring 85 Kr in the same samples. The following isotopes: 14 C, 39 Ar, 85 Kr…
Low-Level Gas Proportional Counting in An Underground Laboratory
Results of measurements in an underground laboratory, 70m of water equivalent below surface, are given. Background values of proportional gas counters with volumes between 16cc and 1.5L are lower by a factor of 2—4.5 compared to the values in the previously used laboratory (7m w.e.). High counting gas pressures, up to 5 at CH 4 and up to 36 at P-10, enable the use of relatively small counters with correspondingly small background contributions fr…
Information on the CO 2 Cycle from Ice Core Studies
Information on the history of the atmospheric CO 2 content and the 13 C/ 12 and 14 C/C ratios is recorded in natural ice. Measurements on samples from very cold accumulation regions show that CO 2 is occluded not only in air bubbles, but also in the ice lattice. The two CO 2 components are of similar size. It is very difficult to measure CO 2 in the bubbles and CO 2 in the ice lattice separately. By melting the samples and extracting the evolving…
C and Other Parameters During the Younger Dryas Cold Phase
Pollen analysis as well as 18 O/ 16 O results on lake marl show that the Younger Dryas climatic period, between about 11,000 and 10,300 bp, was the last vigorous cold phase of the Würm Glacial. Detailed 14 C analyses from a peat bog near Wachseldorn (Switzerland) point to a 14 C anomaly in this period. Further indication of a 14 C anomaly is given by the observation that, during the Younger Dryas period, the sedimentation rates in several lakes a…
Low-Level Liquid Scintillation Counting in An Underground Laboratory
A commercial liquid scintillation counter (LSC) was tested for its ability of low level counting (LLC) in two underground laboratories (70m of water equivalent cover). Reduction of total background and background components compared to the normal counting laboratory (5m w.e. cover) up to a factor of 9 depending on the energy range and the shielding of counting cell and laboratory walls were obtained. First experiments with a large volume cell (50…
C Variations Caused by Changes in the Global Carbon Cycle
A box-diffusion model for the carbon cycle is used to estimate the magnitude of 14 C variations caused by changes of reservoir sizes and exchange fluxes in the global carbon system. The influence of changes in atmospheric CO 2 concentration, biomass, CO 2 exchange rate between atmosphere and ocean, and ocean mixing is considered. Steady-state 14 C concentrations as well as the transients are calculated. For changing biomass, atmospheric CO 2 leve…
Radioisotope Dating with the ETHZ-EN-Tandem Accelerator
During the last three years the ETH-EN-tandem accelerator facility has been adapted for the quantitative determination of the rare isotopes 14 C and 10 Be in mg samples. The goal of this project is to routinely achieve a 1% accuracy when measuring 14 C/ 12 C ratios with a minimum expenditure of human resources and beam time. The concept is similar to that proposed by Purser and Henley (1978). The early evolution of this dating facility was descri…
Temporal 10 Be Variations in Ice
10 Be (T 1/2 = 1.5·10 6 y) is mainly produced in the atmosphere by cosmic ray spallation reactions on nitrogen and oxygen. About 70 % of the production takes place in the stratosphere. 10 Be becomes attached to aerosols within a very short time. If 10 Be is produced in the stratosphere some latitudinal mixing occurs. Most of the 10 Be is transferred to the troposphere during spring and early summer when, mainly at median latitudes, large stratosp…
Laser Resonance Ionization Mass Spectrometry for Krypton-81 Analysis
A new laser-based analytical technique is described for isotope selective noble gas atom counting. The method has been used to detect 81 Kr atoms in a groundwater sample
AMS Radiocarbon Dates on Foraminifera from Deep Sea Sediments
14 C ages were determined on samples of foraminifera separated from cores from three areas of the tropical Pacific (East Pacific Rise, Oontong Java Plateau, and South China Sea). Analyses were made on four planktonic species and on mixed benthics. The purpose of the multiple analysis on planktonic species is to assess the importance of artifacts resulting from the bioturbation-abundance change couple, from the bioturbation-partial dissolution cou…
C Dating of Plant Macrofossils in Lake Sediment
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 14 C dating by AMS. In the same lake carbonate and gyttja (aquatic plant) samples w…
Dating Polar Ice by 14 C Accelerator Mass Spectrometry
Results of 14 C/ 12 C ratio measurements on CO 2 extracted from air bubbles in polar ice are presented. The samples investigated originate from the Dye 3, South Greenland, deep ice core and span approximately the last 10,000 years. The results are calibrated with tree-ring records. The 14 C ages are compared with information obtained from seasonal variations of ice-core parameters and rheologic model calculation
Can the Greenland Climatic Jumps be Identified in Records from Ocean and Land?
Sharp jumps in climate punctuate the records from borings in the Greenland ice cap during the time interval 60,000 to about 20,000 yr ago. Rapid fluctuations are also seen in foraminifera records for cores from the northern Atlantic and in a pollen record from a core from a bog in the Vosges Mountains in France. In this paper we present a new radiocarbon chronology for northern Atlantic deep-sea core V23-81 which permits comparison with the radio…
Atmospheric Radiocarbon at the End of the Last Glacial
The main purpose of this work is to reconstruct the atmospheric Δ 14 C in the glacial-postglacial transition, 14,000 – 10,000 BP, a range not covered by the tree-ring calibration curve. We measured 14 C/ 12 C 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 14 C concentration. Due…
C in the Environment of Swiss Nuclear Installations
The results of a 10-year survey of 14 C content in tree leaves from the vicinity of Swiss nuclear installations are reported. The interpretation is based on the results from a reference station showing a systematic decrease from δ 14 C = +350 in 1977 to ca 4–190 in 1987. Excess activities of up to ca 100 are observed in the vicinity of nuclear power plants which are compatible with release rates and dilution calculations. A higher excess of up to…
Past Global Changes (Pages)
“PAGES” is a Core Project of the International Geosphere-Biosphere Programme (IGBP). Through the organization of coordinated national and international scientific efforts, PAGES seeks to obtain and interpret a variety of paleoclimatic records and to provide the data essential for the validation of predictive climatic models. The PAGES Project is designed to increase our understanding of the natural physical processes which control the Earth's env…
The awareness of global climatic and environmental change
Present understanding suggests that a doubling of CO 2 emission will occur in about 50 years and will lead to global warming of 2–4°C. Data from the past supports this. The paper analyses the factors influencing climatic change and the challenges to humanity this presents
Klimaforschung in der Tiefe der Jahre
Throughout the last few decades, scientists have generated a wealth of information from naturally occurring paleorecords of a wide spectrum of environmental and climate parameters which reflect evolution of Earth systems. A fundamental task of Global Change research is to disentangle human-induced climate change from the natural climatic variability of the past 200 years. A second fundamental task of Global Change research is to describe Earth sy…
Geology (15 works) · Geology and Paleoclimatology Research (12 works) · Radiocarbon dating (11 works) · Environmental Science (9 works) · Paleontology (9 works) · Physics (8 works) · Chemistry (7 works) · Climatology (7 works) · Geography (7 works) · Oceanography (7 works)