106 documents found in 270ms
# 1
Lauterbach, Stefan • Brauer, Achim • Andersen, Nils • Danielopol, Dan • Dulski, Peter • (et. al.)
Abstract: Investigation of the sedimentary record of pre-Alpine Lake Mondsee (Upper Austria) focused on the environmental reaction to rapid Lateglacial climatic changes. Results of this study reveal complex proxy responses that are variable in time and influenced by the long-term evolution of the lake and its catchment. A new field sampling approach facilitated continuous and precisely controlled parallel sampling at decadal to sub-annual resolution for m-XRF element scanning, carbon geochemistry, stable isotope measurements on ostracods, pollen analyses and large-scale thin sections for microfacies analysis. The Holocene chronology is established through microscopic varve counting and supported by accelerator mass spectrometric 14C dating of terrestrial plant macrofossils, whereas the Lateglacial age model is based on d18O wiggle matching with the Greenland NGRIP record, using the GICC05 chronology. Microfacies analysis enables the detection of subtle sedimentological changes, proving that depositional processes even in rather large lake systems are highly sensitive to climate forcing. Comparing periods of major warming at the onset of the Lateglacial and Holocene and of major cooling at the onset of the Younger Dryas reveals differences in proxy responses, reflecting threshold effects and ecosystem inertia. Temperature increase, vegetation recovery, decrease of detrital flux and intensification of biochemical calcite precipitation at the onset of the Holocene took place with only decadal leads and lags over a ca. 100 a period, whereas the spread of woodlands and the reduction of detrital flux lagged the warming at the onset of the Lateglacial Interstadial by ca. 500-750 a. Cooling at the onset of the Younger Dryas is reflected by the simultaneous reaction of d18O and vegetation, but sedimentological changes (reduction of endogenic calcite content, increase in detrital flux) were delayed by about 150-300 a. Three short-term Lateglacial cold intervals, corresponding to Greenland isotope substages GI-1d, GI-1c2 and GI-1b, also show complex proxy responses that vary in time.
# 2
KTB, WG Geophysics
Abstract: The magnetic susceptibility is measured by an inductive AC device (BARTINGTON). The sample is placed inside a coil which generates an alternating magnetic field. The applied frequency is 460 Hz (cuttings, 25.4 mm mini cores), 565 Hz (cores) or 1470 Hz (15 mm mini cores) respectively. A shift in the oscillator frequency is a measure for the magnetic susceptibility of the sample. The applied magnetic field strength is 80 A/m (RMS) and appr. 2 times the total earth magnetic field strength in the KTB area (=38 A/m). The measurement field is lower than the field which is necessary for magnetic saturation and allows therefore to measure the initial susceptibility. The used sensors are insensitive to the electrical conductivity of the samples. Except the determination of the temperature dependent susceptibility, all measurements are done under surface conditions (room temperature and atmospheric pressure).
# 3
KTB, WG Geophysics
Abstract: The magnetic susceptibility is measured by an inductive AC device (BARTINGTON). The sample is placed inside a coil which generates an alternating magnetic field. The applied frequency is 460 Hz (cuttings, 25.4 mm mini cores), 565 Hz (cores) or 1470 Hz (15 mm mini cores) respectively. A shift in the oscillator frequency is a measure for the magnetic susceptibility of the sample. The applied magnetic field strength is 80 A/m (RMS) and appr. 2 times the total earth magnetic field strength in the KTB area (=38 A/m). The measurement field is lower than the field which is necessary for magnetic saturation and allows therefore to measure the initial susceptibility. The used sensors are insensitive to the electrical conductivity of the samples. Except the determination of the temperature dependent susceptibility, all measurements are done under surface conditions (room temperature and atmospheric pressure).
# 4
KTB, WG Geophysics
Abstract: The magnetic susceptibility is measured by an inductive AC device (BARTINGTON). The sample is placed inside a coil which generates an alternating magnetic field. The applied frequency is 460 Hz (cuttings, 25.4 mm mini cores), 565 Hz (cores) or 1470 Hz (15 mm mini cores) respectively. A shift in the oscillator frequency is a measure for the magnetic susceptibility of the sample. The applied magnetic field strength is 80 A/m (RMS) and appr. 2 times the total earth magnetic field strength in the KTB area (=38 A/m). The measurement field is lower than the field which is necessary for magnetic saturation and allows therefore to measure the initial susceptibility. The used sensors are insensitive to the electrical conductivity of the samples. Except the determination of the temperature dependent susceptibility, all measurements are done under surface conditions (room temperature and atmospheric pressure).
# 5
KTB, WG Geophysics
Abstract: The magnetic susceptibility is measured by an inductive AC device (BARTINGTON). The sample is placed inside a coil which generates an alternating magnetic field. The applied frequency is 460 Hz (cuttings, 25.4 mm mini cores), 565 Hz (cores) or 1470 Hz (15 mm mini cores) respectively. A shift in the oscillator frequency is a measure for the magnetic susceptibility of the sample. The applied magnetic field strength is 80 A/m (RMS) and appr. 2 times the total earth magnetic field strength in the KTB area (=38 A/m). The measurement field is lower than the field which is necessary for magnetic saturation and allows therefore to measure the initial susceptibility. The used sensors are insensitive to the electrical conductivity of the samples. Except the determination of the temperature dependent susceptibility, all measurements are done under surface conditions (room temperature and atmospheric pressure).
# 6
KTB, WG Geophysics
Abstract: The magnetic susceptibility is measured by an inductive AC device (BARTINGTON). The sample is placed inside a coil which generates an alternating magnetic field. The applied frequency is 460 Hz (cuttings, 25.4 mm mini cores), 565 Hz (cores) or 1470 Hz (15 mm mini cores) respectively. A shift in the oscillator frequency is a measure for the magnetic susceptibility of the sample. The applied magnetic field strength is 80 A/m (RMS) and appr. 2 times the total earth magnetic field strength in the KTB area (=38 A/m). The measurement field is lower than the field which is necessary for magnetic saturation and allows therefore to measure the initial susceptibility. The used sensors are insensitive to the electrical conductivity of the samples. Except the determination of the temperature dependent susceptibility, all measurements are done under surface conditions (room temperature and atmospheric pressure).
# 7
KTB, WG Geophysics
Abstract: The magnetic susceptibility is measured by an inductive AC device (BARTINGTON). The sample is placed inside a coil which generates an alternating magnetic field. The applied frequency is 460 Hz (cuttings, 25.4 mm mini cores), 565 Hz (cores) or 1470 Hz (15 mm mini cores) respectively. A shift in the oscillator frequency is a measure for the magnetic susceptibility of the sample. The applied magnetic field strength is 80 A/m (RMS) and appr. 2 times the total earth magnetic field strength in the KTB area (=38 A/m). The measurement field is lower than the field which is necessary for magnetic saturation and allows therefore to measure the initial susceptibility. The used sensors are insensitive to the electrical conductivity of the samples. Except the determination of the temperature dependent susceptibility, all measurements are done under surface conditions (room temperature and atmospheric pressure).
# 8
KTB, WG Geophysics
Abstract: The magnetic susceptibility is measured by an inductive AC device (BARTINGTON). The sample is placed inside a coil which generates an alternating magnetic field. The applied frequency is 460 Hz (cuttings, 25.4 mm mini cores), 565 Hz (cores) or 1470 Hz (15 mm mini cores) respectively. A shift in the oscillator frequency is a measure for the magnetic susceptibility of the sample. The applied magnetic field strength is 80 A/m (RMS) and appr. 2 times the total earth magnetic field strength in the KTB area (=38 A/m). The measurement field is lower than the field which is necessary for magnetic saturation and allows therefore to measure the initial susceptibility. The used sensors are insensitive to the electrical conductivity of the samples. Except the determination of the temperature dependent susceptibility, all measurements are done under surface conditions (room temperature and atmospheric pressure).
# 9
KTB, WG Geophysics
Abstract: The magnetic susceptibility is measured by an inductive AC device (BARTINGTON). The sample is placed inside a coil which generates an alternating magnetic field. The applied frequency is 460 Hz (cuttings, 25.4 mm mini cores), 565 Hz (cores) or 1470 Hz (15 mm mini cores) respectively. A shift in the oscillator frequency is a measure for the magnetic susceptibility of the sample. The applied magnetic field strength is 80 A/m (RMS) and appr. 2 times the total earth magnetic field strength in the KTB area (=38 A/m). The measurement field is lower than the field which is necessary for magnetic saturation and allows therefore to measure the initial susceptibility. The used sensors are insensitive to the electrical conductivity of the samples. Except the determination of the temperature dependent susceptibility, all measurements are done under surface conditions (room temperature and atmospheric pressure).
# 10
KTB, WG Geophysics
Abstract: The magnetic susceptibility is measured by an inductive AC device (BARTINGTON). The sample is placed inside a coil which generates an alternating magnetic field. The applied frequency is 460 Hz (cuttings, 25.4 mm mini cores), 565 Hz (cores) or 1470 Hz (15 mm mini cores) respectively. A shift in the oscillator frequency is a measure for the magnetic susceptibility of the sample. The applied magnetic field strength is 80 A/m (RMS) and appr. 2 times the total earth magnetic field strength in the KTB area (=38 A/m). The measurement field is lower than the field which is necessary for magnetic saturation and allows therefore to measure the initial susceptibility. The used sensors are insensitive to the electrical conductivity of the samples. Except the determination of the temperature dependent susceptibility, all measurements are done under surface conditions (room temperature and atmospheric pressure).
spinning wheel Loading next page