Mebus A Geyh
Datos Biográficos
| ID | 5597742 |
|---|---|
| NOMBRE | Mebus A Geyh |
| NOMBRES | Mebus A |
| APELLIDO | Geyh |
| FIRMA | GEYH M A |
| AFILIACIONES | LIAG Institute for Applied Geophysics |
| VERIFICADO | No |
| TOTAL DE OBRAS | 23 |
| TOTAL DE CITAS | 104 |
| TOTAL COMO AUTOR | 23 |
| TOTAL COMO EDITOR | 0 |
| PRIMER AÑO DE PUBLICACIÓN | 1964 |
| AÑO MÁS RECIENTE DE PUBLICACIÓN | 2014 |
| ÍNDICE H | 6 |
Several distinct wet periods since 420 ka in the Namib Desert inferred from U-series dates of speleothems
The scarcity of numerical dates of the arid areas in southern Africa is a challenge for reconstructing paleoclimate. This paper presents a chronological reconstruction in the central part of the Namib Desert, Namibia, for the last 420,000 yr. It is based on 230 Th/U dates (TIMS) from a large stalagmite and a thick flowstone layer in a small cave located in the hyper-arid central Namib Desert. The results provide for the first time evidence of thr…
Th/U Dating of Frozen Peat, Bol'shoy Lyakhovsky Island (Northern Siberia)
The chronology of Quaternary paleoenvironment and climate in northeastern Siberia is poorly understood due to a lack of reliable numerical age determinations. The best climatic archives are ice-rich permafrost sequences, which are widely distributed in northeastern Siberia. For this study, 230 Th/U-ages were determined by thermal ionization mass spectrometry (TIMS) from frozen peat in a permafrost deposit at the southern cliff of the Bol'shoy Lya…
Early to Mid-Holocene Aridity in Central Chile and the Southern Westerlies
Central Chile (32–35°S) lies at the northern border of strong Westerly influence and thus exhibits a steep precipitation gradient. Therefore, the palaeoclimatic archives in the region are suitable for detecting past moisture changes. The study of Laguna Aculeo (33°50'S, 70°54'W) presents a multiproxy Holocene lake record including sedimentology, geochemistry, mineralogy, pollen, diatoms, and radiocarbon dating (17 dates). Results indicate an arid…
Bomb Radiocarbon Dating of Animal Tissues and Hair
Initially, radiocarbon dating by bomb 14 C was used to check vintages of wine and whisky and to estimate the turnover times of carbon in various biological tissues. However, this technique has never been widely used for routine dating, although it has a wide field of application in geriatric medicine and forensic investigations. Fifteen years' experience in this field has shown the potential and limits of this technique. Taking into account the d…
Interglacial Growth of Tufa in Croatia
Tufa samples from the Krka River area in Croatia were dated by 14 C and 230 Th/ 234 U methods. The study area is situated in the karst region of the southern Dinarides. 14 C ages of 40 tufa samples collected at the waterfalls coincide with the early Holocene interglaciation, up to 6000 14 C yr B.P. Comparison of conventional 14 C dates of Holocene tufa and those of speleothems in the Dinaric Karst shows that speleothem formation started several t…
An Overview of 14 C Analysis in the Study of Groundwater
This paper provides a summary overview of the current state-of-art in the radiocarbon dating of groundwater. While the use of natural 14 C measurements in applied hydrogeology still presents a difficult challenge, meaningful dates can be achieved if they are determined and interpreted in conjunction with the analyses of other isotopic species that occur in the natural environment. Although 14 C dating of groundwater can be, and often is, carried …
Radiocarbon Reservoir Effect and the Timing of the Late-Glacial/Early Holocene Humid Phase in the Atacama Desert (Northern Chile)
We revise substantially the regional chronology of lake-level fluctuations from the late-glacial/early Holocene humid phase along a high altitude transect (3500 to 4500 m) between 18°S and 28°S in the Southwestern Altiplano of Northern Chile. Radiocarbon dates and 210 Pb profiles for limnic and terrestrial materials allow us to estimate and justify reservoir correction values for conventional 14 C dates. Our chronology suggests that the latest Pl…
A late-Holocene (<2600 BP) glacial advance in the south-central Andes (29°S), northern Chile
Radiocarbon dates and relative ages of soils on moraines provide evidence of a substantial late-Holocene (<2600 BP) readvance of glaciers in the western part of the arid Andes at 29°S. The glacier in the Encierro valley, northern Chile, reached about 60% of its late-Pleistocene extent. The equilibrium line altitude ELA during this advance remained between 4250 and 4500 m which is above the modern 0°C isotherm of the free atmosphere during summer.…
Mid- and late-Holocene limnogeology of Laguna del Negro Francisco, northern Chile, and its palaeoclimatic implications
Lacustrine sediments from the high elevation, endorheic, saline lake Negro Francisco (27°28'S/69°14'W, 4125 m) provide a detailed mid- and late-Holocene environmental history of the Southern Chilean Altiplano. Mineralogy, chemical composition and sedimentary facies analyses of the deposits confirm the regional significance of mid-Holocene aridity between 6000 and 3800 BP. Precipitation rates were signifi cantly lower than the c. 250 mm yr -1 of t…
Calibration of the 14 C Time Scale Beyond 22,000 BP
The conventional 14 C time scale between 11,500 and 22,000 sidereal years has been calibrated by TIMS U/Th dates for corals. Only a few studies have been made for the time beyond this range. Obtaining samples suitable for numerical dating or estimating the reservoir correction of the 14 C dates has been difficult, but we do not have these problems with TIMS U/Th dating of interstadial and interglacial lignite, because reservoir corrections are un…
Radiometric Dating of Young and Old Calcrete
To obtain a better understanding of the relationship between calcrete genesis and the results of different absolute dating methods, thermoluminescence (TL), radiocarbon ( 14 C) and uranium/thorium (U/Th) were applied to coeval sample; take from a very young calcrete profile in Namibia. The methodically different ages reflect the characteristics of the applied dating methods, the genetics of calcrete and different events of calcrete genesis. The c…
Temporal Changes of the 14 C Reservoir Effect in Lakes
Conventional radiocarbon dates for sediment samples from aquatic systems and of coeval terrestrial samples deviate from each other due to the reservoir effect. The reservoir correction is usually assumed to be constant with time for a specific aquatic system. Our studies confirm that seasonal and secular changes are frequent and are governed by the limnological conditions. Lakes have two principal sources of 14 C: atmospheric CO 2 and the total d…
Holocene environmental changes in the Atacama Altiplano and paleoclimatic implications
Strengthened summer monsoon brought tropical/continental moisture as far south as 25oS during late-glacial and early Holocene times. Precipitation rates in the Altiplano of the western Andes (24oS) increased to 500 mm yr-1 compared to <200 mm yr-1 today. There is evidence of dramatically decreasing lake levels between 8 400 and about 3 000 yr B.P., and conditions drier than today were established. This arid period was interrupted by low-frequency…
Climate Change and Natural Resource Dynamics of the Atacama Altiplano during the Last 18,000 Years
C dating of loess
Radiocarbon Dating Problems Using Acetylene as Counting Gas
An investigation of inconsistent Hannover results in the International Collaborative Study (ICS) led to the conclusion that the main reason was contamination of the acetylene used as counting gas with recent and/or fossil carbon by the lithium used for its preparation. Despite the high level of purity of the lithium guaranteed by the producer and storage under argon in cans, different charges were partly covered with contemporary lithium carbonat…
A Low-Cost Miniature Counter System for Radiocarbon Dating
Despite the great potential of the AMS technique for 14 C dating of milligram samples, the use of multiple miniature counter systems is still promising. Investment costs are relatively low and long-term financing of age determinations can be held within bounds. We have developed a 14 C dating system containing 10 miniature counters for $30,000, whereas commercial systems usually cost more than $ 150,000. Counting is not quite as good as that of t…
Multiple Dating of a Long Flowstone Profile
Dense speleothem samples are considered as closed systems and are, therefore, possibilities for any dating method. Four dating methods ( 14 C, U/Th, paleomagnetism, and electron spin resonance = ESR) were used for samples up to 1,000,000 yr old and taken along a vertical flowstone profile in the Heggen cave in West Germany. Also δ 18 O and δ 13 C analyses were carried out. The reliability of the results of each method is dependent on the diagenet…
The Unreliability of 14 C Dates Obtained from Buried Sandy Podzols
A test for the reliability of 14 C dating of soil was made at two sites with buried, autochthonous, and in parts, allochthonous sandy podzols, dated either litho- and pedostratigraphically or palynologically. The differences between the age ranges obtained and the apparent mean residence times (AMRT) calculated from the 14 C content of alkaline extracts from fossil soil layers and horizons lean in organic matter exceed 10,000 years, corresponding…
Research Notes and Application Reports Histogram Evaluation of 14 C Dates Applied to the First Complete Iron Age Sequence From West Central Africa
Holocene Sea-Level History
The limits of the statistical evaluation of 14 C dates by histograms are discussed. The method of the attempt to establish a global chronology of the short-term eustatic sea-level changes during the Holocene is examined as well as its correlation with the precisely determined Suess wiggles
Hannover Radiocarbon Measurements V
This date list contains a selection of C 14 dates of geological samples obtained from March 1963 until July 1966. The preceding date lists (Hannover I, III, IV) give a description of preparation and measuring methods
Hannover Radiocarbon Measurements III
The following list covers the measurements in our institute from January 1962 to March 1963. Sample preparation and conversion into acetylene are described by Wendt, Schneekloth and Budde (1962). An Oeschger counter with an effective volume of 1.5 L came into operation in 1962. It is shielded by 4 cm of iron and 10 cm of lead. The background amounts to 2.24 cpm, the standard C 14 counting-rate 17.05 cpm. In routine measurements, the impure acetyl…
Bomb Radiocarbon Dating of Animal Tissues and Hair
Initially, radiocarbon dating by bomb 14 C was used to check vintages of wine and whisky and to estimate the turnover times of carbon in various biological tissues. However, this technique has never been widely used for routine dating, although it has a wide field of application in geriatric medicine and forensic investigations. Fifteen years' experience in this field has shown the potential and limits of this technique. Taking into account the d…
Temporal Changes of the 14 C Reservoir Effect in Lakes
Conventional radiocarbon dates for sediment samples from aquatic systems and of coeval terrestrial samples deviate from each other due to the reservoir effect. The reservoir correction is usually assumed to be constant with time for a specific aquatic system. Our studies confirm that seasonal and secular changes are frequent and are governed by the limnological conditions. Lakes have two principal sources of 14 C: atmospheric CO 2 and the total d…
An Overview of 14 C Analysis in the Study of Groundwater
This paper provides a summary overview of the current state-of-art in the radiocarbon dating of groundwater. While the use of natural 14 C measurements in applied hydrogeology still presents a difficult challenge, meaningful dates can be achieved if they are determined and interpreted in conjunction with the analyses of other isotopic species that occur in the natural environment. Although 14 C dating of groundwater can be, and often is, carried …
Holocene Sea-Level History
The limits of the statistical evaluation of 14 C dates by histograms are discussed. The method of the attempt to establish a global chronology of the short-term eustatic sea-level changes during the Holocene is examined as well as its correlation with the precisely determined Suess wiggles
Mid- and late-Holocene limnogeology of Laguna del Negro Francisco, northern Chile, and its palaeoclimatic implications
Lacustrine sediments from the high elevation, endorheic, saline lake Negro Francisco (27°28'S/69°14'W, 4125 m) provide a detailed mid- and late-Holocene environmental history of the Southern Chilean Altiplano. Mineralogy, chemical composition and sedimentary facies analyses of the deposits confirm the regional significance of mid-Holocene aridity between 6000 and 3800 BP. Precipitation rates were signifi cantly lower than the c. 250 mm yr -1 of t…
Multiple Dating of a Long Flowstone Profile
Dense speleothem samples are considered as closed systems and are, therefore, possibilities for any dating method. Four dating methods ( 14 C, U/Th, paleomagnetism, and electron spin resonance = ESR) were used for samples up to 1,000,000 yr old and taken along a vertical flowstone profile in the Heggen cave in West Germany. Also δ 18 O and δ 13 C analyses were carried out. The reliability of the results of each method is dependent on the diagenet…
The Unreliability of 14 C Dates Obtained from Buried Sandy Podzols
A test for the reliability of 14 C dating of soil was made at two sites with buried, autochthonous, and in parts, allochthonous sandy podzols, dated either litho- and pedostratigraphically or palynologically. The differences between the age ranges obtained and the apparent mean residence times (AMRT) calculated from the 14 C content of alkaline extracts from fossil soil layers and horizons lean in organic matter exceed 10,000 years, corresponding…
Research Notes and Application Reports Histogram Evaluation of 14 C Dates Applied to the First Complete Iron Age Sequence From West Central Africa
A Low-Cost Miniature Counter System for Radiocarbon Dating
Despite the great potential of the AMS technique for 14 C dating of milligram samples, the use of multiple miniature counter systems is still promising. Investment costs are relatively low and long-term financing of age determinations can be held within bounds. We have developed a 14 C dating system containing 10 miniature counters for $30,000, whereas commercial systems usually cost more than $ 150,000. Counting is not quite as good as that of t…
Calibration of the 14 C Time Scale Beyond 22,000 BP
The conventional 14 C time scale between 11,500 and 22,000 sidereal years has been calibrated by TIMS U/Th dates for corals. Only a few studies have been made for the time beyond this range. Obtaining samples suitable for numerical dating or estimating the reservoir correction of the 14 C dates has been difficult, but we do not have these problems with TIMS U/Th dating of interstadial and interglacial lignite, because reservoir corrections are un…
Radiocarbon Dating Problems Using Acetylene as Counting Gas
An investigation of inconsistent Hannover results in the International Collaborative Study (ICS) led to the conclusion that the main reason was contamination of the acetylene used as counting gas with recent and/or fossil carbon by the lithium used for its preparation. Despite the high level of purity of the lithium guaranteed by the producer and storage under argon in cans, different charges were partly covered with contemporary lithium carbonat…
Radiometric Dating of Young and Old Calcrete
To obtain a better understanding of the relationship between calcrete genesis and the results of different absolute dating methods, thermoluminescence (TL), radiocarbon ( 14 C) and uranium/thorium (U/Th) were applied to coeval sample; take from a very young calcrete profile in Namibia. The methodically different ages reflect the characteristics of the applied dating methods, the genetics of calcrete and different events of calcrete genesis. The c…
Hannover Radiocarbon Measurements III
The following list covers the measurements in our institute from January 1962 to March 1963. Sample preparation and conversion into acetylene are described by Wendt, Schneekloth and Budde (1962). An Oeschger counter with an effective volume of 1.5 L came into operation in 1962. It is shielded by 4 cm of iron and 10 cm of lead. The background amounts to 2.24 cpm, the standard C 14 counting-rate 17.05 cpm. In routine measurements, the impure acetyl…
Hannover Radiocarbon Measurements III
The following list covers the measurements in our institute from January 1962 to March 1963. Sample preparation and conversion into acetylene are described by Wendt, Schneekloth and Budde (1962). An Oeschger counter with an effective volume of 1.5 L came into operation in 1962. It is shielded by 4 cm of iron and 10 cm of lead. The background amounts to 2.24 cpm, the standard C 14 counting-rate 17.05 cpm. In routine measurements, the impure acetyl…
Hannover Radiocarbon Measurements V
This date list contains a selection of C 14 dates of geological samples obtained from March 1963 until July 1966. The preceding date lists (Hannover I, III, IV) give a description of preparation and measuring methods
Holocene Sea-Level History
The limits of the statistical evaluation of 14 C dates by histograms are discussed. The method of the attempt to establish a global chronology of the short-term eustatic sea-level changes during the Holocene is examined as well as its correlation with the precisely determined Suess wiggles
Research Notes and Application Reports Histogram Evaluation of 14 C Dates Applied to the First Complete Iron Age Sequence From West Central Africa
The Unreliability of 14 C Dates Obtained from Buried Sandy Podzols
A test for the reliability of 14 C dating of soil was made at two sites with buried, autochthonous, and in parts, allochthonous sandy podzols, dated either litho- and pedostratigraphically or palynologically. The differences between the age ranges obtained and the apparent mean residence times (AMRT) calculated from the 14 C content of alkaline extracts from fossil soil layers and horizons lean in organic matter exceed 10,000 years, corresponding…
A Low-Cost Miniature Counter System for Radiocarbon Dating
Despite the great potential of the AMS technique for 14 C dating of milligram samples, the use of multiple miniature counter systems is still promising. Investment costs are relatively low and long-term financing of age determinations can be held within bounds. We have developed a 14 C dating system containing 10 miniature counters for $30,000, whereas commercial systems usually cost more than $ 150,000. Counting is not quite as good as that of t…
Multiple Dating of a Long Flowstone Profile
Dense speleothem samples are considered as closed systems and are, therefore, possibilities for any dating method. Four dating methods ( 14 C, U/Th, paleomagnetism, and electron spin resonance = ESR) were used for samples up to 1,000,000 yr old and taken along a vertical flowstone profile in the Heggen cave in West Germany. Also δ 18 O and δ 13 C analyses were carried out. The reliability of the results of each method is dependent on the diagenet…
C dating of loess
Radiocarbon Dating Problems Using Acetylene as Counting Gas
An investigation of inconsistent Hannover results in the International Collaborative Study (ICS) led to the conclusion that the main reason was contamination of the acetylene used as counting gas with recent and/or fossil carbon by the lithium used for its preparation. Despite the high level of purity of the lithium guaranteed by the producer and storage under argon in cans, different charges were partly covered with contemporary lithium carbonat…
Climate Change and Natural Resource Dynamics of the Atacama Altiplano during the Last 18,000 Years
Holocene environmental changes in the Atacama Altiplano and paleoclimatic implications
Strengthened summer monsoon brought tropical/continental moisture as far south as 25oS during late-glacial and early Holocene times. Precipitation rates in the Altiplano of the western Andes (24oS) increased to 500 mm yr-1 compared to <200 mm yr-1 today. There is evidence of dramatically decreasing lake levels between 8 400 and about 3 000 yr B.P., and conditions drier than today were established. This arid period was interrupted by low-frequency…
Mid- and late-Holocene limnogeology of Laguna del Negro Francisco, northern Chile, and its palaeoclimatic implications
Lacustrine sediments from the high elevation, endorheic, saline lake Negro Francisco (27°28'S/69°14'W, 4125 m) provide a detailed mid- and late-Holocene environmental history of the Southern Chilean Altiplano. Mineralogy, chemical composition and sedimentary facies analyses of the deposits confirm the regional significance of mid-Holocene aridity between 6000 and 3800 BP. Precipitation rates were signifi cantly lower than the c. 250 mm yr -1 of t…
Calibration of the 14 C Time Scale Beyond 22,000 BP
The conventional 14 C time scale between 11,500 and 22,000 sidereal years has been calibrated by TIMS U/Th dates for corals. Only a few studies have been made for the time beyond this range. Obtaining samples suitable for numerical dating or estimating the reservoir correction of the 14 C dates has been difficult, but we do not have these problems with TIMS U/Th dating of interstadial and interglacial lignite, because reservoir corrections are un…
Radiometric Dating of Young and Old Calcrete
To obtain a better understanding of the relationship between calcrete genesis and the results of different absolute dating methods, thermoluminescence (TL), radiocarbon ( 14 C) and uranium/thorium (U/Th) were applied to coeval sample; take from a very young calcrete profile in Namibia. The methodically different ages reflect the characteristics of the applied dating methods, the genetics of calcrete and different events of calcrete genesis. The c…
Temporal Changes of the 14 C Reservoir Effect in Lakes
Conventional radiocarbon dates for sediment samples from aquatic systems and of coeval terrestrial samples deviate from each other due to the reservoir effect. The reservoir correction is usually assumed to be constant with time for a specific aquatic system. Our studies confirm that seasonal and secular changes are frequent and are governed by the limnological conditions. Lakes have two principal sources of 14 C: atmospheric CO 2 and the total d…
A late-Holocene (<2600 BP) glacial advance in the south-central Andes (29°S), northern Chile
Radiocarbon dates and relative ages of soils on moraines provide evidence of a substantial late-Holocene (<2600 BP) readvance of glaciers in the western part of the arid Andes at 29°S. The glacier in the Encierro valley, northern Chile, reached about 60% of its late-Pleistocene extent. The equilibrium line altitude ELA during this advance remained between 4250 and 4500 m which is above the modern 0°C isotherm of the free atmosphere during summer.…
Radiocarbon Reservoir Effect and the Timing of the Late-Glacial/Early Holocene Humid Phase in the Atacama Desert (Northern Chile)
We revise substantially the regional chronology of lake-level fluctuations from the late-glacial/early Holocene humid phase along a high altitude transect (3500 to 4500 m) between 18°S and 28°S in the Southwestern Altiplano of Northern Chile. Radiocarbon dates and 210 Pb profiles for limnic and terrestrial materials allow us to estimate and justify reservoir correction values for conventional 14 C dates. Our chronology suggests that the latest Pl…
Interglacial Growth of Tufa in Croatia
Tufa samples from the Krka River area in Croatia were dated by 14 C and 230 Th/ 234 U methods. The study area is situated in the karst region of the southern Dinarides. 14 C ages of 40 tufa samples collected at the waterfalls coincide with the early Holocene interglaciation, up to 6000 14 C yr B.P. Comparison of conventional 14 C dates of Holocene tufa and those of speleothems in the Dinaric Karst shows that speleothem formation started several t…
An Overview of 14 C Analysis in the Study of Groundwater
This paper provides a summary overview of the current state-of-art in the radiocarbon dating of groundwater. While the use of natural 14 C measurements in applied hydrogeology still presents a difficult challenge, meaningful dates can be achieved if they are determined and interpreted in conjunction with the analyses of other isotopic species that occur in the natural environment. Although 14 C dating of groundwater can be, and often is, carried …
Bomb Radiocarbon Dating of Animal Tissues and Hair
Initially, radiocarbon dating by bomb 14 C was used to check vintages of wine and whisky and to estimate the turnover times of carbon in various biological tissues. However, this technique has never been widely used for routine dating, although it has a wide field of application in geriatric medicine and forensic investigations. Fifteen years' experience in this field has shown the potential and limits of this technique. Taking into account the d…
Th/U Dating of Frozen Peat, Bol'shoy Lyakhovsky Island (Northern Siberia)
The chronology of Quaternary paleoenvironment and climate in northeastern Siberia is poorly understood due to a lack of reliable numerical age determinations. The best climatic archives are ice-rich permafrost sequences, which are widely distributed in northeastern Siberia. For this study, 230 Th/U-ages were determined by thermal ionization mass spectrometry (TIMS) from frozen peat in a permafrost deposit at the southern cliff of the Bol'shoy Lya…
Early to Mid-Holocene Aridity in Central Chile and the Southern Westerlies
Central Chile (32–35°S) lies at the northern border of strong Westerly influence and thus exhibits a steep precipitation gradient. Therefore, the palaeoclimatic archives in the region are suitable for detecting past moisture changes. The study of Laguna Aculeo (33°50'S, 70°54'W) presents a multiproxy Holocene lake record including sedimentology, geochemistry, mineralogy, pollen, diatoms, and radiocarbon dating (17 dates). Results indicate an arid…
Several distinct wet periods since 420 ka in the Namib Desert inferred from U-series dates of speleothems
The scarcity of numerical dates of the arid areas in southern Africa is a challenge for reconstructing paleoclimate. This paper presents a chronological reconstruction in the central part of the Namib Desert, Namibia, for the last 420,000 yr. It is based on 230 Th/U dates (TIMS) from a large stalagmite and a thick flowstone layer in a small cave located in the hyper-arid central Namib Desert. The results provide for the first time evidence of thr…
Geography (17 obras) · Radiocarbon dating (16 obras) · Geology (15 obras) · Geology and Paleoclimatology Research (15 obras) · Physical geography (13 obras) · Archaeology (12 obras) · Paleontology (12 obras) · Holocene (10 obras) · Archaeology and ancient environmental studies (8 obras) · Absolute dating (7 obras)