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Uranium/thorium dating of Quaternary carbonates |
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Boreas,
Volume 1,
Issue 4,
1972,
Page 247-274
JOHN E. GUSTAVSSON,
S. A. CHRISTER HÖGBERG,
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摘要:
Gustavsson, J. E.&Högberg, S. A. C.: Uranium/thorium dating of Quaternary carbonates.Boreas,Vol. 1, pp. 247–274. Oslo, 1st December, 1972.The U/Th methods and particularly the theory of the230Th‐deficiency method are reviewed. The closed system question is discussed against the background of the growth and structure of the molluscan shells measured. The choice of the half‐life value for230Th, 75,200 years, is accounted for in a review of the five half‐life determinations known to the authors. The measurement procedure starts with the mechanical and ultrasonic cleaning of the sample. Small portions are taken for X‐ray analysis. The sample is then divided into two parts. One is treated chemically to separate the uraninium and the thorium, in order to determine the ratio between the activities of the uranium isotopes and to determine the content of226Ra. The other part of the sample is used to make the total measurement on the uranium and thorium isotopes simultaneously from the same part of the sample without any chemical pr
ISSN:0300-9483
DOI:10.1111/j.1502-3885.1972.tb00004.x
出版商:Blackwell Publishing Ltd
年代:1972
数据来源: WILEY
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| 2. |
Lateral fluctuations in pelagic sedimentation during the Pleistocene glaciations |
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Boreas,
Volume 1,
Issue 4,
1972,
Page 275-288
KURT BOSTRÖM,
DAVID E. FISHER,
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摘要:
Boström, K.,&Fisher, D. E.: Lateral fluctuations in pelagic sedimentation during the Pleistocene glaciations.Boreas,Vol. 1, pp. 275–288. Oslo, 1st December, 1972.A total of 308 sediment samples of dated cores from 7 different locations have been analyzed for several major and trace elements. Our results, as well as previously published ones, show that during the Pleistocene the pelagic sediments have high concentrations of Mn, Cu, Co, REE, etc., in deposits of glacial age and low concentrations in corresponding interglacial ones; for hemipelagic sediments the situation is reversed. This shows that the boundary between reducing hemipelagic sediments and well‐oxidized pelagic sediments has been migrating laterally back and forth due to climatic variations. Such sediment sequences may be easily confused with deposits where postdepositional migration of Mn and other elements has taken p
ISSN:0300-9483
DOI:10.1111/j.1502-3885.1972.tb00005.x
出版商:Blackwell Publishing Ltd
年代:1972
数据来源: WILEY
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| 3. |
The Lundergård Clay and its Foraminifera, a new formation in the marine Quaternary of Denmark |
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Boreas,
Volume 1,
Issue 4,
1972,
Page 289-297
KAREN LUISE KNUDSEN,
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摘要:
Knudsen, Karen Luise: The Lundergard Clay and its Foraminifera, a new formation in the marine Quaternary of Denmark.Boreas,Vol. 1, pp. 289–297. Oslo, 1st December, 1972.Samples from marine Quaternary clay deposits at Lundergård in Vendsyssel have been analysed for their content of Foraminifera. The clay, which is called the Lundergård Clay, contains a typical arctic foraminifer fauna withQuinqueloculina stalkeriandElphidium ustulatumas characteristic species. To attempt an age determination of the Lundergård Clay, the fauna is compared with foraminifer assemblages from other marine Quaternary deposits of Vendsyssel and adjacent areas. The deposit may represent a hitherto unknown facies of the OlderYoldiaClay of Vendsyssel, which is supposed to be of Weichselian interstadial age, or it may be older and can perhaps be correlated with the Holderness Basement Till of Saale interstadial
ISSN:0300-9483
DOI:10.1111/j.1502-3885.1972.tb00006.x
出版商:Blackwell Publishing Ltd
年代:1972
数据来源: WILEY
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