Precise timing of the last interglacial period from mass spectrometric determination of thorium-230 in corals
The development of mass spectrometric techniques for determination of STTh abundance has made it possible to reduce analytical errors in STYU-STUU-STTh dating of corals even with very small samples. Samples of 6 x 10Y atoms of STTh can be measured to an accuracy of +/- 3% (2sigma) and 3 x 10 atoms of STTh can be measured to an accuracy of +/- 0.2%. The time range over which useful age data on corals can be obtained now ranges from about 50 to about 500,000 years. For young corals, this approach may be preferable to UC dating. The precision should make it possible to critically test the Milankovitch hypothesis concerning Pleistocene climate fluctuations. Analyses of a number of corals that grew during the last interglacial period yield ages of 122,000 to 130,000 years. The ages coincide with, or slightly postdate, the summer solar insolation high at 65N latitude which occurred 128,000 years ago. This supports the idea that changes in Pleistocene climate can be the result of variations in the distribution of solar insolation caused by changes in the geometry of the earth's orbit and rotation axis.
- Research Organization:
- California Institute of Technology, Pasadena
- OSTI ID:
- 6278621
- Journal Information:
- Science (Washington, D.C.); (United States), Journal Name: Science (Washington, D.C.); (United States) Vol. 236; ISSN SCIEA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Aquatic-- Radioactive Materials Monitoring & Transport-- (1989)
54 ENVIRONMENTAL SCIENCES
58 GEOSCIENCES
580100* -- Geology & Hydrology-- (-1989)
ACCURACY
ACTINIDE ISOTOPES
ACTINIDE NUCLEI
AGE ESTIMATION
ALPHA DECAY RADIOISOTOPES
CENOZOIC ERA
CLIMATES
CNIDARIA
CORALS
EVEN-EVEN NUCLEI
GEOLOGIC AGES
HEAVY NUCLEI
ISOTOPE DATING
ISOTOPES
MASS SPECTROSCOPY
NUCLEI
QUATERNARY PERIOD
RADIOISOTOPES
SPECTROSCOPY
THORIUM 230
THORIUM ISOTOPES
VARIATIONS
YEARS LIVING RADIOISOTOPES