D/H ratios in speleothem fluid inclusions: A guide to variations in the isotopic composition of meteoric precipitation?
D/H ratios of fluid inclusion waters extracted from230Th/234U-dated speleothems that were originally deposited under conditions of isotopic equilibrium should provide a direct estimate of the hydrogen isotopic composition of ancient meteoric waters. We present here D/H ratios for 47 fluid inclusion samples from thirteen speleothems deposited over the past 250,000 years at cave sites in Iowa, West Virginia, Kentucky and Missouri. At each site glacial-age waters are depleted in deuterium relative to those of interglacial age. The average interglacial/glacial shift in the hydrogen isotopic composition of meteoric precipitation over ice-free areas of east-central North America is estimated to be −12‰. This shift is consistent with the present climatic models and can be explained in terms of the prevailing pattern of atmospheric circulation and an increased ocean-continent temperature gradient during glacial times which more than compensated for the increase in deuterium content of the world ocean.
Citation Information
Publication Year | 1979 |
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Title | D/H ratios in speleothem fluid inclusions: A guide to variations in the isotopic composition of meteoric precipitation? |
DOI | 10.1016/0012-821X(79)90033-5 |
Authors | R.S. Harmon, H.P. Schwarcz, J. R. O'Neil |
Publication Type | Article |
Publication Subtype | Journal Article |
Series Title | Earth and Planetary Science Letters |
Index ID | 70012499 |
Record Source | USGS Publications Warehouse |