Deuterium in interstitial water from deep-sea cores

As part of the Joint Oceanographic Institutions Deep Earth Sampling project, the interstitial waters of cores from 69 holes were sampled for deuterium analysis to examine changes in the deuterium content of the oceans with time. Changes in the abundance of deuterium can be related to changes in the amount of ice stored in continental glaciers, inasmuch as precipitation in the form of snow is highly depleted in deuterium compared with the oceans. Many of the cores show a change in isotopic composition of samples from early to late Miocene that can be ascribed to the buildup of the Antarctic ice sheets. After correcting for the role of diffusion in reducing the isotopic contrast between samples from a single core, we estimate an incrase of 10 per mil (???) ??D (corresponding to a ??18O change of about 1.2???) between the early and late Miocene. A similar analysis of Pleistocene to Holocene changes indicates a ??D rise of 8??? during the time of maximum continental ice, which corresponds to a ??18O increase of about 1.0???. On the basis of limited data, we find no ??D change in the oceans from Cretaceous to Miocene. -from Authors