Early Maastrichtian stable isotopes: Changing deep water sources in the North Atlantic?

Friedrich, O., Herrle, J.O., Koessler, P. and Hemleben, C. (2004) Early Maastrichtian stable isotopes: Changing deep water sources in the North Atlantic? Palaeogeography, Palaeoclimatology, Palaeoecology, 211 (1-2), 171-184. (doi:10.1016/j.palaeo.2004.05.004).

Abstract

We propose that the observed short-term stable isotope fluctuations reflect changes in high- and low-latitude intermediate to deep water sources, based on a high-resolution stable isotope record of planktic and benthic foraminifera from the Early Maastrichtian (71.3 to 69.6 Ma) of Blake Nose (DSDP Site 390A, North Atlantic). Sources of these waters may have been the low-latitude eastern Tethys and high-latitude North Atlantic. Changes in intermediate to deep water sources were probably steered by eccentricity-controlled insolation fluctuations. Lower insolation favored the formation of high-latitude deep waters due to positive feedback mechanisms resulting in high-latitude cooling. This led to a displacement of low-latitude deep waters at Blake Nose. Higher insolation reduced intermediate to deep-water formation in high latitudes, yielding a more northern flow of low-latitude deep waters.

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