First Miami Conference on Isotope Climatology and Paleoclimatology



Oxygen isotope analysis of deep-sea cores of Globigerina ooze facies has revolutionized the classical picture of four great Quaternary glaciations, separated by long interglacials. It now appears that eight major glaciations occurred during the Brunhes magnetic epoch; that many more occurred before, at least as far back as 3 m.y. ago; and that climate similar to that of today existed for only 5% of Quaternary time. The total number of late Cenozoic glaciations may have been more than thirty, spaced at about 90,000-year intervals. Oxygen isotope analysis of oceanic drill cores has shown that global temperature dropped abruptly 38 m.y. ago and again 16 m.y. ago, the latter drop being related to intensified glaciation in Antarctica, and the analysis of piston cores from the Gulf of Mexico and from off the Niger delta has provided apparent evidence for major surges of the Laurentide and Antarctic ice caps. The more recent climatic record is being studied in detail by means of isotopic analysis of dated tree rings and of Greenland and Antarctic ice cores. Global causes for the onset of the late Cenozoic glaciation may include volcanism, as suggested by the spectacular increase of volcanic dust in Quaternary oceanic sediments, and solar instability, as suggested by the current ‘neutrino crisis.’ These and other topics were discussed by 84 scientists from ten countries during the First Miami Conference on Isotope Climatology and Paleoclimatology.