On possible relationships between Upper Quaternary glaciations, geomagnetism, and vulcanism

Abstract

Sea-level changes, representing ice-volume changes during the last 0.25 m.y., now have been well identified from raised coral reefs dated by 230Th/234U. This detailed record allows hypotheses relating glaciation to magnetism or vulcanism to be tested more accurately than previously. There is strong temporal correlation between 7 transgression-regression cycles and those variations of seasonal radiation which arise from the effects of orbital eccentricity and precession. Similar close correlation does not exist with known records of magnetic intensity and dip, or with vulcanism, identified in deep-sea cores. It is argued that orbital perturbations theoretically are unlikely to affect magnetism or vulcanism, and these also are unlikely to be affected by global isostatic changes associated with changing ice and water loads. However, certain testing is needed, by finer-scale analysis of deep-sea core volcanic records, and by eliminating chronologic vagueness between deep-sea and coral-reef records. Show more