Revisions in the dates of reported geomagnetic excursions during the Brunhes Epoch are proposed in light of possible correlations between a section at Gioia Tauro, Italy, deep-sea cores, a core from Lake Biwa, Japan, and some lava flows. The anomalously long, double Blake Event reported at Gioia Tauro is here correlated with the Blake Event (~110 kyr) and the Biwa 1 event (180¿5 kyr); an hiatus may be present in the section between these two events. The &agr; event at Gioia Tauro is correlated with the Biwa 2 event at about 295 kyr; the &bgr; event with the ''Biwa 3'' event at about 400 kyr; the &ggr; event with the Snake River event at 480¿50; and the Δ event, not recorded elsewhere, is estimated to have occurred at ~620 kyr. These proposed refinements in the age estimates of the excursions suggest an approximately 100 kyr cyclicity. If the events are real and the revised dating is correct, the timing of the geomagnetic events seems to coincide with times of peak eccentricity of the earth's orbit, suggesting a causal connection. |