Abstract

Numerical geological time-scales rest firmly on the analysis of radiometric data. Since the discovery of oceanic magnetic stripes and their signification, alternative time-scales have been constructed whose numerical predictions are based on the hypothesis of a constant rate of sea-floor spreading. The most recent such scale uses only five tie-points, plus present day, to subdivide a span of over 80 million years. The present paper demonstrates that the rate of ocean-floor spreading has varied markedly, and without obvious pattern both in time and in space. Thus, magnetostratigraphic scales based on large interpolations are fundamentally flawed. An alternative scale, based on a consideration of all radiometric data and using magnetostratigraphic data only for small interpolations is commended.

First Page Preview

First page PDF preview
You do not currently have access to this article.