Preliminary Palaeomagnetic Data from the Plio-Pleistocene of Jamaica

Abstract

CORRELATIONS, using deep sea cores, between the geomagnetic time scale1–3 and the planktonic foraminiferal biostratigraphy of the later Tertiary and Quaternary have received much attention in the past few years4–9, but only a few studies of other Quaternary sediments have yet been published. Montfrans and Hospers10 have given an account of progress made in Pleistocene continental strata of the Netherlands, but there seems to have been little attempt to relate the recently developed Plio-Pleistocene planktonic foraminiferal biostratigraphy to the geomagnetic time scale in land-based sections, although there should be several advantages of sampling such sections. For example, the initial orientation of each sample can be determined with precision; field inspection of the collecting site can ascertain the nature of the structural or stratigraphical complications; sampling can often be carried out repeatedly at any required interval; and samples for palaeontological analysis can also be collected. In general, land-based sections are considerably more expanded than deep sea cores arid so might be expected to yield more reliable data on geomagnetic events of short duration. An accurate appraisal of the geomagnetic stratigraphy beyond the past 3 million years or so should therefore be effectively developed using land-based sequences.