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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 63 (1979)

Issue: 3. (March)

First Page: 426

Last Page: 426

Title: Pan-Pacific Neogene Diatom Correlations: ABSTRACT

Author(s): Lloyd H. Burckle, Neil D. Opdyke

Article Type: Meeting abstract


On the basis of piston cores and DSDP sites, a Neogene diatom correlation for Pacific Ocean sediments was determined. Where possible, these correlations rely on the paleomagnetic-reversal record in piston cores. In the central Pacific, diatom datum levels are directly tied to this reversal record. Furthermore, they are extended eastward to DSDP Sites 77 and 158. Although datum levels are generally isochronous in the low-latitude Pacific, some forms have substantially longer ranges in upwelling regions of the easternmost equatorial Pacific. In addition, some high-latitude elements are also present in this region. A mixed assemblage containing both high- and low-latitude diatoms is present at DSDP sites and in piston cores in the northwest and southwest Pacific. This fact p rmits correlation across several zonal schemes and verifies correlations to such high-latitude sites as 178, 183, and 192 in the North Pacific and 278 in the South Pacific. A series of time-slice maps for the Pacific Neogene depicts changes in the temporal and spatial distribution of diatoms. Diatom-distribution maps reflect accurately the productivity of the overlying water with diatom-bearing sediment present in the eastern equatorial regions and the higher latitude North Pacific. In the South Pacific, diatoms are present south of the Subtropical Convergence. Elsewhere, in the Central Water Masses, the surface sediments are free of diatoms. This pattern holds true generally for much of the Neogene, but major changes in diatom species distribution are indicated in the early Miocene and ear the middle/late Miocene boundary.

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