Micropaleontologic correlations by means of planktonic microfossil zones, defined on either an evolutionary or paleoceanographic basis, show that there are major time-transgressive features for paleontologic zones based upon benthic forams. This problem is especially acute in tectonically active basins where rapid sedimentation is combined with differential subsidence rates. Stage boundaries based on benthic species may occur progressively down-section toward submarine fans; conversely, such boundaries are progressively higher in the section toward deep-water depositional areas that are far from sediment sources. Thus, the misidentification of stratigraphic objectives can lead to drilling errors of many hundreds of meters in exploring different depositional centers within a basin. This aspect of correlation precision is especially acute in areas of continental margins.

Paleoenvironmental logging of sections and wells, employing primarily benthic foram faunas, makes possible (1) definition of paleobathymetric cycles, (2) detection of areas with truncated cycles, (3) definition of principal depositional centers and their migration in time, (4) proper evaluation of sediment bodies such as turbidites and submarine landslides, and (5) definition of paleotectonic rates which lead to the definition of structural trends developing within a basin.

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