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The AAPG/Datapages Combined Publications Database

AAPG Bulletin


Volume: 65 (1981)

Issue: 5. (May)

First Page: 946

Last Page: 946

Title: Radiolarian Distribution and Enhanced Preservation in Modern Sediments: Indicators of Oceanographic Environments: ABSTRACT

Author(s): Florence R. Kunze, Richard E. Casey

Article Type: Meeting abstract


Analysis of the geographic distribution of radiolarians shows that they are preserved in restricted zones and/or enhanced under particular oceanographic environments. Surface, warm-water-dwelling radiolarians are preserved in the equatorial region. However, intermediate and deep, cold upwelling radiolarians exhibit cosmopolitan distributions in the sediments with enhancement under oceanographic convergences and divergences. Specifically artostrobids and plectopyramids appear to be enhanced in the sediments under oceanographic convergence and divergences; the Dictyocoryne profunda-truncatum group is enhanced under high productivity regions; and actinommids in general and collosphaerids in particular are enhanced under the oligotrophic gyre regions. The enhancement under co vergences and divergences may be due to (1) mass mortality of deep and/or cold forms brought into warm surface waters via upwelling at a divergence or laterally at a convergence, (2) an increase in standing crop of deep forms under high productivity regions or higher productivity at the convergence's nutricline, or (3) a stripping of the metallic protective coating of shallow forms by bacteria at the nutricline. Collosphaerids may be enhanced in oligotrophic gyres owing to the acquisition of detrital aluminum on their surfaces which might deplete the deeper waters and inhibit deeper water radiolarian preservation. Collosphaerids are also enhanced along the Mid-Atlantic Ridge which may be due to metal abundance in the sediments, low sedimentation rates, and/or high silica concentration of interstitial and bottom waters.

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