A high resolution late Miocene-Pliocene diatom biostratigraphy for the eastern equatorial Pacific. Academic Article uri icon

abstract

  • Quantitative procedures are used here for DSDP Sites 572, 573 and 503 to refine the stratigraphic resolution for upper Neogene sediments of the eastern equatorial Pacific Ocean. As a result, six new diatom events are defined for the stratigraphic interval 6.2 to 1.5 Ma. The carbonate minimums 53, Gu3, and M21, as well as the carbonate maximums 5f and 5d, are correlated to diatom datums and are useful in refining the stratigraphic resolution of the upper Neogene. In addition to allowing stratigraphic refinement, quantitative procedures aid in determining paleoceanographic conditions. The greater abundance of Coscinodiscus nodulifer at Site 593 as compared with Sites 572 and 573 suggests that this species is associated with equatorial upwelling. The greater abundance of Thalassionema nitzschioides at Site 572 suggests that this species is associated with the Equatorial Undercurrent. Furthermore, the gradual decline in the abundance of T. nitzschioides between 4.2 and 3.7 Ma at Sites 572 and 503 may have resulted from restriction in surface-water communication between the Atlantic and Pacific Oceans as a result of the emergence of the Isthmus of Panama.-Author

published proceedings

  • Initial reports DSDP, Leg 85, Los Angeles to Honolulu

author list (cited authors)

  • Baldauf, J. G

complete list of authors

  • Baldauf, JG

publication date

  • January 1985