Biostratigraphy of the Equatorial North Pacific DOMES Sites A, B, and C
Radiolarians from box cores and gravity cores indicate that Quaternary sediment covers the sea floor at DOMES Sites A, B, and C; however, at Sites A and B dissolution-resistant, reworked Tertiary species (predominantly middle and late Eocene and early Miocene) generally outnumber the fragile Quaternary forms. In contrast, at Site C an early Miocene calcareous nannofossil flora underlies the Quaternary layer in three cores, and specimens of different ages are not mixed; barren sediment generally underlies the Quaternary in the remainder of cores from Site C. The abundant admixture of Tertiary radiolarians in Quaternary sediment at Sites A and B is most likely caused by an increase ill bottom current activity during the Pleistocene, resulting in several cycles of erosion and redeposition of Tertiary sediment. This physical process of erosion, aided by selective dissolution of fragile radiolarians, explains the dominance of dissolution-resistant forms in the mixtures.
KeywordsMiddle Eocene Quaternary Sediment Late Eocene Manganese Nodule Calcareous Nannoplankton
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- Bukry, David, (1973) Coccolith stratigraphy, eastern equatorial Pacific Leg 16, Deep Sea Drilling Project, In: van Andel, T.H., Heath, G.R., et al., Initial Reports Deep Sea Drilling Project, 16, Washington D.C., U.S. Govt Printing Office, 653–711.Google Scholar
- Dinkelman, M.G., (1973) Radiolarian stratigraphy: Leg 16, Deep Sea Drilling Project, In: van Andel, T. H., Heath, G.R., et al., Initial Reports Deep Sea Drilling Project, 16, Washington, D.C., U.S. Govt Printing Office, 747–813.Google Scholar
- Johnson, D.A., and Johnson, T.C., (1970) Sediment redistribution by bottom currents in the Central Pacific, Deep-sea Res. 17, 157–169.Google Scholar
- Lisitzin, A.P., (1972) Sedimentation in the World Ocean, Soc. Econ. Paleon, and Mineral., Spec. Publ. No. 17, 218 p.Google Scholar
- Loeblich, A.R., and Tappan, H., (1964) Treatise on Invertebrate Paleontology, R.C. Moore (ed.), Pt. C, Protista, Lawrence, Kansas, Geol. Soc. Am. and Univ. Kansas Press, 900 p.Google Scholar
- Moore, T.C., (1970) Abyssal hills in the central equatorial Pacific: sedimentation and stratigraphy, Deep-sea Res. 17, 573–593.Google Scholar
- Nigrini, C.A., (1971) Radiolarian zones in the Quaternary of the equatorial Pacific Ocean, In: The Micropaleontology of the Oceans ( Funnell, B.M. and Riedel, W.R., eds.), Cambridge Univ. Press, 443–461.Google Scholar
- Parker, F.L., (1964) Foraminifera from the experimental Mohole drilling near Guadalupe Island, Mexico, Jour. Paleo. 38, no. 4, 617–636.Google Scholar
- Postuma, J.A., (1971) Manual of Planktonic Foraminifera, Amsterdam, Elsevier Publ. Co., 420 p.Google Scholar
- Piper, D.Z., Cannon, W., and Leong, K., (1977) Composition and abundance of ferromanganese nodules at DOMES Sites A, B, and C: relationship with bathymetry and stratigraphy, In: Piper, D.Z. et (compilers) Deep Ocean Environmental Study: Geology and Geochemistry of DOMES Sites A, B, and C, equatorial North Pacific, U.S. Geol. Survey Open-file Rept. 77–778, 217–266.Google Scholar
- Theyer, F., (1977) Micropaleontological dating of DOMES Project box cores from Test Areas A and B, Tropical Pacific, In: Piper, D.Z. et al, (compilers) Deep Ocean Environmental Study: Geology and Geochemistry of DOMES Sites A, B, and C, equatorial North Pacific, U.S. Geol. Survey Open-file Rept. 77–778, 179–194.Google Scholar