Advances in Ichthyolith Stratigraphy of the Pacific Neogene and Oligocene

Cenozoic evolution of Asian climate and sources of Pacific seawater Pb and Nd derived from eolian dust of sediment core LL44‐GPC3

“…For the period between the Cretaceous‐Tertiary boundary and the Pliocene, there are two age models that diverge up to 8 Ma (Table 1). One model is based on ichthyolith biostratigraphy [ Doyle and Riedel , 1980; Gottfried et al , 1984], which provides only limited time resolution. The model of constant flux of hydrogenous Co (2.32 mg/(cm Ma) [ Kyte et al , 1993]) provides a continuous age versus depth scale that leads to much more detailed mass accumulation rate (MAR) profiles, the accuracy of which, however, is limited by the model assumption.…”

“…For the period between the Cretaceous-Tertiary boundary and the Pliocene, there are two age models that diverge up to 8 Ma (Table 1). One model is based on ichthyolith biostratigraphy [Doyle and Riedel, 1980;Gottfried et al, 1984], which provides [Doyle and Riedel, 1980] as employed by Janecek and Rea [1983]. d Chronostratigraphic age based on the age model of constant flux of hydrogenous Co [Kyte et al, 1993].…”

Ichthyolith Biostratigraphy of Western North Pacific Pelagic Clays, Deep Sea Drilling Project Leg 86

“…In samples from the Pacific dated by other microfossils, the first appearance of Rounded apex triangle corresponds with nannofossil Zone CP16, the first appearance of Triangle with high inline apex with nannofossil Zone CP17, and the first appearance of Small triangle long striations with Zone CN1. This succession is also present in sequences without other microfossils (Edgerton et al, 1977;Riedel, 1979b, Kaneps et al, 1981;Gottfried et al, 1985). In Hole 576A, this places (along with some supporting evidence from less common taxa-Flexed triangle shallow inbase 120, Rectangular saw-toothed, Triangle with base angle) the Oligocene/Miocene boundary between Sections 3 and 5 of Core 4, and the Eocene/Oligocene boundary between Sections 1 and 3 of Core 5.…”

“…INTERPRETATIONS Over the past 10 yr., we have built up an ichthyolith stratigraphy by establishing the ranges of approximately 120 taxa (subtypes) in sediment sequences in which ages have been determined on the basis of other groups of microfossils, mainly calcareous nannoplankton (Doyle et al, 1974;Dunsworth et al, 1975;Doyle et al, 1977;Gottfried et al, 1985). Application of this ichthyolith stratigraphy to pelagic clay sequences results in age assignments to about the level of epochs within the Cenozoic (Edgerton et al, 1977;Doyle and Riedel, 1979b;Kaneps et al, 1981).…”

“…In addition to providing a time-stratigraphic interpretation of the Leg 86 cores, we improved our understanding of Paleocene ichthyolith stratigraphy (describing seven new subtypes) and continued development of a procedure for probabilistic stratigraphic interpretations by employing a method of indexing the reliability of biostratigraphic events as applied in Gottfried et al (1984).…”