Demersal habitat of Late Cretaceous ammonoids: Evidence from oxygen isotopes for the campaign (Late Cretaceous) northwestern Pacific thermal structure

Kazuyoshi Moriya, Hiroshi Nishi, Hodaka Kawahata, Kazushige Tanabe, Yokichi Takayanagi

研究成果: Article

67 引用 (Scopus)

抜粋

Comparison of oxygen isotope data for exceptionally well preserved cooccurring plankton and benthos from the Campanian of Hokkaido, Japan, with nine species of ammonoids clearly indicates the demersal (nektobenthic) habitat of ammonoids; unlike Nautilus, the ammonoids studied did not engage in significant short-term vertical migrations in the water column. The new foraminiferal isotopic data suggest that sea-surface and sea-bottom temperatures were ∼26 and 18 °C, respectively, at 40°N in the Campanian northwestern Pacific. The temperatures were significantly warmer than those in the modern northwest Pacific. This finding provides the first reliable evidence for the warm Late Cretaceous mid-latitude North Pacific. Isotopic analyses of ammonoids show that the average calcification temperature of all ammonoid shells analyzed was ∼19 °C, comparable to those of cooccurring benthos. None of these ammonoids display calcification temperatures equivalent to those of planktonic foraminifers.

元の言語English
ページ(範囲)167-170
ページ数4
ジャーナルGeology
31
発行部数2
DOI
出版物ステータスPublished - 2003 2
外部発表Yes

ASJC Scopus subject areas

  • Geology

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