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Demersal habitat of Late Cretaceous ammonoids; evidence from oxygen isotopes for the Campanian (Late Cretaceous) northwestern Pacific thermal structure

Kazuyoshi Moriya, Hiroshi Nishi, Hodaka Kawahata, Kazushige Tanabe and Yokichi Takayanagi
Demersal habitat of Late Cretaceous ammonoids; evidence from oxygen isotopes for the Campanian (Late Cretaceous) northwestern Pacific thermal structure
Geology (Boulder) (February 2003) 31 (2): 167-170

Abstract

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 approximately 26 and 18 degrees C, respectively, at 40 degrees 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 approximately 19 degrees C, comparable to those of cooccurring benthos. None of these ammonoids display calcification temperatures equivalent to those of planktonic foraminifers.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 31
Serial Issue: 2
Title: Demersal habitat of Late Cretaceous ammonoids; evidence from oxygen isotopes for the Campanian (Late Cretaceous) northwestern Pacific thermal structure
Affiliation: University of Tokyo, Department of Earth and Planetary Science, Tokyo, Japan
Pages: 167-170
Published: 200302
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 28
Accession Number: 2003-018505
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2003015
Illustration Description: illus.
N45°00'00" - N45°00'00", E142°00'00" - E142°00'00"
Secondary Affiliation: Kyushu University, JPN, JapanNational Institute of Advanced Industrial Science and Technology, JPN, JapanTohoku University, JPN, Japan
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 200306
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