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| Titel |
Stable isotope compositions of a late Jurassic ammonite shell: a record of seasonal surface water temperatures in the southern hemisphere? |
| VerfasserIn |
C. Lécuyer, H. Bucher |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1815-381X
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| Digitales Dokument |
URL |
| Erschienen |
In: eEarth ; 1, no. 1 ; Nr. 1, no. 1 (2006-08-21), S.1-7 |
| Datensatznummer |
250000101
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| Publikation (Nr.) |
 copernicus.org/ee-1-1-2006.pdf |
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| Zusammenfassung |
| Exceptional preservation of aragonite secreted by ammonites offers an
opportunity to determine the seasonal temperature variations of Mesozoic
surface waters. Ontogenetic profiles of carbon and oxygen isotope
compositions have been obtained from the nacreous layer of a well-preserved
Late Jurassic (Oxfordian) ammonite (Perisphinctes) from Madagascar. A similar range of
oxygen isotope compositions was also obtained from an associated benthic
bivalve (Astarte) which suggests the absence of sampling bias. Late Jurassic
seasonal variations in the southern hemisphere were close to 2.5°C and
relatively weak when compared to the 2.5–6.5°C temperature range
prevailing in the present-day Indian Ocean at a paleolatitude of 40±1° S. According to the hypothesis of an ice cap-free Late Jurassic
Earth, average sea surface temperatures may have been up to 7°C higher
than now. |
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