Stable oxygen isotope chemostratigraphy and paleotemperature regime of mosasaurs at Bentiaba, Angola

Abstract Stable oxygen isotope values of inoceramid marine bivalve shells recovered from Bentiaba, Angola, are utilised as a proxy for paleotemperatures during the Late Cretaceous development of the African margin of the South Atlantic Ocean. The δ 18 O values derived from inoceramids show a long-te...

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Bibliographic Details
Published in:Netherlands Journal of Geosciences - Geologie en Mijnbouw
Main Authors: Strganac, C., Jacobs, L.L., Polcyn, M.J., Ferguson, K.M., Mateus, O., Gonçalves, A. Olímpio, Morais, M.-L., da Silva Tavares, T.
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 2015
Subjects:
South Atlantic Ocean
Online Access:http://dx.doi.org/10.1017/njg.2015.1
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0016774615000013
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Summary:Abstract Stable oxygen isotope values of inoceramid marine bivalve shells recovered from Bentiaba, Angola, are utilised as a proxy for paleotemperatures during the Late Cretaceous development of the African margin of the South Atlantic Ocean. The δ 18 O values derived from inoceramids show a long-term increase from –3.2‰ in the Late Turonian to values between –0.8 and –1.8‰ in the Late Campanian. Assuming a constant oceanic δ 18 O value, an ∼2‰ increase may reflect cooling of the shallow marine environment at Bentiaba by approximately 10°. Bentiaba values are offset by about +1‰ from published records for bathyal Inoceramus at Walvis Ridge. This offset in δ 18 O values suggests a temperature difference of ∼5° between coastal and deeper water offshore Angola. Cooler temperatures implied by the δ 18 O curve at Bentiaba coincide with the stratigraphic distribution of diverse marine amniotes, including mosasaurs, at Bentiaba.

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