Copyright © 2001 Elsevier Science B.V. All rights reserved.
Atlantic paleobathymetry, paleoproductivity and paleocirculation in the late Albian: the benthic foraminiferal record
Received 28 July 2000;
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Abstract
Spatial distribution patterns of benthic foraminifers in upper Albian sediments from 25 DSDP/ODP sites and 31 onshore sections of the North and South Atlantic Ocean are used to generate paleobathymetric reconstructions and to identify areas of high primary production such as coastal and equatorial upwelling zones. New paleobathymetric estimates are provided for DSDP/ODP sites and onshore locations that are not situated on oceanic crust. Paleobathymetric reconstructions indicate shallow water exchange between the North and South Atlantic but show the existence of a deep-water connection between the western and eastern Tethys (>2500 m) through the Gibraltar Gateway. Strikingly, there is no evidence for a strong latitudinal gradient in deep-water benthic foraminiferal distribution during the late Albian: South Atlantic assemblages show close affinity to North Atlantic and Tethyan assemblages, exhibiting only a minor degree of provincialism. Biogeographic patterns reveal a distinct asymmetry in late Albian paleoproductivity for the North Atlantic. As for the present day, the eastern margins of the Atlantic were generally more productive than the western margins, and a belt of enhanced carbon flux export to the seafloor can be traced around the north African coast, which probably corresponded to a zone of vigorous coastal upwelling. By contrast, assemblage composition in the South Atlantic generally reflects mesotrophic to oligotrophic conditions. Benthic foraminiferal distribution patterns, thus, provide robust proxy data to test predictions from paleocirculation and paleobathymetric models for the mid-Cretaceous Atlantic Ocean and adjacent margins.
Author Keywords: Late Albian; Benthic foraminifers; Atlantic; Bathymetry; Productivity; Circulation
Article Outline
- 1. Introduction
- 2. Material and methods
- 3. Diversity patterns: how cosmopolitan were late Albian benthic foraminifers?
- 4. Paleobathymetry
- 4.1. Correspondence analysis of complete dataset
- 4.2. Paleobathymetric model
- 4.3. Evaluation of paleobathymetric model
- 4.4. Paleobathymetry of Gibraltar and Equatorial Gateways
- 5. Carbon flux and paleoproductivity
- 5.1. Correspondence analysis of bathyal dataset
- 5.2. Carbon flux preferences of late Albian bathyal taxa
- 5.3. Paleoproductivity gradients in the Atlantic
- 6. Conclusion
- Acknowledgements
- References
- Supplementary Files







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