|TITLE||HIGH RESOLUTION STUDY IN ALBORAN SEA (ODP 977) DURING THE MIS 11: A MID-
BRUNHES EVENT INTERPRETATION PERSPECTIVE BASED ON COCCOLITHOPHORES.|
|AUTHORS||A González-Lanchas (1), JA Flores (1), FJ Sierro (1), JO Grimalt (2)|
- Departament of Geology, Salamanca, Spain
- I. of Environmental Assessment and Water Research, Barcelona, Spain
|ABSTRACT||A submillennial study based on variability in the coccolithophore assemblage is carried out in order to improve the understanding dynamics in the surface waters as well as changes in paleoproductivity in the Alboran Sea during Marine Isotope Stage (MIS) 11, along the Mid-Brunhes event interval in the Atlantic – Mediterranean exchange area.
The age-model is based on calcareous nannofossil biostratigraphy and planktonic foraminifera δ18O records, showing an orbital with a suborbital cyclicity overimposed.
During the MIS 11, coccolithophore assemblage was widely dominated by the Gephyrocapsa group, with a high representation of “Gephyrocapsa caribbeanica” and small Gephyrocapsa (<3m). Primary productivity proxies, such as total number of coccoliths and nannofossil accumulation rates (NAR), reveals a constant and intense high productivity conditions. Abrupt events (interstadial-type oscillations) reveals interesting changes in surface water conditions in the area. Characterization of this short-lived climatic events from a multiproxy approach and its relations with oceanographic dynamics variability arises as one of the main scopes of future work.
Another outstanding issue of this preliminary study is the identification of several morphotypes of Gephyrocapsa (“G. caribbeanica”, G. oceanica and G. muellerae) with variable calcification features, analyzed by the use of image analysis techniques (C-Calcita). We hypothesized about the relationship of these changes and oceanic processes occurred during the Mid-Brunhes at local and global level.|