IMIS

Publicaties | Instituten | Personen | Datasets | Projecten | Kaarten
[ meld een fout in dit record ]mandje (1): toevoegen | toon Print deze pagina

one publication added to basket [231177]
Latitudinal differences in the amplitude of the OAE-2 carbon isotopic excursion: pCO2 and paleo productivity
van Bentum, E.C.; Reichart, G.J.; Forster, A.; Sinninghe Damsté, J.S.S. (2012). Latitudinal differences in the amplitude of the OAE-2 carbon isotopic excursion: pCO2 and paleo productivity. Biogeosciences 9(2): 717-731. dx.doi.org/10.5194/bg-9-717-2012
In: Gattuso, J.P.; Kesselmeier, J. (Ed.) Biogeosciences. Copernicus Publications: Göttingen. ISSN 1726-4170; e-ISSN 1726-4189, meer
Peer reviewed article  

Beschikbaar in  Auteurs 

Auteurs  Top 
  • van Bentum, E.C.
  • Reichart, G.J., meer
  • Forster, A.
  • Sinninghe Damsté, J.S.S., meer

Abstract
    A complete, well-preserved record of the Cenomanian/Turonian (C/T) Oceanic Anoxic Event 2 (OAE-2) was recovered from Demerara Rise in the southern North Atlantic Ocean (ODP site 1260). Across this interval, we determined changes in the stable carbon isotopic composition of sulfur-bound phytane (delta C-13(phytane)), a biomarker for photosynthetic algae. The delta C-13(phytane) record shows a positive excursion at the onset of the OAE-2 interval, with an unusually large amplitude (similar to 7 parts per thousand) compared to existing C/T proto-North Atlantic delta C-13(phytane) records (3-6 parts per thousand). Overall, the amplitude of the excursion of delta C-13(phytane) decreases with latitude. Using reconstructed sea surface temperature (SST) gradients for the proto-North Atlantic, we investigated environmental factors influencing the latitudinal delta C-13(phytane) gradient. The observed gradient is best explained by high productivity at DSDP Site 367 and Tarfaya basin before OAE-2, which changed in overall high productivity throughout the proto-North Atlantic during OAE-2. During OAE-2, productivity at site 1260 and 603B was thus more comparable to the mid-latitude sites. Using these constraints as well as the SST and delta C-13(phytane)-records from Site 1260, we subsequently reconstructed pCO(2) levels across the OAE-2 interval. Accordingly, pCO(2) decreased from ca. 1750 to 900 ppm during OAE-2, consistent with enhanced organic matter burial resulting in lowering pCO(2). Whereas the onset of OAE-2 coincided with increased pCO(2), in line with a volcanic trigger for this event, the observed cooling within OAE-2 probably resulted from CO2 sequestration in black shales outcompeting CO2 input into the atmosphere. Together these results show that the ice-free Cretaceous world was sensitive to changes in pCO(2) related to perturbations of the global carbon cycle.

Alle informatie in het Integrated Marine Information System (IMIS) valt onder het VLIZ Privacy beleid Top | Auteurs