Evidence for high sea-surface temperatures during the early Aptian OAE 1a in the Boreal Realm
Abstract
Data di Pubblicazione:
2014
Citazione:
Evidence for high sea-surface temperatures during the early Aptian OAE 1a in the Boreal Realm / J. Mutterlose, C. Bottini, S. Schouten, J.S. Sinninghe Damsté (SCHRIFTENREIHE DER DEUTSCHEN GESELLSCHAFT FÜR GEOWISSENSCHAFTEN). - In: Dynamik des Systems Erde / Earth System Dynamics[s.l] : Schweizerbart, 2014 Sep. (( convegno GeoFrankfurt conference : Dynamik des Systems Erde : Earth system dynamics tenutosi a Frankfurt nel 2014.
Abstract:
The early Aptian was characterized by the
widespread occurrence of anoxia in the oceans,
known as Oceanic Anoxic Event (OAE) 1a.
Intense degassing from submarine volcanic
plateaus presumably resulted in high
atmospheric CO2 concentrations, culminating
in greenhouse conditions (e.g., Hochuli et al.,
1999; Jenkyns, 2003; Erba et al., 2010). OAE
1a can, therefore, be considered as a past
“natural experiment” important to understand
the evolution of our future climate.
Paleotemperature estimates for OAE 1a are,
however, predominantly based on bulk
oxygen-isotopes, which are susceptible for
diagenetic overprinting, while TEX86
paleotemperature estimates are limited in
number or derived from stratigraphically
poorly constrained sections.
We reconstructed for the first time sea-surface
water (SST) temperatures based on the TEX86
paleothermometer from an OAE 1a section
from the middle northern latitudes (39° N
paleolatitude). We find a SST rise starting
prior to OAE 1a and reaching a maximum
during the event with SSTs around 31–34 °C,
4–9 °C higher than those of older Hauterivian -
lower Aptian sediments from the same
sedimentary basin (Mutterlose et al., 2014).
The end of OAE 1a is marked by relatively
lower SSTs around 30 °C. These observations
are supported by belemnite-based oxygen
isotope data and calcareous nannofossils. Our
integrated data set clearly indicates that ‘super
greenhouse’ conditions prevailed during OAE
1a at northern latitudes. SSTs are similar to
those estimated for coeval low latitudinal sites,
suggesting that an equable warm climate, with
reduced latitudinal gradients, characterized the
early Aptian.
References
Erba, E., Bottini, C., Weissert, J.H. & Keller, C.E.
(2010): Calcareous nannoplankton response to
surface-water acidifi cation around Oceanic
Anoxic Event 1a: Science, v. 329, p. 428–432.
Hochuli, P.A., Menegatti, A.P., Weissert, H., Riva,
A. Erba, E. & Premoli Silva, I. (1999): Episodes
of high productivity and cooling in the early
Aptian Alpine Tethys: Geology, v. 27, p. 657–
660.
Jenkyns, H.C. (2003): Evidence for rapid climate
change in the Mesozoic–Palaeogene greenhouse
world: Philosophical Transactions of the Royal
Society of London, Series A, v. 361, p. 1885–
1916.
Mutterlose, J., Bottini, C., Schouten, S. &
Sinninghe Damsté, J.S. (2014) : High sea-surface
temperatures during the early Aptian Oceanic
Anoxic Event 1a in the
Tipologia IRIS:
03 - Contributo in volume
Elenco autori:
J. Mutterlose, C. Bottini, S. Schouten, J.S. Sinninghe Damsté
Link alla scheda completa:
Titolo del libro:
Dynamik des Systems Erde / Earth System Dynamics