『Abstract
The early Aptian Oceanic Anoxic Event (OAE 1a) resulted from
an exceptional set of interactions between the geosphere, the
biosphere, and the ocean-atmosphere system. We present new Re-Os
data from two sites spanning OAR 1a in the Tethys and Pacific
Oceans. The patterns of variation in the seawater Os-isotope composition
from both sites are very similar, and together they constrain
the timing and duration of continental weathering in relation
to the large-scale volcanic activity of the Ontong Java Plateau.
The dominant feature through the OAE is an interval of 〜880 k.y.
when the Os-isotope composition of the global ocean was exceptionally
unradiogenic, implicating unambiguously the Ontong Java Plateau
as the trigger and sustaining mechanism for OAE 1a. A relatively
short-lived (〜100 k.y.) Os-isotope excursion to radiogenic compositions
in the Tethyan record is clearly linked to an abrupt perturbation
to the global carbon cycle, and is fully consistent with the Pacific
record. These highly distinctive features of seawater Os in contemporaneous
samples from three high-resolution sections, two of which were
very remote from the Ontong Java Plateau, indicate that ocean
mixing at that time was very efficient. The results suggest that
OAE 1a was also related to rapid global warming and elevated rates
of silicate weathering both on the continents and in the oceans.』
Introduction
Results
Discussion
Re-Os data from OAE 1a
Integration with biotic and geochemical proxy data
Comparison with other OAEs and hyperthermals
Conclusions
Acknowledgments
References cited