10.6084/m9.figshare.3454220.v1
Emanuela Mattioli
Emanuela
Mattioli
Bernard Pittet
Bernard
Pittet
RaffaellaBucefalo Palliani
RaffaellaBucefalo
Palliani
Hans-Joachim RÖhl
Hans-Joachim
RÖhl
Annette Schmid-RÖhl
Annette
Schmid-RÖhl
Elena Morettini
Elena
Morettini
Phytoplankton evidence for the timing and correlation of palaeoceanographical changes during the early Toarcian oceanic anoxic
event (Early Jurassic)
Geological Society of London
2016
duration
reactive neritic system
crisis
p CO 2
abundance
magmatic activity
matter
excursion
nannoplankton
Carinolithus superbus nannofossil Zone
Toarcian oceanic anoxic event
Toarcian anoxic event
correlation
Geology
2016-06-21 11:58:59
Dataset
https://geolsoc.figshare.com/articles/dataset/Phytoplankton_evidence_for_the_timing_and_correlation_of_palaeoceanographical_changes_during_the_early_Toarcian_oceanic_anoxic___event_Early_Jurassic_/3454220
<p>The causes and duration of the early Toarcian anoxic event are controversial. Integration of data from calcareous and organic
phytoplankton provides a biochronological framework that allows precise correlations across the western Tethys. In particular,
the <em>Carinolithus superbus</em> nannofossil Zone can be used to correlate the levels enriched in organic matter and the related <em>δ</em><sup>13</sup>C negative excursion. Although a variable duration is given in the literature for this negative excursion, it is likely that
it lasted between 520 and 650 ka. Increased atmospheric <em>p</em>CO<sub>2</sub>, related to excess volcanic emissions (magmatic activity in the Karoo and Ferrar Provinces), had an impact on climate and
ocean chemistry, and marked the inception of a biotic crisis affecting many organisms. The beginning of the crisis within
shallow carbonate platforms, documented at southern latitudes, predates the levels enriched in organic matter. Dinoflagellate
cysts experienced a decrease in abundance in the <em>C. superbus</em> Zone, until they temporarily disappeared. The nannoplankton crisis was twofold: a decrease in size and low calcified specimens
are observed in addition to a drastic decrease in absolute abundance. The increased atmospheric <em>p</em>CO<sub>2</sub>, as a result of the magmatic activity and temporarily amplified by transient methane release, could have been the trigger
for the biocalcification crisis, which first affected the probably more reactive neritic system, and eventually the nannoplankton
community.
</p>