New range data for marine invertebrate species across the early Toarcian (Early Jurassic) mass extinction
Bryony A. Caswell
Angela L. Coe
Anthony S. Cohen
10.6084/m9.figshare.3454661.v1
https://geolsoc.figshare.com/articles/journal_contribution/New_range_data_for_marine_invertebrate_species_across_the_early_Toarcian_Early_Jurassic_mass_extinction/3454661
<p>We have reinvestigated the marine mass extinction interval that occurred during the early Toarcian, which was a time of widespread
marine anoxia. The ranges of marine benthic invertebrates are significantly altered using new observations from the Cleveland
Basin, UK. <em>Goniomya rhombifera</em> is reported for the first time from the Whitby Mudstone Formation and together with an increased epifaunal bivalve diversity
indicates a brief, relatively oxygenated period towards the end of the event. The new data, together with published results,
suggest three apparent extinction horizons on a global scale; the first is just above the Pliensbachian–Toarcian boundary,
and the following two are in the <em>semicelatum</em> ammonite Subzone. As a result of the Signor–Lipps effect there may be only one, or possibly two, true extinctions. The youngest
extinction horizon coincides with the first of the abrupt carbon isotope shifts that characterize this interval, and with
increases in sea surface temperature, continental weathering rates, and seawater anoxia. <em>Pseudomytiloides dubius</em> is the only abundant benthic macroinvertebrate during the most hostile environmental conditions but it and all other benthic
species are almost entirely absent for many thousands of years immediately after each abrupt negative carbon isotope shift.
</p>
2016-06-21 12:16:19
Toarcian
marine invertebrate species
New range data
benthic species
marine benthic invertebrates
oxygenated period
Goniomya rhombifera
sea surface temperature
semicelatum ammonite Subzone
Whitby Mudstone Formation
weathering rates
benthic macroinvertebrate
Cleveland Basin
extinction horizon
marine mass extinction interval
carbon isotope shift
extinction horizons
seawater anoxia
mass extinction
Pseudomytiloides dubius
marine anoxia
UK
epifaunal bivalve diversity
carbon isotope shifts
Geology