Data from: Recognizing pulses of extinction from clusters of last occurrences

The distribution of last occurrences of fossil taxa in a stratigraphic
column are used to infer the pattern, timing, and tempo of extinction from
the fossil record. Clusters of last occurrences are commonly interpreted
as an abrupt pulse of extinction. However, stratigraphic architecture
alone can produce clusters of last occurrences that can be misinterpreted
as an extinction pulse. These clusters will typically occur in strata that
immediately underlie facies changes and sequence-stratigraphic surfaces.
It has been proposed that a basin-wide analysis of the fossil record
within a sequence-stratigraphic framework can be used to distinguish
between clusters of last occurrences caused solely by extinction pulses
from those generated by sequence-stratigraphic architecture. A basin-wide
approach makes it possible to observe lateral facies shifts in response to
sea-level change, mitigating the effects of stratigraphic architecture.
Using computer simulations of plausible Late Ordovician mass-extinction
scenarios tuned to an inferred Upper Ordovician sea-level curve, we show
that stratigraphically-generated clusters of last occurrences are observed
even in basin-wide analyses of the simulated fossil records due to the
basin-wide loss of preferred facies for many taxa. Nonetheless, we
demonstrate that by coarsening the stratigraphic resolution to the
systems-tract level and identifying facies preferences of simulated taxa,
we can filter out taxa whose last occurrences coincide with the basin-wide
loss of their preferred facies. This enables consistent identification of
the underlying extinction pattern for a wide variety of extinction
scenarios. Applying this approach to empirical field data can help to
constrain underlying extinction patterns from the fossil record.