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 Late 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.

中文翻译：

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从最后一次出现的簇中识别灭绝脉冲

在地层列中最后一次出现的化石类群的分布被用来从化石记录中推断出灭绝的模式，时间和速度。通常将最后出现的星团解释为突然灭绝的脉冲。但是，仅地层构造会产生最后出现的星团，这些星团可能被误认为是灭绝脉冲。这些团簇通常会出现在相变和层序地层表面直接下层的地层中。有人提出，在层序地层学框架内对整个化石记录进行全盆范围的分析，可以用来区分仅由灭绝脉冲引起的最后一次事件的聚类与层序地层学构造所产生的那些。盆地范围的方法使得观察海相变化引起的侧相变化成为可能，从而减轻了地层构造的影响。利用计算机模拟，调整到推断的奥陶纪晚期海平面曲线，将合理的晚奥陶纪大灭绝情景模拟，即使在盆地范围内对模拟化石记录的全盆地分析中，也观察到了最后一次发生的地层生成的星团。许多类群的首选相的广泛丧失。但是，我们证明了通过将地层分辨率粗化到系统域级别并确定模拟类群的相偏好，我们可以过滤出最近一次发生的盆地与其首选相的流域范围内的损失相吻合的类群。这使得能够针对各种灭绝场景对潜在的灭绝模式进行一致的识别。将这种方法应用于实地数据可以帮助限制化石记录中的基本灭绝模式。