Sea-level change and rock-record bias in the Cretaceous: a problem for extinction and biodiversity studies

Abstract

The association between mass extinction in the marine realm and eustatic sea-level change in the Mesozoic is well documented, but perplexing, because it seems implausible that sea-level change could actually cause a major extinction. However, large-scale cycles of sea-level change can and do alter the ratio of shallow to deep marine continental-shelf deposits preserved in the rock record both regionally and globally. This taphonomic megabias alone could be driving patterns of first and last occurrence and standing diversity because diversity and preservation potential both change predictably with water depth. We show that the Cenomanian/Turonian faunal event in western Europe has all the predicted signatures expected if taphonomic megabias was the cause. Grade taxa terminating in pseudoextinction and Lazarus taxa are predominantly found in the onshore facies that disappear for extended periods from the rock record. Before other mass extinctions are taken at face value, a much more careful analysis of biases in the rock record needs to be carried out, and faunal disappearances need to be analyzed within a phylogenetic framework.

Rapid recovery from the Late Ordovician mass extinction

“…Indeed, the Late Ordovician mass extinction has been linked directly to a significant fall and rise in eustatic sea level associated with the waxing and waning of a large Gondwanan ice sheet (46), and this record of sea-level change is directly associated with fluctuations in the quantity of sedimentary rock available for study (14). Our results are consistent with a number of recent modeling (47,48) and empirical studies (9,10,13,14) that suggest the need for a reassessment of stratigraphic bias on perceived trends in diversity and taxonomic rates across all mass extinction horizons. Such studies are critical for understanding the full impact of environmental perturbations on biodiversity and the processes of postextinction recovery.…”

“…However, it has long been known that variability of sampling through time may exert a strong control on perceptions of Phanerozoic diversity trends (7). Recent studies have begun to evaluate in greater detail sampling biases on diversity by using a variety of methods and databases (8)(9)(10). Some intervals of mass extinction have come under close scrutiny because they tend to have a close association with sea-level changes and drops in rock volume that bias the preserved record of diversity, extinction, and origination (10)(11)(12)(13)(14)(15).…”

“…This analytical approach should be extended to other Phanerozoic mass extinctions where variations in sampling intensity are of concern. † Data There are many sources of bias inherent in measuring diversity through time, including variations in sampling intensity (8,(17)(18)(19), variations in sampling across environmental gradients (10,20,21), and variations in sampling among geographic regions (22,23). We attempted to minimize these biases in compiling the data for this study.…”

Encrustation patterns on Late Cretaceous (Turonian) echinoids from southern Poland

“…This time interval is of interest because it follows the controversial CenomanianTuronian extinction event (e.g., Smith et al 2001). Epibionts may add new data and other perspectives in this regard (cf.…”

Interdependence of specialization and biodiversity in Phanerozoic marine invertebrates

“…Fossil-based estimates of marine diversity can be distorted by heterogeneities in the rock record and changing preservation probabilities within different sedimentary environments through time 8,35,36 . We use subsampling procedures that explicitly account for sampling biases (see Methods), and that should minimize the effects of potential biases on diversity patterns.…”