Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (6) Citing Articles via Google Scholar Google Scholar Articles by Peters, S. E. Search for Related Content GeoRef GeoRef Citation

Genus extinction, origination, and the durations of sedimentary hiatuses

¹ Shanan E. Peters. Department of Geological Sciences and Museum of Paleontology, University of Michigan, Ann Arbor, Michigan 48109. shananp{at}umich.edu

Short-term variations in rates of taxonomic extinction and origination in the fossil record may be the result of true changes in rates of turnover, variable rates of fossil preservation, or some combination of the two. Here, positive extinction and origination rate excursions among Phanerozoic marine animal genera are reexpressed in terms of the amount of normal, background time they represent. In addition to providing a background-adjusted calibration of rate intensities, this reexpression determines the durations of sampling gaps that would be required to explain entirely all observed rate excursions as sampling artifacts. This possibility is explored by analyzing a new compilation of the timing and duration of sedimentary hiatuses in North America.

Hiatuses spanning more than approximately one million years (Myr) in the marine sedimentary rock record have a mean duration of 73 Myr. There are two major hiatus types—those that form in response to long-duration tectonic cycles and that bound the major Sloss-scale sequences (mean duration 200 Myr), and those that form in response to shorter-duration changes in sediment accommodation space and that occur within major Sloss-scale sequences (mean duration less than 23 Myr). The latter are approximately exponentially distributed and have a mean duration that is comparable to the mean duration of intervening sedimentary rock packages.

Although sedimentary hiatuses are generally long enough in duration to accommodate the hypothesis that short-term variations in rates of genus origination and extinction are artifacts of sampling failures at major unconformities ("Unconformity Bias" hypothesis), the observed evolutionary rates are not correlated with hiatus durations. Moreover, hiatuses that follow the major mass extinctions are not long in comparison to most other non–mass extinction intervals. These results do not support the hypothesis that hiatuses at major unconformities alone have artificially clustered genus first and last occurrences, thereby causing many of the documented statistical similarities between the temporal structure of the sedimentary rock record and macroevolutionary patterns. Instead, environmental changes related to the expansion and contraction of marine environments may have been the primary forcers of both biological turnover and the spatio-temporal pattern of sediment accumulation. Fully testing this "Common Cause" hypothesis requires quantifying and overcoming lingering taxonomic, biostratigraphic, facies, and numerous other biases that are both inherent in geologic data and imposed by imperfect knowledge of the fossil record.

This article has been cited by other articles:

				A. J. McGowan and A. B. Smith Are global Phanerozoic marine diversity curves truly global? A study of the relationship between regional rock records and global Phanerozoic marine diversity Paleobiology, January 1, 2008; 34(1): 80 - 103. [Abstract] [Full Text] [PDF]

				S. E. Peters and W. I. Ausich A sampling-adjusted macroevolutionary history for Ordovician-Early Silurian crinoids Paleobiology, January 1, 2008; 34(1): 104 - 116. [Abstract] [Full Text] [PDF]

				A. M. BUSH, M. KOWALEWSKI, A. P. HOFFMEISTER, R. K. BAMBACH, and G. M. DALEY POTENTIAL PALEOECOLOGIC BIASES FROM SIZE-FILTERING OF FOSSILS: STRATEGIES FOR SIEVING Palaios, December 1, 2007; 22(6): 612 - 622. [Abstract] [Full Text] [PDF]

				A. B. SMITH Marine diversity through the Phanerozoic: problems and prospects Journal of the Geological Society, July 1, 2007; 164(4): 731 - 745. [Abstract] [Full Text] [PDF]

				S. DOMINICI and M. ZUSCHIN SEA-LEVEL CHANGE AND THE STRUCTURE OF MARINE ECOSYSTEMS Palaios, May 1, 2007; 22(3): 225 - 227. [Full Text] [PDF]