Hostname: page-component-6766d58669-nf276 Total loading time: 0 Render date: 2026-05-19T13:46:39.612Z Has data issue: false hasContentIssue false

Aragonite bias, and lack of bias, in the fossil record: lithological, environmental, and ecological controls

Published online by Cambridge University Press:  24 February 2015

Michael Foote
Affiliation:
Department of the Geophysical Sciences, University of Chicago, Chicago, Illinois 60637, U.S.A. E-mail: mfoote@uchicago.edu
James S. Crampton
Affiliation:
GNS Science, Post Office Box 30-368, Lower Hutt 5040, New Zealand, and School of Geography, Environment and Earth Sciences, Victoria University of Wellington, Post Office Box 600, Wellington 6140, New Zealand. E-mail: J.Crampton@gns.cri.nz
Alan G. Beu
Affiliation:
GNS Science, Post Office Box 30-368, Lower Hutt 5040, New Zealand. E-mail:A.Beu@gns.cri.nz
Campbell S. Nelson
Affiliation:
School of Science, University of Waikato, Private Bag 3105, Hamilton 3240, New Zealand. E-mail: c.nelson@waikato.ac.nz

Abstract

Macroevolutionary and macroecological studies must account for biases in the fossil record, especially when questions concern the relative abundance and diversity of taxa that differ in preservation and sampling potential. Using Cenozoic marine mollusks from a temperate setting (New Zealand), we find that much of the long-term temporal variation in gastropod versus bivalve occurrences is correlated with the stage-level sampling probabilities of aragonitic versus calcitic taxa. Average sampling probabilities are higher for calcitic species, but this contrast is time-varying in a predictable way, being concentrated in stages with widespread carbonate deposition.

To understand these results fully, we link them with analyses at the level of individual point occurrences. Doing so reveals that aragonite bias is effectively absent in terrigenous clastic sediments. In limestones, by contrast, calcitic species have at least twice the odds of sampling as aragonitic species. This result is most pronounced during times of widespread carbonate deposition, where the difference in the per-collection odds of sampling species is a factor of eight. During carbonate-rich intervals, calcitic taxa also have higher odds of sampling in clastics. At first glance this result may suggest simple preservational bias against aragonite. However, comparing relative odds of aragonitic versus calcitic sampling with absolute sampling rates shows that the positive calcite bias during carbonate-rich times reflects higher than average occurrence rates for calcitic taxa (rather than lower rates for aragonitic taxa) and that the negative aragonite bias in limestones reflects lower than average occurrence rates for aragonitic taxa (rather than higher rates for calcitic taxa).

Our results therefore indicate a time-varying interplay of two main factors: (1) taphonomic loss of aragonitic species in carbonate sediments, with no substantial bias in terrigenous clastics; and (2) an ecological preference of calcitic taxa for environments characteristic of periods with pervasive carbonate deposition, irrespective of lithology per se.

Information

Type
Articles
Copyright
Copyright © 2015 The Paleontological Society. All rights reserved. 

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

Article purchase

Temporarily unavailable