Aragonite bias exhibits systematic spatial variation in the Late Cretaceous Western Interior Seaway, North America
File(s)
Published version
Author(s)
Dean, Christopher D
Allison, Peter A
Hampson, Gary J
Hill, Jon
Type
Journal Article
Abstract
Preferential dissolution of the biogenic carbonate polymorph aragonite promotes preservational bias in shelly marine faunas. While field studies have documented the impact of preferential aragonite dissolution on fossil molluscan diversity, its impact on regional and global biodiversity metrics is debated. Epicontinental seas are especially prone to conditions that both promote and inhibit preferential dissolution, which may result in spatially extensive zones with variable preservation. Here we present a multifaceted evaluation of aragonite dissolution within the Late Cretaceous Western Interior Seaway of North America. Occurrence data of mollusks from two time intervals (Cenomanian/Turonian boundary, early Campanian) are plotted on new high-resolution paleogeographies to assess aragonite preservation within the seaway. Fossil occurrences, diversity estimates, and sampling probabilities for calcitic and aragonitic fauna were compared in zones defined by depth and distance from the seaway margins. Apparent range sizes, which could be influenced by differential preservation potential of aragonite between separate localities, were also compared. Our results are consistent with exacerbated aragonite dissolution within specific depth zones for both time slices, with aragonitic bivalves additionally showing a statistically significant decrease in range size compared with calcitic fauna within carbonate-dominated Cenomanian–Turonian strata. However, we are unable to conclusively show that aragonite dissolution impacted diversity estimates. Therefore, while aragonite dissolution is likely to have affected the preservation of fauna in specific localities, time averaging and instantaneous preservation events preserve regional biodiversity. Our results suggest that the spatial expression of taphonomic biases should be an important consideration for paleontologists working on paleobiogeographic problems.
Date Issued
2019-09
Date Acceptance
2019-08-27
Citation
Paleobiology, 2019, 45 (4), pp.571-597
ISSN
0094-8373
Publisher
Cambridge University Press (CUP)
Start Page
571
End Page
597
Journal / Book Title
Paleobiology
Volume
45
Issue
4
Copyright Statement
© The Paleontological Society. All rights reserved 2019
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
This is an Open Access article, distributed under the terms of the Creative Commons Attribution licence (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted re-use, distribution, and reproduction in any medium, provided the original work is properly cited.
Subjects
0403 Geology
0602 Ecology
0603 Evolutionary Biology
Paleontology
Publication Status
Published
Date Publish Online
2019-09-23