Global factors constrain body size trends across the Great Ordovician Biodiversification Event at a regional scale: a case study from the Arbuckle Mountains of Oklahoma
Data files
Jul 07, 2025 version files 6.93 MB
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AppendixS1.pdf
6.81 MB
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AppendixS2.csv
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AppendixS3.csv
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AppendixS4.csv
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AppendixS5.csv
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AppendixS6.csv
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AppendixS7.csv
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AppendixS8.csv
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README.md
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Abstract
The Great Ordovician Biodiversification Event (GOBE) records a global increase in marine biodiversity which reached maximum diversification rates during the Middle Ordovician. The degree to which the drivers of the GOBE are regional or global is a question which must be addressed through analysis of regional data. In this study, stratigraphically constrained field-based data from the Middle Ordovician Simpson Group of Oklahoma were collected to identify temporal trends in body volume and determine whether body volume trends are more closely associated regional or global environmental and diversity changes. Volume increase was primarily associated with global-scale factors such as age, δ18O (temperature), 87Sr/86Sr (tectonics), and taxonomic diversity trends; whereas local-scale factors of Δ13C (carbon cycle) and lithologic trends were more weakly associated with local volume trends. Notably, all factors had a non-zero influence over brachiopod volume, indicating that local diversification was driven by multifaceted interactions among abiotic and biotic controls. These results support the argument that Ordovician diversification included a substantial biotic shift during the Middle Ordovician and support the hypothesis that global factors were dominant influencing diversification patterns during the main phase of the GOBE.
This dataset includes stratigraphic columns, ltihology, shell measurements, and isotopic data used in the analysis.
Dataset DOI: 10.5061/dryad.fj6q5746d
Description of the data and file structure
Data include sedimentological data, brachiopod shell measurement data, and geochemical data.
Files and variables
AppendixS1.pdf Stratigraphic columns with lithologic descriptions for all outcrops of Simpson Group strata along I-35 in Oklahoma included in this analysis.
AppendixS2.csv Lithologic data collected during field work for Simpson Group. Unit ID and formations match stratigraphic columns in Appendix 1. **cover and float intervals do not have unit ID #
AppendixS3.csv Brachiopod shell measurement data. Unit ID and formations match stratigraphic columns in Appendix 1. The quality of each measurement (length & width) was recorded as ‘A,’ ‘B,’ or ‘C’ quality according to the following criteria: A: Clear and complete length or width measurement, easily identifiable brachiopod; B: Clear measurement, ~80% complete length or width exposed; C: Measurement incomplete, but brachiopod identifiable. ATD volume = log10(L*W).
AppendixS4.csv Temporal bins for isotope values used in boosted regression analysis with value of 87Sr/86Sr, Δ13C, and δ18O per each age interval in Ma. Values for each isotope were obtained from published LOWESS curves generated using data from Simpson group outcrops. 87Sr/86Sr are from Avila et al. 2022. Δ13C are from Edwards and Salzman 2015. δ18O values from Appendix 8.
AppendixS5.csv Age model for time series analysis and boosted regression model. Conodont zone and ages from Bauer 1987 and Goldman et al. 2020.
AppendixS6.csv Values used in time series analysis. Sample count indicates number of brachiopod shells from which the mean volume and the variance of that volume was calculated. Data for shells in Appendix S3. Ages are determined from age model in Appendix S5.
AppendixS7.csv Values used in boosted regression analysis. Data combined from Appendices S2, S4, and S6.
AppendixS8.csv Geochemical data compiled by Avila et al. 2022 used to calculate δ18O LOWESS curve. 18O values compiled by Avila et al. 2022 from the following studies: Edwards et al. 2021, Grossman & Joachimski 2020, and Mannik et al. 2021.