Data from: 283,821 concretions, how do you measure the Mazon Creek? Assessing the paleoenvironmental and taphonomic nature of the Braidwood and Essex assemblages
Data files
May 02, 2025 version files 400.26 KB
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README.md
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Schiffbauer_et_al_Paleobiology_SOM_Mazon_Creek_Data.xlsx
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Abstract
The Mazon Creek Lagerstätte (late Carboniferous Period, Moscovian Stage; Illinois, USA) captures a diverse view of ecosystems in delta-influenced coastal settings through exceptional preservation of soft tissues in siderite concretions. The generally accepted paradigm of the Mazon Creek biota has been that of an inferred paleoenvironmental divide between what have been termed the Braidwood and Essex assemblages, wherein the former represents a freshwater ecosystem with terrestrial input and the latter a marine-influenced prodelta setting with abundant cnidarians, bivalves, worm phyla, and diverse arthropods. Here, we revisit the paleoecology of the Mazon Creek biota by analyzing data from nearly 300,000 concretions from 270 locations with complementary multivariate ordinations. Rather than a homogenization of ecological communities, our results show the Braidwood assemblage as a legitimate shoreward community and provide evidence for further subdivision of the Essex assemblage into two distinct subassemblages, termed here the Will-Essex and Kankakee-Essex. The Will-Essex represents a benthos dominated by clams and trace fossils along the transition between nearshore and offshore deposits. The Kankakee-Essex is dominated by cnidarians, presenting an ecosystem approaching the geographic margin of this taphonomic window. These new insights also allow a refined taphonomic model, wherein recalcitrant tissues of Braidwood organisms were subject to rapid burial rates while organisms of the Essex assemblage typically had more labile tissues and were subject to slower burial rates. Consequently, we hypothesize that the Braidwood fossils should record more complete preservation than the Essex, which was exposed for longer periods of aerobic decomposition. This is supported by a higher proportion of non-fossiliferous concretions in the Essex than in the Braidwood.
Dataset DOI: 10.5061/dryad.z8w9ghxr2
Description of the data and file structure
The raw dataset from Baird et al. (1985) comprises 286,953 concretions from 342 separate collections from the Mazon Creek Lagerstätte. These and other non-included samples and all available metadata are detailed in the Supplementary Online Materials (SOM), Appendix 1. Samples were collected from exposed mine dump surfaces in over 270 locations, including 25 strip mines and more than 80 shaft mines (Baird et al. 1985). The complete data set comprises 229 original identification groups (IDs), whether taxonomic or otherwise, including some subgroupings, taphomorphs, or other distinct characterizations (e.g., crushed bivalves vs. intact shells). IDs were originally coded by Baird as 4-character abbreviations, which have been included and defined in the SOM, Appendix 2. The original concretion tally includes both fossiliferous (specimens hereafter) and non-fossiliferous concretions. The original ledgers from each included sample have been digitized and are appended in the SOM, Appendix 3.
We revised the ID groupings by combining IDs that were confidently considered junior synonyms and/or taphomorphs. Further details are included in the supplementary tables of SOM, Appendix 2. We culled the raw dataset for multivariate ordination and diversity analyses by removing duds, poorly preserved specimens that could not be identified below the phylum level, problematica, samples with fewer than 50 specimens, and taxa represented in only one sample. All pertinent datasheets, including both the raw data tally and the culled dataset used for statistical analyses, are included as supplementary online files in Microsoft Excel format. In addition, for each sample not removed, we analyzed the proportion of duds to explore emergent trends in fossil preservation.
The accompanying Excel file includes the raw dataset from Baird et al. (1985), which comprises 283,821 concretions from 342 separate collections from the Mazon Creek Lagerstätte. These and other non-included samples and all available metadata are detailed in the associated PDF file. These files constitute the Supplementary Materials for Schiffbauer, Baird, and colleagues in Paleobiology.
Files and variables
File: Schiffbauer_et_al_Paleobiology_SOM_Mazon_Creek_Data.xlsx
Description: The tabulated and digitized raw dataset from Baird et al. (1985), comprising 283,821 concretions from 342 separate collections from the Mazon Creek Lagerstätte.
Variables/abbreviations included in the raw dataset are as follows:
Sample = locality number as defined during Baird's original collections
Grouping = assigned environmental/ecological characterization based on abundance of key taxa (Braidwood = freshwater-dominated taxa; Will = marine assemblage dominated by clams and traces; Kankakee = cnidarian-dominated marine assemblage)
Lat & Long = Latitude and longitude, in decimal format
NMDS1, NMDS2, NMDS3: These columns represent the coordinates of each sample along the first three axes of the Non-metric Multidimensional Scaling (NMDS) analysis.
Clade: The taxonomic classification of the organism, such as "Fish," "Amphibian," or "Plants."
Habitat: The environmental setting where the organism is typically found (e.g., "Marine," "Freshwater," or "Terrestrial").
Tissue: The biological material or anatomical part of the organism being studied
All four-letter identifications = call IDs for taxa preserved. This extensive list includes:
87 animal taxa: ACAN, AICH, AMPH, ANMD, ARAC, ARTH, BELO, BLOB, CAEN, CBAR, CCYC, CCYZ, CESS, CFLE, CHOP, CKAL, CKEL, CMES, CMRS, COST, CPAL, CPEA, CPYG, CSYN, CTYR, CUND, EDMO, EGGS, ESSX, ETAC, EUCH, EUPR, FCRT, FCTN, FESC, FGIL, FISH, FMEG, FPAL, FRHB, FWCL, FXNT, HDEV, HFTR, HOLT, INSC, KOTT, LIMU, LING, MBCR, MCEP, MCHT, MDUN, MEUP, MHTW, MLIM, MSCZ, MSOL, MSTR, MUND, MYAL, NCYC, OCTO, PECT, PLXS, REGC, SHRP, TFTR, TMON, WBLN, WCAP, WDRY, WESC, WFAN, WFSH, WHYS, WILY, WNEM, WOLH,WPJM, WPLN, WPRI, WSJW, WSPR, WTTH, WUND, and YWHY
45 plant taxa: ALTH, ANNL, ASTR, LEPD, LSTP, LSTR, LYCO, NEUR, ODON, PAPH, PASO, PBRK, PCAL, PCON, PCRC, PCRD, PCRS, PCYC, PDRN, PECO, PFUN, PLEP, PLIN, PMAC, PMAR, PPIN, PSAR, PSEL, PSPR, PSTM, PSUL, PTAE, PUND, SCBR, SEED, SPFR, SPHN, SPMG, SPRS, STIG, TCAR, TFBR, THAL, THRN, and TWSC
6 traces and other taxa: INCG, LETT, FCOP, TDPL, TPEL, and TRAL
and 33 distinct descriptors for dud concretions: DBLB, DBLG, DBRN, DCOM, DDBL, DDGB, DDGF, DDGR, DFGR, DGBR, DGGR, DGRB, DGRF, DGRY, DLBG, DLBR, DLGH, DLGR, DMOT, DODD, DPYC, DREJ, DSBR, DSEP, DSGB, DSGR, DSLG, DSND, DSPH, DWTH, DYLB, DUDS, and DTOT
We have provided extensive descriptions of each of the included taxa in Appendix 2 of the associated pdf, which includes Phylum, Class, and Genus designations for all animal taxa, as well as clade and habitat descriptors and any other relevant information.
File: Schiffbauer_et_al_Paleobiology_SOM_Mazon_Creek.pdf
Description: All metadata for the accompanying Excel data sheet as well as R markdown file for analyses used in Schiffbauer, Baird, and colleagues, Paleobiology.