Conulariids from the Silurian (late Telychian) Waukesha Lagerstätte, Wisconsin

ABSTRACT

The Silurian (late Telychian) Brandon Bridge Formation, Wisconsin, USA, is renowned for hosting the Waukesha Konservat-Lagerstätte, in which several rare, enigmatic constituents have received detailed taxonomic and taphonomic study. However, more common species from this deposit remain poorly described. This study provides the first systematic description of two conulariid species documented from the Waukesha Konservat-Lagerstätte – Conularia niagarensis and Metaconularia cf. manni – and assesses their general taphonomy and preservation within this deposit. Specimens were examined using a combination of light microscopy, scanning electron microscopy and energy dispersive X-ray spectroscopy to assist in taxonomic, taphonomic and compositional analyses. Conulariid specimens display an array of preservational modes, primarily diagenetic phosphatisation and kerogenization, with minor associated pyritisation. This result suggests a taphonomic history involving post-burial demineralisation associated with falling pH conditions, subsequent compression with minimal breakage, and finally diagenetic mineralisation of the compressed thecae by francolite.

KEYWORDS:

• Conulariid
• Silurian
• taxonomy
• taphonomy
• Waukesha
• Lagerstätte

Acknowledgments

We thank Carrie Eaton, Museum Curator of the University of Wisconsin Geology Museum for access and loan of the specimens. We are also particularly grateful to Heyo Van Iten and Nigel Hughes for their constructive comments on an earlier version of the manuscript. Research presented herein was supported by National Science Foundation (NSF) CAREER Award 1652351 (JDS) and NSF Earth Sciences Postdoctoral Fellowship Award (ER-PF) 1725762 (EPA). AAM and SMJ were supported by NSF Sedimentary Geology and Paleobiology Award (EAR-SGP) 1917031. JDS and the X-ray Microanalysis Core were also supported by NSF Instrumentation and Facilities (EAR/IF) 1636643.

Disclosure statement

No potential conflict of interest was reported by the author(s).

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Additional information

Funding

This work was supported by the National Science Foundation (NSF) CAREER Award [1652351]; NSF Sedimentary Geology and Paleobiology Award (EAR-SGP) [1917031]; NSF Earth Sciences Postdoctoral Fellowship Award (ER-PF) [1725762].