Coprolites in mid-Cambrian (Series 2-3) Burgess Shale-type deposits of Nevada and Utah and their ecological implications

 

Authors: Kimmig J, Strotz LC

Article in press: Received 8 March 2017; Accepted in revised form 13 June 2017; Online 3 August 2017

Keywords: coprolites, Spence Shale, Pioche Formation, Cambrian, ichnology, burrows, Burgess Shale-type deposit,

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Abstract

Five types of coprolites, represented by 40 specimens from the Cambrian (Series 2-3) Burgess Shale-type deposits in the Pioche Shale of Nevada and the Spence Shale of Utah, are described. They are preserved in finely laminated deep-water calcareous mudstones. Round to ellipsoid features 13–42 mm in diameter consisting of black carbon film and variable amounts of skeletal fragments are interpreted as coprolites that were originally deposited in a burrow. Two kinds of elongated coprolites are also preserved and either consist of small pellets or skeletal debris. The pellets are typically 0.5 to 2mmacross and have a round to ellipsoid outline. Two different types of pellet-filled burrows are also present. The presence of organic tissue and skeletal fragments in some coprolites provides direct evidence of predatory or scavenging activity, and may advance understanding of the food chain in these Cambrian deposits