75 Paleontology, Biogeography/Biostratigraphy (Posters)

Sunday, 25 September 2016
9:00 AM - 5:30 PM
Exhibit Hall E/F

THE NEAL TRACE FOSSIL LOCALITY: A NEW PENNSYLVANIAN ICHNOFOSSIL ASSEMBLAGE IN GREENWOOD COUNTY, KANSAS.

Paper number: 75-13
Program: Technical Sessions
Time: 9:00 AM – 5:30 PM

Authors

Abstract

An abundant assemblage of Pennsylvanian trace fossils is weathering out of the bank of an unnamed tributary of Walnut Creek, approximately 3 km southwest of the City of Neal in Greenwood County, eastern Kansas. Nearly all the traces are cast in positive hyporelief at the base of a discontinuous, up to 5 cm thick bed of reddish-brown very fine-grained sandstone within the Stull Shale Member (Kanwaka Shale, Shawnee Group). The Stull Shale is a medium to dark gray, silty shale that has a diverse invertebrate body fossil fauna, though such fossils are mostly rarer and mostly fragmentary at the Neal trace fossil locality. The traces are mostly fodinichnia made by vagile to hemisessile deposit feeding organisms; most of which have been previously documented in the Stull Shale and elsewhere. These include actively and passively filled fodinichnia such as Asterosoma radiciforme, Chondrites isp., very small Diplocraterion isp., Lockeia siliquaria, Planolites isp., and Rhizocorallium isp.; and such passively filled domichnia as Ophiomorpha nodosa, Palaeophycus tubularis, Pentichnus gugelhupf, and Skolithos isp. Most of these are common constituents of the Cruziana ichnofacies suggesting a low energy, upper to lower offshore marginal marine environment. This locality is distinct, however, in that it also contains previously undescribed large-scale, lobate digging traces. The ichnofossils resemble deep, u-shaped furrows up to 4 cm wide and 10 cm deep cut into the shale substrate and lined with shallow straight glyphs that run parallel with the direction of the excavation. Most appear to be composed of multiple excavations, often parallel with previous ones, though at differing depths and sometime cross-cutting each other. These new ichnofossils superficially resemble Cruziana goldfussi, but are distinct in several ways: 1) they are much deeper than typical C. goldfussi and are not obviously bilobate; 2) endopod (crawling limb) impressions are generally parallel with the long axis of the trace, but not with each other or in groups and not arching away from the long axis as in C. goldfussi; and 3) there are no traces of genal spines or carapace ornamentation.

Geological Society of America Abstracts with Programs. Vol. 48, No. 7

doi: 10.1130/abs/2016AM-287434

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