Event Title

Trace Fossil Assemblages of the Lower Pilot Shale, Great Basin, U.S.A.

Poster Number

057

Faculty Mentor

Diana Boyer, Ph.D.

College

College of Arts and Sciences

Department

Chemistry, Physics, and Geology

Location

Richardson Ballroom

Start Date

20-4-2018 2:15 PM

End Date

20-4-2018 4:15 PM

Description

Ichnodisparity is a classification system for trace fossils that relies on the architectural structure of trace fossils to categorize them and can be used to interpret and compare community structure. The lower Pilot Shale, Famennian in age, was sampled at two localities in western Utah to record Late Devonian infuanal communities and investigate lateral variability in community structure. The two localities, Deadman Wash and Conger Mountain, are approximate 30 km apart and preserve variable trace fossil communities within calcareous shale to fine grained sandstones. Categories of architectural design were used in place of ichnotaxa to determine relative abundance of each category at each locality, and from this the diversity, richness, and evenness, as well as the density packing of trace fossils present was calculated. The assemblages from each locality were described using the eight identified categories of architectural designs, and the categories of simple horizontal burrows, passive horizontal burrows, vertical burrows, and paired trackways were found at both localities. Overall, the assemblages were similar, although richness at Deadman Wash was higher and the density of vertical burrows was higher at the Conger Mountain locality. These assemblages preserve conditions before the onset of the Hangenberg extinction event and, therefore, provide a baseline for comparison against post-extinction infaunal communities, as well as other studies of trace fossil ecology in the Late Devonian of the Great Basin.

Previously Presented/Performed?

Southeastern Geological Society of America Conference, Knoxville, Tennessee, April 2018;

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Apr 20th, 2:15 PM Apr 20th, 4:15 PM

Trace Fossil Assemblages of the Lower Pilot Shale, Great Basin, U.S.A.

Richardson Ballroom

Ichnodisparity is a classification system for trace fossils that relies on the architectural structure of trace fossils to categorize them and can be used to interpret and compare community structure. The lower Pilot Shale, Famennian in age, was sampled at two localities in western Utah to record Late Devonian infuanal communities and investigate lateral variability in community structure. The two localities, Deadman Wash and Conger Mountain, are approximate 30 km apart and preserve variable trace fossil communities within calcareous shale to fine grained sandstones. Categories of architectural design were used in place of ichnotaxa to determine relative abundance of each category at each locality, and from this the diversity, richness, and evenness, as well as the density packing of trace fossils present was calculated. The assemblages from each locality were described using the eight identified categories of architectural designs, and the categories of simple horizontal burrows, passive horizontal burrows, vertical burrows, and paired trackways were found at both localities. Overall, the assemblages were similar, although richness at Deadman Wash was higher and the density of vertical burrows was higher at the Conger Mountain locality. These assemblages preserve conditions before the onset of the Hangenberg extinction event and, therefore, provide a baseline for comparison against post-extinction infaunal communities, as well as other studies of trace fossil ecology in the Late Devonian of the Great Basin.