39 D25. Paleontology, Systematics and Morphological Patterns (Posters)

Sunday, 4 November 2018
9:00 AM - 5:30 PM
Halls J-K

TENTACULITOIDS FROM THE UPPER SODUS SHALE, SILURIAN, WESTERN NEW YORK

Paper number: 39-12
Program: Technical Sessions
Time: 9:00 AM – 5:30 PM

Authors

Abstract

The Sodus Shale, a portion of the Lower Clinton Group, is a greenish-gray, fossiliferous silty shale that overlies the Reynales Limestone and is unconformably overlain by the Williamson Shale, a unit that is notable for current aligned graptolites. At Palmer’s Glen in Rochester, New York, the upper Sodus Shale consists of three distinct shale units separated by light gray, brachiopod grainstones. Tentaculitoids, preserved as external molds as well as calcite or pyrite internal molds, are relatively common in thin carbonate laminae as well as within the shale. The fauna is dominated by Tentaculites minutus Hall, 1843, which is characterized by a ~ 6 mm long conch with evenly spaced angular primary rings; the interspaces contain evenly-spaced annulations parallel to the primary rings. Oriented samples containing T. minutus were collected from limestone laminae in the lower and middle shale beds. The azimuth of the long axis of complete, unbroken specimens (n=51) were recorded and plotted on rose diagrams. Around 45% (23/n) of the tentaculitids had a NE-SW orientation and 10% (5/n) were NW-SE, perpendicular to the dominant orientation, suggesting a NE or SW paleocurrent. Previous work in the overlying Williamson Shale interpreted a to-the-south downslope paleocurrent based on N to NE oriented graptolites.

Geological Society of America Abstracts with Programs. Vol. 50, No. 6

doi: 10.1130/abs/2018AM-321097

© Copyright 2018 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.