Geological Society of America

15 Undergraduate Research Poster Session II (Posters)

Monday, 16 April 2018
8:00 AM - 5:30 PM
First Floor Lobby

CARBON ISOTOPE STRATIGRAPHY OF THE LITTLE CEDAR FORMATION IN EASTERN IOWA

Paper number: 15-6
Program: Theme Sessions
Time: 8:00 AM – 5:30 PM

Authors

Riley McMorran Presenting Author
University of Northern Iowa, Cedar Falls, IA
Xinhua Shen
University of Northern Iowa, Cedar Falls, IA
Joshua Sebree
University of Northern Iowa, Cedar Falls, IA
Alexa Sedlacek
University of Northern Iowa, Cedar Falls, IA
William Spurr
University of Northern Iowa, Cedar Falls, IA
Emma Shipley
University of Northern Iowa, Cedar Falls, IA
Madeline Roach
University of Northern Iowa, Cedar Falls, IA
Juliana Herran
University of Northern Iowa, Cedar Falls, IA
Jessica Wayson
University of Northern Iowa, Cedar Falls, IA
Kayla Beck
University of Northern Iowa, Cedar Falls, IA
Michael Lashbrook
University of Northern Iowa, Cedar Falls, IA
Lucas Krakow
University of Northern Iowa, Cedar Falls, IA

Abstract

The Devonian Period (~419.2-358.9 million years ago) was marked by a rapid radiation of plants into continental environments, and associated global cooling lead to the development of continental ice sheets. During the Devonian, Iowa was located at low latitudes south of the equator and submerged in a shallow epicontinental sea that experienced multiple marine transgressions and regressions. The limestones deposited in this environment are widespread in the eastern portion of the state and are well exposed in the Cedar Valley. Limestone samples were collected from the Eagle Center and Hinkle members of the Little Cedar Formation from the Waterloo South Quarry and Raymond Quarry. Samples from the Eagle Center Member are brecciated, mottled, and contain banded chert and chert nodules. The Eagle Center is largely unfossiliferous, though heavily burrowed, and contains stromatolites. The fine grained limestone of the Hinkle Member conformably overlies the Eagle Center. Twenty samples were analyzed for δ¹³C carbonate at NASA Goddard Spaceflight Center using a Costech Elemental Analyzer coupled to a Thermo Scientific Delta Plus. The negative δ¹³C shift (from -0.2‰ to -3.5‰) through this section shown by the samples is consistent with reports of a long-term negative shift spanning from the early Givetian to the mid-upper Frasnian.

Geological Society of America Abstracts with Programs. Vol. 50, No. 4

doi: 10.1130/abs/2018NC-313016

© 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.