Geological Society of America

T288 The Early Paleozoic World: Radiations, Extinctions, and Paleoenvironmental Change II

Wednesday, 28 September 2016
8:00 AM - 12:00 PM
Mile High Ballroom 3C

INTEGRATED HIGH-RESOLUTION BIOCHEMOSTRATIGRAPHY OF THE SCHLAMER #1 DRILL CORE, SOUTHERN ILLINOIS, USA: MARINE REDOX CYCLING DURING THE IREVIKEN AND MULDE POSITIVE CARBON ISOTOPE EXCURSIONS

Paper number: T288-10
Program: Technical Sessions
Time: 10:20 AM – 10:35 AM

Authors

Bradley Cramer Presenting Author
University of Iowa Dept of Earth & Environmental Sciences, Iowa City, IA
Neo E.B. McAdams
University of Iowa, Iowa City, IA
Alyssa Marie Bancroft
University of Iowa, Iowa City, IA
Terryl L. Bandy
University of Iowa, Iowa City, IA
Joseph Devera
Prairie Research Institute, University of Illinois, Carterville, IL

Abstract

The Schlamer #1 Drill Core was recovered from Alexander County, Southwestern Illinois, and contains more than 250 feet of Silurian strata. Conodont and carbon isotope data demonstrate that the core spans an interval at least from the Hirnantian Stage through the Pridoli Series. At present more than 400 carbonate carbon isotope samples, 150 conodont samples, 1,200 pXRF data points, and 150 solution ICP-MS samples have already been completed and demonstrate that the core contains the Hirnantian, Ireviken, Mulde, and Lau positive carbon isotope δ¹³C_carb excursions and associated biogeochemical events.

As suggested by previous studies, significant increases in redox-sensitive elements occur at the onset of both the Ireviken and Mulde biogeochemical events that may have played important roles in the development of the ocean-atmosphere-biosphere system during the Wenlock Epoch. In particular, REE and redox-sensitive elemental abundance data from the Schlamer #1 Core show evidence of marine anoxia during the Ireviken and Mulde positive δ¹³C_carb excursions. These findings provide support for a marine anoxia cause for the positive carbon isotope excursions of the Wenlock Epoch as opposed to their being the result of either carbonate weathering or diagenetic processes.

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

doi: 10.1130/abs/2016AM-286225

© Copyright 2016 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.