University of New Mexico
Investigating evidence of high frequency glacial eustacy in the Lower Mississippian (Tournasian) Lodgepole Formation of southwest Montana : insights from conodont oxygen isotopes
Abstract
dc:description.abstractThis study focuses on high-frequency, subtidal-carbonate cycles (1-8 m thick) within the Woodhurst Member of the Lower Mississippian Lodgepole Formation of southwest Montana. We combined conodont-oxygen isotopes (δ18Oapatite¬) and carbonate-carbon isotopes (δ13Ccarb) with cyclostratigraphy of Woodhurst cycles to test the hypothesis that the cycles developed in response to glacial eustasy, evaluate the timing and initiation of the Late Paleozoic Ice Age (LPIA), and to better understand the carbon budget in response to cycle formation. δ18Oapatite trends across targeted cycles support the hypothesis of glacial eustatic origins along with cooling surface seawater temperatures. High-resolution δ13Ccarb analysis of whole-rock limestones within eleven cycles reveal invariant or nonsystematic δ13Ccarb trends, but the long term trend confirms a major positive excursion reported in previous studies of coeval deposits, values peak at ~ 7.5 ° in the upper S. isosticha conodont Zone.
Degree
thesis:*- Name thesis:degree_name
- Earth and Planetary Sciences
- Level thesis:degree_level
- Masters
- Discipline thesis:degree_discipline
- Department of Earth and Planetary Sciences
- Year
- 2011
Author and committee
dc:creator, dc:contributor.*- Author dc:creator
-
- Wallace, Zachary
- Contributors dc:contributor
-
- Elrick, Maya
- Atudorei, Viorel
- Fawcett, Peter
Subjects
dc:subject × 4Rights
- Language dc:language
- English
Identifiers
dc:identifier.*- OAI identifier oai:identifier
- oai:digitalrepository.unm.edu:eps_etds-1096