Abstract
Is an orbitally tuned Paleozoic timescale achievable?
Abstracts with programs - Geological Society of America, Vol.40(6), p.283
Geological Society of America, 2008 annual meeting
10/2008
Abstract
Astrochronology has revolutionized Cenozoic chronostratigraphy, and is gradually being applied to older parts of the geologic timescale, however there are a number of substantial challenges that have limited the utility of this method for refining Paleozoic chronostratigraphy. First, the lack of deep-sea cores containing Paleozoic strata makes intercontinental correlation and global chronostratigraphy significantly more complicated than working in younger eras. Paleontological endemism, an incomplete epicontinental record, regional biological and lithological terminology ("state-line faults"), and a lack of integration between fields have all hindered Paleozoic efforts towards high-resolution chronostratigraphy. Second, the lack of sufficient radiometric data to reliably calibrate observed stratigraphic rhythms to temporal periods has served as a major obstacle to the development of accurate orbital time scales. Detailed biostratigraphic and carbon isotopic data amassed from European and North American study sites demonstrates that high-resolution global correlations are now clearly within reach for portions of the Silurian. In addition, the recent development of an inverse method for quantitative identification and calibration of orbital signals preserved in the rock record (Average Spectral Misfit, or ASM) overcomes the second major challenge of insufficient radiometric data. Here we present the results of ASM analysis of a high-resolution delta (super 13) C (sub carb) data set from the Silurian Visby Formation in Gotland (Sweden) that captures the onset of the early Sheinwoodian (Ireviken) positive carbon isotope excursion. Our analysis indicates that the null hypothesis (no orbital signal) can be rejected with a high degree of confidence (<0.2% probability) and provides the first segment of an orbitally-tuned Silurian timescale demonstrating that, although difficult and replete with challenges unique to the era, an orbitally-tuned Paleozoic timescale is indeed achievable.
Details
- Title: Subtitle
- Is an orbitally tuned Paleozoic timescale achievable?
- Creators
- Bradley D Cramer - Ohio State University, School of Earth Sciences, Division of Geological Sciences Columbus, OH USA United StatesStephen R Meyers - University of North Carolina USA United StatesAxel Munnecke - Universitaet Erlangen, GeoZentrum Nordbayern DEU GermanyLennart Jeppsson - Lund University
- Resource Type
- Abstract
- Publication Details
- Abstracts with programs - Geological Society of America, Vol.40(6), p.283
- Conference
- Geological Society of America, 2008 annual meeting
- Publisher
- Geological Society of America (GSA)
- ISSN
- 0016-7592
- Alternative title
- Geological Society of America, 2008 annual meeting
- Language
- English
- Date published
- 10/2008
- Academic Unit
- Earth and Environmental Sciences; International Programs; Office Of The Provost
- Record Identifier
- 9984240796402771
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