Event Title
Fluctuations at the Onset: A Study of the Mississippian Hydrosphere
Location
Parker-Reed, SSWAC
Start Date
30-4-2015 2:00 PM
End Date
30-4-2015 3:55 PM
Project Type
Poster
Description
The Mississippian period (~360-325 million years ago; Ma) of the Late Paleozoic represents the onset of the Late Paleozoic Ice Age (LPIA). This project explores the Mississippian hydrosphere using stratigraphic and geochemical data of near- and far-field evidence during a time of transitional climate. Globally-correlated cyclic stratigraphic transgressive-regressive sequences (sedimentation at varying sea levels) depict high-frequency, low-magnitude sea-level fluctuations, followed by larger magnitude low-frequency fluctuations that signify an icehouse-greenhouse transition. Global sea-level fluctuations (eustasy) directly correlate with the volume of accumulated glacial ice, and indicate changes in paleoclimate. Glacially driven eustasy is expressed as incised valley fills that depict rapid sea-level fall, which indicates widespread glaciation. Isotopic analyses of shallow-marine carbonate invertebrate shells act as proxies to constrain paleoceanographic chemistries. Implications of δ13C and δ18O isotope values depict a cool early Mississippian (Tournasian), followed by a warmer middle Mississippian (Visan), and a plunge in global temperature to glacial climates as the Mississippian came to a close. Cyclic stratigraphic successions, incised valley fill deposition, and isotope analyses of carbonates are correlated to indicate the driving forces of global climate change. These changes are observed in glacio-eustatic sea-level fluctuations and chemical composition of the Mississippian hydrosphere. These driving forces are a combination of: Milanković orbital cycles, eccentricity, obliquity, and precession; atmospheric pCO2 concentrations, and tectonics. Studying the effects of these forces offers insight on the magnitude of impact that modern climate change could have on humanity.
Faculty Sponsor
Herb Wilson
Sponsoring Department
Colby College. Geology Dept.
CLAS Field of Study
Natural Sciences
Event Website
http://www.colby.edu/clas
ID
1457
Fluctuations at the Onset: A Study of the Mississippian Hydrosphere
Parker-Reed, SSWAC
The Mississippian period (~360-325 million years ago; Ma) of the Late Paleozoic represents the onset of the Late Paleozoic Ice Age (LPIA). This project explores the Mississippian hydrosphere using stratigraphic and geochemical data of near- and far-field evidence during a time of transitional climate. Globally-correlated cyclic stratigraphic transgressive-regressive sequences (sedimentation at varying sea levels) depict high-frequency, low-magnitude sea-level fluctuations, followed by larger magnitude low-frequency fluctuations that signify an icehouse-greenhouse transition. Global sea-level fluctuations (eustasy) directly correlate with the volume of accumulated glacial ice, and indicate changes in paleoclimate. Glacially driven eustasy is expressed as incised valley fills that depict rapid sea-level fall, which indicates widespread glaciation. Isotopic analyses of shallow-marine carbonate invertebrate shells act as proxies to constrain paleoceanographic chemistries. Implications of δ13C and δ18O isotope values depict a cool early Mississippian (Tournasian), followed by a warmer middle Mississippian (Visan), and a plunge in global temperature to glacial climates as the Mississippian came to a close. Cyclic stratigraphic successions, incised valley fill deposition, and isotope analyses of carbonates are correlated to indicate the driving forces of global climate change. These changes are observed in glacio-eustatic sea-level fluctuations and chemical composition of the Mississippian hydrosphere. These driving forces are a combination of: Milanković orbital cycles, eccentricity, obliquity, and precession; atmospheric pCO2 concentrations, and tectonics. Studying the effects of these forces offers insight on the magnitude of impact that modern climate change could have on humanity.
https://digitalcommons.colby.edu/clas/2015/program/165