Event Title

From Icehouse to Greenhouse: Are Atmospheric Changes the Driver of Deglaciation?

Presenter Information

Jacob Wall, Colby CollegeFollow

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 Earths atmosphere experienced vast changes throughout the transition from the icehouse to greenhouse world during the Early Permian (~299-260 ma) as deglaciation occurred on the southern supercontinent, Gondwana. The extent and implication of these changes are still disputed. This paper employs a literature review to explore how the atmosphere played a role in climate, glacial dynamics, and glacioeustasy (sea level) changes at that time in the Early Permian. The widespread Early Permian collapse of ice sheets corresponds with rising temperatures due to an increase of CO2 concentrations. Throughout this time, pCO2 represent the primary control over the high-latitude glaciation and low-latitude climate changes. Pangaean (northern supercontinent) climate responded to Gondwanan deglaciation evidenced by the paleoequatorial transition from humid to arid conditions beginning in the Late Pennsylvanian (~304-299 ma). During this time, the Pangaean climate reacted with continental warming from 22 to 35 C, increasing aridity, displacing of tropical biomes, expanding of deserts, forests loss, and increasing low-latitude precipitation. Long-term Milancović eccentricity cycles (100-400 ka) play a strong secondary role in controlling climate as revealed in the pCO2 window of 420- to 840-ppm. Eccentricity cycles controlled glacioeustasy and precipitation distribution when pCO2 was in this window, represented by rhythmic sedimentary cycles in Pangaea. Atmospheric changes including an increase in CO2 playing the most important role in determining ice sheet dynamics, states of climate changes and glacioeustasy during the Early Permian, and forced the collapse of the Late Paleozoic Ice Age.

Faculty Sponsor

Herb Wilson

Sponsoring Department

Colby College. Geology Dept.

CLAS Field of Study

Natural Sciences

Event Website

http://www.colby.edu/clas

ID

1449

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Apr 30th, 2:00 PM Apr 30th, 3:55 PM

From Icehouse to Greenhouse: Are Atmospheric Changes the Driver of Deglaciation?

Parker-Reed, SSWAC

The Earths atmosphere experienced vast changes throughout the transition from the icehouse to greenhouse world during the Early Permian (~299-260 ma) as deglaciation occurred on the southern supercontinent, Gondwana. The extent and implication of these changes are still disputed. This paper employs a literature review to explore how the atmosphere played a role in climate, glacial dynamics, and glacioeustasy (sea level) changes at that time in the Early Permian. The widespread Early Permian collapse of ice sheets corresponds with rising temperatures due to an increase of CO2 concentrations. Throughout this time, pCO2 represent the primary control over the high-latitude glaciation and low-latitude climate changes. Pangaean (northern supercontinent) climate responded to Gondwanan deglaciation evidenced by the paleoequatorial transition from humid to arid conditions beginning in the Late Pennsylvanian (~304-299 ma). During this time, the Pangaean climate reacted with continental warming from 22 to 35 C, increasing aridity, displacing of tropical biomes, expanding of deserts, forests loss, and increasing low-latitude precipitation. Long-term Milancović eccentricity cycles (100-400 ka) play a strong secondary role in controlling climate as revealed in the pCO2 window of 420- to 840-ppm. Eccentricity cycles controlled glacioeustasy and precipitation distribution when pCO2 was in this window, represented by rhythmic sedimentary cycles in Pangaea. Atmospheric changes including an increase in CO2 playing the most important role in determining ice sheet dynamics, states of climate changes and glacioeustasy during the Early Permian, and forced the collapse of the Late Paleozoic Ice Age.

http://digitalcommons.colby.edu/clas/2015/program/160