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6 Cards in this Set
- Front
- Back
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Polar Sharks and the arctic Greenhouse: Location of research
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Banks Island, Canadian Arctic: 50 million year old [Eocene-age] fossil from the Cyclic Member Eureka Sound Formation—The Arctic Greenhouse
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Polar Sharks and the arctic Greenhouse:
Ancient Arctic Ocean |
Arctic Ocean 50 million years ago:
• Nearly landlocked • Near freshwater salinity • Mild temperate to subtropical terrestrial environment have been studied especially form Ellesmere Island |
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Polar Sharks and the arctic Greenhouse:
Eocene Environment of Ellesmere Island |
Eocene environment of Ellesmere Island:
Lush mixed conifer-broad leaf trees forest with alligator turtles , diverse mammals Mild temperature: winters above freezing > 20C summer |
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Polar Sharks and the arctic Greenhouse:
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Peak of greenhouse condition about 50 million years ago at research location
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Polar Sharks and the arctic Greenhouse:
Cyclic Shale: Eureka Sound Formation |
• Early- middle Eocene ca 50 Ma based on pollen [Art Sweet]
• Coarsening-upward cycles of shale, silt, unconsolidated sand, paleosol, and coal • Interpreted as deltaic sequence in near-shore marine setting • Abundant shark teeth |
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Polar Sharks and the arctic Greenhouse: Shark Fossils found at Banks Island
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Banks Islands: In 3 field season, over 8,000 shark teeth collected from banks island >> of shark fauna belong to one genuse: Carcharias
Usually multiple types of sharks? Explanation: Breeding aggregation? Nursing/pupping ground Faunal diversity reduced due to very low salinity |
