EAS212 Lecture Notes - Lecture 28: Asthenosphere, Oceanic Basin, Seafloor Spreading

• School: University of Alberta
• Department: Earth and Atmospheric Sciences
• Course: EAS212
• Professor: Juliana Marson

Document Summary

Changes in sea level: rising or lowering of the land surface relative to sea level through movement of earth"s crust isostatic sea level changes (relative, alteration of the level of sea itself eustatic sea level changes. Hudson bay: was covered by ice during last ice age, ice started to melt in this region 8,000 years ago, it will be close or above sea level by the time it stops isostatically rebounding (present average depth: Eustatic sea level changes: simultaneous worldwide changes in sea level, changes in ocean basin capacity sea floor spreading, changes in seawater volume, formation/melting of ice sheets. When climate cools, the oceans cool and contract and polar ice sheets expand as water is transferred to the land as snow and ice. Conversely, in warm periods, the oceans expand as heating melts ice and snow, which then flows to the ocean, raising sea level: reduction/elevation of average temperature (water contracts/expands) steric sea level change.