FINAL REVIEW Lecture 25 • When so much ice (like 2 miles thick), it starts to move – Glacier • When it meets the boundary, it fights the rocks and carries it to the edge (maximum extent to which the tongue of ice extended to) – MORAINE/GLACIAL TILL • Glacial erratic – big boulders carried to random spot by the movement of glaciers • Snowball Earth – End Ordovician – Permian (3 great ice ages; we’re in the 4 th ) • Glacial and interglacial are controlled by the planet (eccentricity, tilt, and precession (wobbling)); when combine three waves, get one that follows the temperature curve – MILANKOVICH CYCLE • ALBEDO – how much sunlight is reflected back without contributing to the energy of this planet (ice high albedo) • How have things been in this latest ice age that we are in? – quarternary is the one we’re still in; appearance of the Antarctic circumpolar current created a refrigerator decreasing temperature, this current hasn’t been consistent, cooling in Oligocene and slight warming in Miocene, then
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