EARTHSC 1G03 Lecture Notes - Lecture 14: Taconic Mountains, Dolostone, Canadian Shield
11 Sep 2018
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Document Summary
Layer ii: paleozoic rocks: shield covered by younger sedimentary rocks in southern. Ontario: deposited 600-350 million years ago, paleozoic rocks are exposed along the niagara. Rock layers in escarpment: limestones, dolostones, sandstones, and shales, 400-500 million years old, relatively flat-lying sedimentary rocks, slight dip to south. Sandstones and shales: sandstones and shales were from the erosion of highlands, large deltas formed by rivers draining the taconic mountains. Limestones and dolostones: warm, shallow seas, near old reefs, lots of fossils. Dinosaurs: no rocks preserved between 350 and 2 million years ago, no mesozoic = no dinosaurs. About 20,000 years ago, southern ontario was covered by ice more than 2 km thick: as ice retreated about 12,000 years ago, ice blocked the st. lawrence large deep lakes formed (like lake iroquois) Niagara escarpment: rocks are old 400-500 million years, escarpment as a landform is young, formed by glacial and fluvial erosion, ex.
