GEO 1111 Lecture Notes - Lecture 3: Mariana Trench, Continental Crust, Oceanic Crust

• School: University of Ottawa
• Department: Geology
• Course: GEO 1111
• Professor: Robert Jack Cornett

Document Summary

It is the dense solid part of the earth that consists of rocks and sediment. Antarctica and greenland are part of the cryosphere. Two peaks of elevation distribution (800m above sea level and 4000m below) Variation in density between the two crusts explains the two peaks. Oceanic rocks : mafic (mg and fe rich), very homogeneous compared to continental crust. Continental crust : felsic crust (rich in quartz and feld spars) No oceanic crust older than 200 million years, it is young because it keeps going under the continental crust into the mantle (denser) Mantle dynamics affect the elevations of the continental crust only slightly. Challenger expedition identified new species, determined sea depths, identified ridges underwater. Mariana trench : deepest part of the ocean (11 km) Ocean trenches: depression at the bottom of the ocean, narrow, where the oceanic crust is being subducted into the mantle, conversion point. Glaciers scratch the sea floor and create glacial striation.