EARTH 222 Lecture Notes - Lecture 2: Mariana Trench, Oceanic Basin
11 Jun 2016
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Document Summary
General features of the earth"ssurface: areas total = 510x106 km2. Land: average =840 m maximum = 8,848 m at mt. Ocean: average= 3,800m maximum = 11,035 m at mariana trench. Type of continental margins: geologically quiet continental margins are called passive margins or atlantic-like margins, geologically active continental margins are called active margins or pacific-like margins. Passive continental margins: continental margins can be divided into: continental shelf, slope, and rise. Trenches and island arcs: trenches are narrow steep-sided troughs as deep as 11 km, 50-200 km wide, and thousand of km long, island arcs are curving chains of volcanic islands and seamounts. Deep ocean basin: the deep ocean floor includes a variety of features: abyssal plains, abyssal hills, seamounts, mid-oceanic ridges, and deep sea trenches. Abyssal plains and abyssal hills: abyssal plains are flat portions of the ocean floor covered by sediments, abyssal hills are small extinct volcanoes or intrusions of once molten rock covered by sediments.
