Kendall McLeanChapter 4 Homework2. There is granite underneath the continent, and basalt underneath the oceans. Granite and basalt are different in color and texture. It suggests that since continents float above the deep ocean basins, that granite is also less dense than basalt.3. According to plate tectonics, passive margins developed during continental rifting and the formation of a new ocean basin. A passive margin is the "trailing edge" of a continent-ocean plate. The margin of the Pacific side of the Americas is called an active margin. In this margin, continental shelves are narrow, slopes are narrow and deep, and rises are usually absent. According to plate tectonics, active margins are convergent or transform plate boundaries. Therefore, an active continental margin is at the "leading edge" of one of the interacting plates. 4. The continental shelf is a shallow submerged extension of a continent. Continental shelves, an extension of the adjacent continents, are underlain by granitic continental crust.
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