What is the Ocean

The topography and structure of the ocean floor are highly variable from place to place and reflect tectonic processes within the Earth s 

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The relationships between ocean depths and land elevations are shown in Fig. 10-2. On the average continents are 840 m above sea level, while the average depth of the oceans is 3730 m. 

If the Earth were a smooth sphere with the land planed off to fill the ocean basins the earth would be uniformly covered by water to a depth of 2430 m. 

The area, volume and average depth of the ocean basins and some marginal seas are given in Table 10-1. The Pacific Ocean is the largest and contains more than one-half of the Earth s water. It also receives the least river water per area of the major oceans (Table 10-2). Paradoxically it is also the least salty (Table 10-3). The land area of the entire Earth is strongly skewed toward the northern hemisphere. 

The topography and structure of the ocean floor are highly variable from place to place and reflect tectonic processes within the Earth s interior. These major features are shown in Fig. 9-1. These features have varied in the past so that the ocean bottom of today is undoubtedly not like the ocean bottom of 50 Ma ago. The major topographic systems, common to all oceans, are the continental margins, the ocean-basin floors, and the oceanic ridge systems. Tectonic features such as fracture zones, plateaus, trenches, and mid-ocean ridges act to subdivide the main oceans into a larger number of smaller basins. 

The continental margin regions are the transition zones between the continents and ocean basins. Though the features may vary, the general features shown occur in all ocean basins in the form of either 

The relationships between ocean depths and land elevations are shown in Fig. 9-2. On the average, the continents are 840 m above sea level, while the average depth of the oceans is 3730 m. If the Earth were a smooth sphere with the land planed off to fill the ocean basins, it would be uniformly covered by water to a depth of 2430 m. The hypsographic curve 

The area, volume, and average depth of the ocean basins and some marginal seas are given in Table 

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