The Structure of Earth

Principle surface features of the Earth –

(a) Continents

(b) Ocean basins

· Both are distinctly different in composition, density, rock type, structure and origin

(a) Continental Masses:

· Part of the earth - covers about 29% of the earth’s surface and has an average elevation of about 5 km above the floors of the ocean basins and about 1 km above sea level.

· It composed largely of rocks known as granite. The continents rise above the ocean basins as large platforms.

· The highest mountain on the continental surface is Mount Everest which is 29000 feet above sea level but the deepest part of the ocean is about 35000 feet below sea level at Pacific Ocean.

(b) Ocean Basins

• The greatest part of the hydrosphere - covers about 70% of the earth's surface.

• The ocean floors are also as irregular and posses many deep trenches and mountain ranges as the continental masses.

• The rocks of the ocean are rather dense, dark basaltic rock.

A graph of the elevation of the continents and ocean basins