SUPPLY CHAIN DEFINITIONS. Definitions of a supply chain virtually universally encompass the following three functions: i. supply of materials to a manufacturer; ii. the manufacturing process; and, iii. the distribution of finished goods through a network of distributors and retailers to a final customer.
The thickest parts are under the continents and the thinnest parts are under the oceans. Crust. Earth's crust is made up of several elements: oxygen, 47 percent; silicon, 27 percent; aluminum, 8 percent; iron, 5 percent; calcium, 4 percent; magnesium, potassium and sodium, 2 percent. The crust is divided into huge plates that float on the mantle, the next layer.
The answer lies in the composition of the rocks. Continental crust is composed of granitic rocks which are made up of relatively lightweight minerals such as quartz and feldspar. By contrast, oceanic crust is composed of basaltic rocks, which are much denser and heavier.