But the cotton gin also resulted in the expansion of slavery in the South. Because cotton is a labor-intensive crop, the spread of cultivation deepened and broadened the region's dependence on slave labor. While southern planters would reap great profits as a result of his invention, Whitney was less fortunate.
1 The oldest rocks on Earth, found in western Greenland, have been dated by four independent radiometric dating methods at 3.7-3.8 billion years. 2  Rocks 3.4-3.6 billion years in age have been found in southern Africa, western Australia, and the Great Lakes region of North America. Rocks 3.4-3.6 billion years in age have been found in southern Africa, western Australia, and the Great Lakes region of North America. 2  These oldest rocks are metamorphic rocks but they originated as lava flows and sedimentary rocks.
Igneous rocks are rocks formed from the crystallization of a liquid (molten rock). Igneous rocks may be divided into two categories. Intrusive or plutonic rocks crystallize from magma beneath the earth's surface.gneous Rocks. Of the three principal rock types (igneous, sedimentary, and metamorphic), igneous rocks can be thought of as primary rocks because they crystallize from a liquid. Sedimentary and metamorphic rocks, which we will study later, may be thought of as derivative rocks.