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 that have formed out of magma (molten rock). The two types of igneous rocks most common on Earth are called granite and basalt. Granite is a rock that typically looks pink and white with black specks.Basalt generally just looks black.he Six Types of Igneous Rocks. To recap, granite is a coarse-grained felsic rock, while basalt is a fine-grained mafic rock. All of the other combinations have names too. A coarse-grained mafic rock is called gabbro, and a fine-grained felsic rock is called rhyolite.