Читать книгу Geology For Dummies - Alecia M. Spooner - Страница 45

While catastrophism attempted to explain the creation of earth’s features, questions about the origin of earth’s rocks remained. Where did the rocks on the crust of the earth come from before they were subjected to the catastrophes that shaped and shifted them?

Two theories dominated early thoughts on the origin of rocks: Neptunism and Plutonism.

 Neptunists proposed oceanic origins. The Neptunist theory of rock origins proposed that all the rocks on Earth were created from sea water, having crystallized from the earth’s first oceans. (The theory is named after the Roman god of the sea, Neptune.)

 Plutonists proposed volcanic origins. The Plutonists believed that all Earth’s rocks originated from volcanoes and were then changed by pressure and heat into other rocks. (The theory is named after the Roman god of the underworld, Pluto.)

While neither of these theories accurately explains how all rocks are formed, each contains partial truths. Some rocks do precipitate from ocean water, some rocks do form from volcanoes, and many rocks are changed into other rocks through heat and pressure, as you discover in Chapter 7.