igneous concentration
11Ore genesis — The various theories of ore genesis explain how the various types of mineral deposits form within the Earth s crust. Ore genesis theories are very dependent on the mineral or commodity. Ore genesis theories generally involve three components:… …
12duricrust — /door i krust , dyoor /, n. a hard crust that forms on or in soil in semiarid climates owing to cementation of soil particles. Cf. caliche, hardpan (defs. 1, 2). [ < L dur(us) hard + I + CRUST] * * * ▪ geology Introduction surface or near… …
13Australia — /aw strayl yeuh/, n. 1. a continent SE of Asia, between the Indian and the Pacific oceans. 18,438,824; 2,948,366 sq. mi. (7,636,270 sq. km). 2. Commonwealth of, a member of the Commonwealth of Nations, consisting of the federated states and… …
14Earth — This article is about the planet. For other uses, see Earth (disambiguation). Earth   …
15Uranium mining — The Ranger Uranium Mine in Australia …
16South America — South American. a continent in the S part of the Western Hemisphere. 271,000,000; ab. 6,900,000 sq. mi. (17,871,000 sq. km). * * * Continent, Western Hemisphere. The world s fourth largest continent, it is bounded by the Caribbean Sea to the… …
17metamorphic rock — Any of a class of rocks that result from the alteration of preexisting rocks in response to changing geological conditions, including variations in temperature, pressure, and mechanical stress. The preexisting rocks may be igneous, sedimentary,… …
19atmosphere, evolution of — Introduction the development of Earth s (Earth) atmosphere across geologic time. The process by which the current atmosphere arose from earlier conditions is complex; however, evidence related to the evolution of Earth s atmosphere, though… …
20Precambrian time — Interval of geologic time from с 3. 8 billion years ago, the age of the oldest known rocks, to 544 million years ago, the beginning of the Cambrian Period. This interval represents more than 80% of the geologic record and thus provides important… …
