igneous concentration
61Géologie de la planète Mars — La géologie de la planète Mars, parfois appelée aréologie[1], recouvre l étude scientifique de Mars et de ses propriétés physiques, de ses reliefs, de sa composition, de son histoire, et de tous les phénomènes qui ont affecté ou affectent encore… …
62United States — a republic in the N Western Hemisphere comprising 48 conterminous states, the District of Columbia, and Alaska in North America, and Hawaii in the N Pacific. 267,954,767; conterminous United States, 3,022,387 sq. mi. (7,827,982 sq. km); with… …
63Nickel — This article is about the chemical element. For other uses, see Nickel (disambiguation). cobalt ← nickel → copper ↑ Ni ↓ Pd …
64Virginia — This article is about the U.S. state, the Commonwealth of Virginia. For other uses, see Virginia (disambiguation). Commonwealth of Virginia …
65Laterite — (from the Latin word later meaning brick or tile) is a surface formation in hot and wet tropical areas which is enriched in iron and aluminium and develops by intensive and long lasting weathering of the underlying parent rock. Nearly all kinds… …
66List of National Monuments of the United States — The United States has 101 protected areas known as national monuments. The President of the United States can establish a national monument by executive order, and the United States Congress can by legislation. The Antiquities Act of 1906… …
67Asia — /ay zheuh, ay sheuh/, n. a continent bounded by Europe and the Arctic, Pacific, and Indian oceans. 2,896,700,000; ab. 16,000,000 sq. mi. (41,440,000 sq. km). * * * I Largest continent on Earth. It is bounded by the Arctic Ocean, the Pacific Ocean …
68History of the Earth — For the history of modern humans, see History of the world. Geological time put in a diagram called a geological clock, showing the relative lengths of the eons of the Earth s history The history of the Earth describes the most important events… …
69Europium — (pronEng|jʊˈroʊpiəm) is a chemical element with the symbol Eu and atomic number 63. It was named after the continent Europe. Characteristics Europium is the most reactive of the rare earth elements; it rapidly oxidizes in air, and resembles… …
70Iridium — (pronEng|ɪˈrɪdiəm) is a chemical element that has the symbol Ir and atomic number 77. A very hard, brittle, silvery white transition metal of the platinum family, iridium is the second densest element and is the most corrosion resistant metal,… …
