formation in depth
61atmosphere — atmosphereless, adj. /at meuhs fear /, n., v., atmosphered, atmosphering. n. 1. the gaseous envelope surrounding the earth; the air. 2. this medium at a given place. 3. Astron. the gaseous envelope surrounding a heavenly body. 4. Chem. any… …
62Silurian Period — Interval of geologic time, 443–417 million years ago. The third period of the Paleozoic Era, the Silurian follows the Ordovician Period and precedes the Devonian. It marks the first appearance of land plants and jawed fishes. The continents were… …
63Geology of Mars — Mars   Mars as seen by the Hubble Space Telescope Designations …
64microscope — /muy kreuh skohp /, n. 1. an optical instrument having a magnifying lens or a combination of lenses for inspecting objects too small to be seen or too small to be seen distinctly and in detail by the unaided eye. 2. (cap.) Astron. the… …
65Overdeepening — Sognefjord in Norway, the second longest fjord in the world, shows characteristic overdeepening. Overdeepening is a characteristic of basins and valleys eroded by glaciers. An overdeepened valley profile is often eroded to depths which are… …
66Earth — This article is about the planet. For other uses, see Earth (disambiguation). Earth   …
67Sedimentary rock — Middle Triassic marginal marine sequence of siltstones (below) and limestones (above), Virgin Formation, southwestern Utah, USA Sedimentary rock are types of rock that are formed by the deposition of material at the Earth s surface and within… …
68Drilling fluid — This article is about fluids used when drilling a well. For fluids used with drill bits during metal working, see cutting fluid. Driller pouring a foaming agent down the rod string on a drilling rig In geotechnical engineering, drilling fluid is… …
69Roman infantry tactics — refers to the theoretical and historical deployment, formation and maneuvers of the Roman infantry from the start of the Roman Republic to the fall of the Western Roman Empire. The article first presents a short overview of Roman training. Roman… …
70Geology of the Iberian Peninsula — The geology of the Iberian Peninsula consists of the study of the rock formations on the Iberian Peninsula, which includes Spain, Portugal, Andorra, and Gibraltar. The peninsula contains rocks from every age from Ediacaran to Recent, and almost… …
