formation in depth
51plate tectonics — plate tectonic, adj. Geol. a theory of global tectonics in which the lithosphere is divided into a number of crustal plates, each of which moves on the plastic asthenosphere more or less independently to collide with, slide under, or move past… …
52star — starless, adj. /stahr/, n., adj., v., starred, starring. n. 1. any of the heavenly bodies, except the moon, appearing as fixed luminous points in the sky at night. 2. Astron. any of the large, self luminous, heavenly bodies, as the sun, Polaris,… …
53chemical element — Introduction also called element, any substance that cannot be decomposed into simpler substances by ordinary chemical processes. Elements are the fundamental materials of which all matter is composed. This article considers the… …
54Association football tactics and skills — There are various individual skills and team tactics needed to play effective Association football. Football is in theory a very simple game, as illustrated by Kevin Keegan s famous assertion that his tactics for winning a match were to score… …
55Abiogenic petroleum origin — is a largely abandoned hypothesis that was proposed as an alternative to theory of biological petroleum origin. It was relatively popular in the past, but it went largely forgotten at the end of the 20th century after it failed to predict the… …
56Well logging — Gamma ray logging Spontaneous potential logging Resistivity logging Density logging Sonic logging Caliper logging Mud logging LWD/MWD v · …
57coal — coalless, adj. /kohl/, n. 1. a black or dark brown combustible mineral substance consisting of carbonized vegetable matter, used as a fuel. Cf. anthracite, bituminous coal, lignite. 2. a piece of glowing, charred, or burned wood or other… …
58mining — /muy ning/, n. 1. the act, process, or industry of extracting ores, coal, etc., from mines. 2. the laying of explosive mines. [1250 1300; ME: undermining (walls in an attack); see MINE2, ING1] * * * I Excavation of materials from the Earth s… …
59Atoll — For other senses of this word, see atoll (disambiguation). Satellite picture of the Atafu atoll in Tokelau in the Pacific Ocean. An atoll ( …
60Electric Line — The term wireline usually refers to a cabling technology used by operators of oil and gas wells to lower equipment or measurement devices into the well for the purposes of well intervention and reservoir evaluation. Braided line can contain an… …
