boundary layer thickness
111Precambrian 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… …
112Oceanic crust — Age of oceanic crust. The red is most recent, and blue is the oldest. Oceanic crust is the part of Earth s lithosphere that surfaces in the ocean basins. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and… …
113Atmosphere of Venus — Atmosphere of Venus …
114glacier — glaciered, adj. /glay sheuhr/, n. an extended mass of ice formed from snow falling and accumulating over the years and moving very slowly, either descending from high mountains, as in valley glaciers, or moving outward from centers of… …
115metamorphic 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,… …
116Disc brake — Close up of a disc brake on a car On automobiles, disc brakes are often located with …
117Saturn — /sat euhrn/, n. 1. an ancient Roman god of agriculture, the consort of Ops, believed to have ruled the earth during an age of happiness and virtue, identified with the Greek god Cronus. 2. Astron. the planet sixth in order from the sun, having an …
118igneous rock — Any of various crystalline or glassy, noncrystalline rocks formed by the cooling and solidification of molten earth material (magma). Igneous rocks comprise one of the three principal classes of rocks, the others being metamorphic and sedimentary …
119Debye sheath — The Debye sheath (also electrostatic sheath) is a layer in a plasma which has a greater density of positive ions, and hence an overall excess positive charge, that balances an opposite negative charge on the surface of a material with which it is …
120geochronology — geochronologic /jee oh kron l oj ik/, geochronological, adj. geochronologist, n. /jee oh kreuh nol euh jee/, n. the chronology of the earth, as based on both absolute and relative methods of age determination. [1890 95; GEO + CHRONOLOGY] * * *… …
