geologic age . (a) The age of a fossil organism or of a particular geologic event or feature referred to the geologic time scale and expressed in terms either of years or centuries ( absolute age ) or of comparison with the immediate surroundings ( relative age ); an age datable by geologic methods. (b) The term is also used to emphasize the long-past periods of time in geologic history, as distinct from present-day or historic times. Cf: age [geochron].
glance pitch . A variety of asphaltite with a brilliant conchoidal fracture, sometimes called manjak. It is similar to gilsonite, but has a higher specific gravity and fixed-carbon content. It fuses between 230°F and 250°F.
parataxon (par-a-tax'-on). An informal designation for those fossilized remains, esp. of animals, that are only part of the whole individual and that usually occur widely separated from other parts; e.g. a particular conodont element. Cf: form genus. See also: taxon.
smaragdite (sma-rag'-dite). A fibrous or thinly foliated green amphibole (near actinolite) pseudomorphous after pyroxene (such as omphacite) in rocks such as eclogite.
flood lavas . A term applied to the very large scale lava flows in flood basalt fields; also to extensive trachyte and phonolite flows described from the East African rift system (Cas and Wright, 1987). Cf: flood basalt.
tectonosphere (tec-ton'-o-sphere). The zone or layer of the Earth above the level of isostatic equilibrium, in which crustal or tectonic movements originate. Rarely used. Cf: crust [interior Earth].
sai . A term used in central Asia for a gravelly talus, a river bed filled with stones, and a dry wash (Stone, 1967, p.258); also for a piedmont plain covered with pebbles showing desert varnish (Termier and Termier, 1963, p.413).
