bulk density

bulk density . The weight of an object or material divided by its volume, including pore spaces and in situ moisture. It is identified as dry density for the weight per unit volume of a soil mass that has been oven-dried to a constant weight at 105°C.


aviolite (av-i-o'-lite). A type of hornfels whose main constituents are mica and cordierite. Rarely used. Type locality: Monte Aviolo, Italian Alps. Cf: astite; edolite.

erosion caldera

erosion caldera . A type of caldera that is developed by the erosion and resultant widening of a caldera or by erosion of a volcanic cone, resulting in a large, central cirquelike depression. It is considered by some not to be a true caldera type, since it is not formed by volcanic processes. Cf: explosion caldera; collapse caldera.


anal (a'-nal). adj. Pertaining to or situated near the anus of an animal; e.g. an "anal opening" representing a large thecal orifice marking the position of the anus in the CD interray of a blastoid or crinoid. n. anal plate.


colloid (col'-loid). (a) A particle-size range of less than 0.00024 mm, i.e. smaller than clay size (U.S. Naval Oceanographic Office, 1966). (b) Originally, any finely divided substance that does not occur in crystalline form; in a more modern sense, any fine-grained material in suspension, or any such material that can be easily suspended (Krauskopf, 1967).

fault valley

fault valley . A linear depression produced by faulting; e.g. a small, narrow valley created within a major fault zone by relative depression of narrow slices, or a large graben situated between tilted block mountains, or a valley created by relative uplift on opposite sides of two parallel thrust faults. Cf: fault-line valley.

mound [arch]

mound [arch] . A small, human-made hill, composed either of debris accumulated during successive occupations of the site (syn: tell; teppe ) or of earth heaped up to mark a burial site.


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