macroscopic (mac-ro-scop'-ic). (a) megascopic. (b) According to Dennis (1967, p.152), a term introduced to describe tectonic features that are too large to be observed directly in their entirety. Cf: mesoscopic.
GeoWord of the Day
The GeoWord of the Day is a free service of the American Geosciences Institute. All of the terms and definitions are from the Glossary of Geology, 5th Edition Revised.
hydrous pyrolysis . Breakdown of organic matter at high temperature in the presence of water.
costa [paleont] . (a) One of the usually paired spines united medially and commonly laterally with neighboring spines to form a frontal shield overarching the frontal membrane in cribrimorph cheilostomes (bryozoans). Syn: costula; costule. (b) A round-topped elevation of moderate width and prominence disposed collabrally on the surface of a gastropod shell. (c) One of several moderately broad and prominent elevations of the surface of a bivalve-mollusk shell, directed radially or otherwise from the beak. Syn: rib [paleont]. (d) A radial ridge on the external surface of a brachiopod shell, originating at the margin of the protegulal node. Also, any coarse rib of a brachiopod, without reference to origin (usually fewer than 15 costae in a width of 10 mm). Cf: costella; capilla. (e) A ridge on the external surface of a foraminiferal test. It may run along a suture or be transverse to it. (f) The prolongation of a septum on the outer side of a corallite wall. (g) A long narrow raised area or ridge of a conodont. (h) A transverse ridge, straight or slightly curved, on the surface of whorls of coiled cephalopod conchs. (i) Anything that might be riblike in shape, including vertebrate ribs. Pl: costae.
törnebohmite-(Ce) (tor'-ne-bohm-ite'). An olive-green monoclinic mineral: Ce2Al(SiO4)2(OH).
retipilate (re-tip'-i-late). Of palynomorphs, having a reticulum formed by rows of columellae ( pila ) instead of muri.
homeostasis (ho-me-ost'-a-sis). The trend toward a relatively stable internal condition in the bodies of the higher animals as a result of a sequence of interacting physiologic processes; e.g., the ability to maintain relatively constant body heat during widely varying external temperatures.
excess pore pressure . Transient pore pressure at any point in an aquitard or aquiclude in excess of the pressure that would exist at that point if steady-flow conditions had been attained throughout the bed (Poland et al., 1972).
salt proximity survey [geophys exploration] . A survey to determine the location of the salt-sediment interface at a salt-dome flank. May involve recording offset and azimuthal VSP surveys in a borehole into the salt or near the salt flank from various surface locations, or a borehole gravimeter, long-spaced electrical log measurements, or other types of measurements.
melt-out till . Till derived from slow melting of thick masses of debris-rich stagnant ice buried beneath sufficient overburden to inhibit deformation under gravity, thus preserving structures derived from the parent ice (Boulton, 1970).
stream segment . A link, or sequence of links, along a stream channel, extending from the fork where the stream achieves a given stream order to the downstream fork where it joins a stream of equal or higher order. Syn: channel segment.
Pages
