In the glossary terms are defined under the following categories:
- Recommended terms are those recommended for use in international
papers and books. When used without a further qualification it is assumed
that they refer to the definition given in the SCMR glossary.
- Restricted terms are those not recommended for international
use, or if used, such terms have explicitly to be defined, either by
referring to the corresponding definition given in the SCMR glossary,
or by citing the author's own definition. The SCMR recommends the replacement
of restricted terms by recommended terms whenever practical.
- Unnecessary terms are those not recommended for further use
and which should be replaced by recommended rock names.
The glossary has been published in hardcopy along with the specialist
recommendations (see home page)
EXAMPLES OF GLOSSARY ENTRIES
Barrovian-type facies series:(in honour
of G Barrow , 1853–1932, who first described and mapped series
in 1893 and 1912, using mineral zones; Grampian Highlands of Scotland,
Dalradian supergroup, UK) . Type of facies series characterised
by the progressive development of garnet, kyanite from lower to higher
grades; andalusite, cordierite and glaucophane are absent. The facies
represents medium P/T conditions (see Smulikowski et al., Fig. 3, this
vol.) and is common in regional metamorphism . It is equivalent
to the medium-P/T type of regional metamorphism of Miyashiro
(see baric types of metamorphism ). See also Barrow's zones . (Read,
1952, p.278; Fyfe et al., 1958, p.228; Miyashiro, 1961, p.278; Hietanen,
1967, p.195; Turner, 1981, p.375).
Epizone: (Greek epi , upon and zônê ,
zone). Zone of low-grade metamorphic rocks characterised by illite Kübler
index (KI) mean values less than
0.25 Δº2Θ CuK α. The term was
originally proposed by Becke and by Grubenmann to indicate a shallow
depth of metamorphism (including contact
metamorphism for Grubenmann); as such it was synonymous with epimetamorphic
zone . This latter usage is now regarded as unnecessary
and at present epizone is mainly used in the context of illite Kübler
index investigations. Cf. epimetamorphism . (Grubenmann
1904, p.57;Grubenmann & Niggli 1924, p.374, 397; Lindgren 1933, p.95;
Kübler 1967, p.111; Kübler 1968, p.393; Kübler 1984, p.578)
Impact pseudotachylite: (Greek pseudês ,
false, tachys ,quick, and lithos , stone). Pseudotachylite produced
by impact metamorphism . Dyke -like breccia formed
by frictional melting in the basement of impact craters , resulting
often in irregular vein-like networks. Typically, it contains unshocked
and shocked mineral and lithic clasts in a fine-grained aphanitic matrix.
See also melt vein . (Shand, 1916, p.198; Dence, 1971, p.5555;
Stöffler et al., 1988, p.289, Fig.8, Table2; Reimold, 1995, p.247;
Spray, 1998, p.195; Dressler & Reimold, 2004, p.2–36).
P-T- t path: Changing
pressure-temperature conditions experienced by a mineral or a rock with
time, or a line-curve on a P-T grid showing these changes. (OU; Yardley,
1989, p. 198; Spear, 1993, p.2; Miyashiro, 1994, p. 352).
Pressure shadow: (German Streckungshof ).
Area of low strain in a deformed rock that was protected from the maximum
compressive stress by its proximity to a rigid body, either a porphyroblast or
a porphyroclast . The area of low strain may preserve pre-existing
structures or space may be created in which new minerals may grow. The
growth of new minerals, typically quartz or calcite, in the low-strain
area may resemble a beard particularly if the minerals have a fibrous
habit, hence bearded structure . Syn. strain shadow. (Mügge,
1930, p.475; Spry, 1969, p.240; Ramsay & Huber, 1983, p.279; Vernon,
Schollen: (German Scholle , clod, flake). In a migmatite
, blocks or rafts of paleosome within the neosome ; the structure is
similar to agmatite but the neosome is more abundant so that the disrupted
blocks float like rafts. (OU; Mehnert, 1968, p.15; Ashworth, 1985, p.3).
Solvus: (Latin solvere , to dissolve). Curved
P-T-X line or surface that separates the field of homogeneous solid solution
from the field of limited mutual solid solution; Cf. liquidus. (Edgar,
1974, p.21; Bucher & Frey, 1994, p.122).
Tektite: (Greek têktos , molten). Impact
glass formed at terrestrial impact craters from melt
ejected ballistically and deposited as aerodynamically shaped bodies
in a strewn field outside the continuous ejecta blanket .
The size of tektites ranges from the submillimetre range ( microtektites ,
generally found in deep-sea sediments) to the subdecimetre range, rarely
to decimetres. (Suess, 1900, p.191; Spencer, 1933a, p.117; Park, 1989b,
p.554; Glass, 1990, p.393).