TERMIUM Plus®

The Government of Canada’s terminology and linguistic data bank.

ROCHE BASIQUE [5 records]

Filter results by subject field Alphabetical list of terms

Filter results by subject field

Alphabetical list of terms

Record 1 2011-05-06

English

Subject field(s)
  • Petrography
  • Geochemistry
DEF

An igneous rock having a relatively low silica content, sometimes delimited arbitrarily as 44% to 51% or 45% to 52%.

CONT

Igneous rocks [are subdivided] into the following groups: silicic or felsic (or acid, an old and discredited but unfortunately entrenched term), rocks having more than 66 percent silica; intermediate, rocks with 55 to 66 percent silica; and subsilicic, rocks containing less than 55 percent silica. The latter may be further divided into two groups: mafic, rocks with 45 to 55 percent ...

OBS

"Basic" is one of four subdivisions of a widely used system for classifying igneous rocks based on their silica content: acidic, intermediate, basic, and ultrabasic.

OBS

The term "subsilicic rock" is preferred to "basic rock" (the most commonly used term) which is misleading.

OBS

"Basic" must not be confused with "alkaline."

Key term(s)
  • sub-silicic rock

French

Domaine(s)
  • Pétrographie
  • Géochimie
CONT

L'acidité d'une roche est liée à sa teneur en silice, [...] les roches dites basiques en contiennent environ 50 %.

CONT

[...] un très grand nombre de dépôts cuprifères, aurifères, cobaltifères, nickélifères, et argentifères se localisent dans des roches basiques [...]

OBS

La notion d'acidité, quelque peu ambiguë pour les roches, a été introduite au milieu du siècle dernier par Élie de Beaumont qui, en fonction de la teneur en SiO2, distingue les roches acides [plus de 65 %], les roches intermédiaires [entre 52 et 65 %], les roches basiques [entre 45 et 52 %] et les roches ultra-basiques [moins de 45 %].

Spanish

Campo(s) temático(s)
  • Petrografía
  • Geoquímica
DEF

Roca que posee menos de un 60% de SiO2 y en la que no hay sílice libre, sino que toda forma parte de silicatos.

Save record 1

Record 2 2011-01-13

English

Subject field(s)
  • Petrography
  • Geochemistry
DEF

[An] igneous rock consisting essentially of ferromagnesian minerals to the virtual exclusion of quartz, feldspar, and feldspathoids.

CONT

Economic deposits of the mineral chromite are almost universally associated with mafic or ultra-mafic rocks.

OBS

Originally defined as rocks containing less than 45% silica, this artificial boundary has now been abandoned as a result of the recognition of many rock types which while undoubtedly ultrabasic by other tests, contain more than 45% silica ...

OBS

According to the source MROCK, 1985 (Richard Scott Mitchell, Dictionary of Rocks), the terms "ultramafic rock" and "ultrabasic rock" are nearly synonymous. They differ in that ultrabasic rocks contain little or no feldspar while ultramafic rocks contain no feldspar.

OBS

As a noun, the term "ultramafic" is used in the plural.

OBS

ultramafics: term used at Natural Resources Canada - Earth Sciences Sector.

Key term(s)
  • ultra-basic rock
  • ultra basic rock
  • ultra mafic rock
  • ultra-basite
  • ultra basite
  • ultra-mafite
  • ultra mafite
  • ultra-mafics
  • ultra mafics

French

Domaine(s)
  • Pétrographie
  • Géochimie
DEF

Roche magmatique mélanocrate à holomélanocrate pauvre en silice (SiO2 <45 %) et riche en calcium, fer et magnésium, constituée essentiellement d'un ou plusieurs minéraux ferromagnésiens (péridot, pyroxène, amphibole).

OBS

La notion d'acidité, quelque peu ambiguë pour les roches, a été introduite au milieu du siècle dernier par Élie de Beaumont qui, en fonction de la teneur en SiO2, distingue les roches acides [plus de 65 %], les roches intermédiaires [entre 52 et 65 %], les roches basiques [entre 45 et 52 %] et les roches ultra-basiques [moins de 45 %].

OBS

ultramafite : terme en usage à Ressources naturelles Canada - Secteur des sciences de la Terre.

Key term(s)
  • roche ultra basique
  • ultra-basite
  • ultra basite
  • roche ultra-mafique
  • roche ultra mafique
  • ultra-mafite
  • ultra mafite
  • ultra-mafitite
  • ultra mafitite

Spanish

Campo(s) temático(s)
  • Petrografía
  • Geoquímica
Save record 2

Record 3 2001-03-15

English

Subject field(s)
  • Petrography
  • Geochemistry
  • Vulcanology and Seismology
CONT

The weathering of basic volcanics in the greenstone belts would have yielded ample iron and silica.

CONT

The formation of these copper concentrations was probably dependent on a supply of copper from the erosion of neighbouring basic volcanic rocks ...

CONT

The general correlation of ore types with basic to acid volcanics favours a magmatic origin.

OBS

"Basic" is one of four subdivisions of a widely used system for classifying igneous rocks based on their silica content: acidic, intermediate, basic, and ultrabasic.

OBS

See records "basic rock" and "volcanic rock."

OBS

As a noun, "volcanic" is usually plural.

Key term(s)
  • basic volcanics

French

Domaine(s)
  • Pétrographie
  • Géochimie
  • Volcanologie et sismologie
CONT

Les roches volcaniques basiques dans le faciès schiste vert son formées de plagioclase, d'actinolite et de chlorite.

CONT

[...] on distingue [...] trois sous-ensembles : or des faciès sédimentaires associés au volcanisme acide, or dans un ensemble de volcanites basiques évoluant vers l'acide, or dans volcanites basiques et, notamment, ceintures de roches vertes métamorphisées.

Spanish

Save record 3

Record 4 2001-03-15

English

Subject field(s)
  • Geochemistry
  • Petrography
CONT

Volcanics, sediments and basic intrusives.

OBS

As a noun, intrusive is usually plural.

Key term(s)
  • basic intrusives

French

Domaine(s)
  • Géochimie
  • Pétrographie
CONT

La Scandinavie [...] possède des gisements étendus de pyrites cuivreuses [...] au contact de roches intrusives basiques (gabbros) ou de batholites granitiques.

Spanish

Save record 4

Record 5 1998-04-07

English

Subject field(s)
  • Petrography
  • Geochemistry
CONT

... non-economic nickel-copper mineralization and economic chromite deposits occur in the basic plutonic rocks.

French

Domaine(s)
  • Pétrographie
  • Géochimie
Key term(s)
  • roche plutonique basique

Spanish

Save record 5

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