alkali rock: meaning, definition, pronunciation and examples
Very Low (C2)Technical/Scientific
Quick answer
What does “alkali rock” mean?
An igneous rock containing a high proportion of alkali metals (sodium and potassium) relative to silica.
Audio
Pronunciation
Definition
Meaning and Definition
An igneous rock containing a high proportion of alkali metals (sodium and potassium) relative to silica.
A general term for silicate rocks rich in alkali feldspars, forming a major class within igneous petrology. It often describes rocks like syenite and trachyte, which are relatively silica-undersaturated.
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning. Spelling conventions (e.g., 'analyse' vs. 'analyze' in surrounding text) may apply.
Connotations
Purely technical term with identical scientific denotation in both varieties.
Frequency
Used with equal rarity in professional geology circles in both the UK and US.
Grammar
How to Use “alkali rock” in a Sentence
The [geological region] is composed predominantly of alkali rock.[Noun Phrase: Alkali rock] is typically found in [tectonic setting].Vocabulary
Collocations
Examples
Examples of “alkali rock” in a Sentence
verb
British English
- The magma crystallised to alkali-rock.
American English
- The magma crystallized to form alkali rock.
adjective
British English
- The alkali-rock composition was confirmed.
American English
- The alkali rock composition was confirmed.
Usage
Meaning in Context
Business
Not used.
Academic
Used in geology, petrology, and earth science papers and lectures.
Everyday
Not used.
Technical
Core term for classification in igneous petrology and mineral exploration.
Vocabulary
Synonyms of “alkali rock”
Strong
Neutral
Weak
Vocabulary
Antonyms of “alkali rock”
Watch out
Common Mistakes When Using “alkali rock”
- Confusing with 'alkaline rock' (which can refer to carbonate rocks or high pH rocks).
- Using as a general term for any 'basic rock' (a related but broader category).
FAQ
Frequently Asked Questions
No, in precise geological terminology, 'alkali rock' refers specifically to igneous rocks high in Na and K relative to Si. 'Alkaline rock' is a broader, sometimes ambiguous term that can include carbonate rocks or simply rocks with high pH.
Yes, syenite (a coarse-grained intrusive rock) and its volcanic equivalent, trachyte, are classic examples of alkali rocks.
They are key indicators of specific tectonic environments (like continental rifts) and are often associated with valuable mineral deposits, including rare earth elements.
Typically, no. Most granites are calc-alkaline or subalkaline. True alkali granites exist but are a specific, less common variety.
An igneous rock containing a high proportion of alkali metals (sodium and potassium) relative to silica.
Alkali rock is usually technical/scientific in register.
Alkali rock: in British English it is pronounced /ˈæl.kə.laɪ rɒk/, and in American English it is pronounced /ˈæl.kə.laɪ rɑːk/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “none”
Learning
Memory Aids
Mnemonic
Think: 'A-lie' on a 'rock'? No, it's 'Alkali' rock – a rock lying in a chemical family (alkali metals).
Conceptual Metaphor
NONE (Literal scientific classification).
Practice
Quiz
In which tectonic setting are alkali rocks MOST commonly formed?