Chalk is classified as which type of sedimentary rock?

Chalk is classified as which type of sedimentary rock?

• A. Clastic
• B. Chemical
• C. Biochemical
• D. Organic

Answer: (C)

Chalk forms from the accumulation and lithification of calcium carbonate shells and ooze produced by tiny marine organisms. This makes it a biochemical sedimentary rock, because its rock-forming material comes from biological activity rather than from cemented rock fragments (clastic) or from minerals that precipitate directly from water (chemical). Chalk is basically a limestone built up from skeletal remains, so it isn’t organic in the sense of preserved plant matter, but its origin is tied to biological processes, placing it in the biochemical category.

Chalk forms from the accumulation and lithification of calcium carbonate shells and ooze produced by tiny marine organisms. This makes it a biochemical sedimentary rock, because its rock-forming material comes from biological activity rather than from cemented rock fragments (clastic) or from minerals that precipitate directly from water (chemical). Chalk is basically a limestone built up from skeletal remains, so it isn’t organic in the sense of preserved plant matter, but its origin is tied to biological processes, placing it in the biochemical category.