BGS Rock Classification Scheme

Chalk, clay-rich

Code CLKCR
Description Chalk, clay-rich
Qualifiers clay-rich      
Definition Friable & porous sedimentary rock with components >50% calcite/aragonite largely of biogenic origin i.e coccoliths Usually white, fine-grained, particles 0.032-0.25mm. >20% of <0.004mm particles from pre-existing siliciclastic rocks. A limestone.
Linked data http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/CLKCR

CAVEAT

"Thumbnail" definitions attached to some of the table entries are an interim attempt to provide simple short descriptions of the "unqualified" rock types presented within the BGS Rock Classification Scheme. Every effort has been made to ensure accuracy and consistency but minor contradictions or omissions might be present. The BGS welcomes any feedback pointing out such minor imperfections and/or providing constructive comment and suggestions for improvement of the definitions. In the first instance such feedback should be directed to Dr Tim McCormick.