BGS Rock Classification Scheme

Semipelite, migmatitic

Code SPMM
Description Semipelite, migmatitic
Qualifiers migmatitic      
Definition Medium to coarse-grained (av. 0.25-16mm), crystalloblastic metasedimentary rock, semipelite modal composition <10% carb/calc, 60-80% Q+F, <20-40% other minerals, the mesosome & megascopic composite, of one or more petrologically different layers/parts
Linked data http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/SPMM

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.