BGS Rock Classification Scheme

Metabasalt, hornfelsed

Code MBAHF
Description Metabasalt, hornfelsed
Qualifiers hornfelsed      
Definition Meta-basalt protolith rock recrystallised by contact metamorphism to a hard rock lacking parting planes. Was <0.25mm grained intrus/extrus CI >35 vol% >40 wt%; quartz <20% or feldspathoid <10% of QAPF, feld >65% plagio; TAS SiO2 45-52wt%, Na2O+K2O <5wt%.
Linked data http://data.bgs.ac.uk/id/EarthMaterialClass/RockName/MBAHF

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.