{"thcode":4,"term":{"code":"4.2","name":"Porphyry","parent":"4","scope":"An igneous rock of any composition that contains conspicuous phenocrysts in a fine-grained groundmass."},"uf":[],"bt":[{"code":"4","name":"Plutonic rock","parent":"0","scope":"A rock formed at considerable depth by crystallization of magma and\/or by chemical alteration.  It is characteristically medium- to coarse-grained, of granitoid texture."},{"code":"0","name":"Earth material","parent":null,"scope":"Geologic map unit classification (Bruce R. Johnson) version 6.2: A hierarchical classification of earth materials for digital geologic maps."}],"nt":[{"code":"4.2.1","name":"Lamprophyre","parent":"4.2","scope":"A group of porphyritic igneous rocks in which mafic minerals form the phenocrysts; feldspars, if present, are restricted to the groundmass."}],"rt":[]}