{"thcode":4,"term":{"code":"3.4.2","name":"Rhyolite","parent":"3.4","scope":"A volcanic rock defined in the QAPF diagram as having Q\/(Q+A+P) between 20 and 60% and P\/(P+A) between 10 and 35%..."},"uf":[],"bt":[{"code":"3.4","name":"Felsic volcanic rock","parent":"3","scope":"A light-colored, fine-grained or aphanitic extrusive or hypabyssal rock, with or without phenocrysts and composed chiefly of quartz and feldspar."},{"code":"3","name":"Volcanic rock","parent":"0","scope":"A generally finely crystalline or glassy igneous rock resulting from volcanic action at or near the Earth's surface, either ejected explosively or extruded as a lava.  The term includes near-surface intrusions that form a part of the volcanic structure."},{"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":[],"rt":[]}