{"thcode":4,"term":{"code":"3.6.1","name":"Trachybasalt","parent":"3.6","scope":"A volcanic rock defined modally by Q\/(Q+A+P) < 20% or F\/(F+A+P) < 10%, P\/(A+P) between 65 and 90%, and M > 35."},"uf":[],"bt":[{"code":"3.6","name":"Mafic volcanic rock","parent":"3","scope":"A solidified body of volcanic rock having abundant dark-colored minerals in its mode "},{"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":[]}