METAMORPHIC ROCKS
RESULT FROM
ALTERATION OF PRE-EXISTING ROCKS BYHEAT, PRESSURE, AND CHEMICAL REACTIONS
CAN INVOLVE CHANGES IN MINERALOGY, TEXTURE, AND CHEMICAL COMPOSITION
ALTHOUGH SHALLOW BURIAL CAN PRODUCE LITHIFICATION AND DIAGENESIS OF SEDIMENT INTO SEDIMENTARY ROCK,
ONLY PLATE TECTONIC PROCESSES CAN CAUSE PRESSURES AND TEMPERATURES HIGH ENOUGH TO PRODUCE METAMORPHIC ROCKSMETAMORPHIC ROCKS TELL US ABOUT THE TEMPERATURE AND PRESSURE CONDITIONS UNDER WHICH THEY FORMED