METAMORPHISM AM o TRANSPORTATION
CKYSTALLIZATION
Th« rock cycle CRITERIA USED TO CLASSIFY METAMORPHIC ROCKS:
1. TEXTURE--THE SIZE, SHAPE, AND RELATIONSHIP OF THE MINERAL GRAINS TO EACH OTHER
2. COMPOSITION-WHAT MINERAL OR MINERALS ARE PRESENT OBJECTIVES IN STUDYING METAMQRPHIC ROCKS
1. IDENTIFICATION AND CLASSIFICATION OF THE ROCK
2. IDENTIFICATION OF THE ORIGINAL ROCK
3. TELL WHAT TYPE OF METAMORPHISM OCCURRED
4. TELL THE GRADE OF METAMORPHISM AGENTS OF METAMORPHISM
1. HEAT A. NEARBY MAGMA B. RADIOACTIVE DECAY C. NORMAL GEOTHERMAL GRADIENT D. FRICTIONAL HEAT DURING DIASTROPHISM
2. PRESSURE A. OVERBURDEN PRESSURE B. TECTONIC PRESSURE C. HYDRAULIC PRESSURE
3. CHEMICALLY ACTIVE FLUIDS A. JUVENILE WATER B. METEORIC WATER C. CONNATE WATER D. WATER OF FORMATION TYPES OF CHANGES DURING METAMORPHISM
1. SHEARING
2. GROWTH OF NEW MINERALS A. HIGH TEMP./HIGH PRESSURE POLYMORPHS B. NEW ELEMENTS INTRODUCED
3. RECRYSTALLIZATION
4. BAKING
5. DIFFERENTIAL MELTING
6. SEGREGATION OF MINERALS
7. ORIENTATION OF MINERAL GRAINS A. FOLIATION B. LINEATION C. BANDING TABLE 6-1. CLASSIFICATION OF MS7AMOHPHIC ROCKS
TEXTURE PARTICLE SIZS COMPOSITION COMMENTS ROCK NAME
Dense Slate Foliated Fine grained, Clay minerals, micas minerals not visible Clay minerals, micas . . Satiny luster Phyllite Medium to coa.-ss Muscovite, biotite. chlorite, talc, Rock name Is preceded by Schist Fclia'-ed grained, minerals garnet, kyanite. s'aurolita, diagnostic minerals cr visible quartz, ferromagnesian such as garnet mica Uneated minerals. schist, kyanite biotit? schist, hornblende schist i ORIENTE D GRAIN S Feldspars, quart!, micas, Banding due to Gneiss Banded ferromagnesian minerals. alternation of light and dark minerals Medium to coarse Calcite (CaCO,) Hardness of 3: fizzes grained, minerals rapidly with dilute HCI Marble visible Dolomite (Ca.Mg) (COj), Fizzes with dilute HCI Dolomitic only when powdered Marble M
< C Quartz {SiOiJ Hardness of 7; breaks Quartzite O across grains Q IU u Amphiboles Generally black; prismatic Amphibclite E crystals with 2 directions O c.' cteavage-at 120* 0 Anything that could be a Breaks across grains as Metaconglomerate conglomerate well as around them
Fine grained, Clay minerals, micas Dense, dark colored Kornfels minerals not Carbonaceous material Slack, shiny, conchoidal Anthracite Coal visible fracture
^VM -\s k*y >l» **«.tir».U Tr*.^c/H,TS . H^Uxv'Ve. CftAfc&lfcfr^tfi' t»«-Yi«. LOW GRADE MEDIUM GRADE HIGH GRADE ^^^^_ INDEX MINERALS ^ Original rock Chlorite Zone Biotite Zone Garnet Zone Staurolite zone Sillimanite zone
Rhyolite Rhyolite Biotite Biotite Biotite schist Biotite schist schist or schist or or gneiss or gneiss gneiss gneiss
Granite Granite Granite Granite Granite Granite gneiss gneiss gneiss gneiss
IGNEOU S ROCK Basalt Chlorite- Chlorite- Albite- Amphibolite Amphibolite epidote- epidote- epidote albite schist albite schist amphibolite
Limestone and Limestone and Marble Marble Marble Marble dolostone dolostone
Quartz sandstone Quartzite Quartzite Quartzite Quartzite Quartzite
Clayey Micaceous Quartz-mica Quartz-mica Quartz-mica Quartz-mica sandstone sandstone schist garnet schist garnet schist garnet schist or gneiss or gneiss or gneiss DIMENTAR Y ROCK S HI CO Shale SUte Phyllite Biotite- Biotite-garnet Siliimanite garnet phyllite Staurolite schist or schist gneiss Products of metamorphism METAMORPHIC ROCKS NAME LAB SEC.
Sample Grains: Visible or not? Grain size Hardness, HCI reaction, Rock name Possible original number Oriented or non-oriented? Mineral composition luster, color, etc. rock Type of orientation? METAMORPHIC ROCKS NAME LAB SEC.
Sample Grains: Visible or not? Grain size Hardness, HCI reaction, Rock name Possible original number Oriented or non-oriented? Mineral composition luster, color, etc. rock Type of orientation?