LABORATORY FOUR – Rock-Forming Processes and the Rock Cycle

LABORATORY FIVE –Igneous Rocks and Volcanic Hazards

Laboratory Manual in Physical Geology by The American Geological Institute (AGI) and the National Association of Geoscience Teachers (NAGT); Richard M. Busch, Editor; 6th Edition, 2003.

LABORATORY FOUR

ROCKS:

ROCK CYCLE

IGNEOUS

SEDIMENTARY

METAMORPHIC

ROCK PROPERTIES

General Color

General Form

COMPOSITION

TEXTURE (SIZE, SHAPE, and ARRANGEMENT of crystals or grains

TYPES CRYSTALLINE

Glassy

Vesicular

CLASTIC

FOLIATED

LABORATORY FIVE

IGNEOUS ROCKS

MAGMA

LAVA

INTRUSIVE

EXTRUSIVE

TEXTURE (Size, shape, arrangement of crystals or grains)

CRYSTALLINE TEXTURES (based in crystal size)

GLASSY

FINE GRAINED OR APHANITIC (< 1mm)

COARSE GRAINED OR PHANERITIC (1-10 mm)

PEGMATITIC (> 1cm)

PORPHYRITIC –Phenocrysts and Groundmass (matrix)

OTHER TEXTURES

VESICULAR

PYROCLASTIC

IGNEOUS ROCK-FORMING MINERALS

QUARTZ

POTASSIUM FELDSPAR (ORTHOCLASE)

PLAGIOCLASE

MUSCOVITE

BIOTITE

AMPHIBOLE (hornblende)

PYROXENE (augite)

OLIVINE

MINERAL COMPOSITION

ROCK COLOR / COMPOSITION

Quartz, Na-plagioclase, K feldspar, Muscovite

LIGHT / FELSIC

Biotite, Amphibole, Pyroxene, Olivine, (Ferromagnesian minerals) Ca-plagioclase

DARK / MAFIC

COLOR INDEX (CI)

CLASIFFICATION AND IDENTIFICATION OF IGNEOUS ROCKS (based on texture and mineral composition; Figures 5.2 and 5.3; pp 78 and 79)

FELSIC

INTERMEDIATE

MAFIC

ULTRAMAFIC

SEDIMENTARY ROCKS