MINERALS AND ROCKS

COMPOSITION, ORIGIN AND IDENTIFICATION

COPOYRIGHT 2002, TERRY WRIGHT

MINERALS

• SOLID• INORGANIC• NATURALLY OCCURRING• CONSTANT PHYSICAL PROPERTIES

AND CHEMICAL CHEMICAL COMPOSITION

• SET INTERNAL STRUC TURE OF ATOMS

CHEMISTRY

• ATOMS– NEUTRONS– PROTONS– ELECTRONS

• ATOMS HAVE SNUG FIT• ATOMS HAVE NEUTRAL CHARGE• ATOMS HAVE BONDING

– IONIC– COVALENT– METALLIC

• TO FORM MINERALS

CRYSTAL CHEMISTRY

• POPULARITY LIST:• Si, O, Al, Fe, Mg, K,Na, Ca• Si and O form basic silica tetrahedron and has

snug fit and covalent bonding• SiO4 does not have 0 net charge, but Oxygen

sharing and other ions give 0 net charge• Different arrangements result in different Silicate

minerals.

MINERAL PHYSICAL PROPERTIES

• LUSTER• COLOR TRUE/STREAK(FOR METALLIC

MINERALS)• HARDNESS• CLEAVAGE/FRACTURE• DENSITY• REACTION TO ACID• MAGNETISM• TASTE

VARIETY OF IGNEOUS ROCKS

• BOWENS REACTION SERIES-SEQUENCE OF CRYSTALLIZATION

• DIFFERENTIATION– GRAVITY SETTLING– MAGMA MIXING

VISCOSITY OF MAGMA

• SILICA CONTENT INCREASE

• TEMPERATURE DECREASE

• GAS CONTENT

• INCREASES VISCOSITY

VOLCANIC IGNEOUS ROCKS

QUIET ERUPTIONS:LAVA FLOWS, FINE GRAINED, LOW

VISCOSITY, QUIET ERUPTIONS, LOW SILICA, HIGH TEMPERATURE, GAS. SHIELD VOLCANOES, MELTING IN

MANTLE

EXPLOSIVE ERUPTIONS:PYROCLASTIC ROCKS, HIGH VISCOSITY

HIGH SILICA, FRAGMENTAL, LOW TEMPERATURE, GAS, STRATO- VOLCANOS, CONVERGENT BOUNDARIES-MELTING IN

SUBDUCTION ZONE

PLUTONIC ROCKS

• COOLED SLOWLY DEEP BENEATH THE SURFACE

• COARSE GRAINED, CRYSTALLINE

• DIKES, SILLS, BATHOLITHS

• GRANITE, DIORITE, GABBRO, PERIDOTITE

SEDIMENTARY ROCKS

• CLASTIC-BROKEN ORIGIN

• CHEMICAL/BIOCHEMICAL ORIGIN

• HISTORY OF SEDIMENTARY ROCKS

METAMORPHIC ROCKS

• RECRYSTALLIZATION

• FOLIATION VS NON-FOLIATION

• REGIONAL METAMORPHISM

• CONTACT METAMORPHISM

• HYDROTHERMAL METAMORPHISM

• FAULT METAMORPHISM