1. Classification of Igneous, Sedimentary and Metamorphic Rocks

2. ROCK CYCLE Equilibrium Interrelationships between igneous rocks
sediment
sedimentary rocks
metamorphic rocks
weathering and erosion

4. EXTRUSIVE Volcanic- Fine-grained INTRUSIVE Plutonic- Coarse-grained
IGNEOUS ROCKS
EXTRUSIVE
Volcanic- Fine-grained
INTRUSIVE
Plutonic- Coarse-grained

5. MAGMA Molten Rock Generated at depth
Usually with dissolved gasses
Generated at depth
Eruptions if magma (lava) reaches surface
If doesn’t reach surface, Solidifies underground
Intrudes country or host rock
Intrusive contact
Xenolith- ‘foreign body’ 2

7. Igneous Rocks
Names based on mineral composition reflects chemical composition of the magma and... Grain size
Very coarse-grained Pegmatitic
Coarse-grained: Phaneritic > 1 mm.
Fine-grained: Aphanitic < 1 mm.
Porphyritic- 2 crystal sizes 3

12. Igneous Rocks- Classification
Coarse-grained-
Plutonic (Intrusive)
Granite (Sialic) (SIlica and ALuminum rich)
Diorite
Gabbro (Mafic) (MAgnesium and iron (FE) rich)
Dunite & Peridotite (Ultramafic)
Fine-Grained
Volcanic (Extrusive)
Rhyolite (Sialic)
Andesite
Basalt (Mafic) 4

14. Igneous Rock Identification
Granite (& Rhyolite)
High in Si + O
Low in Fe + Mg
Mostly feldspar & quartz
Light-colored
Basalt (& Gabbro)
“Low” in Si + O
High in Fe + Mg
no quartz, abundant ferromagnesian minerals
Dark colored
Andesite (& Diorite- intermediate) 5

21. WEATHERING, EROSION, TRANSPORTATION
Weathering- Physical disintegration and chemical decomposition of rocks
Erosion- Physical removal
Transportation- Movement of eroded particles
Chemical vs. Physical Weathering
Effects of weathering
Surface alteration of outcrops
Spheroidal weathering
Differential weathering

22. Physical Weathering

26. Differential Weathering

29. Frost Action

31. Exfoliation

33. Organic Action

34. ROCK CYCLE

35. Relative Percentages of Sedimentary Rocks

36. SEDIMENT Particle size Pebbles, cobbles, boulders Gravel- > 2mm
Sand- 2mm mm
Silt mm mm
Clay- < 0.004
Deposition Clay-sized particle vs. clay mineral

39. TYPES OF SEDIMENTARY ROCKS
Clastic or Detrital
Chemical- inorganic precipitation or evaporation
Biochemical- Organic remains
shells, charcoal, plant fragments

40. CLASTIC (Detrital) ROCKS
Breccia and Conglomerate (> 2mm)
Sedimentary Breccia- angular fragments
Conglomerate- rounded fragments
Sandstone (2mm mm)
Quartz sandstone
Arkose (feldspar)
Graywacke (appreciable amounts of silt/clay)
Fine-grained Matrix
Usually from turbidity currents

43. Quartz Sandstone

44. CHEMICAL SEDIMENTARY ROCKS
Carbonate Rocks
Limestone- made of calcite
Inorganic varieties
micrite, oolites, travertine
Dolomite
Recrystallization
Chert- silica
Evaporites
Rock gypsum
Rock salt

46. BIOCHEMICAL SEDIMENTARY ROCKS
Coal
Develops from peat
plant fragments
Lignite
Bituminous Coal
Carbonate Rocks
Limestone- made of calcite
organic varieties
Coquina
Fossiliferous Limestone
Chalk

50. SEDIMENTARY STRUCTURES
Cross-bedding
Graded bed
Mud cracks
Ripple marks
Fossils

52. Mudcracks

55. Sedimentary Rocks as Resources
Non-Metallic
Sand and gravel
Limestone
Clay
Gypsum
Energy Resources
Oil and Gas
Coal

56. Formation of Oil and Gas

61. U.S. Coal Production

62. Metamorphic Rocks Metamorphism Metamorphic rock
Increase in Pressure; increase in Temperature
Burial
Contact
Regional
Metamorphic rock
Pre-existing rock
Parent rock

66. Foliation

72. Classification
A- Slate
C- Phyllite
D- Schist
E- Gneiss
F- Migmatite

73. Classification