From GeoClasses

Contents 1 Week 2: Chapters 2 and 3 1.1 Plate tectonics 1.1.1 internal structure of the Earth 1.1.2 what do we know from seismology? 1.1.3 what did we learn from seafloor spreading? 1.2 types of plate boundaries 1.2.1 divergent 1.2.2 convergent 1.2.3 transform 1.3 history of plate motion 1.3.1 what do fossils and hot spots tell us? 1.4 hazards 1.5 The Rock Cycle 1.5.1 Weathering 1.5.2 On sedimentary rocks 1.5.2.1 original horizontality 1.5.2.2 superposition (relative ages of rocks) 1.5.2.3 crosscutting relationships 1.6 Plate boundaries and rock types 1.6.1 intrusive igneous 1.6.2 extrusive igneous (volcanic) 1.6.3 Chemical composition 1.7 sedimentary rocks 1.7.1 'detrital (mechanically formed)' 1.7.2 'chemically formed' 1.7.3 metamorphic (formed by high heat and pressure) 1.8 what else can happen to rocks?

Week 2: Chapters 2 and 3

Plate tectonics

• Theory of Plate Tectonics
• What is a Tectonic Plate

internal structure of the Earth

what do we know from seismology?

• Plate tectonics and earthquakes

what did we learn from seafloor spreading?

• Continental Jigsaw
• continental drift animations

types of plate boundaries

• Plate Boundaries

divergent

(paleomagnetism taught us)

• Divergent margins
  • Continental rifting
  • Mid-ocean rifting

convergent

• Convergent margins
  • Continent-oceanic crust collisions
  • Continental-continental crust collisions
  • Oceanic-oceanic crust collisions

transform

• Transform margins

history of plate motion

what do fossils and hot spots tell us?

• Hot spots

hazards

• volcanoes and earthquakes
  • how do the we know which to expect at different plate boundaries?

The Rock Cycle

• Minerals and Rocks
• igneous rocks/ sediments/ sedimentary rocks/ metamorphic rocks

Weathering

• weathering: mechanical weathering or chemical weathering

On sedimentary rocks

original horizontality

superposition (relative ages of rocks)

crosscutting relationships

Plate boundaries and rock types

Which plate boundaries give us which rock types?

intrusive igneous

(batholiths, plutons)

• Igneous rocks

• granite, diorite, gabbro
• cooled slowly = large crystals
• good building stone, strong rock, resistant to weathering

Coarse grained igneous rocks

Granite

Diorite

Gabbro

extrusive igneous (volcanic)

• basalt, rhyolite, andesite
• cooled fast = small crystals

Fine grained igneous rocks

Rhyolite

Basalt

Chemical composition

• chemically,
  • rhyolite = granite;
  • andesite = diorite;
  • basalt = gabbro

sedimentary rocks

• Sedimentary rocks

'detrital (mechanically formed)'

• organized by grain size - shale, siltstone, sandstone, conglomerate

Conglomerate

Sandstone

Shale

'chemically formed'

• Evaporitic minerals
• organized by composition - halite, gypsum (CaSO4), limestone

• cements for any sedimentary rock can be silica, carbonate, clay

metamorphic (formed by high heat and pressure)

• high P, low T = subduction
• high T, high P = regional metamorphism = continent collision
• regional met. creates foliated rocks: shale - slate - schist - gneiss
• high T, low P = contact metamorphism = intrusion
  • contact met. creates nonfoliated rocks: limestone to marble, sandstone to quartzite

• why do people care about foliation? (fig. 3.28, 3.29, 3.13; Keller, 2005)

what else can happen to rocks?

• they can bend = folding
• they can break = faulting (earthquakes)

they can be eroded away = unconformities

A fold

A fault