The difference between dikes, sills, and laccoliths.  

-All intrusive

1.     Dike – Vertical, wall-like intrusion (cuts through)

2.     Sill – horizontal, table-top like intrusion (layer)

3.     Lacolith - cause layers to dome upward

The difference between volcanic necks, plutons, and batholiths.  

1.     Plutons - large, deep, irregular igneous formation (a solidified magma chamber)

2.     Batholiths - lots of plutons clumped together

3.     Volcanic neck – When the soft parts of the volcano erodes, and the solid igneous rock that cooled in a magma chamber within the volcano

How to distinguish between the three main types of volcanoes.

-Shield volcano 

Shield volcanoes

- Broad, gentle domes

- Mainly low viscosity basaltic lava

- Effusive activity (formed from multiple lava flows)

- Found at oceanic hotspots

How to distinguish between the three main types of volcanoes.

-Cinder cones 

- Steep, smaller

- Mainly basaltic lava

- Formed from small explosive eruptions of tuff

- Very short lived

- Found at both hotspots and convergent boundaries

How to distinguish between the three main types of volcanoes.

-Stratovolcano 

Stratovolcanoes

-large and cone shaped

-Range of magma types (basalt-rhyolite) – altering layers of lava and tephra

- Explosive and Effusive activity (known for its explosive activity)

- Typically found at subduction zones

Lava type-

Basaltic lava flows

-Mafic

-Little silica, very low viscosity – flows fast

Andesitic lava flows

-intermediate

-Higher silica content, greater viscosity – does not flow as easily

Rhyolitic lava flows

-Felsic

-Highest viscosity level, coolest – moves slowly

Eruption style

Effusive Eruptions

- Produce mainly lava flows, low viscosity basaltic lava

- Mid-ocean Ridges & Oceanic Hotspots

Explosive (pyroclastic) eruptions

- Produce clouds and avalanches of pyroclastic debris.  Occurs when gas expands in the rising magma but cant escape

- Subduction zones

Be able to name an example of each type. 

Shield volcano – Hawaii/ Kilimanjaro

Stratovolcano – Vesuvius

Cinder cone – sunset crater

How a caldera is formed. 

After major eruptions, the center of the volcano may collapse into the large, partly drained magma chamber below, creating a caldera – a big circular depression with steep walls and a flat floor 

When a dike sill or lava flow cools and it fractures to yield rough hexagonal columns of basalt

when an intrusive igneous bakes surrounding rocks (older rocks)