Exam Study Guide 1

1. Definition of a mineral and rock. 

A mineral is a naturally occurring, inorganic solid with a specific chemical composition and crystalline structure, meaning it has a consistent arrangement of atoms, while a rock is a solid aggregate of one or more minerals, formed through geological processes and often composed of different mineral grains mixed together with no single, defined crystal structure 

2. Bowen's Reaction Series. 

How solids turn to liquids, by the temperature.  

 Elastic Rebound Theory. 

How the earthquake itself happens. How earthquakes occur when stress builds up along a fault line, causing the rocks on either side to gradually deform until they reach a breaking point, then suddenly "snap back" to their original shape, releasing stored energy as seismic waves during an earthquake. 

6. Richter scale magnitude 

Measures the size of the earthquake and the damage the earthquake might do.  

7. Controls on eruptions explosiveness 

The explosiveness of a volcanic eruption is primarily controlled by the magma's viscosity, gas content, and the rate at which gas can escape. 

Magma composition (Silica content): 

Low silica (mafic magma): Less viscous, allows gas to escape more easily, leading to less explosive eruptions (e.g., Hawaiian volcanoes).  

High silica (felsic magma): More viscous, traps gas more readily, resulting in highly explosive eruptions (e.g., rhyolite eruptions).  

Gas content: 

High gas content: More potential for explosive eruptions as gas expands rapidly when pressure decreases during ascent.  

Low gas content: Less explosive potential.  

Magma viscosity: 

High viscosity: Impedes gas escape, leading to more explosive eruptions.  

Low viscosity: Allows gas to escape more easily, resulting in less explosive eruptions.