Igneous Rocks Flashcards
What is Bowen’s reaction
What are its two branches
Predicts the general order that minerals will crystallize or melt in a magma or rock
Discontinuous
Continuous
Define the discontinuous series
Reaction series that occurs in the Fe-Mg minerals
Define the continuous series
The reaction series that occur in the plagioclase Feldspars
Sea floor composition
Four layers Top layer- sediment Basalt layer Gabbro layer Peridoite layer
Ophiolite Surface or complex
Oceanic crust that is thrust onto a continent
Chemotrophs vs Phototrophs
A chemotroph is an organism that turns H2S into energy and life supporting nutrients.
A phototroph uses sunlight to produce energy
Common Igneous Minerals
Quartz Feldspar Mica Pyroxene Amphibole Olivine
What are the two components to measure rock appearance
Mineralogy
Texture
Traits of an Igneous Rock formation
Form by crystallization from magma (+700C)
As magma comes to the surface, it cools and crystals form
Different magma have different mineral compositions
What are Intrusive or Plutonic, Igneous Rocks
Rocks that form deep in the earths crust as magma cools
They have large interlocking crystals because cooling process is slow
Have a phaneritic texture
What are extrusive or volcanic igneous rocks
Form from magma which erupts at the surface of the earth through volcanoes
Are very fine grained or glassy texture because of rapid cooling
Have a aphanitic texture
What is the geothermal gradient
The rate of temperature increase in accordance with depth
The average temperature rate in the upper 100km of the crust is 25C/Km
What is Solidus
The temperature that rocks start to melt at
What are the three steps of Igneous rock formation
Pre-existing rock melts
Magma is transported to another location (usually upwards)
Magma begins to cool and minerals begin to crystallize
What is a dike
Magma intrudes into a weakness like a crack or fissure and solidifies, resulting in a cross-cutting feature.
