Volcanic Stones The Origins of Magma and Igneous Rocks Introduction to Geology.
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Transcript of Volcanic Stones The Origins of Magma and Igneous Rocks Introduction to Geology.
Volcanic StonesThe Origins of Magma and Igneous Rocks
Introduction to Geology
The Rock Cycle
05.03.a1
Accumulates into rising magma body
Partial melting of source
Forms magma chamber (solidifies or rises)
Eruption as lava or ash
The Formation of Igneous Rocks
The Origins of Magma
The four main factors that influence the origins of magma are:
* Temperature * Water Content
* Pressure * Mineral Composition
Geologic Settings in which Magma Originates
Magma Formation and the Geothermal Gradient
The Formation of Magma
05.05.c2
The Formation of Magma
05.05.a1-3
Melting Rocks
Solid
Increasing temperate vibrates atoms and can break bonds
Liquid
Pressure tends to hold lattice together
The Formation of Magma
05.06.a1
Decompression melting
Solid asthenosphere rises to fill gap
05.06.c2
The Formation of Magma
05.06.b4
Sheeted dikes of basalt
Pillow basalt
Gabbro
Mantle
The Formation of Magma
05.06.c
Dec
ompr
essi
on
Cru
stal
Hea
ting
The Formation of Magma
05.07.c1
Few volcanoes
Burial and heating of crustal rocks
Melting during subduction before collision (but shuts off)
Felsic rocks (granite)
The Formation of Magma
05.08.a
Oceanic island
Rising mantle plume
Crustal melting and caldera in continent
Huge basalt
flows on continents
The Formation of Magma
05.07.b1
Mafic magma melts crust
Adding water melts mantle
Mostly felsic and intermediate rocks
The Formation of Magma
05.07.a
Add water to hot mantle
Mostly mafic and intermediate rocks
The Formation of Magma
05.07.d1
Water in minerals released at depth
Hot water circulates in ridge; added in pores and in minerals
The Formation of Magma
Mantle Melting and Plate TectonicsThe Formation of Magma
05.11.b1
Mid-ocean ridge
Oceanic hot spot
Subduction beneath continent
Continental hot spot
Continental collision
Observe these settings where large magma chambers form, and propose causes of melting for each site
The Formation of Magma
Volcanic StonesThe Origins of Magma and Igneous Rocks
This Concludes