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


05.05.a1-3

Melting Rocks

Solid

Increasing temperate vibrates atoms and can break bonds

Liquid

Pressure tends to hold lattice together


05.06.a1

Decompression melting

Solid asthenosphere rises to fill gap

05.06.c2


05.06.b4

Sheeted dikes of basalt

Pillow basalt

Gabbro

Mantle


05.06.c

Dec

ompr

essi

on

Cru

stal

Hea

ting


05.07.c1

Few volcanoes

Burial and heating of crustal rocks

Melting during subduction before collision (but shuts off)

Felsic rocks (granite)


05.08.a

Oceanic island

Rising mantle plume

Crustal melting and caldera in continent

Huge basalt

flows on continents


05.07.b1

Mafic magma melts crust

Adding water melts mantle

Mostly felsic and intermediate rocks


05.07.a

Add water to hot mantle

Mostly mafic and intermediate rocks


05.07.d1

Water in minerals released at depth

Hot water circulates in ridge; added in pores and in minerals


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


Volcanic StonesThe Origins of Magma and Igneous Rocks

This Concludes

volcanic stones the origins of magma and igneous rocks introduction to geology

Documents