igneous rocks n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Igneous Rocks PowerPoint Presentation
Download Presentation
Igneous Rocks

Loading in 2 Seconds...

play fullscreen
1 / 34

Igneous Rocks - PowerPoint PPT Presentation


  • 263 Views
  • Uploaded on

Igneous Rocks. Fig. 7.16. Complete the following table by identifying which of the characteristics in the left-hand column are present in volcanic and/or plutonic igneous rocks by stating yes or no for the appropriate number. One characteristic has been completed as an example. Koryakskaya

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Igneous Rocks' - clara


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide3

Complete the following table by identifying which of the characteristics in the left-hand column are present in volcanic and/or plutonic igneous rocks by stating yes or no for the appropriate number. One characteristic has been completed as an example.

overview of igneous rocks

Koryakskaya

Sopka Volcano,

Eastern Russia

Overview of Igneous Rocks
  • Form when minerals crystallize from magma
    • IntrusivePlutonic
    • ExtrusiveVolcanic
  • Magmas derived from below the Earth’s surface in the mantle
  • Magma is hot and buoyant
it s all about heat and density
Heat source??

Geothermal Gradient

Composition

Hot stuff

It’s all about heat and density
intrusive vs extrusive
Plutonic

Formed within the Earth

Magma

Reach Surface by uplift and erosion of the Earth’s Crust

Volcanic

Formed at the Surface

Lava

Intrusive Vs. Extrusive
texture
Texture
  • Related to the cooling history of the rock
    • Really Fast = no grains glassy
    • Fast = Fine-grained aphanitic
    • Slow = Coarse-grained phaneritic
    • Complex = Mixture  porphyritic
    • Why??
  • Other textures:
    • Vesicular: trapped gases in lava
    • Pyroclastic: ash and rock fragments formed explosively
texture1

Peanut Butter or

Sugar Cookie

Texture
  • Aphanitic
    • Fine –grained
    • Cooled quickly
    • Crystallized at the Earth’s surface
  • Porphyritic Aphanitic
  • Phaneritic
  • Porphyritic Phaneritic
texture2

Chocolate Chip Cookie

Texture
  • Aphanitic
  • Porphyritic Aphanitic
    • Two stages of cooling
      • 1st cooled slowly within the Earth (larger cyrstals - Phenocrysts)
      • 2nd cooled rapidly on the Earth’s surface (fine-grained matrix)
  • Phaneritic
  • Porphyritic Phaneritic
texture3
Texture
  • Aphanitic
  • Porphyritic Aphanitic
  • Phaneritic
    • Coarse –grained
    • Cooled slowly
    • Crystallized within the Earth
  • Porphyritic Phaneritic

Ooopps!! I must have

eaten the Oatmeal Cookie

texture4

Oatmeal Raisin Cookie

Texture
  • Aphanitic
  • Porphyritic Aphanitic
  • Phaneritic
  • Porphyritic Phaneritic
    • Two stages of cooling
      • 1st cooled slowly within the Earth (larger crystals - Phenocrysts)
      • 2nd cooled faster but still slow enough that crystals fully develop – within the Earth (coarse-grained matrix)
texture5
Texture
  • Aphanitic
  • Porphyritic Aphanitic
  • Phaneritic
  • Porphyritic Phaneritic
  • Vesicular –voids left by trapped gas
  • Glassy
  • Pyroclastic
texture6
Texture
  • Aphanitic
  • Porphyritic Aphanitic
  • Phaneritic
  • Porphyritic Phaneritic
  • Vesicular
  • Glassy
    • Very rapid cooling
    • Ions do not have time to from crystalline structures
  • Pyroclastic
texture7
Texture
  • Aphanitic
  • Porphyritic Aphanitic
  • Phaneritic
  • Porphyritic Phaneritic
  • Vesicular
  • Glassy
  • Pyroclastic – welded shards of rock & ash ejected from a vent during an eruption
composition of igneous rocks
Composition of Igneous Rocks
  • Silica (Si02) is primary ingredient of all magmas
  • Viscosity: Resistance to flow
    • Silica content
    • temperature
composition silica content
Composition—Silica Content
  • Felsic: Feldspar & Silica
    • >65% silica  High Viscosity
  • Intermediate:
    • 53-65% silica  Intermediate Viscosity
  • Mafic: Magnesium and Iron (Fe)
    • 45-52% silica  Low Viscosity
  • Ultramafic:
    • <45% silica  Very Low Viscosity
composition
Composition
  • Felsic-rhyolitic:
    • <900EC; Na, K, Al-rich
    • Light colored
composition1
Composition
  • Mafic-basaltic:
    • >1100EC; Ca, Fe, Mg-rich
    • Dark Colored
composition2
Composition
  • Intermediate-andesitic:
    • 900-1100EC; Na, Al, Ca, Fe, Mg, K
    • Salt & Pepper appearance

Andesite Porphyry

Diorite

bowen s reaction series

Hot

Melting

Crystallization

Cold

Bowen’s Reaction Series
  • Different minerals crystallize from magmas at different temperatures
magmatic differentiation
Magmatic Differentiation
  • Formation of more than one magma from a single parent magma
magmatic differentiation1
Magmatic Differentiation
  • Crystal Settling: crystallized minerals have a density greater than the magma and settle to the bottom due to gravity
  • Because Fe and Mg are first removed, melt becomes rich in SiO2, Na, and K
    • Marbles analogy
magmatic differentiation2
Magmatic Differentiation
  • Assimilation: magma reacts with the “country rock” which is adjacent to the magma chamber
    • Magma composition is altered according to the composition of the assimilated country rock
    • Inclusions are rocksIncompletely melted chunks of country rock
magmatic differentiation3
Magmatic Differentiation
  • Magma Mixing: Magmas of different compositions are mixed together
    • Resulting magma is of a composition intermediate between the parents
composition quiz
Composition Quiz
  • Which type of lava would flow most easily?
  • Mafic/Ultramafic
  • Which type of volcano would erupt most violently?
  • Felsic