Skip to content

GoConqr has a new look! Let us know what you think.

Sign up free

Mind map

CLASSIFICATION OF IGNEOUS ROCKS

jimgeorget CVE314 college English

Mind map on classification of igneous rocks: texture, colour, silica content and compositional classification

Mind map: classification of igneous rocks

Map content

CLASSIFICATION OF IGNEOUS ROCKS

Rocks formed by the melting cooling and crystallization of other rocks.

TEXTURE
- Glassy
  - -Formed by the very rapid cooling of magma. Usually around water bodies.  - No crystals
- Aphanitic
  - -Formed by the rapid cooling of magma above the ground - Small homogenous crystals
- Phaneritic
  - -Formed by the slow cooling of magma -Large crystals 
- Porphyritic
  - -Large crystals embedded in small crystals -Phenocrysts embedded in groundmass 
COMPOSITIONAL CLASSIFICATION
- COLOUR
  - Light
    - -Termed 'felsic' because of the high silica content. -Very viscous and formed @ 850C -Non_Ferromagnesian
  - Dark
    - -Termed 'Mafic' cos of High Magnesium and Fe content -Formed at 1000C -Ferromagnesian
- SILICA CONTENT
  - Felsic Granitic
    - Composed of a lot of silica minerals
    - Granite
      - Phaneritic
    - Rhyolite
      - Aphanitic
    - Obsidian
      - Dark glassy texture
    - Pumice
      - Frothy, Glassy texture, contains a lot of air voids.
  - Intermediate/ Andesitic
    - -Contains 25% or More Dark silica  -due to explosive volcanic activity
    - Andesite
      - Aphanitic
    - Diorite
      - Phaneritic
  - Mafic Basalt
    - Dark silicate materials denser than Granitic rocks and is found on ocean floors. 
    - Basalt
      - -Aphanitic texture  -Composed of Calcium rich Plagioclase Feldspar and pyroxene 
    - Gabbro
      - Intrusive equivalent of Basalt

Information

Description: This has to do with the classification of Igneous rocks.
Created by: jimgeorget
Views: 39
Rating