Intrusive Volcanic Landforms

Refers to AQA A2 Geography

Plate Tectonics and Assosiated Hazards Topic

HideShow resource information
  • Created by: Bethany
  • Created on: 31-03-14 15:44
View mindmap
  • Intrusive Volcanic Landforms
    • Batholiths
      • DESCRIPTION
        • Often several hundreds of km in diameter.
        • They appear dome shaped and are often exposed by later erosion e.g. Dartmoor/ Isle of Arran, Scotland.
          • e.g. Hambledown Tor, Dartmoor batholith
      • FORMATION
        • Formed deep below the surface when large masses of magma cool and solidify.
          • As the magma cools, large crystals are formed in the rock e.g. granite.
        • The area around the batholith is altered by heat and pressure to form a METAMORPHIC AUREOLE.
          • Here limestone may be transformed into marble.
        • Smaller injections of magma form a lens shape that is intruded between layers of rock.
          • Forces the overlying strata to arch upwards forming a dome.
            • This feature is known as a LACCOLITH
              • May be exposed by later weathering/ erosion to form a small range of hills for example, the Eildon Hills, Scottish borders.
    • Dykes
      • FORMATION
        • Vertical intrusions with hotizonatal colling cracks.
        • They cut across the bedding planes of the rocks into which they have been intruded.
        • When magma is forced to the surface, only a small amount of the mass actually reaches it
      • DESCRIPTION
        • Occur in groups known as 'DYKE SWARMS'
        • Many Scottish islands, such as Mull and Skye, have clusters of dykes all assosiated with one intrusive event.
    • Sills
      • FORMATION
        • When magma is forced to the surface, only a small amount of the mass actually reaches it
        • Horizonatal intrusions along the lines of bedding plances.
        • Vertical cooling cracks
      • DESCRIPTION
        • Examples include the Great Whin Sill, and Drumadoon on the Isle of Arran.
    • Intrusive Features
      • Most magma is INTRUDED into the crust where it solidifies into a range of features
        • These features are often exposed by later erosion
          • e.g. Hambledown Tor, Dartmoor batholith

Comments

No comments have yet been made

Similar Geography resources:

See all Geography resources »See all Plate tectonics resources »