Petrology: Geological classification of rocks into igneous.pptx

Petrology: Geological classification of rocks into igneous.pptx

• 1.
  Petrology: Igneous Rocks GeologicalClassification of Rocks
• 2.
  Introduction to Petrology •Petrology is the branch of geology that studies rocks, their origin, composition, texture, and classification.
• 3.
  Classification of Rocks •Geologically, rocks are classified into three major types: • 1. Igneous Rocks • 2. Sedimentary Rocks • 3. Metamorphic Rocks
• 4.
  Definition of IgneousRocks • Igneous rocks are formed by the cooling and solidification of molten magma or lava.
• 5.
  Types of IgneousRocks • Igneous rocks are broadly classified into: • 1. Intrusive (Plutonic) Rocks • 2. Extrusive (Volcanic) Rocks
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  Intrusive Igneous Rocks •Formed when magma cools slowly beneath the Earth's surface. • Examples: Granite, Diorite, Gabbro.
• 7.
  Extrusive Igneous Rocks •Formed when lava cools quickly on the Earth’s surface. • Examples: Basalt, Rhyolite, Andesite.
• 8.
  Textures of IgneousRocks • Based on cooling rate: • 1. Coarse-grained (slow cooling) • 2. Fine-grained (rapid cooling) • 3. Glassy (very rapid cooling) • 4. Porphyritic (mixed cooling)
• 9.
  Chemical Classification • Igneousrocks are chemically classified into: • 1. Felsic (silica-rich) • 2. Intermediate • 3. Mafic (iron & magnesium-rich) • 4. Ultramafic
• 10.
  Importance of IgneousRocks • • Provide construction materials (granite, basalt) • • Contain valuable minerals (nickel, chromium) • • Help understand Earth’s interior processes.
• 11.
  Conclusion • Igneous rocksform the foundation of the Earth’s crust. Their study helps in construction, resource exploration, and geological understanding.