Lesson 2

• Endogenic Process is a geological processes associated with energy originating in the interior of the solid earth.
• Magmatism: molten rocks that are found beneath Earth’s surface are called magma. When magma emerges at the surface it is called lava
• FACTORS THAT AFFECT MAGMA FORMATION

  • Temperature
  • Pressure
  • Water Content
  • Mineral Composition
• Decompression Melting: Happens when temperature stays the same but the pressure decreases.
• Flux Melting: Melting triggers when volatiles or gaseous substances are added into the hot solid rocks.
• Heat Transfer Melting: Melting of surrounding rocks caused by very hot magma bringing in additional heat.
• Partial Melting: Rocks begin to melt but only certain minerals are melting.
• Volcanism: The eruption of Molten rocks onto the surface of the earth.
• THREE TYPES OF VOLCANOES

  • Composite
  • Cinder Cone
  • Shield
• Composite Volcanoes: Emit a stiff, rapidly solidifying lava which forms high, Steep-sided cones.
• Cinder Cone Volcanoes: Regularly throw out ash and build up flatter domes called cinder cones.
• Shield Volcanoes: Lava does not eject violently, but flows over the crater rim forming a broad low profile.
• TWO TYPES OF ERUPTION:

  • Effusive Eruption
  • Explosive Eruption
• Effusive Eruption: Dominated by the flow of lava and formation of lakes and fountains
• Explosive Eruption: Ejects ash and larger fragments of broken pyroclastic materials.
• Metamorphism: The process when a rock changes its form into a new one without undergoing melting or disintegration
• METAMORPHISM PROCESSES:

  • Recrystallization
  • Phase Change
  • Neocrystallization
  • Pressure Solution
  • Plastic Deformation
• Recrystallization: changes in shape and size of minerals w/o changing its identity.
• Phase Change: transformation of one mineral to another mineral
• Neocrystallization: growth of new minerals that differs from the old rocks.
• Pressure Solution: the dissolution of mineral grains when rock is squeezed dominantly in one direction at low temperature and pressure with presence of water.
• Plastic Deformation: minerals become flattened or elongated w/o changing the composition
• CAUSES OF METAMORPHISM

  ● Heat

  ● Pressure

  ● Hydrothermal Solution
• Contact Metamorphism: occurs adjacent to igneous intrusions and results from high temperatures associated with igneous intrusion.
• Regional Metamorphism: occurs over large areas and generally does not show any relationship to igneous bodies. Results to strongly foliated rock such as slate and schist.
• Cataclastic Metamorphism: occurs as a result of mechanical deformation like when two bodies of rock slide past one another along a fault zone.
• Hydrothermal Metamorphism: where cold sea water penetrates the crust through the faults.
• Burial Metamorphism: occurs when sedimentary rocks are buried to depths of several kilometers , temperatures greater than 300 degree Celsius.
• Shock Metamorphism: occurs when an extraterrestrial body, such a meteorite or comet impacts the Earth.
• Tectonic forces operation inside the earth causes rocks to undergo deformation
• Stress causes rocks to deform
• Tensional Stress: occurs when the dominant force is directed away from each other.
• Compressional Stress: formed when the dominant force is directed towards each other
• Shear Stress: develops when the two dominant forces are directed towards each other but not along the same axis.
• The resulting change in the rocks due to different types of stress is called Strain
• THREE STAGES OF DEFORMATION

  ● Elastic Deformation (1st stage) ○ reversible strain

  ● Ductile Deformation (2nd stage) ○ irreversible strain

  ● Permanent Stage (last stage) ○ reaches elastic limit
• Joints: natural cracks in the rocks produced by brittle deformation
• Faults: a fracture or zone of fractures between two blocks of rock. It is the boundary where plate movement occurs
• Folds: are produced by deformation of ductile materials. ● contortions of rock layers forming wave - like curves