Term 2 - Natural Science

• The Rock Cycle


  A group of changes in which: Igneous rock can change into sedimentary rock or into metamorphic rock, Sedimentary rock can change into metamorphic rock or into igneous rock, Metamorphic rock can change into igneous or sedimentary rock
• Igneous rock


  • Formed when magma cools and makes crystals, Magma is a hot liquid made of melted minerals, Can form underground where magma cools slowly or above ground where lava cools quickly, Can be classified by composition or grain size
• Igneous rock

  • Obsidian
  • Granite
  • Basalt
• Weathering


  Processes at or near Earth's surface that cause rocks and minerals to break down in the same place
• Erosion


  Process of removing Earth materials from their original sites to another location through transport
• Types of weathering


  • Physical weathering
  • Chemical weathering
  • Biological weathering
• Agents of erosion


  • Wind
  • Moving water
  • Ice
• Sediment


  Material, originally suspended in a liquid, that settles at the bottom of the liquid when it is left standing for a long time, Material eroded from preexisting rocks that is transported by water, wind, or ice and deposited elsewhere
• Compaction


  As sediment piles up, its mass causes pressure that leads to a reduction in pore space and a sticking together of the grains
• Cementation


  Minerals precipitate from water flowing through the pores between sediment grains, effectively gluing the sediment together into a cohesive, solid Sedimentary Rock
• Sedimentary rock


  • Forms at or near the earth's surface at relatively low temperatures and pressures primarily by deposition, precipitation, or growth in position, Classified by grain size
• Sedimentary rock


  • Sandstone
  • Coal
  • Limestone
• Subduction


  A rock that gets caught up in a subduction zone may undergo metamorphism as it gets dragged down with a plate, the intense heat and pressure can change the minerals that make up the rock
• Heat and pressure


  Pressure comes from the incredible weight of material surrounding the rock on all sides, The pressure and/or heat rearranges the structure of minerals within the rock without changing the chemical composition, forming new minerals and new rocks
• Uplifting


  Certain rocks created under the Earth's surface are brought to the surface through orogeny and volcanic processes, then become recycled again
• Metamorphic rock


  • Formed when a rock is changed by experiencing intense heat and pressure in the crust of the earth, Heat and pressure change the mineral structure and physical properties without changing the chemical makeup
• Metamorphic rock


  • Slate
  • Marble
  • Gneiss
• Melting


  Continued heating leads to production of magma and new igneous rocks which are formed when the magma cools
• Crystallization


  Hot magma will cool, and the melted minerals will crystallize and form an inter-grown mass of crystals - an igneous rock, The longer it takes to cool, the bigger the crystals
• The Rock Cycle is a group of changes in which: Igneous rock can change into sedimentary rock or into metamorphic rock, Sedimentary rock can change into metamorphic rock or into igneous rock, Metamorphic rock can change into igneous or sedimentary rock
• Igneous Rocks and Volcanoes


  Natural sciences
• Igneous Rocks


  All igneous rocks form through the cooling and solidification of magma
• Categories of igneous rocks

  • Intrusive
  • Extrusive
• Intrusive


  Forms when magma cools under the surface of the crust. They "intrude" through the crust.
• Extrusive


  Forms when lava cools on the surface of the crust – it exits the crust.
• Texture


  • Intrusive rocks have larger crystals as the magma cools more slowly, and extrusive rocks have smaller crystals, as they cooled more quickly
• Textural styles


  • Coarse grained
  • Fine grained
  • Vesicular (i.e. it has holes in it)
  • Glassy (no crystals evident)
• Felsic rocks


  Light coloured, composed mainly of feldspars and quartz, high in silica (greater than 65% by weight)
• Mafic rocks


  Dark coloured, composed mainly of amphibole, pyroxene and olivine, low in silica (lower than 55% by weight)
• Volcanoes


  Features that produce extrusive igneous rock
• Plutons


  Bodies of intrusive igneous rock that are crystallized from magma slowly cooling below the surface of the Earth
• Granite


  • Coarse grained, felsic
• Basalt

  • Fine grained, mafic
• Types of volcanoes

  • Composite/Stratovolcanoes
  • Cinder/Tephra Cones
  • Shield Volcanoes
• Composite/Stratovolcanoes

  Formed from ash and lava layers that stack up into mountains with steep sides, have viscous lava with high silica content, found along subduction zones, form felsic rocks, generally lower temperatures
• Cinder/Tephra Cones


  Created from high eruptions of lava that creates cinder or ash that falls into a cone shaped hill, the smallest type of volcano, commonly found on the flanks of other volcanoes, often formed from basaltic lava, but can form from andesitic or rhyolitic lava
• Shield Volcanoes


  Gently-sloping volcanoes comprised of basaltic lava (very fluid lava) that flows in long-lasting, relatively gentle eruptions - explosions are minimal, found at hot-spots and along divergent boundaries, low silica lava allows gas to escape, higher temperature lava
• Write a short reflective paragraph detailing which learning objectives you feel you have done well in, and any that may require extra study. Justify your answers using the LO and explain how you will improve in any weaker areas identified.
• Plate tectonics


  A theory of the dynamics of the outer shell of the Earth
• Plate tectonics


  • The Earth is broken into several large plates
  • The size and position of these plates change
  • The plates' edges interact with each other in geologic activity
  • Represents the cause of Earthquakes & Volcanoes
  • Explains the ages and evolution of the Earth's surface