MIDTERMS

• Earth is a closed system that allows the exchange of heat and energy between the Sun and the Earth, but doesn't allow the exchange of matter
• Earth's subsystems follow an open system where matter and energy can flow across their boundaries
• Geosphere contains rocks, minerals, and ground found on and in Earth
• Crust:

  • Continental crust is thick and mainly granite rocks
  • Oceanic crust extends 5 to 10 km beneath the ocean floors and is made up of basalt
• Mantle is the thickest layer of the Earth (2,900 km thick) and comprises hot, dense rocks
• Core:

  • Outer Core is made up of melted nickel and iron
  • Inner Core is made up of iron metal
• Discontinuities inside the Earth separate layers and are called discontinuities

  • Conrad Discontinuity separates upper continental crust from the lower one
  • Mohorovicic Discontinuity is the transition zone between the crust and upper mantle
  • Repiti Discontinuity is between upper and lower Mantle
  • Gutenberg Discontinuity is the Mantle-Core zone
  • Lehmann Discontinuity is the transition between outer and inner core
• Pangea:

  • Proposed by Alfred Wegener 200 million years ago as part of the theory of continental drift
  • Surrounded by a global ocean called Panthalassa
• Atmosphere is a gaseous envelope composed of 78% nitrogen, 21% oxygen, 0.9% argon, and trace greenhouse gases
• Atmosphere extends 120 km from Earth's surface and comprises five layers: troposphere, stratosphere, mesosphere, thermosphere, and exosphere
• Hydrosphere includes all liquid, gaseous (water vapor), and solid (ice) water on Earth
• Water Cycle drives the hydrosphere and enables water to move and be recycled around Earth
• Evaporation: water to gaseous state, energy needed to break water molecules' bonds

  • Condensation: gaseous to liquid state, forms clouds
  • Precipitation: transports water from atmosphere to Earth's surface in forms like rain, snow, hail, or sleet
  • Infiltration: precipitation seeps into the ground, produces groundwater
  • Runoff: precipitation that does not infiltrate soil, flows to creeks, streams, and rivers
  • Collection: precipitation that stays in bodies of water called the collection basin
• Biosphere contains all living organisms on Earth, forming communities called biomes filled with ecosystems
• Types of Biomes:

  • Rainforests, Grassland, Coniferous Forest, Desert, Tundra, Deciduous Forest, Shrub Land, Marine, Freshwater
• Minerals are naturally occurring substances with specific chemical composition and atomic structure, serving as the building blocks of rocks and chemically bonded elements or compounds
• Silicates are minerals containing Silicon and Oxygen, forming a silicate ion (SiO4+) making up over 90% of rocks
• Physical Properties of Minerals:

  • Color, Streak, Luster, Hardness, Cleavage, Fracture, Specific Gravity, Magnetism, Reaction to Acids, Odor, Taste
• Rocks are solid, inorganic, naturally-formed without a particular atomic structure or chemical composition
• Igneous Rocks are formed from the cooling and solidification of magma and lava
• Intrusive Igneous Rocks form when magma is trapped inside the Earth and cools very slowly until it solidifies, forming large crystals
• Igneous Rocks:

  • Formed when magma is trapped inside the Earth and cools very slowly until it solidifies
  • Forms large crystals due to the slow cooling of magma
  • Has a phaneritic texture (medium to coarse-grained texture) due to the crystals
  • Extrusive Igneous Rocks:
  • Formed when magma makes it to the surface of the Earth
  • Cools quickly which means that crystals don’t have time to grow
  • Has an aphanitic texture (very fine-grained texture) and can also be glassy
  • Gas bubbles can also form in this type of rock
• Sedimentary Rocks:

  • Formed by the accumulation of sediments and often have distinctive layering or bedding
  • Formed on or near the Earth’s surface
  • Dependent on surface processes such as weathering and erosion
  • Clastic Sedimentary Rocks:
  • Formed when sediments are lithified or formed from mechanical weathering rocks
  • Classification is based on the size of the sediments rather than the mineral composition of the rock
  • Chemical Sedimentary Rocks:
  • Formed from dissolved minerals that are precipitated or separated from a solution (evaporated)
• • Occurs when water evaporates, leaving the minerals behind
  • Can also be when minerals are precipitated from water due to differences in temperatures
  • Organic Sedimentary Rocks:
  • Formed from the accumulation of plant or animal debris
  • These rocks are usually formed in swamp regions with abundant vegetation and low oxygen levels
• Metamorphic Rocks:

  • Formed when "parent rocks" are subjected to high heat, high pressure, high mineral-rich fluids, or a combination of these three
  • Metamorphism does not melt the rocks, but instead transforms them into denser, more compact rocks
  • Foliated Metamorphic Rocks:
  • Rocks that are formed when pressure squeezes to flatten or elongate the minerals within a rock so they become aligned
  • These rocks appear to be strongly banded or foliated
  • Non-Foliated Metamorphic Rocks:
• • Formed when the pre-existing rock or "parent rock" is essentially "baked" by the heat, changing the mineral structure of the rock without the addition of pressure
• The Rock Cycle:

  • All rock types can undergo metamorphism (heat and pressure) to create metamorphic rocks
  • All rock types undergo weathering and erosion to create sediments needed for sedimentary rocks
  • All rock types when exposed to extreme heat undergo melting to form magma necessary for igneous rocks to form
• Mineral Resources:

  • Mineral resources are non-renewable natural resources important for various industries
  • These minerals are mostly deposited below the Earth’s surface
  • New mineral deposits take millions of years to form
  • The Philippines is rich in minerals due to its location near the Pacific Ring of Fire
• Mining:

  • Mining is the extraction of non-renewable resources like mineral deposits and fossil fuels from Earth
  • Acquiring any resource that cannot be grown or fabricated artificially
• Types of Mining:

  • Surface mining:
  • Removes terrain surfaces and plant life to access minerals beneath
  • Commonly used is open-pit mining
  • Advantage: significant ore production without the high cost of removing overburden
  • Disadvantages: heavy rain can cause environmental damage
  • Underground Mining:
  • Involves digging underground to create tunnels and shafts for mineral deposits
  • Mine metallic ores found in veins deep under the Earth’s surface
  • Advantage: hidden operations, reclaimed land, environmental protection
• • Disadvantages: exposes miners to hazards like poisonous gases, fire, explosions
  • Placer Mining:
  • Involves sifting valuable materials from sediments in riverbeds or other sedimentary environments
  • Advantages: high productivity with low cost
  • Disadvantages: environmentally-destructive type of mining
  • In-situ Mining:
  • Also known as solution mining or in-place mining
  • Involves leaving ore on the ground and recovering minerals by pumping chemicals underground to dissolve the ore
• How Mining Works:

  • Exploration: search for information about the location
  • Development: planning, construction of access roads and mining sites
  • Active Mining: actual and active mining
  • Disposal of Overburden and Waste Rock: excavation of overburden to access the mineral ore deposit
  • Ore Extraction: extraction of the ore
  • Beneficiation: separating the relatively small quantities of metal from the non-metallic materials
  • Tailings Disposal: disposing what is left and non-profitable
  • Site Reclamation and Closure: rehabilitation process
• Energy Resources:

  • Refers to any material that can be used as a basis or source of energy
  • Used to generate electricity and other forms of power for human use
• Non-Renewable Resources:

  • Coal, oil, and natural gas are known as fossil fuels
  • Coal: combustible black or brownish-black sedimentary rock composed predominantly of organic matter
  • Oil and Natural Gas: oil is a thick, black, flammable liquid consisting of hydrocarbons; natural gas is a colorless, highly flammable gaseous hydrocarbon primarily made up of methane
• Soil Resources:

  • A nonrenewable source; not recoverable within a human lifespan
  • Main component of land resources, agriculture, and ecological sustainability
  • Provides food and a foundation for shelter
• Renewable Resources:

  • Energy resources that naturally replenish themselves
  • Examples include solar, wind, hydropower, geothermal, and biomass energy
• Water Resources:

  • Water is vital for life, supporting agriculture, commerce, and transportation
  • Hydroelectric Energy: generates electricity through the gravitational force of falling or flowing water
  • Human Activities Affecting Water Resources:
  • Population Growth
  • Changes in Landscape
  • Pollution
  • Overexploitation
• Geothermal Energy:

  • Heat energy continuously produced and stored in the Earth's interior
  • Water and/or steam carry the geothermal energy to the Earth's surface