IGCSE Environmental Management: Rocks and Lithosphere

• This guide covers the 9 chapters of IGCSE Environmental Management.
• It is broken down into concise subtopics.

Rocks & Minerals and Their Exploitation

• Igneous rocks form from cooled magma; examples include basalt and granite.
• Sedimentary rocks form from deposition and compression; examples include limestone and sandstone.
• Metamorphic rocks form under heat and pressure; examples include marble and slate.

Rock Cycle

• The rock cycle follows this sequence: Erosion & Weathering → Transport → Deposition → Compression → Metamorphism → Melting → Igneous Rocks.

Extraction & Use of Minerals

• Open-pit mining uses large holes for extraction.
• Underground mining uses shafts and tunnels.
• Sustainable solutions include recycling metals and land reclamation.

The Lithosphere – Plate Tectonics

• The Earth has four key layers.
• Crust: Thin, outer layer.
• Mantle: Semi-molten rock.
• Outer Core: Liquid iron and nickel.
• Inner Core: Solid iron and nickel.

Plate Tectonics

• At convergent boundaries, plates collide, creating volcanoes and earthquakes.
• At divergent boundaries, plates move apart, forming mid-ocean ridges.
• At transform boundaries, plates slide past each other, causing earthquakes.

Earthquakes & Volcanoes

• The focus is where an earthquake starts underground.
• The epicenter is the point directly above the focus.
• Seismic waves are measured using the Richter Scale.

Volcano Types

• Shield volcanoes have gentle eruptions, as seen in the Hawaiian Islands.
• Composite volcanoes have explosive eruptions, such as Mt. St. Helens.

Water & Marine Resources

• The water cycle includes Evaporation → Condensation → Precipitation → Infiltration → Runoff.

Aquifers & Groundwater

• An aquifer is underground water stored in porous rock like limestone.
• Over-extraction can cause subsidence and saltwater intrusion.

Water Pollution & Eutrophication

• Eutrophication unfolds in four steps.
• Fertilizers wash into rivers.
• Algae grows, blocking sunlight.
• Plants die, bacteria use oxygen.
• Fish die due to lack of oxygen.

Waterborne Diseases

• Cholera is caused by bacteria in dirty water.
• Malaria is spread by mosquitoes in stagnant water.

Agriculture & Food Production

• Subsistence farming is small-scale and for families.
• Commercial farming is large-scale and for sale.
• Mixed farming combines crops and livestock.

Soil Erosion Causes & Prevention

• Deforestation leads to soil erosion because there are no roots to hold the soil.
• Overgrazing exposes topsoil, leading to soil erosion.
• Conservation methods include terracing, crop rotation, and windbreaks.

Sustainable Farming

• Organic farming avoids the use of chemicals.
• Hydroponics involves growing plants in water with nutrients.

Energy & Power Resources

• Coal, oil, and natural gas are polluting and finite non-renewable energy sources.
• Solar, wind, hydro, geothermal, and biomass are more sustainable renewable energy sources with no CO₂ emissions.
• Nuclear power uses uranium and produces no CO₂ but creates radioactive waste.

Atmosphere & Climate Change

Greenhouse Effect & Global Warming

• Key greenhouse gasses include:
• CO₂: from fossil fuels.
• CH₄: Methane from cows and rice paddies.
• N₂O: Nitrous Oxide from fertilizers.

Ozone Layer Depletion

• Ozone layer depletion is caused by CFCs from aerosols and fridges.
• This increases UV radiation exposure, leading to skin cancer and crop damage.
• The Montreal Protocol was created to ban CFCs.

Pollution & Waste Management

Air Pollution

• Acid rain is created by SO₂ + H₂O → H₂SO₄.
• Catalytic converters reduce car emissions by converting CO → CO₂.

Water Pollution

• Heavy metals, like mercury and lead, come from factories and cause water pollution.
• Oil spills kill marine life.

Waste Management

• Waste management follows the principles of Reduce, Reuse, Recycle.
• Incineration reduces waste volume but releases CO₂.

Weather, Cyclones & El Niño

Weather & Climate

• Climate is long-term patterns of temperature and rainfall.
• Weather refers to short-term atmospheric conditions.

El Niño & La Niña

• El Niño is a warm ocean current that causes droughts and floods.
• La Niña is the opposite of El Niño and brings more rainfall.

Cyclones (Hurricanes/Typhoons)

• Cyclones need warm ocean water (above 27°C).
• Low pressure creates high-speed winds.

Managing Resources for Sustainability

Sustainable Development

• Sustainable development meets today’s needs without harming future generations.

Conservation Strategies

• Strategies include National Parks, Wildlife Reserves, Sustainable Fishing, & Forestry.

Predicted Exam Questions & Answers

• Human activities cause soil erosion through deforestation, overgrazing, and poor farming practices.
• Eutrophication is when fertilizers enter water, causing algae to overgrow and block sunlight, plants die, bacteria use oxygen, and fish die due to lack of oxygen.
• Two ways to reduce water pollution include using biodegradable detergents and building wetlands to filter water.
• Catalytic converters convert CO to CO₂, NOx to N₂, and unburnt fuel to CO₂ + H₂O, reducing car pollution.
• The greenhouse effect happens when CO₂ and methane trap heat, warming Earth, melting ice, and causing sea levels to rise.