Earth Processes
What is the difference between weathering and erosion?
Weathering is the breakdown of rock in situ, while erosion is the removal and transport of weathered material by agents such as water, wind, ice or gravity.
What is a mineral resource?
A mineral resource is a naturally occurring concentration of minerals or other geological materials that has potential economic value.
What is biodiversity?
Biodiversity refers to the variety of life, including diversity within species, between species and of ecosystems.
What is an earthquake?
An earthquake is the sudden release of stored elastic energy within Earth's crust, producing seismic waves.
What is sustainability?
Sustainability involves managing resources and environments in ways that meet present needs while maintaining their capacity to support future generations.
What are the three main types of plate boundaries?
Distinguish between a renewable and non-renewable resource.
A renewable resource can be replenished naturally within a relatively short timescale, while a non-renewable resourceforms much more slowly than it is consumed and therefore exists in finite quantities.
Identify two natural factors that can cause climate change.
Volcanic activity and Milankovitch cycles can cause natural climate variability. Changes in solar activity and ocean circulation can also influence climate.
Explain how earthquakes are generated along faults.
Tectonic forces cause stress to accumulate in rocks surrounding a fault. When the stress exceeds the strength of the rocks or frictional resistance along the fault, the rocks suddenly move, releasing stored elastic strain energy as seismic waves
Identify two human activities that can negatively affect ecosystems.
Habitat clearing and the introduction of invasive species can negatively affect ecosystems. Other examples include pollution, overexploitation and unsustainable tourism.
Explain how convection currents within the mantle contribute to tectonic plate movement.
Heat from Earth's interior creates convection currents within the mantle. Hot, less-dense material rises while cooler, denser material sinks. This movement contributes to the movement of tectonic plates above the underlying mantle. Other mechanisms, including slab pull and ridge push, also contribute to plate movement.
Explain how geological processes can concentrate valuable mineral deposits.
Geological processes can concentrate minerals through processes such as magmatic differentiation, hydrothermal activity, weathering and sedimentary deposition. For example, hydrothermal fluids can transport dissolved minerals through fractures before changes in temperature or pressure cause the minerals to precipitate and form concentrated deposits.
Explain how increasing atmospheric CO₂ can contribute to climate change and ocean acidification
Increasing atmospheric CO₂ enhances the greenhouse effect, causing more outgoing infrared radiation to be absorbed and contributing to global warming. Some atmospheric CO₂ is also absorbed by the oceans, where it reacts with water to form carbonic acid. This reduces ocean pH and contributes to ocean acidification, which can interfere with calcification in organisms such as shellfish and some marine invertebrates.
Explain the difference between magnitude and intensity.
Magnitude measures the energy released by an earthquake at its source, whereas intensity describes the effects and level of ground shaking experienced at a particular location. Magnitude is therefore associated with the earthquake itself, while intensity varies spatially depending on factors such as distance from the epicentre, depth and local geology.
Explain how invasive species can alter ecosystem structure and functioning.
Invasive species can compete with native organisms for food, habitat and other resources, while some act as predators or alter vegetation. This can reduce native biodiversity and change species abundance. These changes can disrupt food webs, nutrient cycling, habitat structure and ecological interactions, ultimately modifying ecosystem functioning.
Explain how plate tectonic processes can contribute to the formation of both earthquakes and volcanic activity.
subduction can cause intense friction and stress to accumulate along faults, producing earthquakes. As the subducting plate descends, water and other volatiles contribute to partial melting in the overlying mantle, producing magma that can rise and generate volcanic activity. At divergent boundaries, mantle upwelling and decompression melting produce magma, while movement along faults can generate earthquakes. Therefore, tectonic plate interactions can produce both hazards through related geological processes.
Analyse how the extraction of a mineral resource can create environmental impacts throughout its life cycle.
Mineral extraction can produce environmental impacts at multiple stages. During exploration and extraction, vegetation may be cleared and soils disturbed, while mining can alter drainage patterns and generate waste rock. Processing may require substantial energy and water and can produce contaminated waste. Following mine closure, inadequate rehabilitation can leave disturbed landscapes and ongoing pollution. Effective rehabilitation, waste management and monitoring can reduce these impacts and improve the long-term environmental sustainability of resource extraction.
Analyse how Milankovitch cycles, solar activity and volcanic activity can contribute to natural climate variability.
Milankovitch cycles alter Earth's orbital characteristics, including eccentricity, axial tilt and precession, changing the distribution of incoming solar radiation over long timescales. Changes in solar activity can alter the amount of solar energy reaching Earth. Large volcanic eruptions can inject aerosols into the atmosphere, increasing the reflection of incoming radiation and producing temporary cooling. These mechanisms demonstrate that Earth's climate has natural variability; however, their timescales and mechanisms differ, and they do not alone account for the observed pattern of contemporary anthropogenic warming.
Analyse the relationship between an earthquake's focus, epicentre, depth and intensity.
The focus, or hypocentre, is the point within Earth where an earthquake begins, while the epicentre is the point on Earth's surface directly above it. Earthquakes with a shallow focus can produce stronger surface shaking because seismic energy has travelled a shorter distance before reaching the surface. Intensity generally decreases with increasing distance from the epicentre, although local geology and building characteristics can modify the level of observed damage. Consequently, earthquake impacts are determined by an interaction between the characteristics of the earthquake and the vulnerability of the affected environment.
Analyse how tourism, resource exploitation and climate change can interact to affect ecosystem resilience.
Tourism and resource exploitation can place anthropogenic pressures on ecosystems through habitat disturbance, pollution, resource depletion and the introduction of invasive species. Climate change can further increase environmental stress through changes in temperature, precipitation and species distributions. When multiple pressures occur simultaneously, ecosystems may have reduced capacity to absorb disturbance and recover, lowering ecosystem resilience. Effective management therefore needs to address cumulative impacts rather than treating each environmental pressure in isolation.
Evaluate how interactions between tectonic, volcanic and surface processes can progressively reshape a landscape
Tectonic, volcanic and surface processes operate together over different spatial and temporal scales to progressively modify landscapes. Tectonic uplift can increase relief and expose rocks to weathering and erosion. Volcanic activity can then create new landforms through the accumulation of lava and volcanic material. Following formation, weathering, erosion, transportation and deposition progressively modify these features. For example, uplifted mountainous terrain can experience enhanced erosion due to increased relief, with rivers transporting sediment into lower-lying environments. Consequently, landscapes are not static; they represent the cumulative interaction between endogenic processes, which generate and uplift landforms, and exogenic processes, which break down and redistribute material.
A region contains a large economically valuable mineral deposit but also contains a highly sensitive ecosystem. Evaluate the environmental trade-offs associated with developing the resource.
Developing the deposit could provide economic benefits through employment, government revenue, infrastructure and resource supply. However, extraction may result in habitat destruction, biodiversity loss, soil disturbance, water contamination and landscape modification. The significance of these impacts depends on the sensitivity and ecological value of the environment, as well as the effectiveness of management. Strategies such as environmental impact assessment, restricted clearing, water treatment, progressive rehabilitation and post-mining monitoring can reduce environmental degradation. Therefore, decisions about resource development require consideration of both economic benefits and the long-term ecological consequences of extraction.
Assess the relative influence of natural and anthropogenic climate forcings on contemporary climate change.
Earth's climate is influenced by both natural and anthropogenic forcings, but contemporary climate change is strongly associated with human activities that have increased atmospheric greenhouse-gas concentrations. Natural influences such as solar variability, volcanic eruptions and orbital cycles operate across different timescales and can produce warming or cooling. However, the rapid increase in greenhouse gases from activities including fossil-fuel combustion has enhanced the greenhouse effect. Climate models can compare simulations incorporating natural forcings with those incorporating both natural and anthropogenic forcings. This allows the contribution of different forcings to observed climate trends to be investigated. Therefore, understanding contemporary climate change requires distinguishing between natural climate variability and human-induced forcing rather than attributing all climate change to a single mechanism.
A densely populated region experiences a high-magnitude earthquake followed by landslides and tsunami activity. Analyse how multiple hazards can amplify impacts.
A major earthquake can initiate a sequence of cascading hazards, increasing overall environmental and human impacts. Strong ground shaking can destabilise slopes and trigger landslides, while displacement of the seafloor can generate a tsunami. These hazards may occur sequentially and compound disruption to infrastructure, transport, settlements and emergency services. The severity of impacts is also influenced by exposure, vulnerability and preparedness. Strategies such as hazard mapping, earthquake-resistant infrastructure, early-warning systems, evacuation planning and public education can reduce vulnerability and improve community resilience.
Evaluate the effectiveness of management strategies used to maintain ecosystem resilience in the face of invasive species, climate change and human disturbance.
Maintaining ecosystem resilience requires a combination of preventative, regulatory and adaptive management strategies. Biosecurity measures can prevent invasive species from entering an ecosystem, while monitoring and rapid-response programs can limit their establishment. Human disturbance can be reduced through protected areas, visitor restrictions, sustainable-use regulations and infrastructure such as hardened tracks and boardwalks. However, climate change presents a more complex challenge because its drivers operate at global scales and cannot be addressed solely through local management. Consequently, effective conservation depends on integrated management, ongoing monitoring and the ability to adapt strategies as environmental conditions change.