Topic 1 - Describe what occurs at a divergent plate boundary. What happens at a transform plate boundary? Compare and contrast the types of processes that can occur at a convergent plate boundary.
Topic 2 - List five factors that can influence how long global supplies of a given mineral will last, and explain how each might increase or decrease the time span the mineral will be available to us.
Topic 1:
At a divergent plate boundary, two tectonic plates move away from each other. This movement creates a gap, which causes magma from the mantle to rise up and fill the space between the two plates. As the magma cools and solidifies, it forms new oceanic crust. This process is known as seafloor spreading and occurs along mid-ocean ridges.
At a transform plate boundary, two tectonic plates slide past each other. Unlike at divergent and convergent plate boundaries, there is no creation or destruction of crust. Instead, the plates grind and scrape against each other, causing earthquakes. The San Andreas Fault in California is an example of a transform plate boundary.
At a convergent plate boundary, two plates move towards each other. The type of boundary and the direction of movement determine the type of processes that occur. There are three types of convergent plate boundaries: oceanic-oceanic, oceanic-continental, and continental-continental.
At an oceanic-oceanic convergent plate boundary, one oceanic plate subducts beneath another, forming a deep-sea trench. The subducting plate melts as it descends into the mantle, creating magma that rises to the surface, forming volcanoes on the overlying plate. Over time, this process can lead to the formation of island arcs.
At an oceanic-continental convergent plate boundary, an oceanic plate subducts beneath a continental plate. This can create a volcanic arc on the continental side of the subduction zone, such as the Andes in South America. Continental-continental convergent plate boundaries result in the formation of mountain ranges like the Himalayas.
Topic 2:
1. Consumption rate: The faster a mineral is consumed, the shorter the lifespan of the global supply. This can be influenced by changes in demand from industries, population growth, and technological advancements.
2. Resource quality: Lower quality deposits are more expensive and difficult to extract, which can decrease the lifespan of the global supply.
3. Exploration and discovery: Exploration efforts can lead to the discovery of new deposits, while lack of exploration can limit supplies and decrease the lifespan of the global supply.
4. Recycling and substitution: Increased recycling and the development of alternative materials can extend the lifespan of the global supply.
5. Political and economic instability: Political unrest, war, and changes in trade policies can disrupt the supply chain and limit access to mineral resources, which can decrease the lifespan of the global supply.
Topic 1 - Plate Boundaries:
1. Divergent Plate Boundary:
- At a divergent plate boundary, two tectonic plates move away from each other.
- As the plates separate, magma rises from the mantle and fills the gap, forming a new crust.
- This process creates a continuous chain of volcanic activity and results in the formation of mid-ocean ridges or rift valleys on land.
2. Transform Plate Boundary:
- At a transform plate boundary, two plates slide horizontally past each other in opposite directions.
- The movement of the plates results in significant stress buildup, which is ultimately released in the form of earthquakes.
- Transform boundaries do not create or destroy crust, and there is no volcanic activity associated with this type of boundary.
3. Convergent Plate Boundary:
- At a convergent plate boundary, two plates collide, resulting in a variety of geological processes.
- Subduction occurs when an oceanic plate collides with a continental plate, causing the denser oceanic plate to sink beneath the lighter continental plate. This leads to the formation of trenches, volcanic arcs, and mountains.
- When two continental plates collide, neither plate subducts. Instead, the crust crumples and thickens, forming extensive mountain belts.
Comparison:
- Divergent and transform boundaries involve horizontal movement, while convergent boundaries involve plates colliding.
- Divergent boundaries create new crust, transform boundaries result in earthquakes, and convergent boundaries involve crustal deformation, subduction, and mountain building.
Contrast:
- Divergent boundaries are associated with mid-ocean ridges or rift valleys, while transform boundaries have faults.
- Divergent boundaries have volcanic activity, unlike transform boundaries.
- Convergent boundaries involve subduction and can form trenches, volcanic arcs, and mountains, which are absent in divergent and transform boundaries.
Topic 2 - Factors That Influence Global Mineral Supply:
1. Geological Reserves:
- The size and quality of mineral deposits determine how long they can last. Larger reserves can sustain longer rates of extraction.
2. Technological Advancements:
- Innovations in mining and extraction technologies can increase the efficiency of mineral extraction, extending the lifespan of deposits.
3. Recycling:
- The ability to recover and recycle minerals from products and waste reduces the reliance on new mineral extraction, thereby extending the lifespan of existing deposits.
4. Economic Factors:
- Economic conditions, such as fluctuating prices and demand, can influence the rate of mineral extraction and the search for new deposits.
5. Exploration and Discovery:
- Continued exploration efforts and discovery of new mineral deposits can extend global supplies, providing alternative sources for minerals.
The combined effect of these factors can either extend or decrease the time span that global supplies of a mineral will last. Technological advancements, recycling efforts, and the discovery of new deposits can prolong the availability of a mineral, while economic factors and the limited size of geological reserves can decrease its lifespan.