Question

Consider the following statements:

1. A transform boundary is also called a fault zone.

2. Ocean trenches are formed when plates slide past each other.

3. The San Andreas Fault Zone is a prime example of a transform boundary.

Choose the correct option:

• A. 2 and 3 are correct
• B. 1 and 3 are correct
• C. 1 and 2 are correct
• D. All are correct

Answer 1

Answer:

B. 1 and 3 are correct

Plate Tectonics and Boundary Types

Transform Boundaries

• Transform boundaries, also known as transform faults or fault zones, are a type of tectonic plate boundary where two plates slide horizontally past each other.
• This sliding motion occurs along a fault line.
• These boundaries are characterized by significant geological activity, including frequent earthquakes.
• Key characteristic: Plates move laterally, neither creating nor destroying crust.

Other Plate Boundaries (for comparison)

• Divergent boundaries: Plates move apart, leading to the formation of new crust (e.g., Mid-Atlantic Ridge).
• Convergent boundaries: Plates move towards each other, resulting in subduction and mountain formation (e.g., Himalayas, Andes).

Ocean Trenches

• Ocean trenches are deep depressions on the seafloor, formed primarily at convergent plate boundaries where one oceanic plate subducts beneath another plate (oceanic or continental).
• They are associated with subduction zones and are sites of intense seismic and volcanic activity.
• Incorrect statement analysis: Statement 2 is incorrect because ocean trenches are formed at convergent boundaries, not transform boundaries where plates slide past each other.

Examples

• The San Andreas Fault Zone in California is a classic and well-studied example of a transform boundary. It marks the boundary between the Pacific Plate and the North American Plate.
• Another example is the Alpine Fault in New Zealand.

Exam Relevance

• Understanding the different types of plate boundaries (divergent, convergent, transform) and their associated geological features (e.g., trenches, ridges, faults) is crucial for geography and Earth science exams.
• Memorizing key examples like the San Andreas Fault is often tested.
• The distinction between features formed at different boundary types is a common area for multiple-choice questions.