Understanding Rift Valley Formation Through Faulting

This question explores the geological concept of rift valleys, examining their physical characteristics and the processes that create them. Let's break down the assertion and the reason provided.

Assertion Analysis: Rift Valley Characteristics

The assertion states: "Rift valley represents a trough, depression or basin between two crustal parts."

• A rift valley is indeed a landform.
• It is characterized by a long, linear, and relatively narrow trough or depression.
• This depression forms when large blocks of the Earth's crust move downwards relative to the surrounding land.
• These downward-moving blocks create a valley-like structure bounded by steep slopes or fault scarps on either side.
• Therefore, the assertion accurately describes the physical shape and location of a rift valley. The assertion is true.

Reason Analysis: Rift Valley Formation Process

The reason states: "Rift valley is a major relief feature resulting from faulting activities."

• Faulting refers to the fracturing and displacement of rock strata in the Earth's crust.
• Rift valleys are primarily formed by extensional forces (pulling apart) within the Earth's crust.
• When tensional forces dominate, the crust stretches and breaks along normal faults.
• The central block between these faults drops down, creating the characteristic depression of a rift valley.
• Prominent examples include the East African Rift Valley.
• Thus, faulting is the fundamental geological process responsible for the creation of rift valleys. The reason is true.

Relationship Between Assertion and Reason

The question asks if the reason correctly explains the assertion.

• The assertion describes what a rift valley looks like (a trough/depression between crustal parts).
• The reason explains how it forms (through faulting activities).
• The process of faulting (Reason r) directly leads to the formation of the trough or depression described in the assertion (Assertion a). Specifically, the block faulting mechanism associated with tensional forces causes the crustal blocks to subside, forming the rift valley.
• Therefore, the reason provides a correct explanation for the assertion.

Conclusion: Both the assertion and the reason are true, and the reason is a correct explanation of the assertion.