Question

For each set of terms below, choose the one term that does not belong and explain why it does not belong. fault-block mountain-upwarped mountain-plateau

Short answer

Plateau does not belong as it is not a type of mountain like the others.

Step-by-step solution

Identify the Terms

The terms we are analyzing are: fault-block mountain, upwarped mountain, and plateau. Each of these terms describes a type of geological formation.

Define Fault-Block Mountain

Fault-block mountains are formed when large blocks of Earth's crust are tilted, uplifted, or displaced along faults. They typically have a block-like shape and steep front faces, resulting from faulting.

Define Upwarped Mountain

Upwarped mountains are created when broad areas of Earth's crust are pushed upward by forces within the Earth. This process creates elongated ranges or domes due to broad uplifts without significant cracking or faulting.

Define Plateau

A plateau is an area of highland, usually consisting of relatively flat terrain. Plateaus are formed mostly through processes such as volcanic activity or the erosion of mountains, resulting in a flat-topped region.

Compare Formation Processes

Both fault-block mountains and upwarped mountains are formed through tectonic activities involving the uplifting of Earth's surface. However, a plateau is typically characterized as a large, relatively flat elevated region and is often not a direct result of the same tectonic processes.

Determine the Odd Term Out

Since fault-block and upwarped mountains are directly related to mountain formation through tectonic uplifts, whereas a plateau is mainly defined by its flat topography, the term 'plateau' is the one that does not belong within the context of mountain formation.

Key concepts

Fault-Block Mountains

Fault-block mountains are fascinating geological formations created by the movement of Earth's crust. These mountains form when large blocks of the crust are either tilted, uplifted, or displaced due to the action of fault lines. This action causes a block-like shape with steep, dramatic front faces, and gentler sloping backs. The process behind the formation of fault-block mountains typically involves tensional forces pulling the crust apart.

• The tension creates cracks, or faults, in the crust.
• Large blocks between these faults move up or down.
• As a result, some parts of the crust rise to form mountains while others sink, forming valleys in between.

An example of this type of mountain is the Sierra Nevada range in the western United States, where the movements along the faults have created visually striking and steep features.

Upwarped Mountains

Upwarped mountains, sometimes known as domed mountains, are formed by forces beneath the Earth's crust. These forces cause the crust to lift upwards, creating broad, elevated mountain regions with rounded peaks. What's intriguing here is that upwarping happens without significant cracking or faulting, differentiating these from fault-block mountains.

• Broad areas are pushed slowly upward by internal pressures.
• This kind of uplift can cover quite extensive areas, forming elongated ranges.
• These mountains might also form life bowing upwards due to what scientists call isostatic rebound.

A well-known example is the Black Hills of South Dakota, showcasing how tectonic movements have softly shaped the land without disrupting the surface significantly.

Plateaus

A plateau is a majestic and expansive geological formation characterized by its vast, flat terrain elevated high above sea level. Unlike mountains, plateaus do not generally form through tectonic uplifting to produce pointy peaks. Instead, various processes such as volcanic activity or erosion lead to their creation.

• Volcanic plateaus form from lava flows that spread over a large area and solidify into vast, flat landforms.
• Erosional plateaus result when high mountain ranges are worn down over time into a flat surface.
• Another origin method is the uplift of land due to tectonic forces, but without much faulting or folding.

The Colorado Plateau in the United States serves as a classic example, where erosion has sculpted beautiful flatlands with deep canyons, offering rich insight into Earth's geological history.