Which forms as a result of compressional stress?
A. anticline and syncline B. normal fault C. strike-slip fault D. fault-block mountain
The Correct Answer and Explanation is :
The correct answer is A. anticline and syncline.
Explanation:
Compressional stress occurs when forces act to push materials together, typically within the Earth’s crust. This stress leads to deformation in the rock layers, resulting in various geological structures. Two primary formations that emerge from this compressional stress are anticlines and synclines, which are types of folds.
- Anticlines: These are arch-like structures that form when rock layers are compressed. In an anticline, the oldest rock layers are typically found at the core, while younger layers are on the outer edges. This upward bending occurs due to the compressive forces, which can occur at convergent plate boundaries where tectonic plates collide.
- Synclines: In contrast, synclines are trough-like formations that develop in response to compressional stress, with younger layers of rock located at the center and older layers on the outer sides. When the rock layers are pushed together, they bend downwards, creating a U-shape.
Both anticlines and synclines are indicative of the larger tectonic processes at work within the Earth. They are commonly observed in mountainous regions, where extensive geological forces have shaped the landscape over millions of years. Understanding these structures is crucial for geologists as they explore the Earth’s crust, assess potential natural resources, and study seismic activity.
In contrast, the other options listed refer to different geological formations that arise from various types of stress. A normal fault (B) is associated with extensional stress, where rocks pull apart, while a strike-slip fault (C) involves lateral movement due to shear stress. Fault-block mountains (D) form from a combination of faults but are not directly the result of compressional stress alone. Thus, anticlines and synclines are the direct products of compressional forces in the Earth’s crust.