As a geologist with extensive experience in studying the Earth's crust and its various forces, I can provide a detailed explanation on what compressional stress causes.

Compressional stress, often referred to as compressive stress, is a type of mechanical stress that acts to shorten or compress an object along the direction of the applied force. This force is perpendicular to the surface it acts upon, such as geological faults, rock layers, or any other planar structure. It is one of the primary forces responsible for the deformation and movement of the Earth's crust.

### Causes of Compressional Stress


1. Plate Tectonics: The primary cause of compressional stress is the movement of the Earth's tectonic plates. The Earth's lithosphere is divided into several large and small plates that float on the semi-fluid asthenosphere. These plates interact with each other at their boundaries, leading to compressional stress. The most common types of plate interactions that generate compressional stress are:

- Convergent Boundaries: Where two plates move towards each other, causing one plate to be forced under the other in a process known as subduction, or they collide, forming mountain ranges.
- Transform Boundaries: Although primarily associated with horizontal movement, the friction and locking of plates can lead to compressional stress when plates get stuck and then suddenly slip.


2. Forces from Remote Locations: Compressional stress can also be transmitted through the Earth's crust from remote locations. Forces generated at one part of the Earth can be transmitted through the rock, affecting areas far from the source.


3. Gravity: The weight of overlying rock layers exerts a compressive force on the layers below, contributing to compressional stress.


4. Magma Intrusion: The intrusion of magma into the Earth's crust can exert pressure on surrounding rocks, leading to compressional stress.


5. Ice Loading and Unloading: During glacial periods, the weight of ice can cause compressional stress on the Earth's crust. When glaciers retreat, this stress is reduced, leading to crustal rebound.

### Effects of Compressional Stress


1. Faulting: Compressional stress can lead to the formation of faults where the rock breaks and moves along a plane. This is a common mechanism for releasing stress in the Earth's crust.


2. Folding: Rocks can also deform plastically, bending and folding under compression without breaking.


3. Mountain Building: Compressional stress is a key factor in the formation of mountain ranges, as plates push against each other, uplifting the Earth's surface.


4. Earthquakes: The sudden release of built-up compressional stress can cause earthquakes, particularly in areas with high tectonic activity.


5. Rock Deformation: Compressional stress can cause rocks to deform, changing their shape and structure.


6. Metamorphism: High pressures associated with compressional stress can lead to metamorphism, where the minerals in rocks recrystallize under pressure and temperature changes.

7.
Resource Formation: Compressional stress can also play a role in the formation of certain mineral deposits and hydrocarbon reservoirs, as it can influence the migration and concentration of these resources.

In conclusion, compressional stress is a critical force in the Earth's geological processes, influencing the shape and behavior of the Earth's crust. Understanding this force is essential for predicting and mitigating the impacts of natural hazards such as earthquakes and for exploring the Earth's resources.

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compressional stress. The stress that squeezes something. It is the stress component perpendicular to a given surface, such as a fault plane, that results from forces applied perpendicular to the surface or from remote forces transmitted through the surrounding rock.read more >>