Understanding Geological Processes and Terrain Models

Types of Effort:

• 1. Compression caused by opposing forces and convergent (crush)
• 2. Strain or tension (stretch) caused by opposing forces and divergent
• 3. Parallel shear force caused by divergent and convergent (rip)

The Rock Cycle: Rocks are always formed from earlier ones. The rock cycle is an example of interaction with internal and external phenomena:

• 1. Internal geological processes: magmatism and metamorphism caused by the heat of the Earth
• 2. External geological processes: transport, sediment erosion, weathering, and diagenesis caused by solar energy.

Agent of Erosion:

• 1. Weathering
• 2. Erosion
• 3. Sediment transport

Internal Processes:

• 1. Magmatism and plate tectonics: The internal heat causing the magma is known as the geothermal gradient. The rocks would have to be melted at temperatures that are in the mantle, but the high pressures remain solid. Fusion can occur by:
  • 1. Increasing temperature
  • 2. Declining presence of fluid pressure
• 2. Metamorphism and plate tectonics: Plate boundaries are destructive, with huge pressure on the rocks undergoing changes in type and disposition of minerals (metamorphism). Isochemical metamorphism is a process where the composition of the rock remains invariable.
  • 1. Subduction zones will form a belt along the wing pit and another volcanic chain (metamorphic). The first shock is produced by the pressure plate, while the second is the ascent of magmas due to continental collision.
  • 2. Large areas of regional metamorphism occur since pressure and heat join.

Isostasy: Float balance between the lithosphere and mantle plastic. If its mass increases, the lithosphere tends to sink into the mantle, and if it tends to rise, it reduces. Factors That Control the Terrain Model:

• 1. Climate: Controls the agent acting and, in the absence of vegetation, promotes physical weathering and erosion of soil.
• 2. Lithology: Two rocks can be modeled in different ways, formed by layers or strata, depending on their disposition.
• 3. Human activity: Increasingly influential, directly or indirectly.

Morphoclimatic Systems: Landforms characteristics of each type of climate (glacial, periglacial, desert, wetlands, subdesert):

• 1. Morphoclimatic glacier: Favors snow accumulation and its transformation into ice, preventing the development of vegetation. Ice streams are the modeling agent in these zones.
• 2. Morphoclimatic periglacial: Climate allows the development of very low vegetation (mosses, lichens). The agent is gelifraction. Peligraciar modeling is the accumulation of fragments on slopes and debris cones.
• 3. Morphoclimatic desert: Rain shortage and high evaporation rate; groundwater does not exist. The absence of water vapor in the air and cover leads to sharp temperature fluctuations. These variations produce:
• 4. Morphoclimatic thermoclasia: Wetlands with milder temperatures that allow water in liquid form. Thermal fluctuations are not very pronounced, facilitating the development of deciduous forests. The vegetation and water favor the chemical weathering of rocks, with moving water being the main agent of erosion, transport, and deposition.