Notes, summaries, assignments, exams, and problems for Geology

Tectonic Dispositions

• Horizontal or Aclinal Relief: Self-sedimented areas with horizontal strata, alternating hard and soft layers. Water systems erode softer layers, creating residual relief.
• Monoclinal Relief: Gently sloping sedimentary areas with alternating hard and soft materials. Erosion forms steep slopes and isolated hills.
• Faulted or Germanic Structure: Results from pressure exceeding rock deformation capacity, leading to fractures, uplifted blocks, and sunken areas.
• Folded Relief: Formed by folding of sedimentary rocks due to compression. Anticlines are prone to erosion, while synclines retain more compact materials.

Appalachian Relief

Folded relief leveled by erosion, forming a base.

Jurassic Relief

Found in young mountain ranges with alternating... Continue reading "Understanding Landforms: Tectonics and Stress Factors" »

Fossil Fuels: A Deep Dive

Most of the energy used worldwide today comes from fossil fuels. They are used in transportation, to generate electricity, to heat rooms, and for cooking.

Fossil fuels include oil, coal, and natural gas, formed millions of years ago from the organic remains of dead plants and animals. Over millennia, the remains of organisms were deposited at the bottom of seas, lakes, and other water bodies, covered by layers of sediment. Chemical reactions of decomposition and the pressure exerted by the weight of these layers transformed these organic remains into gas, oil, or coal.

The Non-Renewable Nature of Fossil Fuels

Fossil fuels are nonrenewable resources; we cannot replace what we consume. They will eventually run out, and it... Continue reading "Fossil Fuels: Formation, Uses, and Future Availability" »

Atmospheric Pollution

The combustion of hydrocarbons, largely due to industrial processes or transportation, generates smoke, suspended particulates, and gaseous pollutants. The most common are carbon monoxide, carbon dioxide, sulfur oxides, nitrogen oxides, and hydrogen sulfide.

Industrial facilities and power plants usually emit a greater volume of contaminants. In the developed world, the danger of some issues has forced the relocation of industries to industrial belts outside of densely populated urban areas. However, emissions are still causing serious environmental problems.

Acid Rain and Smog

Emissions of sulfur and nitrogen react in the atmosphere when in contact with oxygen, water vapor, and light, producing mainly sulfuric acid and nitric... Continue reading "Atmospheric Pollution and Environmental Degradation: Causes and Effects" »

Physical Properties of Oil

Color: Varies from yellow to reddish-brown. The color darkens with increasing specific gravity, which increases with the percentage of asphalt.

Odor: Varies depending on the amount of light hydrocarbons and impurities. Examples include a pleasant smell of petrol to an unpleasant odor similar to combustion.

Specific Weight: Oil is lighter than water. Its weight is influenced by factors such as the percentage of asphalt.

Viscosity: Depending on the specific gravity and chemical composition, oil can be either very fluid or viscous.

Solubility: Insoluble in water; due to its lighter weight, it remains on the surface. It is soluble in benzene, ether, chloroform, and other organic solvents.

Chemical Properties of Oil

Crude oil... Continue reading "Understanding Oil: Physical, Chemical Properties and Types" »

Understanding Cavitation in Fluid Dynamics

Cavitation, sometimes referred to as suction vacuum, is a hydrodynamic effect that occurs when water or another liquid fluid passes at high speed over a sharp edge, producing a fluid decompression due to the conservation of the Bernoulli constant (Bernoulli's Principle). It can reach the vapor pressure of the liquid so that its constituent molecules immediately change to a vapor state, forming bubbles or, more correctly, cavities. The formed bubbles travel to areas of higher pressure and implode (the vapor suddenly returns to a liquid state, abruptly collapsing the bubbles), producing a trail of gas and potentially damaging the metal surface where this phenomenon occurs.

Discharge Cavitation Explained

Discharge... Continue reading "Cavitation and Water Hammer Phenomena in Fluid Systems" »

Earthquake Causes, Effects, and Prevention

Causes of Earthquakes

• Regional-Global Scale: Lithospheric subduction zones (cause of large earthquakes).
• Local Causes:
  • Volcanic eruptions
  • Escape of materials related to large surface currents
  • Fractures
  • Fluid extraction: groundwater, petroleum
  • Excavation collapse: mining, filling of reservoirs

Effects of Earthquakes

• Shaking of soil and buildings (the majority of deaths are caused by the collapse of buildings).
• Ground displacements taking place across fault lines.
• Landslides (a violent earthquake can trigger thousands of them).
• Tsunamis or tidal waves (traveling at high speed).
• Explosions: nuclear tests, exploration for mineral and oil deposits, mining operations.

Increased Seismic Risk Factors

• Human overpopulation

Characteristics of Earth as a Planet

Source: Earth was formed approximately 4.6 billion years ago by the agglomeration of matter subject to gravitational attraction.

Mass: Approximately 5,976 trillion tons (estimated from the formula of universal gravitation and gravitational acceleration).

Gravity: This force influences the arrangement of materials according to their density (less dense at the top, more dense at the bottom). On Earth, air, water, and rocks are arranged in this way.

Greenhouse Effect

Visible solar radiation penetrates the atmosphere and warms the Earth's surface. The Earth radiates heat as infrared radiation into the atmosphere; some of it escapes into space, and some is sent back to the surface. Increasing greenhouse gases in the... Continue reading "Earth's Characteristics and Atmospheric Layers" »

Tidal Power

Tidal energy is produced by the movement of water masses caused by rising and falling tides and the waves that originate on the sea surface due to wind action.

Benefits:

• It is a clean energy source.
• No waste.
• Almost inexhaustible.

Disadvantages:

• They can only be in sea areas.
• May be affected by weather disasters.
• Depends on the tidal ranges.
• Facilities are large and expensive.

Hydraulic Power

Hydropower is produced by the water retained in dams and reservoirs at high altitudes (which has gravitational potential energy). If at one point dropped to a lower level, this energy is converted into kinetic energy and then into electricity in a hydroelectric power station.

Advantages:

• It is a source of clean energy.
• No waste.
• Easy to store.
• The water stored

Eutrophication: A Threat to Lakes

Rivers, due to their erosive power, carry salts, organic matter, and suspended solids. To this, human action adds waste from domestic and industrial activities (solids and metals mining), agriculture, and livestock (nitrates, phosphates, pesticides, etc.). The self-purification capacity of rivers cannot always handle this load, which triggers pollution processes. The effects of this pollution include:

• Restriction on the use of water
• Alteration in wildlife and/or aquatic flora
• Unpleasant appearance and odor

Rivers are better equipped to handle pollution dynamics, allowing them to dilute pollutants. In contrast, lakes tend to accumulate waste. One of the main problems affecting lakes is the process of eutrophication.... Continue reading "Eutrophication in Lakes: Causes and Solutions" »

Geological risk is any condition, process, phenomenon, or event that, due to its location, severity, and frequency, can cause health damage or death to humans, economic losses, and environmental damage.

Wilson Cycle

1. First Volcanic Eruptions

Initial magmatism occurs, leaving a long area. It is forming a long fault line that divides the two lithospheric plates.

2. Formation of an Incipient Rift

The fracture of the previous phase is enlarged to be more clearly defined. In the central part of the opening, magma cools, forming oceanic lithosphere. The presence of magma at depth causes lithospheric swelling, forming a thermal dome. A rift valley, surrounded by topographic elevations, lies in the central part.

3. Expansion of the New Ocean Floor

New... Continue reading "Geological Risks: Understanding Plate Tectonics and Continental Drift" »