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

Parallels and Meridians

Parallels: Circles perpendicular to the Earth's axis. Latitude 0° is the Equator, which divides the Earth into two hemispheres.

Meridians: Semicircles that run from pole to pole. The 0° meridian, also known as the Prime Meridian, passes through Greenwich, a town near London.

Geographic Coordinates

Latitude: The angular distance from any point on Earth to the Equator. It can be north or south.

Longitude: The angular distance from any point on Earth to the Prime Meridian (0°). It can be east or west.

Maps and Scale

Map: A representation of the Earth's spherical surface on a flat, reduced, and simplified form.

Scale: The relationship between a measured length on a map and the corresponding length in reality.

Landforms

Plateau:

Deserts: Arid Ecosystems

A desert is an ecosystem that receives little precipitation. While often reputed to have little life, this depends on the type of desert. Many deserts support abundant life, with vegetation adapted to low humidity. Fauna typically hide during the day to preserve moisture. A desert ecosystem is arid, and this characteristic even enables the establishment of sustainable social groups.

Deserts are the most extensive land area on the planet, covering a total area of 50 million square kilometers, approximately one-third of the land surface. This constitutes 30% of the land surface (16% hot deserts and 14% cold deserts).

Dunes of the Namib Desert

Common Desert Characteristics

Deserts share several characteristics. The desert... Continue reading "Deserts: Ecosystems, Characteristics, and Adaptations" »

External Geological Cycle

The external geological cycle describes how land areas, primarily the land surface of the continents, are subject to the continuous action of the atmosphere, hydrosphere, and biosphere. This leads to the destruction or denudation of topographic relief in the so-called cycle of denudation of the continents. This cycle comprises phases of erosion, transport, and sedimentation of the products resulting from the fragmentation and breakdown of surface rocks.

Weathering

Weathering is a set of processes due to the action of the atmosphere, hydrosphere, and living things, which cause the decomposition of rocks and the minerals that constitute them. Depending on the type of mechanisms that act on the rock, there are two types... Continue reading "External Geological Cycle: Weathering, Erosion, Transport, Sedimentation" »

Workshop Building Summary

Buildings are structures created throughout history to provide shelter.

Tunnels

Tunnels are complex and costly constructions, including walkways, highways, waterways, and rail tunnels.

Tunnel Guidance

Excavation occurs simultaneously from both ends, requiring precise alignment using modern laser systems or traditional methods like theodolites.

Digging, Blasting, and Securing

Tunnels are dug using compressed air drills on vehicles. Explosives break rock, conveyor belts remove debris, and concrete linings support the tunnel. Boring machines with rotating heads are also used.

Tunnel Challenges

Risks include flooding, landslides, computer malfunctions, and dust from explosions.

Bridges

Bridges span depressions or obstacles like water,... Continue reading "Civil Engineering Structures: Tunnels, Bridges, Ports, and More" »

Young Heartwood

Young heartwood is a defect that occurs in wood from trees that have had a strong initial growth rate in diameter. This rapid growth results from favorable ecological conditions or growing up in a forest of low mass density (low density of trees per hectare or defective). This rapid growth results in wood that differs from normal wood of a particular species, with the following characteristics:

• In the late wood, there is a lower proportion of cells with thick walls.
• The apparent specific gravity is lower.
• The fibers are shorter.
• Tangential and radial contractions are lower, while the longitudinal contraction is higher, this being 10 times more intense than in normal wood.
• Sawn pieces that contain young heartwood tend to warp during

Agenda 21: A Program for Sustainable Development

Agenda 21 is a program of the United Nations focused on sustainable development. It was adopted at the Earth Summit in 1992, held in Rio de Janeiro, by more than 178 governments. In 1997, five years after the Earth Summit, another conference was held to study the progress of Agenda 21's implementation. Agenda 21 emphasizes that education can be a transformative force.

Key Environmental and Development Concepts

Sustainable Development

Sustainable Development, as defined in 1987 by the Brundtland Commission Report, states: "Development that meets the needs of the present without compromising the ability of future generations to meet their own needs."

Environment

The Environment, as defined by the United... Continue reading "Core Concepts of Sustainable Development and Environment" »

Factors Determining Erosion Effectiveness

The energy of a geological agent: A great river with steep and erosive capacity has more than one of lower flow and calmer course. A large glacier erodes more than a smaller one.

The strength of rocks: Some rocks such as clay, limestone, and sandstone are easily eroded, while granite and gneiss are hard rocks where erosion progresses slowly.

Related Geological Agents

Wild Water

• Water with no fixed course, from rains.

Rivers

• Permanent water courses.

Torrents

• Located in mountains, always with water.

Glaciers

• Rivers of ice in polar regions or high mountains.

Landform Examples

• Wild-water gully
• River valley in V
• Valley glacier-torrents
• Sea cliff
• Glacier valley

River Characteristics

Upper Course

• Runs through high mountain areas.

Understanding the Ecological Footprint

The ecological footprint is an indicator that measures the soil surface in hectares needed to produce the resources consumed by a citizen, population, etc., and also needed to absorb and detoxify the waste generated. Its purpose is to assess the impact on the planet.

Energy and Development

Population growth and economic development have required the consumption of large amounts of energy. Fossil fuels have been the most used.

The Drawbacks of Fossil Fuels

One drawback is that fossil fuels produce carbon dioxide, carbon monoxide, hydrocarbons, etc. These substances are pollutants.

The Rise of Renewable Energy Sources

For these reasons, and more, we have started to exploit renewable energy sources as they are cleaner.... Continue reading "Ecological Footprint, Renewable Energy, and Soil Conservation" »

New Discoveries Shaping Our Understanding of the Cosmos

New discoveries.

The Immensity of the Universe

The Sun is a star in the Milky Way. Our galaxy is only one among the billions that make up the universe.

The Discovery of Deep Time

It was once believed that Earth was only about 6,000 years old.

Biological Evolution

It was once believed that each species had been created as we know it. Darwin's Origin of Species showed that species change over time.

New structure for the solar system.

Defining a Planet

A planet is a body orbiting a star, with a large mass and a spherical shape, that has cleared the area around its orbit. Its mass should be enough for its shape to be almost spherical, and it must have cleared its orbit.

That should explain a theory about... Continue reading "Unveiling the Universe: Discoveries, Solar System & Theories" »

Understanding and Classifying Risks

Risk: It may be called risk to any action, process, or event which might cause injury, disease, economic loss, or environmental damage. With the exception of wars, natural disasters such as hurricanes, floods, and earthquakes are those which reach a greater magnitude.

Classification of Risks

Cultural Technology Risk

Originating as a result of human error in productive activities (oil spills, radioactive leaks, industrial pollution,...) or lifestyles and socio-political activities (drugs, alcoholism, eating habits, smoking, war, dangerous sports,...).

Natural Hazards

Caused by natural causes (profound alteration of the environment as a result of natural processes). They can be:

Organic Hazards

Due to the action of... Continue reading "Understanding and Classifying Different Types of Risks" »