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

Economic Globalization and Major Institutions

International trade has grown significantly, leading to new production organization models, intensified international financial flows, and increased trade agreements between countries.

Key International Institutions

• World Bank: Aims to reduce poverty.
• IMF (International Monetary Fund): Advises governments on financial matters and provides loans to member countries.

Centers of the World Economy

Major Economic Powers

• United States: Represents over 20% of total world production. The US dollar remains the most important global currency.
• European Union: Stands as a leading economic power, though behind the United States in several aspects.
• East and Southeast Asia: Japan remains a wealthy nation. China has emerged

El Niño and La Niña Phenomena

Causes of El Niño

• Global warming, which reduces the thermal contrast between the two shores of the Pacific. This decreases the intensity of trade winds and ocean currents.
• Increased volcanic activity of oceanic ridges, which raises the temperature of the ocean.

When the trade wind subsides and does not blow westward, upwelling ceases. This leads to storms in the arid zones of Peru and Chile. The El Niño effect implies that fisheries production declines, and the global ocean temperature rises. Storms and rainfall increase in Peru, California, and East Africa, while droughts occur in Brazil and the Philippines.

La Niña

La Niña is characterized by an exaggeration of normal conditions. The trade winds blow harder,... Continue reading "Climate Dynamics: El Niño, Weather Risks, and Global Circulation" »

The landscape around us changes due to the action of external forces acting on its surface. The main energy source is solar energy.

Landscape Transformation by External Forces

The Role of Solar Energy

The amount of solar energy varies with latitude: the sun's rays do not strike all points of the Earth's surface in the same way. The energy received decreases as a function of latitude from the equatorial zones towards the poles, producing a thermal imbalance which is compensated by the flow of energy in the form of heat. This heat propagates through convective cells and is responsible for:

• Maintaining appropriate conditions for the development of life in the biosphere.
• Causing wind, clouds, rain, and snow, forming rivers, torrents, valleys, and glaciers.

Earth's Geological Foundations

Understanding Rocks

Igneous Rocks

Igneous rocks are formed when magma solidifies.

Magma Defined

Magma is a mixture of molten rock and gases.

Metamorphic Rock Classification

Metamorphic rocks are classified, often exhibiting laminar (layered) or crystalline structures.

The Rock Cycle Explained

The rock cycle is the set of processes experienced by rocks and sediments at the surface and inside the Earth's crust.

Uses of Rocks

• Building materials
• Ornamental purposes
• Containers
• Fuel
• Chemical industry

Minerals and Their Properties

Minerals: Definition and Features

Solid minerals are formed by the chemical combination of elements in the Earth's crust. Rocks are composed of minerals, which possess three key features:

• Being natural
• Having

Concrete Components

• Concrete Components

• Fine Aggregate Cement
• Coarse Aggregate
• Water
• Additives

These are substances or products incorporated into the concrete before or during mixing at a rate not exceeding 5% of the fresh concrete and/or to modify some of its characteristics, common properties, or behavior.

Common additives include water reducers, superplasticizers or plasticizers, retarders or accelerators for curing, air-entraining agents, dyes, and air occluders for frost resistance, etc.

• Additions

These are inorganic materials, pozzolanic or latent hydraulic, finely divided, that can be added to concrete to improve some of its properties or confer special properties.

An example includes the use of fly ash as an addenda. Fly ash is obtained by electrostatic... Continue reading "Concrete Composition: Materials, Dosage, and Properties" »

Environmental Impacts and Pollution

Atmospheric Pollution

Environmental contamination results from the introduction of foreign materials into the environment, or the presence of existing materials at concentrations exceeding normal values.

These foreign materials are often caused by contaminating agents and substances.

Atmospheric Contaminants and Control

The most common and widely dispersed air pollutants are described below. Their levels are usually expressed in terms of atmospheric concentration or, in the case of gases, in parts per million air molecules.

Among the air pollutants emitted by natural sources, there is radon, a radioactive gas harmful to human health.

Some contaminants are formed, for example, by the action of the sun on previously... Continue reading "Understanding Environmental Pollution and Resource Scarcity" »

Key Earth Science and Weather Terms Defined

Acid Rain

Rainwater containing chemicals that result from the burning of fossil fuels.

Altitude

The height of a place above sea level.

Anticyclone

An area of high pressure usually associated with fine, settled weather.

Climate

The average weather conditions of a place over many years.

Condensation

The process by which water vapor changes to a liquid or a solid when cooled.

Continental Crust

A part of the thin outer layer of the Earth that is relatively light, so it cannot sink and cannot be destroyed.

Depression

An area of low pressure usually associated with clouds, rain, and strong winds.

Dew Point

The temperature at which moist air becomes saturated.

Drought

A prolonged period of weather that is drier than usual.... Continue reading "Essential Earth Science & Weather Terms Glossary" »

Fundamental Astronomical Definitions

• Dwarf Planet: A celestial body orbiting the Sun that has sufficient mass to assume a nearly spherical shape, but has not cleared its orbital path.
• Sun: The star of our planetary system. It has an average size among stars and derives its energy from thermonuclear reactions occurring in its core.
• Planets: Celestial bodies orbiting the Sun. They can be inner (closer to the Sun) or outer (further from the Sun).
• Satellites: Celestial bodies that revolve around planets.
• Asteroids: Smaller rocky bodies. Most are located in the asteroid belt; others include Trojans and Centaurs.
• Comets: Small celestial bodies composed of ice and dust particles.
• Star: A celestial body that shines in the sky with its own light.
• Nebula: Interstellar

Plains and Valleys: Life and Landscapes

Erosion and the resulting deposition processes create plains and valleys with sediments from rivers. These are related to various aspects, including plains of sand and glacial origins, as well as human settlements. Examples include the plains of the Tigris-Euphrates, Danube, Amazon, and Indo rivers. Civilizations emerged in these valleys, such as those in Mesopotamia and Egypt.

Plains of the Americas

In the Americas, plains are found in:

• Tropical Zone: Orinoco, Amazon
• Temperate Zone: Central North American Plain, Silver Plain

The Amazon plain is shared by Brazil, Peru, Ecuador, Venezuela, Bolivia, and Guyana. It features an equatorial climate. Human intervention, particularly in farming, began around 1840 with... Continue reading "Plains and Valleys: Formation, Characteristics, and Global Significance" »

Topic 1: Mineral and Crystal Formation

Silicates are the most common minerals and crystals. These include:

• Olivine
• Mica (biotite and muscovite)
• Feldspar
• Quartz

Crystals are minerals with a geometric form, flat faces, and vertices. They are ordered solids with an internal structure.

Texture refers to the shape, size, and arrangement of crystals.

Crystal Formation:

• Solidification of molten materials, forming crystals as plutonic rocks cool from magma.
• Sublimation of dissolved substances in gases, creating crystals like sulfur in volcanic conditions.
• Chemical precipitation from an aqueous solution, forming crystals like halite and gypsum. This process requires time, space, and rest.

Metamorphism

Metamorphism alters a rock's mineralogical composition and texture.... Continue reading "Minerals, Crystals, and Metamorphic Rocks" »