Notes, summaries, assignments, exams, and exercises for Geology for Secondary education

External geological agents: External agents, which "destroy" the relief by wearing down the mountains and filling the lower parts of the terrestrial surface. They include: the atmosphere, wind, living organisms, and water (in all its forms: rivers, streams, rain, glaciers, oceans, etc.). External geological processes are: erosion, transportation, and sedimentation.

Physical and Chemical Processes: Changes in temperature, frost, the action of plant roots, wind, and water movements.

Sediments: These are the eroded materials that are deposited when there is no further transport occurring.

Internal Geological Processes: Earthquakes and volcanoes.

External Geological Processes: Wind, ocean tides, rivers, ice, temperature changes, atmospheric components,...

Definitions

• Principle of Actualism: Analyzing present processes is key to interpreting past events.
• Relative Dating: Establishes the order of events without numerical ages.
• Absolute Dating: Provides numerical ages for events (e.g., years or millions of years ago).
• Stratification Planes: Surfaces that delimit layers (strata).
• Roof: The uppermost and youngest part of a stratum.
• Wall (Base): The lowermost and oldest part of a stratum.
• Series Roof: The top and youngest part of a series of strata.
• Series Wall: The bottom and oldest part of a series of strata.
• Thickness: The vertical distance between the roof and wall of a stratum.
• Polarity Criteria (Roof-Wall): Sedimentary structures that help determine the orientation of strata.
• Concordance: Two materials

Plate Tectonics and Earth's Structure

Plate Boundaries

Mid-ocean ridges are constructive plate boundaries where lithospheric plates separate, leading to ocean growth.

Oceanic trenches are destructive plate boundaries where the oceanic lithospheric plate subducts beneath another plate.

Earth's Crust

Continental crust extends 30 to 70 km deep beneath continents.

Oceanic crust extends 5 to 10 km deep beneath oceans.

Three major ocean ridges exist in the Pacific, Atlantic, and Antarctic Oceans.

Volcanoes

Magma

Magma, molten rock found deep within the Earth's crust, can withstand temperatures of 1000 to 1200 °C.

Magma composition consists of silicate rock, gases, and water vapor.

Magma viscosity is determined by the amount of silica (SiO2); higher silica content...

Coastal Desert with Abundant Clouds

Extends from the far north to almost 30 degrees south latitude. Characterized by high humidity, the presence of fog (camanchaca), and low thermal oscillation.

Normal Desert

Extends from the extreme north to Chañaral. Features low relative humidity, high atmospheric dryness, strong thermal oscillation, and a lack of rainfall.

High-Margin Desert

Located to the east of the normal desert. Presents low temperatures, low relative humidity, and rainfall concentrated in the summer.

Low Marginal Desert

Found south of the normal desert. Conditions are less stringent than those of the normal desert.

Coastal Steppe with Abundant Clouds

Extends from the Elqui Valley to Zapallar. Presents high cloud cover and rainfall exceeding...

Study Methods of Earth's Interior

Several methods are used to study the Earth's interior:

• Probes and Mines: Direct observation is limited by depth (radius ~6371 km, probes go as deep as 13km).
• Study of Rocks: Natural phenomena like erosion and volcanic eruptions expose deeper rocks.
• Meteorites: Provide information about the primordial materials of the solar system, including Earth.
• Seismic Methods: The most effective method. Analysis of seismic waves from earthquakes that travel through the Earth's interior, providing data via seismographs.

Inner Layers of the Earth

The Earth's internal layers are distributed in order of increasing density, separated by seismic discontinuities.

Compositional Layers

• Crust and Mantle: Composed of rocks, with the less

Environmental Threats Facing Humanity

Irresponsible human actions are contributing to the emergence of serious problems that threaten humanity, such as:

• The process of desertification
• The destruction of forests
• The deterioration of the ozone layer
• The enhanced greenhouse effect
• Air and water pollution

Air Pollution: Major Sources and Impact

The largest air polluters are oil refineries and power plants. Cities, with their heating systems and vehicles, release carbon dioxide. In our country, approximately 150 pounds of pollutants per person are emitted into the atmosphere annually. The greatest pollution is recorded in urban areas of Madrid, Barcelona, and Bilbao. Acid rain is one of the three most serious environmental problems in Europe and America....

Understanding Minerals: Definition & Properties

A mineral is a naturally occurring solid substance, not produced by living organisms, characterized by a specific chemical composition and an ordered atomic structure. There are approximately 4,000 different minerals, and their identification requires studying various properties.

Key Characteristics of Minerals

• Solid Substance: This criterion excludes all liquids and gases, such as seawater or air.
• Natural Origin: Any product manufactured by humans is excluded.
• Not Produced by Living Organisms: This rule excludes biological products like shells or pearls.
• Specific Chemical Composition: Each mineral possesses a unique and defined chemical formula.

Identifying Mineral Properties

Some characteristic...

Plants: An Introduction

Plants are living, autotrophic organisms, meaning they produce their own food. They are not fixed to the substrate and are capable of moving actively. The primary substance that allows plants to use solar energy is called chlorophyll. Plants incorporate water, carbon dioxide, and mineral salts, which serve to reproduce them. They transform inorganic substances into organic energy, and this process requires sunlight. This process is called photosynthesis.

Plant Organs

• Root: The part that anchors the plant into the soil and absorbs water and mineral salts.
• Stem: The aerial part of the plant where substances circulate from the root to the leaves.
• Leaves: Expansions that grow from the stem, where photosynthesis primarily occurs.

Verticalist Theories and Fixism

Verticalist theories propose that movement in terrestrial materials is primarily vertical. These are considered fixist theories.

Key Aspects of Verticalist Theories

• Movement in terrestrial materials is vertical.
• They are fixist theories.
• Some related phenomena occur in the Earth's crust, such as Eustatic changes and Isostasy.

Understanding Eustatic Changes

Eustatic changes refer to global changes in sea level of greater amplitude than normal tides.

Causes of Sea Level Variation

These variations are driven by two main factors:

1. Variation in the volume of water in the oceans:
   • Glaciations: When ice sheets form, water is locked up, causing sea level to fall.
   • Thermal Contraction or Dilation: Changes in ocean temperature cause

Eutrophication

Eutrophication is the increase in nutrients, which increases the number of producers. This makes the water cloudy and prevents photosynthesis from taking place in the deeper levels, as there is a lack of sunlight. Heterotrophic organisms and decomposers intensify their activity, as there is more organic matter available. They also increase their oxygen consumption. In the end, the oxygen in the deeper level runs out, making it impossible for most species to survive.

Theory of Continental Drift

1912-1960: 225 million years ago, all the continents were joined together as one large supercontinent called Pangea. Over a very long period, the continents drifted apart to the positions they are today.

Evidence for Continental Drift

• Geological: