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

Geological Processes Shaping Earth's Surface

Factors Determining Landform Relief

The process by which the Earth's surface acquires a particular form is called relief modeling. The diversity in landform modeling is due to several significant factors:

• Type of Rock: Each rock type possesses specific characteristics. For instance, granite provides different forms compared to clay due to its inherent properties.
• Climate: The prevailing external geological agent in an area is determined by its climate. In temperate climates, water is the most important agent, while in cold climates, ice dominates.
• Structure of Materials: Often, rocks have been folded or fractured, providing an initial form that significantly influences the subsequent modeling process.

Environmental Risks and Their Prevention

For the prevention of environmental risks, steps are taken based on the specific risks determined by the vulnerability zoning of the territory in planning actions, aiming to minimize the possible effects of damage and risks. Examples include INUNCAT, NEUCAT, seismic, InfoCat, and PLASEQTA. Types of preventive measures include:

• Prediction measures
• Immediate intervention
• Recovery
• Subsequent awareness

The Environmental Hazards and Their Prevention

Risks are uncertain dangers to which a person or group of people may be exposed. Environmental risks are those that can affect the environment and the health of the inhabitants. Risk factors characterizing these hazards include:

• Scale: Size and intensity
• Frequency: Number

Metamorphism: Rock Transformations

Metamorphism refers to the set of transformations that a rock undergoes when subjected to pressure and temperature conditions different from those that prevailed during its genesis.

Factors Influencing Metamorphism

Changes in temperature, pressure, and fluid flow alter the stability of minerals.

• Temperature Increase: This can be due to the confinement of rocks within the Earth's crust and the movement of fault blocks, which release heat.
• Pressure Increase: Pressure increases can result from:
  • Confinement: The accumulation of sediments exerts a uniform pressure inside, known as lithostatic pressure (Pl).
  • Folding: This introduces a horizontal pressure component called tectonic pressure (Pt).
  • Presence of a Fluid Phase:

Classification of Risks by Origin

Risks, according to their origin, are divided into three main categories: natural, technological, and mixed.

Natural Hazards

Natural hazards are incidents defined by the internal and external dynamics of the Earth. They are further classified by their specific origin:

• Geological:
  • Endogenous: Associated with internal geodynamics (e.g., volcanoes, earthquakes).
  • Exogenous: Associated with external geodynamics (e.g., movements of hillsides, torrents).
• Meteorological (Weather): Caused by the action of the atmosphere (e.g., hurricanes, typhoons).
• Cosmic: Due to external phenomena (e.g., meteors, asteroids).
• Physical: Includes risks like natural fires and natural radioactivity.
• Biological: Risks caused by living organisms.

Technological

Analysis of Precipitation

Total Precipitation

• Very abundant: +1000 mm (mountain climate)
• Abundant: +800 mm (oceanic climate)
• Short: 800-300 mm (continentalized coastal Mediterranean climate)
• Very low: <300 mm (sub-desert steppe climate)
• Extremely low: <150 mm (desert climate)

Distribution of Rainfall

• Regular: No dry month with rainfall < 30 mm (oceanic climate)
• Fairly regular: Maximum of 2 dry months (oceanic climate transitioning towards continental Mediterranean)
• Irregular: More than 2 dry months (Mediterranean climate), +7 dry months (dry sub-desert or steppe Mediterranean climate)

Noteworthy points:

• Seasons with more abundant precipitation
• Months with less or no rainfall (dry months)

Analysis of Temperature

Average Annual Temperature and Thermal

Physical Geography of the Galaico-Leonese and Cantabrian Mountains

A) Relief and Geological Structure

The Galaico-Leonese Massif and the Cantabrian Mountains border the plateau to the north. The Galaico-Leonese Massif was fractured and uneven during the Tertiary period. Its distinctive profile is rounded and of low altitude, resulting from continuous erosion. The mountains are separated by deep faults. The most important sierras (mountain ranges) include Segundera, Cabrera, and Hangares. Higher elevations exceed 2,000 meters (m), such as Teleno (2,118 m).

The Cantabrian Mountains are the great massif of Northern Spain, stretching from west to east. Two distinct sectors can be differentiated:

• Western Sector: Predominantly abundant coal strata, which

Geographical and Climatic Terminology of Chile

I. Major Landforms and Mountain Ranges

• Andes Mountain Range

  The chain of mountains in South America that extends almost parallel to the coast of the Pacific, from Cape Horn to the vicinity of Panama.

• Coastal Mountains (Cordillera de la Costa)

  Extends from Cerro Camaraca to the Taitao Peninsula.

• Cerro Camaraca

  The point where the Cordillera starts from the coast.

• Antartandes

  Where the Cordillera of the Andes finishes in the Antarctic.

• Patagonian Range (Cordillera Patagónica)

  A mountain zone shared with Argentina.

• Nahuelbuta Range (Cordillera Nahuelbuta)

  Serves as a separation between the VIII and IX regions.

• Cerro Vicuña Mackenna

  The maximum height of the Coastal Cordillera in the II Region.

II. Relief and Regional

Composition of the Atmosphere: The atmosphere is the envelope of the land held around our planet by gravity. It is composed of a set of gases and other gaseous elements in suspension. The atmosphere's presence avoids large oscillations of temperature on the Earth's surface, as solar radiation decreases during the day and prevents excessive heat loss at night. In the absence of the atmosphere, temperatures could reach over 95°C during the day and drop to -180°C overnight. The atmosphere contains the necessary components for organisms to perform their vital processes.

Origin and Balance of the Atmosphere: Gases in the atmosphere originated from the rocks of the Earth approximately 4.6 billion years ago, when the Earth's materials were in a semi-... Continue reading "Understanding the Composition and Structure of the Atmosphere" »

Conditions for a Habitable Planet

• Suitable Temperature: Must allow metabolic processes to function.
• Tectonic Activity: Volcanic eruptions and magmatic intrusions bring essential elements for life to the surface.
• Presence of Liquid Water.
• Radiation Protection: Shielding against high-frequency photochemical radiation (e.g., magnetosphere, ionosphere, ozone layer).

Earth Systems and Human Interactions

System Components

• Nature: Biosphere, Atmosphere, Geosphere, Hydrosphere.
• Society: Population, Lifestyles, Science, Technology, Culture.
• Economy: Agriculture, Industry, Transport, Housing.

Inter-System Exchanges

• Nature to Society (NS): Provides air, water, energy, protection.
• Society to Nature (SN): Generates waste, causes impacts.
• Nature to Economy (NE): Provides

Mesozoic Era (250-65 Ma)

No geological evolution. Towards the end of the Paleozoic and Mesozoic, all continents of the Earth united to form Pangea. The distribution of land and sea undergoes major changes during this era, during which continents separate.

Life in the Mesozoic

In the Mesozoic, a major diversification of marine fauna, especially molluscs and echinoderms, occurred due to the fracturing of Pangea. Reptiles experienced significant diversification, colonizing air, aquatic, and terrestrial environments (dinosaurs).

Types of Dinosaurs:

• Teropods: Carnivorous with short front legs equipped with strong claws and enormous teeth.
• Sauropods: Large quadrupedal herbivores with very long necks and tails, and columnar legs.
• Ornithopods: Bipedal herbivores.