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

Big Bang Theory

Both matter and energy, and space, were at the same point, called the primeval atom. The expanded atom caused a big explosion: the power went away in all directions and established matter. Helium and hydrogen particles and the stars were created, galaxies due to the condensation of matter.

Instruments Observation

Telescopes collect partial information about the universe. Satellites and probes have provided much relevant information on indirect methods, composition, and the structure of the Earth's interior. Measurements can teach us more about the content of the soil.

Seismic Waves

P waves and S waves, caused by catastrophes, reach Earth's surface. Discontinuities occur when the seismic wave enters another material. As detected in... Continue reading "Cosmos Evolution: Big Bang to Natural Selection" »

The Climate Machine: Understanding Atmospheric and Hydrospheric Dynamics

The Earth's climate system is incredibly complex, driven by movements generated due to the existence of gradients between two points.

What is a Gradient?

A gradient refers to the difference between two points in any atmospheric parameter, such as temperature or humidity. When a thermal gradient exists, determined by a temperature difference between two points, heat will be transported from one extreme to another.

The behavior of the atmosphere and hydrosphere differs significantly due to their variations in:

• Density
• Mobility
• Ability to store heat
• Ability to conduct heat

Vertical Movements of Fluids

Both upward and downward fluid movements depend on the temperature at which they... Continue reading "Earth's Climate System: Atmospheric and Oceanic Circulation" »

Demographic Transition in Spain: A Historical Analysis

The demographic transition describes the process by which a population shifts from a state of high birth rates and high mortality rates (resulting in low natural growth) to one of low birth rates and low death rates (also leading to low natural growth). This transformation typically occurs in several distinct phases.

Phase 1: The Pre-Transitional Phase (Late 19th Century)

This initial phase, beginning in Spain in the late 19th century, was characterized by high birth rates, primarily due to economic and religious factors. Concurrently, high mortality rates prevailed, largely attributable to underdeveloped medicine, a deficient healthcare system, and poor sanitation. In these years, birth rates... Continue reading "Spain's Demographic Evolution: Historical Population Changes" »

Magma Classification and Characteristics

Magmas are molten rock materials found beneath the Earth's surface, characterized by their temperature, silica content, and viscosity. These properties dictate their behavior and the types of igneous rocks they form.

Basic Magmas

• Temperature: High, typically 1000-1200°C.
• Silica Content: Low (around 50%).
• Viscosity: Low, allowing them to easily reach the surface.
• Resulting Rocks: Dark-colored, with densities around 3000 kg/m³. Examples include basalt (extrusive) and gabbro (intrusive).

Acid Magmas

• Temperature: Lower, typically around 700°C.
• Silica Content: High (around 75%).
• Viscosity: Very high, often preventing them from reaching the surface easily.
• Resulting Rocks: Lighter-colored, with densities around 2600

Roman Memorials

Roman memorials were usually located in the forum or on the access roads to the cities.

Triumphal Arches

Triumphal arches were built for parades of victorious troops, dedicated to victorious generals or emperors. They were often placed in strategic locations such as road crossings, near bridges, and especially at the ends of forums.

• Primarily known from the Imperial period, they must have also existed in the Republican period.
• Their typology was diverse:
  • They usually consist of one or three openings, called "eyes," with the central one being the broadest. Above the entablature, a second body called the "attic" or "penthouse" was available, on which inscriptions were placed. The entire structure was completed with architectural and

Binders

Binders are materials that, when mixed with water, produce a chemical reaction that gives cohesion to particles. They are used to join construction pieces.

Chalk

• A naturally occurring calcium sulfate.
• Cooked to 180 °C, it becomes soft.
• Cannot be used outdoors as it becomes solid quickly and oxidizes iron.
• Uses: Wall cladding and ceilings.
• Variety: Plaster, used for plasterboard, decoration, molds, prosthetics, and orthopedic arts.

Lime

• Calcium carbonate, obtained by heating to about 900 °C.
• Highly reactive with water, which can raise the reaction temperature to 150 °C.
• Replaced cement until its discovery.
• Applications: Additive in mortars, whitewashed walls, purification tanks.

Cement

• A mixture of clay and limestone, heated to about 1600 °C.
• Properties

Factors Influencing the Peninsular Rivers

The characteristics of peninsular rivers are influenced by several factors, including:

• Climate: Rainfall and temperature patterns significantly impact river flow.
• Relief: The topography of the land affects the direction and speed of water flow.
• Lithology: The underlying rock type influences water absorption and erosion.
• Vegetation: Plant life can affect water flow and sediment levels.
• Human Action: Activities such as dam construction and irrigation alter river regimes.

River regimes can be classified as rain-fed, snow-fed, or a combination of both (mixed).

Basin Types

• Exorheic Basin: Characterized by water flowing into the open sea.
• Endorheic Basin: Refers to landlocked water bodies.
• Arheic Basin: Describes areas

Biodiversity in Spain

Location: Southwest Europe. Spain has two large biogeographic regions: Atlantic and Mediterranean. The Canary Islands have a tropical climate. The Iberian Peninsula served as a refuge during glaciations. Many animal and plant species evolved, forming new species. The presence of mountain ranges allows species to reproduce at high altitudes, creating a gradation between northern and southern Europe.

Human Impact on Biodiversity

Biodiversity has been affected by human actions, which have transformed the natural landscape (forests replaced by arable fields, etc.). This has led to a loss of vegetation and an increase in urban and industrial sites.

Landscapes of Plants

Oceanic Plant Landscape

Found in the Galician and Biscay regions.... Continue reading "Spain's Biodiversity: Habitats and Threats" »

Weathering of Rocks by Atmospheric Agents

Clasts are fragments of rock torn from a larger rock mass. The fragmentation of rocks is caused by atmospheric agents such as rain and snow. These agents wet the rock, dissolving minerals and reacting with them. Temperature changes also contribute: the expansion of rocks as the sun heats them contrasts with the contraction caused by freezing. Water seeps into cracks in rocks, subjecting them to pressure during freezing (gelifraction).

Weathering is the set of processes due to atmospheric agents that produce the alteration and disintegration of rocks.

• Mechanical Weathering: The rock is fragmented due to expansion and contraction, the freezing of water, or the impact of falling rocks.
• Chemical Weathering:

1. Geological Processes: Origin and Types

1.1 External Geological Processes

• Source:
  • Solar energy
• Type:
  • Weathering: Action of the atmosphere
  • Erosion: Separation of fragments and soil disturbance
  • Transport: Movement of these fragments in favor of gravity

1.2 Internal Geological Processes

• Source:
  • Geothermal energy inside the Earth
• Type:
  • Orogenic Movements: Horizontal displacement
  • Epirogenic Movements: The rise and decline with increasing mass of the Earth's crust

2. Plate Tectonics

• Structure based on geochemical and dynamic models:

• Source of plate movement:
  • Two scenarios:

1. Convection currents or flaring rims creating constructive