Notes, abstracts, papers, exams and problems of Geology

**Sensory Receptors**

Internal Receptors

Internal receptors capture changes in the internal environment, like the standard of the receptors.

External Receptors

External receptors capture stimuli from outside the body. Some are scattered, and others are grouped into sensory organs.

Receptors in the Skin

• Thermoreceptors: These capture external temperature differences in the body. There are two types: those that react to higher temperatures and those that react to lower temperatures. They generate feelings of cold and heat.
• Nociceptors: These respond to skin aggressions. The nerve impulses they generate are painless.
• Mechanoreceptors: These detect changes in pressure on the skin or movement of the hairs.

Smell

1. The molecules of volatile substances enter

Work of Rivers

Rivers erode their beds, making them wider and deeper. Erosion is heightened during periods of high flow rate and increased water volume.

Flow

Flow is the volume of water transported per unit of time. The amount of material a river carries depends on its flow and speed. Materials can be transported as:

• Dissolved salts: Substances dissolved in the water.
• Suspended particles: Small particles traveling within the water.
• Saltating particles: Larger particles bouncing along the riverbed.
• Traction: The rolling or dragging of large particles along the riverbed.

Upper Course

With higher water speed, erosion creates a deeper V-shaped valley.

Middle Course

With reduced speed, materials are deposited at the bottom of the riverbed, and erosion continues... Continue reading "River and Coastal Processes: Shaping the Earth's Surface" »

Earth's Spheres

Earth Subsystems

Atmosphere: The external layer of the planet in a gaseous state.

Hydrosphere: The discontinuous layer that surrounds the Earth's surface with water. Liquid water is fundamentally found under the surface, in continents and oceans. Although in small quantities, glacial ice is the first part of the atmosphere for living beings.

Geosphere: The rocky structure that makes up the Earth system's greatest volume. We will focus on its most external part, the lithosphere.

Biosphere: The system made up of living beings that inhabit the Earth. It occupies the lower part of the atmosphere, the upper part of the lithosphere, and the hydrosphere.

The Gaia Hypothesis

1. The biosphere is an entity whose main properties are the sum of the

Universe Composition

The universe is immense and comprises millions of bodies. Not everything in the universe can be observed, so the universe currently consists of an observable part. We know that there are billions of galaxies. Each galaxy contains thousands of stars, nebulae, and planets.

From a chemical point of view, the observable universe is described as being made up of: 75% hydrogen, 20% helium, and 5% other elements. Isaac Newton discovered that when sunlight passes through a prism, it separates into bands of colors (the light spectrum). We observe some black lines within this spectrum. In the laboratory, if we pass white light through containers with hydrogen and helium gas, these elements absorb specific colors of light, resulting... Continue reading "Universe Composition, Dark Matter, and Cosmic Structures" »

Pressure (p) is the ratio of force (F) to the area (S) over which it is applied: P = F / S.

Hydrostatics and Fluid Density

Hydrostatics is a branch of physics that studies fluids at rest. The density (d) of a fluid is its mass per unit volume. The relationship between mass and volume is used to calculate density.

Hydrostatic Equilibrium and Pressure

Hydrostatic equilibrium refers to the pressure within a fluid generated by its weight. The pressure (p) at a point within a fluid is determined by the fluid's density (d), the acceleration due to gravity (g), and the depth (h) of the point: p = dgh. Pressure applied at any point in a fluid is transmitted equally to all points within the fluid.

Surface Tension

Surface tension relates to the strength of... Continue reading "Understanding Pressure, Density, and Buoyancy in Fluids" »

Understanding Energy

Energy: is the physical quantity by which bodies are able to make changes on themselves or on other bodies.

Forms of Energy

• Mechanical Energy: The energy bodies possess by being in motion (kinetic), by being some distance above the soil surface (potential), or by experiencing deformation (elastic).
• Electrical Power: Current electricity is produced in large facilities called power plants through electric generators. It also occurs in dry cell batteries.
• Nuclear Power: This comes from nuclear fusion and fission reactions. In these reactions, the mass of the nuclei is converted into this form of energy.
• Heat: This is the form of energy that flows from one body to another when there is a temperature difference. It produces effects

Energy Types and Use

Energy Types:

1. Endosomatic: Energy that sustains life, derived from food and plants through photosynthesis.
2. Exosomatic: Energy not derived from food, used to meet social and collective needs (e.g., transportation, manufacturing).

Energy Use:

1. Petroleum: Extracted from oilfields. Formed from marine plankton over 20-50 million years.
2. Gas: Produced when organic matter decomposes. Reserves last 22-49 years.
3. Coal: Reserves last 111-150 years.
4. Radioactive Minerals: Used for nuclear energy.

Water Resources and Applications

Water is essential for life, primarily in the form of freshwater. However, a small percentage of freshwater is readily available, with a portion locked in polar ice caps.

Applications:

1. Agriculture: Irrigation significantly

Key Geological Concepts

Stratigraphic Column

A stratigraphic column represents vertical information about the soil in a specific area. It details the materials that form the strata, their thickness, age, and other relevant characteristics.

Isotopes

Isotopes are different forms of the same element that have varying numbers of neutrons in their nucleus. They are differentiated by their mass number, which is the sum of protons and neutrons in the nucleus (e.g., ¹²C, ¹³C, and ¹⁴C).

Stratigraphic Gap

A stratigraphic gap occurs when sediment deposition is absent between two adjacent layers in one location, while deposition occurred at the same time in another location.

Half-Life

Half-life is the time required for half of the nuclei in an initial sample of... Continue reading "Geological Concepts: Stratigraphy, Isotopes, and Uniformitarianism" »

Refractor and Reflector Telescopes

Refractor (lens) - Galileo 1609
Reflectors (mirrors) - Newton 1670 - Cassagrain 1671
Reflectors (mirrors and lenses) - Schmidt 1930

Galileo's Contributions

Lunar surface phases of Venus, an aspect of Mars, 4 major satellites of Jupiter, solar rotation, stellar appearance of the Milky Way, an aspect of Saturn.

Aberration / Image Deficiencies

1) Spherical: Blurry images. It removes focus from the image.
2) Chromatic (color): Images with distinct edges. It is improved by adding a correcting lens.

Telescope Properties

A - Magnification: Number of times the image is enlarged as seen with the naked eye.
P - Resolving power: The ability of a telescope to distinguish or separate two spaced light sources.
d is the diameter... Continue reading "Telescopes, Astronomy, and Stellar Evolution" »

The Ebro and Guadalquivir River Depressions

The Ebro Depression

The Ebro Depression is wedged between the foothills of the Pyrenees, the Iberian System, and the Catalan Coastal Range. It has a length of 380 km and a maximum width of 150 km. The Ebro River runs through this depression. The river and its tributaries form a communication network, where cities and irrigated areas are located. The Ebro flows through a passage between the Catalan Coastal Range that leads to the Mediterranean, where it forms a very extensive delta.

The Guadalquivir Depression

The Guadalquivir Depression is bordered by the Sierra Morena and the rugged Cordillera mountain ranges. This large, flat, triangular-shaped depression is about 330 km long and 200 km wide at the... Continue reading "Spain's Coastal and River Depression Relief" »