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

1. The Earth and a Long, Changing History

Sedimentary rocks cover most of the Earth's surface, and are found in strata. These layers often contain fossils. The history of the Earth is divided into two parts:

• Precambrian: The planet's formation, the emergence and development of life, the formation of the primitive atmosphere. It is divided into three eons: Hadean, Archean, and Proterozoic.
• Phanerozoic: At this stage, the Earth remained as we know it, with the current continents and existing life forms (including humans). It is divided into three eras: Paleozoic, Mesozoic, and Cenozoic.

2. Precambrian: The Most Ancient Times

2.1. Hadean: Ancient God of Hades = Hell

The oldest rocks (3800 Ma) are magmatic and metamorphic. There was intense volcanic... Continue reading "Earth's History: From Precambrian to Today" »

Evolutionary Theories

Current thought posits that diverse life forms share a common ancestor known as LUCA. Several theories exist, including Charles Darwin's, which centers on morphological variations in species. These changes, slow, gradual, and driven by natural selection, were later understood to result from DNA alterations. This new understanding shifted the focus from individuals to populations. The gradual evolution concept faces challenges due to the incomplete fossil record.

Homo Sapiens

Our species is distinguished by a highly developed brain, tool-making abilities, language, and extended childhood. Africa, where most hominin fossils have been discovered, is considered the cradle of hominization. The oldest fossils, Ardipithecus ramidus,... Continue reading "Human Evolution and the Origins of Life on Earth" »

Divergent Plate Boundaries

Most divergent boundaries, where plate expansion occurs, are located along mid-ocean ridges. Here, as plates move away from the ridge axis, fractures are created and immediately filled with molten rock rising from the hot asthenosphere below. Through the continuous expansion of the plates and the ascent of magma, new oceanic crust (lithosphere) is added between the diverging plates. This crustal extension is accompanied by alternating episodes of fault formation and volcanism. Adjacent to the expansion axis, crustal blocks are bounded by faults, forming elongated valleys known as rift valleys. As rifting continues, the rift valley lengthens and deepens, eventually expanding into an ocean. At this point, the valley... Continue reading "Plate Tectonics: Divergent, Convergent & Transform Boundaries" »

Methods of Food Preservation

Goal

To prevent the growth of microorganisms, action of environmental agents, chemical and biochemical reactions, and insect attacks. Methods include asepsis, treatment, and conditioning.

Factors Favoring Microorganism Growth

• Temperature
• Oxygen
• Water
• Nutrients
• pH

Traditional Methods

• Salt: Dry (covering with salt) or brine (using a liquid solution with salt and spices).
• Drying: Reducing water content through natural (sun) or artificial (heat, lyophilization) means.
• Smoking: Exposing food to smoke from incomplete wood combustion, providing germicidal, antioxidant, and preservative effects.
• Spices: Adding flavor and acting as preservatives.
• Pickling: Treating food with vinegar or other liquids, often with spices and herbs.
• Adobe:

National Water Plan

Project coordinating river basin management plans and water resources. The 2008 plan, aligned with EU guidelines, focuses on environmental actions (supply, treatment, purification, irrigation, forestry impact, channels) and works regularization, including the Ebro water transfer and construction of new dams.

Water Transfer

Interbasin transfer from water surplus to deficit areas. Currently, 38 are operational, including the Tajo-Segura. The National Hydrological Plan proposes new transfers, like the Ebro to the Mediterranean. However, protests in regions like Aragon and potential environmental impacts (Ebro Delta) have led to exploring alternatives, such as the Rhone-Catalonia transfer.

Reservoirs

Artificially stored water extensions... Continue reading "Spanish Environmental Management: Plans, Laws, and Initiatives" »

Types of Rocks

Sedimentary: Rock formed by material eroded and transported by geologic agents, including sedimentary basins, which have been compacted over time.

Magmatic (Igneous): Originated by the cooling of a molten rock mass. There are two types:

• Plutonic: Cooling magma within the Earth's crust. They have a crystal texture.
• Volcanic: Rapid cooling of lava on Earth's surface. They have a microcrystalline texture.

Metamorphic: Rocks formed in the interior of the crust due to the high pressures and temperatures that produce changes in the minerals.

Definitions

Volcanism: The surface expression of rocks melting within the crust.

Earthquake: Brief and sudden movements of the Earth's crust.

Continental Drift: Slow, horizontal movement of continents.

Isostasy:

Raw Materials and Their Properties

Raw materials are substances extracted directly from nature. They can be classified as:

• Animal: Leather, wool, silk
• Vegetable: Flax, esparto, wood
• Mineral: Iron ore (hematite), clay

A material ready for processing is called a field-ready material. These materials undergo physical and chemical transformations to create products like paper, board, and wood.

Technological Products

A technological product is any object created by humans to meet their needs and improve their quality of life. These objects are made from various materials (e.g., books, tables). The process of creating technological products involves transforming raw materials into usable materials and then into the final product.

Common Technological Materials

The... Continue reading "Understanding Raw Materials, Properties, and Technological Products" »

What is Energy?

Energy is the ability or property of bodies and physical systems to produce changes around them. During transformation, energy is exchanged through two mechanisms: work or heat. Energy is conserved and degraded in each transformation, losing the capacity to make further changes.

Thermal Energy or Heat

Thermal energy, or heat, is the energy exchanged between bodies with different temperatures. Heat is a form of energy transferred from one body to another as a consequence of the temperature difference between them.

Body temperature can be measured using the following scales:

• Celsius Scale: The fixed point 0 is the temperature at which water freezes, and point 100 is the temperature at which water begins to boil.
• Kelvin Scale: The fixed

Understanding Material Properties and Classifications

A material is any substance used for the construction of an object. Raw materials are those funds derived from nature in order to use them in any subsequent process of production. The evolution of materials is due to technological progress.

Properties

Properties may be classified as electromagnetic, thermal, chemical, and optical. The mechanical properties are the most important. The main ones are:

• Hardness: The resistance of a material to being pierced or scratched by another.
• Tenacity: The ability of a material not to deform or break when a force is applied.
• Plasticity: The ability of a material to deform under the action of a force and retain the new shape.
• Elasticity: The ability of a material

Dry Columns: Firefighter Access

Dry columns are designed exclusively for firefighters. They consist of galvanized steel studs, typically 80 mm in diameter, and are empty. A water outlet is usually located on the front of the building, on the ground floor. The column ascends or descends within the stairwell of buildings, providing hydrants on each floor. In the event of a fire, dry columns facilitate water flow and pressure for firefighters.

Dry columns are required in all buildings exceeding 24 meters in height, except for hospitals, where the limit is 15 meters. They are also required in parking lots with more than 3 floors below ground or 4 floors above ground, on all floors.

Sprinkler Systems: Automatic Fire Suppression

Sprinkler systems, often... Continue reading "Fire Protection Systems: Dry Columns and Sprinklers Explained" »