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

Weather

Weather is one of the most influential factors in the distribution of living beings on Earth. It is defined as the combination of meteorological phenomena that determine the atmospheric conditions characterizing a place.

Weather Elements

• Air Temperature: The amount of heat contained in the atmosphere at a given time, measured with a thermometer.
• Barometric Pressure: The weight of air exerted on Earth's surface, varying according to temperature and measured using a barometer.
• Wind: The movement of air caused by differences in temperature and atmospheric pressure.
• Atmospheric Moisture: The amount of water contained in the lower layers of the atmosphere, measured with a hygrometer. Clouds form from this moisture.
• Rainfall: The amount of precipitation

**Key Differences Between Western and Eastern Catalan**

Western Catalan (Including Valencian and Northwestern Dialects)

• Clear distinction in the articulation of unstressed vowels.
• Greater presence of the sound **é**, maintained because some words sounded the same in Vulgar Latin.
• Maintenance of the diphthong **ua** after *g*.
• Pronunciation of the vowel in the group following **ix**.
• Retrieval of the etymological **No** behind an unstressed vowel in the plural of some words.

Eastern Catalan (Including Roussillon or Northern, Central, Balearic, and Algherese Dialects)

• Confusion in the articulation of unstressed vowels.
• Greater presence of the sound **ê**, amended because some words sounded like *é* in Vulgar Latin.
• A tendency to reduce the diphthong

The Appearance of Oxygen on Earth

The presence of pyrite, a mineral found in sedimentary rock, can indicate the presence of oxygen in the atmosphere. In older rock strata, pyrite appears dull and lacks the brilliance found in pyrite from younger strata. This suggests that oxygen levels were lower in the past. By calculating the age of these rocks, we can estimate when oxygen first appeared in the Earth's atmosphere.

Miller's Experiment and the Synthesis of Organic Matter

Stanley Miller conducted an experiment to simulate the conditions of early Earth and investigate the synthesis of organic matter from inorganic compounds. He successfully synthesized amino acids from inorganic molecules like methane, ammonia, and water, demonstrating the possibility... Continue reading "The Origin and Early Evolution of Life" »

Background to the Land of Continental Drift

During the nineteenth and twentieth centuries, the prevailing theory was contractionism. It proposed that the Earth, as it cools, contracts, resulting in large folds of the crust. This was later referred to as fixism.

The Wilson Cycle

The Wilson Cycle describes the cyclical process of ocean basin formation and destruction. It consists of the following stages:

1. Continental Fragmentation: Begins with the fragmentation of a continent by a hot spot. Magma from the mantle rises, causing a bulging of the lithosphere.
2. Formation of a Rift Valley: The lithosphere breaks, forming parallel faults. Central blocks sink by gravity, creating the Rift Valley.
3. Formation of a Young and Narrow Sea: Magma ascends from the

Factors That Determine the Shape of Relief:

• The Type of Rock: Every rock has specific characteristics.
• Climate: The type of external geological agent that dominates an area is determined by the climate.
• The Structure of Materials: Rocks that have been folded or fractured provide an initial way.
• Relief Seniority: External geological agents remove materials from one place and deposit them in others.

Clay Reliefs: However, in arid climates with little vegetation, poor but torrential rains originate a dense network of gullies and ravines called badlands. Karst Reliefs: Reliefs arising from the dissolution of limestone or other similar rocks are known as karst relief. Forms of Karst: Rainwater dissolves the surface of the limestone and forms small furrows... Continue reading "Understanding the Factors Influencing Relief Shapes" »

Aridity: Regional Water Scarcity

Features of regions with water shortages due to rainfall insufficiency, where evaporative water loss or evapotranspiration exceeds atmospheric water contributions via precipitation. Example: Periods of aridity in Spain.

Mountain Climate Characteristics

Climate characterized by low temperatures compared to surrounding plains, with high rainfall, sometimes in the form of snow in the most elevated parts. Example: Navacerrada has a mountain climate.

Mediterranean Climate Features

Temperate climate characterized by relatively mild, wet winters and hot, dry summers. Rainfall is most frequent during autumn and spring. It is characteristic of the coasts of the Mediterranean basin. Example: Climate of the Balearic Islands,

Evolution

Fixism

Species remain unchanged.

Creationism

Species are divinely created.

Lamarckism

Species change over time. Proposed by Lamarck. Assumptions: environmental conditions vary, creating changes and modifications.

Darwinism

Survival of the fittest drives species change.

Key Concepts in Evolution

Fossils

Remains of organisms that lived on land and are now extinct.

Geographical Distribution

A common ancestor lived on a continent, and upon separation and isolation, species evolved independently.

Homology

Similarity due to a common ancestor.

Embryonic Development

Vertebrate embryos are very similar at early stages due to a common ancestor.

Molecular Genetics

Comparing DNA to determine kinship.

Mutations

Changes in genetic material that can be beneficial, detrimental,... Continue reading "Evolution and Environmental Factors in Biology" »

Continental Drift and Plate Tectonics

Mechanism of Continent Movement

• The concept suggests oceanic sliding; the ocean floor remains motionless.
• Lithospheric plates slide over the mantle as the continents move. The oceanic floor changes.

Forces Driving Continent Movement

• Not clear. One mechanism suggests Earth's rotation could be the cause of motion.
• Mantle convection currents. Seafloor spreading at the ridges pushes the continents.

Causes of Reliefs

• Wrinkles produced in the leading edge of continents.
• Lithospheric plate collisions.

Oceanic and Continental Lithosphere

• Thickness

  • Oceanic: 100 km
  • Continental: 300 km

• Crust Composition

  • Oceanic: +90% of its mass are basaltic metamorphic rocks. Rocks poor in quartz.
  • Continental: +85% of its mass are granitic metamorphic

There are three major morphostructural groups:

1. Antique Beds: Made up of mountains of medium height, flattened summits (peneplains), consisting of material folded in the Paleozoic era, deformed by Hercynian and Alpine folding.

2. The Alpine Mountains: These are very young and high; their basic material is limestone.

3. Depressions: These can be of different types:

• Some fragments are located on the old sunken Hercynian base, such as the Cuenca del Duero.
• Others occupy former inlets or bays that are silting up by sediments from the Alpine ranges, such as the depression of the Ebro and Guadalquivir.

Mainland Units and Dynamic Stresses

The fundamental unit is the Meseta peninsular relief, which is an area of highlands (600-800 m) divided into two sectors... Continue reading "Major Morphostructural Units and Relief Dynamics of Spain" »

Properties of Minerals

Physical Properties

Exfoliation: The property of minerals to split along a preferred direction. These minerals have a weaker union between each crystalline unit. It depends on the internal structure of the crystal and is constant for each mineral. The following grades are usually distinguished: excellent, perfect, good, very flawed, and imperfect.

Fracture: When a mineral fractures, the chemical bonds are broken irregularly, unrelated to the symmetry of the structure.

Toughness: The resistance of a mineral to being scratched. It depends on the chemical bonds. Its value is calculated by comparing it with other minerals of known hardness (Mohs scale).

Specific Gravity: A number that expresses the relationship between the mineral'... Continue reading "Mineral Properties: Physical, Optical, and Chemical Characteristics" »