Introduction to Geology

Introduction to Geology

• Geology is the study of the origin, occurrence, distribution, and usage of materials (metallic, non-metallic, inorganic), minerals, rocks, sediments, soils, water, oil, and other inorganic natural resources.

Branches of Geology

• Structural Geology: Focuses on the configuration of rocks within the Earth's crust.
• Geomorphology: Studies the formation and evolution of landforms and bathymetric features.
• Crystallography: Examines the external forms and internal atomic structure of crystalline materials.
• Petrology: Studies rocks, including their composition, texture, structure, occurrence, distribution, and origin.
• Stratigraphy: Describes and classifies sedimentary rock layers and interprets their environments of formation.
• Paleontology: The study of fossils and how they can provide information on past organisms and environments.
• Hydrogeology: Focuses on the distribution, movement, and occurrence of groundwater within the Earth's crust.
• Seismology: Studies the Earth's structure through seismic waves, and surface deformations during earthquakes.
• Geochemistry: Studies the chemical composition of the Earth's crust and oceans.
• Mining Geology: Applies geological knowledge to develop mineral resources.
• Spectral Geology: Measures and analyzes the electromagnetic spectrum to identify rock types.
• Marine Surveying: Investigates the ocean floor's processes and features.  
• Mineralogy: Studies the characteristics of minerals.
• Geophysics: Examines the Earth's physical structure, conditions, and evolution.
• Physical Geology: Focuses on geological processes that create landforms and change Earth's surface.
• Engineering Geology: Applies geological knowledge to civil engineering.
• Geodesy: Studies Earth's shapes and dimensions.
• Historical Geology: Reconstructs past geological history
• Oceanography: Studies the composition, motion, and processes responsible for ocean water.
• Sedimentology: Studies sediment grains to understand their formation and distribution.

Compositional Layers of the Earth

• Crust: The outermost rocky layer (0-100 km).
• Mantle: Layer between crust and outer core (100-2900 km).
• Core: Innermost layer (2900-6370 km).

Mechanical Layers of the Earth

• Lithosphere: The rigid outer layer, made of the crust and upper mantle.
• Asthenosphere: The soft, plastic layer of the mantle that allows tectonic plates to move.
• Mesosphere: The strong, lower part of the mantle.
• Outer Core: A liquid layer composed of iron and nickel.
• Inner Core: A solid sphere of iron and nickel.

Plate Tectonics

• Plate tectonics is the theory that Earth's lithosphere is divided into plates that move constantly, causing earthquakes and creating mountain ranges, volcanoes, and continents.
• Boundaries: Divergent, convergent (ocean-ocean, ocean-continent, continent-continent), and transform.

Weathering

• Weathering is the breakdown of rocks into smaller pieces.
• Includes physical weathering (e.g., frost wedging, thermal expansion) and chemical weathering (e.g., dissolution, oxidation).

Erosion

• Erosion is the transportation of weathered material by natural forces (wind, water, ice).
• Erosion is directly related to weathering and deposition.

Geological Works of Wind

• Wind can erode, transport, and deposit sediment.
• Methods include deflation, abrasion, and attrition.

Geological Works of Water

• Water can erode, transport, and deposit sediment.
• Includes erosion by rivers, waves, glaciers, and oceans.

Geological Works of Lakes

• Lakes are accumulations of water that are characterized by many variables (depth, shape, water quality elements)
• Lakes are caused by glacial activity, tectonic movements, meteorite hits, and river courses.

Geological Works of Oceans

• The ocean influences Earth's climate through currents and wind patterns.
• The ocean acts as a major reservoir for water and nutrients.