GEOLOGY

INTRODUCTION TO GEOLOGY

• Geology: Study of the Earth (origin, structure, composition, history, processes).

GEOLOGY IN CIVIL ENGINEERING

• Knowledge of construction materials, erosion, and rock stability is crucial.

• Geology impacts: dam, bridge, building foundations; water supply; geological mapping; pre-surveys reduce costs.

SCOPE OF GEOLOGY

• Engineering Geology: Informs construction materials and site selection.

• Mining Engineering: Guides methods of rock/mineral extraction.

• Ground Water Resources: For storage, pollution disposal, and irrigation.

BRANCHES OF GEOLOGY

• Physical Geology: Processes by physical agents (erosion, transportation, deposition).

• Mineralogy: Study of minerals and their properties.

• Petrology: Study of rocks and their formation.

• Paleontology: Study of fossils for evolutionary insights.

• Hydrology: Focuses on water quality/quantity in rocks.

INTERNAL STRUCTURE OF EARTH

• Divided into three layers: Crust, Mantle, Core.

• Waves: P-waves (solids), S-waves (solids), L-waves (surface).

• Crust: Varies in thickness; includes SIAL (continental) and SIMA (oceanic).

• Mantle: Composed of peridotite, divided into upper and lower layers.

• Core: Inner (solid) and outer (liquid), primarily iron and nickel.

WEATHERING

• Process altering rocks due to atmospheric exposure.

• Types of Weathering:

  • Physical: No chemical change (e.g., frost action).

  • Chemical: Transform rocks chemically (e.g., oxidation, carbonation).

  • Biological: Organisms contribute to rock disintegration.

GEOLOGICAL WORK OF RIVERS

• Rivers as significant geological agents: erosion, transport, deposition.

• River stages: youthful (fast flow, erosion), mature (balanced erosion/deposition), old (extensive deposition).

EFFECTS OF GROUND WATER

• Formation of caves, stalactites, stalagmites, and sinkholes.

• Groundwater prospecting methods: Electrical resistivity, seismic methods.