GEOL 131A.1

GEOL 131A Geology for Civil Engineers

Course Learning Outcomes

  • CLO1: Differentiate the basic terminologies in Geology as well as the various terminologies applicable for Civil Engineering

  • CLO2: Analyze the different phenomenal activities in relation to the movement of rock masses, earth formation such as but not limited to mountain buildings, subdivisions, earthquake, etc..

  • CLO3: Compare the uses of rocks in terms of construction and to determine the strength and stability of Earth’s natural material, foundation and bearing capacity.

  • CLO4: Predict the effect of the various geologic hazards to the affected community by identifying the geologically hazardous area in relation to the erection of foundation and other civil engineering structures.

  • CLO5: Select the appropriate location in building structures based on the knowledge on the geological matters which will affect the wellbeing & survival of human society.

What is GEOLOGY?

  • "geo" – earth or land; "-logia" – the study of

  • The science that deals with the study of the earth, especially the outer solid portion known as crust.

  • The study of the Earth, including the materials that it is made of, the physical and chemical changes that occur on its surface and in its interior, and the history of the planet and its life forms.

The Earth and its Materials

  • Minerals – naturally-occurring, solid, inorganic substances with a defined chemical composition and crystal structure.

  • Rocks – aggregates of minerals.

  • Most of the earth is composed of rocks – rock outcrops form several of our planet’s most spectacular scenery.

Layers of the Earth

  • Crust – composed of rocks & minerals

  • Mantle – composed of rocks so hot where they are partly melted

  • Outer Core – composed of the liquid metal

  • Inner Core – solid ball of Iron & Nickel

Main Principles and Concepts in Geology

  • Original Sediments usually accumulate in horizontal layers.

  • Superposition – sedimentary rocks become younger from bottom to top

  • Crosscutting Relationships – a rock must first exist before anything can happen to it

  • Uniformitarianism – geological change occurs over long periods of time, by a sequence of almost imperceptible events

Plate Tectonics

  • Describes the Earth’s outer layer, the lithosphere, as a shell of hard, strong rock broken into seven large (and several smaller) tectonic plates.

  • The tectonic plates float on the layer below, called the asthenosphere.

  • Most of the Earth’s major geological activities occur at plate boundaries.

Plate Boundaries

  • Convergent boundary – two plates move towards each other

  • Divergent boundary – two plates move apart or separate

  • Transform boundary – they slide horizontally past each other.

Geologic Time Scale

  • Quaternary Period: Holocene, Pleistocene

  • Cenozoic Era: Pliocene, Miocene

  • Mesozoic Era: Jurassic, Triassic

  • Paleozoic Era: Permian, Carboniferous, Pennsylvanian, Mississippian, Devonian, Silurian, Ordovician, Cambrian

  • Pre-cambrian

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  • Geologic Time Scale

    • Eon: Precambrian, Phanerozoic

    • Era: Paleozoic, Mesozoic, Cenozoic

    • Period: Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, Permian, Triassic, Jurassic, Cretaceous, Paleogene, Neogene, Quaternary

    • Epoch: Holocene, Pleistocene, Pliocene, Miocene, Oligocene, Eocene, Paleocene

  • Distinctive Plants and Animals

    • Recent or Humans: Holocene

    • Mammals develop and become dominant: Miocene

    • Extinction of dinosaurs and many other species: Cretaceous, Paleogene

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  • Geologic Time Scale

    • Eon: Precambrian, Phanerozoic

    • Era: Paleozoic, Mesozoic, Cenozoic

    • Period: Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, Permian, Triassic, Jurassic, Cretaceous, Paleogene, Neogene, Quaternary

    • Epoch: Holocene, Pleistocene, Pliocene, Miocene, Oligocene, Eocene, Paleocene

  • Distinctive Plants and Animals

    • Recent or Humans: Holocene

    • Mammals develop and become dominant: Miocene

    • Extinction of dinosaurs and many other species: Cretaceous, Paleogene

Page 28

  • Geologic Time Scale

    • Eon: Precambrian, Phanerozoic

    • Era: Paleozoic, Mesozoic, Cenozoic

    • Period: Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, Permian, Triassic, Jurassic, Cretaceous, Paleogene, Neogene, Quaternary

    • Epoch: Holocene, Pleistocene, Pliocene, Miocene, Oligocene, Eocene, Paleocene

  • Distinctive Plants and Animals

    • Recent or Humans: Holocene

    • Mammals develop and become dominant: Miocene

    • Extinction of dinosaurs and many other species: Cretaceous, Paleogene

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  • Branches of Geology

    • Allied Branches: Engineering Geology, Mining Geology, Structural Geology, Economic Geology, Stratigraphy

    • Main Branches: Mineralogy, Geophysics, Geohydrology, Geochemistry, Paleontology, Petrology

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  • Branches of Geology

    • Allied Branches: Engineering Geology, Mining Geology, Structural Geology, Economic Geology, Stratigraphy

    • Main Branches: Mineralogy, Geophysics, Geohydrology, Geochemistry, Paleontology, Petrology

Page 31

  • Mineralogy

    • Specializes in minerals

    • Focuses on mineral origin, formation, classification, distribution, and utilization

  • Petrology

    • Deals with the study of rocks

    • Focuses on formation, structure, texture, composition, occurrence, and types of rocks

Page 32

  • Geophysics

    • Studies the Earth's physics and structure

    • Uses mathematical and physics methods

  • Geohydrology

    • Deals with the study of groundwater and its interactions with the physical environment

Page 33

  • Geochemistry

    • Uses chemistry to explain geological systems

    • Focuses on the Earth's crust and oceans

  • Paleontology

    • Study of ancient life

    • Reveals how organisms changed over time

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  • Mining Geology

    • Applies geological knowledge in mining

    • Focuses on occurrence, properties, and association of ores

  • Structural Geology

    • Deals with the form, arrangement, and internal structure of rocks

    • Studies deformations, dislocations, and disturbances in rocks

Page 35

  • Economic Geology

    • Concerned with earth materials used for economic and industrial purposes

    • Focuses on formation, occurrence, classification, and uses of economic minerals

  • Stratigraphy

    • Study of the Earth's history through sedimentary rocks

Page 36

  • Engineering Geology

    • Provides knowledge of construction materials and their properties

    • Helps in planning and carrying out civil engineering works

  • Examples of construction materials: building-stones, road materials, clays, limestone, laterite

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  • Engineering Geology

    • Knowledge of groundwater and its occurrence is required for water supply and irrigation

    • Geology is important for foundation problems and interpreting drilling data

  • Geology is necessary for tunnelling, road construction, determining stability of cuts and slopes

Engineering Geology (Page 38)

  • Before starting a major engineering project, a detailed geological report is prepared.

  • The report includes geological maps and sections.

  • The report helps in planning and constructing the project.

Engineering Geologist vs Civil Engineer (Page 39)

  • The engineering geologist provides geological data and interpretations for the civil engineer.

  • Civil engineers deal with soil, rocks, timbers, steel, and concrete.

  • Civil engineering involves constructing structures and facilities for various purposes.

Rocks and Minerals (Page 40)

Rocks and Minerals, their Mode of Occurrence, Identification and Properties (Page 41)

  • Minerals and their properties are important in geology.

  • Igneous rocks are classified and their form is controlled.

  • Sedimentary rocks involve sedimentation, sedimentary facies, diagenesis, and diagnetic effects.

  • Metamorphic rocks are also studied.

Mineral (Page 42)

  • A mineral is a naturally occurring inorganic solid with a characteristic chemical composition and a crystalline structure.

  • Minerals must form by natural processes.

  • Minerals are inorganic and most form independently of life.

Chemistry of a Mineral (Page 43)

  • Atoms and ions unite to form compounds through chemical bonds.

  • Most minerals are made up of two to five essential elements.

  • Quartz, for example, has a specific composition of SiO2.

Crystals: the Crystalline Nature of Minerals (Page 44)

  • A crystal is a substance with atoms arranged in a regular pattern.

  • Sodium and chlorine ions in halite form a crystalline structure.

Crystals: the Crystalline Nature of Minerals (Page 45)

  • Crystals have an orderly, repetitive pattern.

  • A small group of atoms called a unit cell repeats itself in every crystal.

  • Crystal faces develop when a crystal grows freely.

Physical Properties of Minerals (Page 46)

  • Physical properties like crystal habit, cleavage, and hardness are used to identify minerals.

  • Chemical composition alone is not enough for identification.

  • Minerals rarely show perfect development of crystal faces.

Physical Properties of Minerals (Page 47)

  • Physical properties include crystal habit, cleavage, fracture, hardness, specific gravity, color, streak, luster, and other properties.

Physical Properties of Minerals - Crystal habit (Page 48)

  • Crystal habit refers to the characteristic shape of a mineral and how crystals grow.

Physical Properties of Minerals - Cleavage (Page 49)

  • Cleavage is the tendency of some minerals to break along flat surfaces.

Physical Properties of Minerals - Fracture (Page 50)

  • Fracture is the pattern in which a mineral breaks other than along planes of cleavage.

Physical Properties of Minerals - Hardness (Page 51)

  • Hardness is the resistance of a mineral to scratching.

  • The Mohs hardness scale is used to measure hardness.

Physical Properties of Minerals - Specific Gravity (Page 52)

  • Specific gravity is the weight of a substance relative to that of an equal volume of water.

Physical Properties of Minerals - Color (Page 53)

  • Color is the most obvious property of a mineral but is not always reliable for identification.

Physical Properties of Minerals - Streak (Page 54)

  • Streak is the color of a fine powder of a mineral.

Physical Properties of Minerals - Luster (Page 55)

  • Luster refers to the manner in which a mineral reflects light.

  • Other properties like reaction to acid, magnetism, radioactivity, fluorescence, and phosphorescence can also be characteristic of specific minerals.

Rock-forming Minerals, Accessory Minerals, Gems, Ore Minerals, and Industrial Minerals (Page 56)

  • Rock-forming minerals are the most common minerals in the Earth's crust.

  • Accessory minerals are common but found in small amounts.

  • Gems are prized for their beauty.

  • Ore minerals are minerals from which metals or other elements can be profitably recovered.

  • Industrial minerals are mined for purposes other than extracting metals.

Table 3-1 THE EIGHT MOST ABUNDANT CHEMICAL ELEMENTS IN THE EARTH'S CRUST (Page 59)

  • The table shows the weight, atom volume percent, and chemical symbol of the eight most abundant chemical elements in the Earth's crust.

Page 60: Mineral Classification

  • Geologists classify minerals according to their anions (negatively charged ions)

    • Anions can be simple or complex

      • Simple anion: single negatively charged ion (e.g., O2-)

      • Complex anion: two or more atoms bonded together with a negative charge (e.g., (SiO4)4-, (CO3)2-)

  • Each mineral group (except native elements) is named after its anion

    • Oxides contain O2-

    • Silicates contain (SiO4)4-

    • Carbonates contain (CO3)2-

Page 61: Mineral Classification

  • Native Elements

    • About 20 elements occur naturally in their native states as minerals

    • Fewer than ten are economically important

    • Examples: gold, silver, platinum, copper

    • Iron is rarely found in its native state in the Earth's crust but is common in certain meteorites

    • Carbon occurs as graphite and diamond, which are polymorphs with different crystalline structures

Page 62: Mineral Classification

  • Oxides (O2-)

    • Oxygen combined with one or more metals

    • Examples: hematite (Fe2O3), magnetite (Fe3O4), spinel (MgAl2O4), ice (H2O)

Page 63: Mineral Classification

  • Sulfides (S2-)

    • Sulfur combined with one or more metals

    • Major sources of copper, lead, zinc, molybdenum, silver, mercury, and other metals

  • Sulfates (SO4)2-

    • Contain the complex sulfate anion (SO4)2-

    • Examples: gypsum (CaSO4 2H2O), anhydrite (CaSO4)

Page 64: Mineral Classification

  • Phosphates (PO4)3-

    • Phosphate is an essential fertilizer in modern agriculture

  • Carbonates (CO3)2-

    • Complex carbonate anion (CO3)2- is the basis of common rock-forming minerals

    • Examples: calcite (CaCO3), dolomite [CaMg(CO3)2]

    • Limestone is composed of calcite and dolomite, used in cement production

Page 65: Mineral Classification

  • Silicates

    • Silicate minerals contain the (SiO4)4 complex anion

    • Make up about 95% of the Earth's crust

    • Abundant due to the