Untitled Quiz

Lecture Information

• Course Title: Earth Sciences for Civil Engineering
• Lecture Number: 2
• Lecturer: Dr. Moheldeen A. Hejazi
• University: Altınbas University

Earth Sciences

• Definition: The study of the Earth and its systems.

Earth Sciences Branches

• Geology
  • General geology
  • Structural geology
  • Sedimentology/Sedimentary petrography
  • Petroleum Geology
  • Stratigraphy
• Ore deposits-Geochemistry
  • Geochemistry
  • Mineral deposits
• Mineralogy-Petrography
  • Mineralogy
  • Petrography
• Applied Geology
  • Engineering Geology
• Hidrogeology
• Mathematical Geology

Earth's Processes, Potentials, and Hazards

• Includes processes, potentials, and hazards of Earth

Age of the World and Theories of Creation

• Questions regarding the age and creation theories of the world

Layers of the Earth

• Crust
  • Oceanic (0-6 km, young, < 180 million years)
  • Continental (0-34 km, older, up to 3.8 billion years)
• Mantle
  • Upper (34-670 km)
  • Lower (670-2900 km)
• Core
  • Outer (liquid)
  • Inner (solid)

Formation and Erosion of Continents

• Discussion of continental formation process.

Formation and Erosion of Mountains

• Discussion of mountain formation and erosion processes.

Earth Systems

• Atmosphere - Blanket of gases surrounding the Earth; protection from Sun's heat & UV rays
• Hydrosphere - Water portion of Earth; Oceans (most prominent - 71% of Earth's surface)
• Cryosphere - Icy portion of Earth's crust; Glaciers, Permafrost and ground ice, Polar ice caps
• Biosphere - Earth's ecosystems; Earth's surface and subsurface
• Ecology - Interactions between life, atmosphere, hydrosphere, and solid Earth

Earth's Internal Structure

• Crust: Oceanic (0-6 km) and Continental (0-34 km)
• Mantle: Upper (34-670 km) and Lower (670-2900 km)
• Core: Outer (liquid), Inner (solid)

Earth's Internal Structure - Crust

• Avg. rock density (continental crust) about 2.7 g/cm³
• Avg. thickness (continental crust) 35-40 km
• Avg. rock type (continental crust) Granite
• Oceanic crust
  • Avg. rock density about 3.0 g/cm³
  • Avg. thickness 7-10 km
  • Avg. rock type = Basalt/Gabbro

Earth's Internal Structure - Continents

• Underlies continents
• Average rock density is 2.7g/cm³
• Average thickness is 35-40km
• Felsic composition
• Rock type is granite

Earth's Internal Structure - Oceanic crust

• Underlies ocean basins
• Average rock density is 3.0 g/cm³
• Average thickness is 7-10km
• Mafic composition
• Rock type is basalt/gabbro

Plate Tectonics

• Theory dealing with Earth's outer shell (lithosphere) dynamics
• Revolutionized Earth sciences by providing a uniform context for understanding mountain-building processes, volcanoes, earthquakes, and past configurations.
• Lithospheric separation and movement on asthenosphere forms base of plate tectonic theory.
• Types of Plate Boundaries
  • Divergent (plates move apart)
  • Convergent (plates collide)
  • Transform (plates slide past)

Plate Tectonics (Divergent)

• Mid-ocean ridge, volcanic islands.

Plate Tectonics (Convergent)

• Deep ocean trenches, volcanic island arcs, and curved mountain lines. Occurs when one plate slides under another.

Plate Tectonics (Transform)

• Transform faults, plates slide past each other. Famous example is the San Andreas Fault.

Theories of Continental Drift and Plate Tectonics

• Discussion of theories related to continental drift and plate tectonics.

Plate movements and Subduction

• Locations of various plates and their movements.

Earth's System Interconnections

• Interconnected systems that make up earth.

Atmosphere

• Blanket of gases surrounding Earth
• Protection from solar heat and UV rays
• Weather occurs b/w Earth's surface and atmosphere

Hydropshere

• Water portion of Earth
• Oceans (largest)
• Streams, lakes, glaciers, and underground water

Cryosphere

• Icy parts of Earth
• Glaciers, permafrost, polar ice caps
• Frozen polar seas

Biosphere

• Earth's Ecosystems
• Life occupies an extreme range of environments

Earth's Internal Structure

• Three distinct divisions

Physical Properties of Minerals

• Tenacity
• Hardness
• Fracture
• Streak
• Luster
• Density

Tenacity

• Describes a mineral's behavior under stress, like breaking, bending, or twisting.
• Types include brittle, flexible, elastic, malleable, and sectile

Hardness

• Defines resistance to scratching on a scale of 1-10.
• Mohs Hardness Scale used to determine hardness and helps with mineral identification.

Cleavage

• Planar structural weakness along which a mineral breaks smoothly.
• Parallel atomic planes.

Fracture

• Describes how a mineral breaks when it lacks cleavage.
• Types include Conchoidal, fibrous, splintery, hackly, and irregular.

Color

• Diagnostic property of some minerals(e.g., olivine and epidote).

Streak

• Color of a mineral's powder when scratched on a streak plate.
• Usually different from the mineral's color.

Luster

• General appearance of a mineral surface to reflected light.
• Types include metallic, vitreous, resinous, pearly, greasy, silky, and adamantine.

Structure (of minerals)

• Various shapes like kidney, fibrou, radial, and concentric

Specific Gravity

• Relative density used to identify minerals.
• Weight of a mineral divided by the weight of an equal volume of water.

Radioactivity

• Radioactivity in minerals comes from uranium and thorium
• Used to determine the geological age of minerals

Chemical Properties of Minerals

• Composition of minerals.
• Calcite with aragonite and with diamond properties

Optical Properties

• Light-related properties of minerals.
• Colors, fracture properties, single/double breaking properties, and shapes under a polarizing microscope.

Importance of Minerals for Civil Engineering

• Building materials: many minerals used in constructions; cement, gravel, sand, and water
• Engineering materials: various materials that have properties like strength, durability, and stability

Geological Time

• Time scales, May/September 1980

The Rock Cycle

• Processes that transform rocks from one type to another, starting with a pre-existing rock or magma.
  • Igneous, sedimentary, and metamorphic rocks.
• Processes include erosion, uplift, crystallization, melting, burial, compaction, cementation, Increased P & T, deformation.

Magmatic Rocks

• Formed by solidification of molten rock (magma or lava).
• Intrusive (cooled below surface), Extrusive (cooled above surface).
• Physical properties like texture and mineral composition varies depending on cooling time and environmental factors.

Classification of Igneous Rocks

• Based on texture (fine or coarse grained), and chemical/mineral composition (felsic, intermediate, mafic, ultramafic)

Types of Sedimentary Rocks

• Clastic rocks (formed from eroded materials): Examples are sandstone and shale
• Chemical rocks (formed from chemical precipitations): Examples are limestone and rock gypsum
• Organic rocks: Formed due to accumulation of organic matter such as coal.

Sedimentary Rock Properties for Engineering

• Resistance of sedimentary rocks varies depending on composition and other similar properties such as susceptibility.

Sedimentary Structures

• Bedding (layering), Different shapes depending on processes such as cross bedding, graded bedding

Importance of Sedimentary Rocks in Engineering

• Materials for constructions, engineering properties, environmental processes

Metamorphic Rocks

• Formed from pre-existing rocks under pressure/heat
• Important properties include strength, resistance, and texture

Types of Metamorphism

• Contact metamorphism (magma invades host rock)
• Regional metamorphism (mountain building or subduction)
• Burial metamorphism (thick piles of sediment rock)
• Hydrothermal metamorphism (chemical alteration by hot fluids)
• Shock metamorphism (high pressures or impact events)

Metamorphic Rock Properties in Engineering

• Resistance and properties like the texture, composition and the associated stresses

Metamorphic Rock Classification

• Based on texture (foliated, non-foliated) and composition.
• Foliated: Planar layering, often due to pressure
• Non-foliated: lacks layering, often due to chemical processes