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Questions and Answers
Which of the following epochs belongs to the Quaternary period?
The 'Supernova' explosion took place at around how many years ago?
When magma rises from deep in the mantle, it forms new oceanic crust at which location?
How long is the ocean ridge system?
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The outer core and the inner core are _____________ respectively.
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How do low-density and high-density rocks float?
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What does the principle of isostasy govern?
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The Geodynamo system involves interactions between which two layers?
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What causes convection that generates and maintains the Earth's magnetic field?
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Which discontinuity marks the boundary between the outer and inner core?
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Study Notes
Quaternary Period
- Consists of two epochs: Holocene and Pleistocene.
- The Holocene is the most recent epoch, while the Pleistocene preceded it.
Supernova Explosion
- Occurred approximately 7 billion years ago.
- Marks a significant astronomical event.
Magma and Oceanic Crust
- New oceanic crust forms at mid-oceanic ridges.
- Created by mantle upwelling in response to plate separation, where magma rises and cools to form lithosphere.
Ocean Ridge System
- Encompasses a continuous belt of 65,000 km, recognized as the longest mountain range on Earth.
- Mid-Atlantic Ridge is a notable example, bisecting the Atlantic Ocean.
Earth's Internal Structure
- Seismic waves reveal two core layers: the outer core is liquid, while the inner core is solid.
- Inner core consists of iron and nickel, with extreme temperatures reaching up to 5,500°C.
Density and Isostasy
- Low-density rocks float higher and possess deep roots; high-density rocks float lower with shallow roots.
- Isostasy governs the buoyancy and equilibrium of the Earth's lithosphere.
Principle of Isostasy
- Governs the rise or subsidence of the Earth's crust until it achieves buoyant balance.
- Crucial for understanding geological stability and changes.
Geodynamo System
- Involves interactions between the inner and outer core.
- Generates the Earth's magnetic field through convection currents of fluid metal in the outer core, influenced by heat from the inner core.
Magnetic Field Generation
- The heat from the outer core causes convection, vital for maintaining the Earth's magnetic field.
- Organized by the Coriolis force, leading to circulating electric currents.
Lehmann Discontinuity
- Marks the boundary between the outer and inner core.
- Characterized by an abrupt increase in P-wave and S-wave velocities at around 220 km depth.
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Description
Test your knowledge on the Quaternary period and significant astronomical events with this quiz designed for Earth Sciences in Civil Engineering. It covers essential concepts and facts to enhance your understanding of this scientific field.
