Science: Internal Structures of Earth

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Questions and Answers

What is the primary material composition of the inner core?

Iron and nickel (correct)

Granite and limestone

Silicon and oxygen

Magma and basalt

Which layer of the Earth is responsible for the movement of tectonic plates?

Crust

Mantle

Asthenosphere (correct)

Inner core

What is the approximate thickness of the outer core?

2,900 kilometers

2885 kilometers

1,200 kilometers

2,300 kilometers (correct)

What temperature range can be found in the mantle?

1600 ˚F to 4000 ˚F Signup and view all the answers

Which layer of the Earth is solid and where we live?

Crust Signup and view all the answers

What is the function of the Conorod discontinuity?

Marks the transition between the upper crust and lower crust Signup and view all the answers

Which layer of the Earth is bounded by the atmosphere above and the asthenosphere below?

Crust Signup and view all the answers

What occurs at a divergent boundary?

New crust is formed as plates move apart Signup and view all the answers

Which statement about the theory of plate tectonics is true?

It explains the movement of the Earth's crust over the asthenosphere Signup and view all the answers

What geological feature is formed by sea floor spreading at divergent boundaries?

Mid-ocean ridges Signup and view all the answers

What is the primary material composition of the upper mantle?

Plastic rock Signup and view all the answers

How do magnetic stripes form on either side of mid-ocean ridges?

As magma rises and cools, minerals align with Earth's magnetic field reversals Signup and view all the answers

Which mechanical layer of Earth is considered molten?

Outer core Signup and view all the answers

What geological feature is typically formed as an outcome of continental-continental convergent boundaries?

Folded mountains Signup and view all the answers

Which of the following statements is true regarding oceanic-continental convergent boundaries?

They often lead to the creation of deep ocean trenches. Signup and view all the answers

What happens to the oldest rocks found in a divergent boundary setting?

They are located at subduction zones. Signup and view all the answers

What is a significant environmental feature of a rift valley?

Creation of a new ocean over geological time. Signup and view all the answers

What type of boundary is characterized by plates colliding and leading to the destruction of old crust?

Convergent boundary Signup and view all the answers

During oceanic-continental convergence, what is primarily formed as magma rises?

Stratovolcanoes Signup and view all the answers

Which role do subduction zones play in geological processes?

They recycle oceanic plates back into the mantle. Signup and view all the answers

Which of the following examples is a result of oceanic-oceanic divergent boundaries?

Iceland Signup and view all the answers

Study Notes

Internal Structures of Earth

Inner Core: The center and hottest layer, 1,200 km thick, solid due to extreme pressure, composed mainly of iron and nickel, temperatures can reach 5,500 °C.
Outer Core: Liquid layer, 2,300 km thick, made of iron and nickel, with temperatures ranging from approximately 2,200 °C to 5,000 °C (4000 °F to 9000 °F).
Mantle: About 2,900 km thick, semi-liquid composed of magma, with temperatures between 870 °C and 2,200 °C (1600 °F to 4000 °F).
Asthenosphere: Beneath the lithosphere, extends from 100 km to 700 km (60 miles to 450 miles) deep, much hotter and more fluid, contributes to lithospheric plate movements.
Lithosphere: Solid outer layer of Earth, includes crust and uppermost mantle, separates from asthenosphere below.
Crust: The outer layer where life exists, thickness ranges from 0 to 60 km, consists of oceanic (basalt-based, denser, thinner) and continental (granite-based, less dense, thicker) components.
Compositional Layers:
- Crust: 0-45 km
- Mantle: 45-2,900 km
- Core: 2,900-6,371 km
Mechanical Layers:
- Lithosphere: solid
- Asthenosphere: plastic
- Mesosphere: solid
- Outer Core: molten
- Inner Core: solid

Plate Tectonics

Earth's surface divided into large, thick plates that slowly move and change in size; composed of both crust and upper mantle.
The theory of plate tectonics describes the lithosphere's plates moving over the asthenosphere; developed from 1950s to 1970s, building on Alfred Wegener's continental drift theory from 1912.
Plate Boundaries: Areas where plates meet, categorized into three types: Convergent, Divergent, and Transform.

Divergent Boundaries

Plates move away from each other, forming new crust, typically at mid-ocean ridges or rift zones.
Mid-Ocean Ridges: Sites of sea-floor spreading where new crust is created as magma rises and cools; magnetic stripes form due to aligning minerals with Earth's magnetic field.
Rift Valleys: Formed when continental plates diverge, creating young plate boundaries; examples include Great Rift Valley in Africa.

Convergent Boundaries

Plates collide, leading to destruction of old crust and the formation of new mountains. Three types of convergent boundaries exist:
- Continental-Continental: Collision leads to crumpling and formation of high mountain ranges, like the Himalayas.
- Continental-Oceanic: Denser oceanic plates subduct beneath continental plates, forming deep ocean trenches and volcanic activity on continents; examples include the Andes and Cascade mountains.
Subduction Zones: Sites where dense oceanic plates slide under lighter continental plates, creating magma that can lead to volcanic eruptions and metamorphic rock formation through intense heat.

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Description

Explore the fascinating layers of the Earth, including the inner core, outer core, and mantle. This quiz covers the composition, state, and temperature of each layer, providing insights into the planet's internal dynamics. Test your knowledge on Earth's structure and its extreme conditions!