Plate Tectonics Worksheet Answers Pdf - Fill Online, Printable ... - Free Printable

Problem Analysis:

The task involves answering questions related to the Theory of Plate Tectonics and filling in blanks for vocabulary terms. The goal is to demonstrate understanding of key concepts in plate tectonics, including types of plate boundaries, forces causing continental movement, and relevant scientific terminology.

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Solution:

#### Section 1.5: Review and Reinforce

##### Understanding Main Ideas
1. Label each figure to identify the type of plate boundary it shows.
- This part requires identifying the type of plate boundary (convergent, divergent, or transform) based on the diagrams provided. Since the diagrams are not visible here, I will explain how to identify them generally:
- Convergent Boundary: Plates move toward each other.
- Divergent Boundary: Plates move away from each other.
- Transform Boundary: Plates slide past each other horizontally.

2. Answer the following questions to complete sentences.
- a. Describe what happens when two plates carrying oceanic crust collide.
- When two plates carrying oceanic crust collide, a process called subduction occurs. The denser oceanic crust sinks beneath the less dense crust of the overriding plate into the mantle. This creates a deep ocean trench at the surface and can lead to the formation of volcanic arcs or island arcs above the subducting plate.

- b. Two plates carrying continental crust collide—
- When two plates carrying continental crust collide, neither plate subducts because continental crust is less dense and thicker than oceanic crust. Instead, the collision causes the crust to buckle and fold, leading to the formation of mountain ranges. A classic example is the Himalayas, formed by the collision of the Indian and Eurasian plates.

- c. A plate carrying oceanic crust collides with a plate carrying continental crust—
- When an oceanic plate collides with a continental plate, the denser oceanic crust subducts beneath the less dense continental crust. This process forms a deep ocean trench along the subduction zone and can lead to the formation of volcanic activity on the continental side, such as the Andes mountains in South America.

3. Explain what force caused the movement of the continents from one supercontinent to their present positions.
- The movement of continents from a single supercontinent (Pangaea) to their current positions is primarily driven by plate tectonic forces. These forces include:
- Convection currents in the mantle: Heat from Earth's core drives convection currents in the semi-fluid mantle, which moves the rigid lithosphere (Earth's crust and uppermost mantle) above it.
- Ridge push: New oceanic crust is created at mid-ocean ridges due to magma rising and solidifying. This pushes older crust away from the ridge.
- Slab pull: Subducting oceanic plates pull the rest of the plate downward into the mantle.
- Gravity: Uneven distribution of mass on Earth's surface affects the movement of plates.

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##### Building Vocabulary
4. Fill in the blank to complete each statement.
- a. A scientific theory is a well-tested concept that explains a wide range of observations.
- A scientific theory is a comprehensive explanation supported by extensive evidence and repeated testing. It is not just a "guess" but a robust framework used to understand natural phenomena.

- b. Continents in Earth’s crust where rocks have drifted past each other are called tectonic plates.
- The Earth's crust and uppermost mantle are divided into large sections called tectonic plates, which move relative to each other due to forces within the Earth.

- c. The lithosphere is broken into separate sections called plates.
- The lithosphere is the rigid outer layer of the Earth, consisting of the crust and the uppermost part of the mantle. It is broken into several tectonic plates that move independently.

- d. A rift valley is a deep valley on land that forms along a divergent boundary.
- A rift valley forms when the Earth's crust stretches and thins, allowing magma to rise and create new crust. Examples include the East African Rift Valley.

- e. The geophysical law that states that pieces of Earth’s crust are in constant slow motion is called continental drift.
- The concept of continental drift was proposed by Alfred Wegener and later expanded into the theory of plate tectonics. It explains how continents have moved over geological time scales.

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Final Answer:

1. Label each figure: Identify the type of plate boundary (convergent, divergent, or transform) based on the diagrams.
2. Questions to complete sentences:
- a. Oceanic-oceanic collision → Subduction, forming a deep trench and volcanic arcs.
- b. Continental-continental collision → Buckling and folding, forming mountain ranges.
- c. Oceanic-continental collision → Subduction, forming a trench and volcanic activity on the continental side.
3. Force causing continental movement: Plate tectonic forces, including mantle convection, ridge push, slab pull, and gravity.
4. Vocabulary:
- a. Scientific theory
- b. Tectonic plates
- c. Plates
- d. Rift valley
- e. Continental drift

Final Answer Boxed:
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