- Understand the concept of plate tectonics and its significance in the distribution of oceans and continents.
- Explain the theory of continental drift and its historical context.
- Identify the major and minor tectonic plates and their characteristics.
- Describe the evidence supporting the continental drift theory, including geological and paleontological data.
- Analyze the mechanisms behind plate movements, including convection currents and sea floor spreading.
- Discuss the implications of tectonic activity on the formation of mountains, earthquakes, and volcanic activity.
- Evaluate the historical positions of continents and oceans and their changes over geological time.
Distribution of Oceans and Continents
Learning Objectives
TopRevision Notes & Summary
TopDistribution of Oceans and Continents
Overview
- Continents cover 29% of the Earth's surface; the rest is oceanic waters.
- Positions of continents and oceans have changed over time and will continue to do so.
Continental Drift
- Key Figures:
- Abraham Ortelius (1596): Proposed the idea of connected continents.
- Alfred Wegener (1912): Developed the continental drift theory, suggesting all continents were once a single mass called Pangaea.
Evidence Supporting Continental Drift
- Jig-Saw Fit: The coastlines of Africa and South America match remarkably.
- Rocks of Same Age: Similar rock formations found across oceans.
- Distribution of Fossils: Identical species found on different continents suggest they were once connected.
- Tillite and Placer Deposits: Geological evidence of past climates and land connections.
Plate Tectonics
- Definition: Tectonic plates are massive slabs of solid rock, including both continental and oceanic lithosphere.
- Major Plates:
- Antarctica
- North American
- South American
- Pacific
- Indian-Australian
- African
- Eurasian
- Minor Plates:
- Cocos
- Nazca
- Arabian
- Philippine
Sea Floor Spreading
- Proposed by Harry Hess (1961): Ocean floor is created at mid-ocean ridges and consumed at oceanic trenches.
- Key Observations:
- Younger oceanic crust compared to continental crust.
- Similarities in rocks on either side of mid-ocean ridges.
- Thin sediment layers on ocean floors.
Movement of the Indian Plate
- The Indian plate includes Peninsular India and parts of Australia.
- Historical Movement:
- Separated from Asia by the Tethys Sea until about 225 million years ago.
- Collided with Asia 40-50 million years ago, leading to the uplift of the Himalayas.
Important Concepts
- Convection Currents: Proposed by Arthur Holmes; these currents in the mantle drive plate movements.
- Plate Boundaries:
- Divergent: Plates move apart.
- Convergent: Plates collide.
- Transform: Plates slide past each other.
Exercises
- Multiple Choice Questions: Test understanding of key concepts and figures.
- Short Answer Questions: Explore forces behind continental drift and differences between plate boundaries.
- Long Answer Questions: Discuss evidence for continental drift and post-drift discoveries.
Exam Tips & Common Mistakes
TopCommon Mistakes and Exam Tips
Common Pitfalls
- Misunderstanding Plate Boundaries: Students often confuse the types of plate boundaries (convergent, divergent, transform). Ensure you understand the characteristics of each type.
- Forgetting Key Figures: Remember to attribute theories to their proponents, such as Alfred Wegener for continental drift and Harry Hess for sea floor spreading.
- Neglecting Evidence: When discussing continental drift, be sure to mention the various types of evidence (matching coastlines, fossil distribution, etc.) that support the theory.
- Overlooking the Importance of Ocean Floor Mapping: Many students fail to recognize how ocean floor mapping has contributed to our understanding of plate tectonics and continental drift.
Tips for Success
- Review Key Concepts: Make sure to review the definitions and characteristics of major and minor tectonic plates, as well as the forces driving plate movement.
- Practice with Diagrams: Familiarize yourself with diagrams of plate boundaries and ocean floor features, as visual aids can help solidify your understanding.
- Answering Exam Questions: When answering questions, be concise but thorough. For example, when asked about the forces suggested by Wegener, clearly state both the polar-fleeing force and tidal force.
- Use Examples: In your answers, use specific examples from the text, such as the Gondwana system or the distribution of fossils, to support your points.
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Practice Test – MCQs, True/False
TopMultiple Choice Questions
A.
It is primarily a continental plate.
B.
It is surrounded by divergent boundaries.
C.
It is largely an oceanic plate.
D.
It is stationary with respect to other plates.
Correct Answer: C
Solution:
The Pacific Plate is largely an oceanic plate, characterized by its extensive oceanic lithosphere.
A.
Divergent boundary
B.
Transform boundary
C.
Convergent boundary
D.
Continental boundary
Correct Answer: C
Solution:
Convergent boundaries are characterized by the subduction of one tectonic plate beneath another, often leading to the formation of trenches and volcanic arcs.
A.
Mid-oceanic ridge
B.
Deep ocean trench
C.
Transform fault
D.
Abyssal plain
Correct Answer: B
Solution:
Convergent plate boundaries are typically associated with the formation of deep ocean trenches due to the subduction of one tectonic plate beneath another.
A.
Wind currents
B.
Convection currents in the mantle
C.
Magnetic fields
D.
Gravitational pull from the moon
Correct Answer: B
Solution:
Convection currents in the mantle are the primary force driving the movement of tectonic plates.
A.
Oceanic crust is older than continental crust.
B.
Oceanic crust is younger than continental crust.
C.
Oceanic crust and continental crust are the same age.
D.
The age of oceanic crust varies randomly.
Correct Answer: B
Solution:
Oceanic crust is generally younger than continental crust, as it is continuously being formed at mid-oceanic ridges and recycled back into the mantle at subduction zones.
A.
Ocean-continent convergence.
B.
Divergent boundary with oceanic ridge formation.
C.
Transform boundary with lateral sliding.
D.
Continent-continent convergence with mountain formation.
Correct Answer: B
Solution:
The boundary between the Indian plate and the Antarctic plate is characterized by a divergent boundary where oceanic ridges form due to the plates moving apart.
A.
A region in the Atlantic Ocean known for its calm waters.
B.
A zone of active volcanoes and earthquakes encircling the Pacific Ocean.
C.
A series of underwater mountain ranges in the Indian Ocean.
D.
A region in Antarctica known for its ice-covered mountains.
Correct Answer: B
Solution:
The 'Ring of Fire' is a zone of active volcanoes and earthquakes that encircles the Pacific Ocean, characterized by frequent seismic activity.
A.
Three
B.
Five
C.
Seven
D.
Nine
Correct Answer: C
Solution:
The theory of plate tectonics proposes that Earth's lithosphere is divided into seven major plates.
A.
Continental shelf
B.
Abyssal plains
C.
Mid-oceanic ridges
D.
Deep-oceanic trenches
Correct Answer: C
Solution:
Mid-oceanic ridges are characterized by intense volcanic activity due to the upwelling of magma.
A.
Oceanic crust is generally older than continental crust.
B.
Oceanic crust is generally younger than continental crust.
C.
Oceanic and continental crusts are the same age.
D.
The age of oceanic crust is highly variable and can be older or younger than continental crust depending on the location.
Correct Answer: B
Solution:
Oceanic crust is generally younger than continental crust, with the oldest oceanic crust being about 200 million years old, whereas some continental crusts can be over 3 billion years old.
A.
Polar fleeing force
B.
Gravitational pull
C.
Tidal force
D.
Convection currents
Correct Answer: A
Solution:
Wegener suggested that the polar fleeing force, related to the rotation of the Earth, was responsible for the drifting of continents.
A.
Nazca
B.
Arabia
C.
Philippines
D.
Antarctica
Correct Answer: D
Solution:
Antarctica is a major tectonic plate, while Nazca, Arabia, and Philippines are considered minor plates.
A.
Deep oceanic trench
B.
Mid-oceanic ridge
C.
Volcanic island arc
D.
Fold mountain range
Correct Answer: B
Solution:
At a divergent boundary between oceanic plates, new crust is formed as magma rises to the surface, creating a mid-oceanic ridge characterized by volcanic activity and sea floor spreading.
A.
Continental shelf
B.
Abyssal plains
C.
Rift system
D.
Deep-oceanic trenches
Correct Answer: C
Solution:
The rift system at the crest of mid-oceanic ridges is the zone of intense volcanic activity.
A.
Formation of the Andes mountain range
B.
Formation of the Himalayas
C.
Formation of the Rocky Mountains
D.
Formation of the Appalachian Mountains
Correct Answer: B
Solution:
The collision of the Indian plate with the Eurasian plate led to the uplift and formation of the Himalayan mountain range.
A.
The model lithosphere remains static despite the applied heat.
B.
The model lithosphere begins to crack and form new plates.
C.
The model lithosphere moves horizontally over the asthenosphere.
D.
The model lithosphere sinks uniformly into the asthenosphere.
Correct Answer: C
Solution:
The movement of the lithosphere over the asthenosphere due to mantle convection currents is a fundamental aspect of the theory of plate tectonics.
A.
Convergent boundary
B.
Transform boundary
C.
Divergent boundary
D.
Subduction zone
Correct Answer: C
Solution:
A divergent boundary is where two tectonic plates move away from each other, allowing magma to rise and create new oceanic crust, typically at mid-ocean ridges.
A.
Tidal forces
B.
Convection currents in the mantle
C.
Gravitational pull from the moon
D.
Wind currents
Correct Answer: B
Solution:
Convection currents in the mantle, caused by thermal differences due to radioactive elements, are the primary driving force behind plate movements.
A.
Formation of new mid-oceanic ridges
B.
Increased volcanic activity along the Himalayan range
C.
Expansion of the Tethys Sea
D.
Increased seismic activity along the San Andreas Fault
Correct Answer: B
Solution:
An accelerated movement of the Indian plate would likely result in increased tectonic activity, leading to more frequent volcanic eruptions along the convergent boundary of the Himalayas.
A.
Pacific Plate
B.
Eurasian Plate
C.
African Plate
D.
Indian Plate
Correct Answer: A
Solution:
The Pacific Plate is largely an oceanic plate, while the Eurasian, African, and Indian plates have significant continental portions.
A.
Formation of the Andes mountain range.
B.
Expansion of the Atlantic Ocean.
C.
Uplift of the Himalayan mountain range.
D.
Creation of the Great Rift Valley.
Correct Answer: C
Solution:
The northward movement of the Indian plate towards the Eurasian plate has resulted in the uplift of the Himalayan mountain range due to continent-continent convergence.
A.
Mid-oceanic ridges
B.
Deep oceanic trenches
C.
Volcanic island arcs
D.
Fold mountains
Correct Answer: A
Solution:
Divergent plate boundaries are characterized by the formation of mid-oceanic ridges due to the upwelling of magma as tectonic plates move apart.
A.
Ocean-continent convergence
B.
Divergent boundary
C.
Transform boundary
D.
Continent-continent convergence
Correct Answer: D
Solution:
The movement of the Indian plate towards the Eurasian plate represents a continent-continent convergence, which is characterized by the collision of two continental plates leading to the formation of mountain ranges like the Himalayas.
A.
Centrifugal force
B.
Gravitational force
C.
Polar-fleeing force
D.
Electromagnetic force
Correct Answer: C
Solution:
Wegener suggested that the polar-fleeing force, related to the Earth's rotation, was responsible for the drifting of continents.
A.
North America
B.
Europe
C.
Australia
D.
Greenland
Correct Answer: C
Solution:
Australia was part of the southern supercontinent Gondwanaland.
A.
Cocos Plate
B.
Nazca Plate
C.
Pacific Plate
D.
Philippine Plate
Correct Answer: C
Solution:
The Pacific Plate is one of the major plates, while the Cocos, Nazca, and Philippine plates are considered minor plates.
A.
They are the longest mountain chains on Earth.
B.
They are located at the deepest part of the ocean.
C.
They are formed by the collision of tectonic plates.
D.
They have no volcanic activity.
Correct Answer: A
Solution:
Mid-oceanic ridges are the longest mountain chains on Earth and are characterized by volcanic activity.
A.
Volcanic activity along the mid-oceanic ridges.
B.
Stripes of normal and reverse magnetic field observed in rocks of ocean floor.
C.
Distribution of fossils in different continents.
D.
Age of rocks from the ocean floor.
Correct Answer: C
Solution:
The distribution of fossils in different continents was not considered in the concept of sea floor spreading.
A.
It is older than the continental crust.
B.
It is composed mainly of granite.
C.
It is generally younger than 200 million years.
D.
It is thicker than the continental crust.
Correct Answer: C
Solution:
The oceanic crust is generally younger than 200 million years, as opposed to some continental rocks which are over 3,200 million years old.
A.
Convergent boundary
B.
Divergent boundary
C.
Transform boundary
D.
Subduction zone
Correct Answer: B
Solution:
Divergent boundaries are characterized by the creation of new oceanic crust as plates move apart.
A.
Sea floor spreading
B.
Subduction at a convergent boundary
C.
Transform faulting
D.
Erosion of an existing landmass
Correct Answer: B
Solution:
The formation of a volcanic island in the Pacific Ocean is most likely due to subduction at a convergent boundary, where one tectonic plate is forced under another, leading to volcanic activity.
A.
Tidal forces
B.
Gravitational pull
C.
Convection currents in the mantle
D.
Polar fleeing force
Correct Answer: C
Solution:
Convection currents in the mantle, caused by thermal differences due to radioactive elements, are the primary force driving the movement of tectonic plates.
A.
Oceanic rocks are generally older than continental rocks.
B.
Continental rocks are generally younger than oceanic rocks.
C.
Oceanic rocks are generally younger than continental rocks.
D.
Both oceanic and continental rocks have the same age.
Correct Answer: C
Solution:
Oceanic rocks are generally younger than continental rocks, as the oceanic crust is constantly being renewed at mid-ocean ridges, while some continental rocks are billions of years old.
A.
Alfred Wegener
B.
Antonio Pellegrini
C.
Abraham Ortelius
D.
Edmond Hess
Correct Answer: C
Solution:
Abraham Ortelius, a Dutch map maker, first proposed the possibility of continents being joined together in 1596.
A.
Tidal forces from the moon
B.
Convection currents in the mantle
C.
Gravitational pull of the sun
D.
Magnetic field of the Earth
Correct Answer: B
Solution:
Convection currents in the mantle, caused by the heat from the Earth's interior, are the primary driving force behind the movement of tectonic plates.
A.
The presence of similar fossils on different continents
B.
The existence of oceanic trenches
C.
The occurrence of earthquakes
D.
The formation of volcanic islands
Correct Answer: A
Solution:
The presence of similar fossils on different continents supports the theory of continental drift, as it suggests that these continents were once connected, allowing species to spread across them.
A.
Presence of similar rock formations on different continents
B.
Variations in ocean salinity
C.
Differences in atmospheric composition
D.
Changes in the Earth's magnetic field
Correct Answer: A
Solution:
The presence of similar rock formations on different continents is a direct evidence of continental drift, as it suggests that these continents were once connected.
A.
Independent evolution of similar species.
B.
Continental drift and past land connections.
C.
Recent migration of species across continents.
D.
Volcanic activity distributing fossils globally.
Correct Answer: B
Solution:
The presence of similar fossils on widely separated continents is best explained by the theory of continental drift, which suggests that these continents were once connected.
A.
Older age compared to continental rocks.
B.
Younger age and normal magnetic polarity.
C.
Presence of thick sediment layers.
D.
High density and absence of magnetic properties.
Correct Answer: B
Solution:
Rocks formed at mid-oceanic ridges are younger and typically exhibit normal magnetic polarity due to new lava solidifying and aligning with Earth's current magnetic field.
A.
A satellite experiencing increased speed as it moves away from Earth's equator.
B.
Tides rising and falling due to the gravitational pull of the moon.
C.
A glacier melting faster at the poles due to global warming.
D.
A ship moving faster in the ocean currents near the equator.
Correct Answer: A
Solution:
Wegener suggested that the 'polar fleeing force' is related to the rotation of the Earth, causing objects to experience a force away from the equator. This is akin to a satellite experiencing increased speed as it moves away from the equator.
A.
Eurasian Plate
B.
Pacific Plate
C.
African Plate
D.
Indian Plate
Correct Answer: B
Solution:
The Pacific Plate is largely an oceanic plate, as it is mostly covered by oceanic crust.
A.
Mid-oceanic ridge
B.
Oceanic trench
C.
Continental shelf
D.
Abyssal plain
Correct Answer: B
Solution:
An oceanic trench is formed by the subduction of one tectonic plate under another.
A.
Distribution of modern flora and fauna
B.
Presence of similar rock formations and fossils
C.
Current oceanic currents
D.
Climatic differences between the continents
Correct Answer: B
Solution:
The presence of similar rock formations and fossils on the coastlines of South America and Africa provides strong evidence for the continental drift theory, suggesting these continents were once joined.
A.
Mid-ocean ridges with volcanic activity
B.
Deep oceanic trenches with subduction zones
C.
Transform faults with frequent earthquakes
D.
Mountain ranges with fold mountains
Correct Answer: A
Solution:
At a divergent boundary between oceanic plates, such as the hypothetical 'Atlantica Plate' and its neighbors, mid-ocean ridges with volcanic activity are expected due to the upwelling of magma as the plates move apart.
A.
Cocos Plate
B.
Nazca Plate
C.
Pacific Plate
D.
Arabian Plate
Correct Answer: C
Solution:
The Pacific Plate is one of the largest tectonic plates and is primarily oceanic in nature, making it a major plate according to the theory of plate tectonics.
A.
Pacific Plate
B.
Cocos Plate
C.
Nazca Plate
D.
Philippine Plate
Correct Answer: A
Solution:
The Pacific Plate is one of the major tectonic plates, primarily consisting of oceanic lithosphere.
A.
1,000 years
B.
10,000 years
C.
100,000 years
D.
1,000,000 years
Correct Answer: B
Solution:
To find the time taken for the Indian plate to move 500 km (500,000 cm) at a rate of 5 cm per year, use the formula: Time = Distance/Rate = 500,000 cm / 5 cm/year = 100,000 years.
A.
Laurasia
B.
Gondwanaland
C.
Pangaea
D.
Panthalassa
Correct Answer: C
Solution:
Alfred Wegener proposed the existence of a supercontinent called Pangaea.
A.
Nazca
B.
Arabia
C.
Philippines
D.
Antarctica
Correct Answer: D
Solution:
Antarctica is considered a major plate, not a minor one.
A.
Continental shelf
B.
Mid-oceanic ridge
C.
Abyssal plain
D.
Deep-oceanic trench
Correct Answer: B
Solution:
Mid-oceanic ridges are characterized by intense volcanic activity and form an interconnected chain of mountains within the ocean.
A.
Older age
B.
Thicker sediment layers
C.
Younger age
D.
Higher elevation
Correct Answer: C
Solution:
The oceanic crust is much younger than the continental crust, with rocks not older than 200 million years.
A.
Mid-oceanic ridge
B.
Deep oceanic trench
C.
Transform fault
D.
Volcanic island arc
Correct Answer: B
Solution:
The boundary between the new plate and the Indian plate would likely be a convergent boundary, characterized by a deep oceanic trench due to subduction of the oceanic lithosphere beneath the continental lithosphere.
A.
Ocean-continent convergence
B.
Divergent boundary
C.
Transform boundary
D.
Continent-continent convergence
Correct Answer: D
Solution:
The Indian plate boundary along the Himalayan mountains is a continent-continent convergence.
A.
Revolution of the Earth
B.
Gravitation
C.
Rotation of the earth
D.
Tides
Correct Answer: C
Solution:
The polar fleeing force is related to the rotation of the Earth.
A.
Polar fleeing force
B.
Tidal force
C.
Convection currents in the mantle
D.
Gravitational pull from the moon
Correct Answer: C
Solution:
Convection currents in the mantle, caused by the heat from radioactive decay, create a flow that acts as a driving force for the movement of tectonic plates.
A.
Gravitational pull from the moon
B.
Convection currents in the mantle
C.
Tidal forces from the sun
D.
Magnetic forces from the Earth's core
Correct Answer: B
Solution:
The primary driving force behind the movement of tectonic plates is the convection currents in the mantle, which are caused by the heat from the Earth's interior.
A.
It involves the shrinking of oceanic crust due to tectonic activity.
B.
It is characterized by the formation of new oceanic crust at mid-ocean ridges.
C.
It results in the formation of continental mountains.
D.
It leads to the formation of volcanic islands at transform boundaries.
Correct Answer: B
Solution:
Sea floor spreading involves the formation of new oceanic crust at mid-ocean ridges as magma rises and solidifies.
A.
Mid-oceanic ridges
B.
Deep-sea trenches
C.
Hotspots
D.
Transform faults
Correct Answer: B
Solution:
The 'Ring of Fire' is associated with deep-sea trenches and is known for its high volcanic and seismic activity.
A.
Mid-oceanic ridges
B.
Deep ocean trenches
C.
Continental shelves
D.
Volcanic islands
Correct Answer: A
Solution:
Mid-oceanic ridges are characterized by volcanic activity and are the sites where new oceanic crust is formed, leading to the process of sea floor spreading.
A.
Laurasia
B.
Gondwanaland
C.
Pangaea
D.
Panthalassa
Correct Answer: C
Solution:
Pangaea was the supercontinent that existed around 200 million years ago, which later split into Laurasia and Gondwanaland.
A.
The ocean floor is older than the continental areas.
B.
The ocean floor is a vast plain without any relief.
C.
The ocean floor is characterized by mid-oceanic ridges with volcanic activity.
D.
The ocean floor sediments are older than 200 million years.
Correct Answer: C
Solution:
The ocean floor is characterized by mid-oceanic ridges with volcanic activity, and the rocks are much younger than continental areas.
True or False
Correct Answer: True
Solution:
The mid-oceanic ridges form an interconnected chain of mountain systems within the ocean, making it the longest mountain-chain on the surface of the Earth.
Correct Answer: False
Solution:
The oceanic crust rocks are much younger than the continental rocks, with oceanic rocks being less than 200 million years old compared to some continental rocks which are as old as 3,200 million years.
Correct Answer: True
Solution:
Abraham Ortelius, a Dutch map maker, first proposed the possibility of continents being joined together in 1596.
Correct Answer: True
Solution:
The collision of the Indian plate with the Eurasian plate caused the uplift of the Himalayas, a process that continues today.
Correct Answer: False
Solution:
The ocean crust rocks are much younger than the continental rocks. Oceanic crust rocks are nowhere more than 200 million years old, while some continental rocks are as old as 3,200 million years.
Correct Answer: False
Solution:
In the mid-oceanic ridge areas, the earthquake foci have shallow depths, not deep-seated ones.
Correct Answer: True
Solution:
The Nazca plate is listed as one of the minor plates between the South American and Pacific plates.
Correct Answer: False
Solution:
The Indian plate includes Peninsular India and the Australian continental portions, making it primarily a continental plate.
Correct Answer: False
Solution:
The ocean crust rocks are much younger than the continental rocks. The age of rocks in the oceanic crust is nowhere more than 200 million years old, whereas some continental rock formations are as old as 3,200 million years.
Correct Answer: True
Solution:
The Pacific Plate is surrounded by the 'Ring of Fire', which is known for its high volcanic activity and frequent earthquakes.
Correct Answer: True
Solution:
The movement of the Indian plate towards the Eurasian plate caused the outpouring of lava and the formation of the Deccan Traps.
Correct Answer: True
Solution:
The mid-oceanic ridges are zones of intense volcanic activity, where volcanic eruptions are common, bringing large amounts of lava to the surface.
Correct Answer: False
Solution:
The Pacific Plate is largely an oceanic plate.
Correct Answer: True
Solution:
The subduction zone along the Himalayas forms the northern plate boundary of the Indian plate, characterized by continent-continent convergence.
Correct Answer: False
Solution:
The Pacific Plate is largely an oceanic plate.
Correct Answer: False
Solution:
Abraham Ortelius, a Dutch map maker, was the first to propose such a possibility in 1596.
Correct Answer: False
Solution:
The lithosphere includes both the Earth's crust and the uppermost part of the mantle.
Correct Answer: True
Solution:
Volcanic eruptions are common along the mid-oceanic ridges, bringing huge amounts of lava to the surface.
Correct Answer: True
Solution:
The collision of the Indian plate with the Eurasian plate about 40-50 million years ago caused the rapid uplift of the Himalayas.
Correct Answer: True
Solution:
The Pacific Plate is largely an oceanic plate, as mentioned in the description of tectonic plates.
Correct Answer: True
Solution:
Harry Hess proposed the hypothesis of sea floor spreading, suggesting that constant eruptions at the crest of oceanic ridges cause the ocean floor to spread.
Correct Answer: False
Solution:
The Nazca plate is considered a minor tectonic plate.
Correct Answer: True
Solution:
Plate tectonics theory proposes that the Earth's lithosphere is divided into seven major and some minor plates.
Correct Answer: True
Solution:
The shorelines of Africa and South America facing each other have a remarkable and unmistakable match, supporting the continental drift theory.
Correct Answer: False
Solution:
Abraham Ortelius, a Dutch map maker, first proposed the idea that Europe, Africa, and America were once joined together in 1596.
Correct Answer: False
Solution:
The oceanic crust is much younger than the continental crust, with oceanic rocks being no older than 200 million years.
Correct Answer: True
Solution:
Alfred Wegener, a German meteorologist, proposed the continental drift theory in 1912, suggesting that continents were once joined together.
Correct Answer: True
Solution:
The mid-oceanic ridges have a central rift system at the crest, which is a zone of intense volcanic activity.
Correct Answer: True
Solution:
The theory of plate tectonics proposes that the Earth's lithosphere is divided into seven major and some minor plates.
Correct Answer: True
Solution:
The mid-oceanic ridges have a central rift system at the crest, which is a zone of intense volcanic activity.
Correct Answer: True
Solution:
Volcanic eruptions are common along mid-oceanic ridges, where they bring large amounts of lava to the surface.
Correct Answer: True
Solution:
Alfred Wegener, a German meteorologist, proposed the comprehensive argument of the continental drift theory in 1912.
Correct Answer: True
Solution:
The Indian plate collided with Asia about 40-50 million years ago, causing the uplift of the Himalayas, and this process is still continuing.
Correct Answer: False
Solution:
The mid-oceanic ridges are characterized by shallow earthquake foci, not deep-seated ones.
Correct Answer: False
Solution:
The Indian plate includes Peninsular India and the Australian continental portions, making it primarily a continental plate.
Correct Answer: False
Solution:
Sea floor spreading does not cause the shrinking of one ocean as another spreads, as proposed by Harry Hess.
Correct Answer: True
Solution:
Harry Hess proposed the concept of sea floor spreading in 1961, arguing that constant eruptions at the crest of oceanic ridges cause the rupture of the oceanic crust and the new lava wedges into it, pushing the oceanic crust on either side.
Correct Answer: False
Solution:
The Nazca Plate is not a major tectonic plate; it is considered a minor plate.
Correct Answer: False
Solution:
The ocean floor is much younger than the continental areas; oceanic crust rocks are nowhere more than 200 million years old.