Chapter3 Flashcards
What are the two main factors that shape Earth’s surface?
- Climate (weathering & erosion)
- Plate Tectonics
How is climate different from weather?
Climate is the average weather conditions over a long period, while weather changes over short periods.
How do scientists study past climate changes?
Through geological records like marine sediments, ice sheets, and fossils.
What natural factors drive climate change?
- Movement of continents
- Formation of oceans
- Uplift of mountains
- Volcanic eruptions
- Changes in Earth’s orbit and axial tilt
How does climate change affect sea levels?
- Ice ages: Sea levels drop (e.g., Arabian Gulf was dry 12,000 years ago)
- Greenhouse ages: Ice sheets melt, sea levels rise
What is weathering?
The breakdown of rocks into smaller particles.
What are the two main types of weathering?
- Mechanical Weathering – No chemical change.
- Chemical Weathering – Alters rock’s chemical composition.
What are three types of mechanical weathering?
- Frost Wedging – Water in cracks freezes and expands.
- Thermal Cracking – Sudden temperature changes cause rock fractures.
- Root Wedging – Plant roots grow into cracks and break rocks apart.
What are two types of chemical weathering?
- Oxidation – Iron in minerals reacts with oxygen, forming rust.
- Dissolution – Carbonate minerals dissolve in acidic rainwater.
What is erosion?
The movement of weathered materials by water, wind, or ice.
Give an example of how climate affects erosion and weathering.
- Hot arid climate: Jabal Hafit Mountain
- Cold glacial climate: Alps Mountains
What are the two types of Earth’s crust?
- Continental crust – Thicker, less dense, granite composition.
- Oceanic crust – Thinner, denser, basalt composition.
Why do tectonic plates move?
Mantle convection currents transfer heat from Earth’s core to the surface.
What are the three types of plate boundaries?
- Divergent – Plates move apart.
- Convergent – Plates collide.
- Transform – Plates slide past each other.
What happens at a divergent boundary?
- Plates separate, forming a spreading ridge.
- New oceanic crust forms from volcanic activity.
- Examples: Atlantic Ocean, Red Sea, African Rift Valley.
What happens when two continental plates collide?
- Mountain formation (e.g., Himalayas)
- Crust thickening
- Earthquakes
What happens when an oceanic plate collides with a continental plate?
- The denser oceanic plate subducts under the continental plate.
- Forms volcanic arcs and trenches.
- Causes earthquakes and tsunamis.
- Example: Andes Mountains.
What happens when two oceanic plates collide?
- The older, denser plate subducts.
- Forms volcanic island arcs (e.g., Mariana Islands, Japan).
- Creates deep trenches.
- Causes earthquakes and tsunamis.
What happens at a transform plate boundary?
- Plates slide past each other.
- No crust is created or destroyed.
- Causes earthquakes.
- Examples: San Andreas Fault (USA), Dibba Fault Zone (UAE).
What is a subduction zone?
The region where one tectonic plate sinks beneath another.
What is an oceanic trench?
A deep depression in the ocean floor formed at subduction zones.
What is pillow lava, and where is it found?
- Rounded lava formations that form underwater.
- Found at mid-ocean ridges.
How did the Himalayas form?
The Indian plate collided with the Eurasian plate in a continental-continental convergence.
How did the Andes Mountains form?
The Pacific plate subducted under the South American plate, forming a volcanic arc.
