BMST Earth's Geological Cycles 4 — Questions and Answers
Question 1: What drives deep ocean currents in the thermohaline circulation?
- Wind patterns at the surface
- Tidal forces from the Moon
- Differences in water temperature and salinity (Correct answer)
- Geothermal heating from the ocean floor
Correct answer: Differences in water temperature and salinity
Thermohaline circulation is driven by differences in water density caused by variations in temperature and salinity across the ocean.
Question 2: Which rock type can be found at all three stages of the rock cycle as a starting material?
- Only sedimentary rock
- Only igneous rock
- Only metamorphic rock
- Any of the three rock types (Correct answer)
Correct answer: Any of the three rock types
The rock cycle is continuous — any existing rock type can be weathered, melted, or metamorphosed to form another type.
Question 3: What is the name of the supercontinent that existed approximately 300 million years ago?
- Gondwana
- Laurasia
- Pangaea (Correct answer)
- Rodinia
Correct answer: Pangaea
Pangaea was the supercontinent that existed roughly 300 million years ago before breaking apart into today's continents through plate tectonics.
Question 4: During the hydrological cycle, what process describes water moving from plant leaves into the atmosphere?
- Evaporation
- Condensation
- Transpiration (Correct answer)
- Precipitation
Correct answer: Transpiration
Transpiration is the process by which plants release water vapor through their leaves into the atmosphere.
Question 5: Which feature forms at a divergent boundary on the ocean floor?
- Ocean trench
- Volcanic arc
- Mid-ocean ridge (Correct answer)
- Fold mountain
Correct answer: Mid-ocean ridge
Mid-ocean ridges form at divergent boundaries where plates pull apart and magma rises to create new oceanic crust.
Question 6: What is the process called when carbon dioxide dissolves into the ocean and forms carbonic acid?
- Ocean acidification (Correct answer)
- Carbonation weathering
- Carbon sequestration
- Bicarbonate buffering
Correct answer: Ocean acidification
Ocean acidification occurs when CO₂ dissolves in seawater to form carbonic acid, lowering the pH of the ocean.
Question 7: Which of the following best describes the relationship between erosion and deposition in the rock cycle?
- Erosion and deposition are the same process
- Erosion removes material; deposition lays it down elsewhere (Correct answer)
- Deposition always occurs before erosion
- Only erosion contributes to forming new rocks
Correct answer: Erosion removes material; deposition lays it down elsewhere
Erosion transports weathered rock fragments away from their source, while deposition occurs when those fragments settle in a new location to form sediment.
BMST Earth's Geological Cycles 4
What drives deep ocean currents in the thermohaline circulation?