Earth Science Flashcards

A geologist measures the half-life of Carbon-14 as 5,730 years. If a sample contains 25% of its original C-14, how old is the sample?

Answer: 11,460 years

After one half-life (5,730 yr), 50% remains; after two half-lives (11,460 yr), 25% remains.

What term describes the bending of rock layers caused by compressional tectonic forces?

Answer: Fold

Folds are bends in rock layers that result from compressional stress, forming structures like anticlines and synclines.

Which ocean current transports warm water northward along the eastern coast of the United States?

Answer: Gulf Stream

The Gulf Stream is a powerful, warm Atlantic ocean current that flows northward along the U.S. East Coast and moderates climates of western Europe.

Which factor most directly determines the climate of a region rather than its day-to-day weather?

Answer: Long-term average temperature and precipitation patterns

Climate is defined as the long-term average of atmospheric conditions including temperature and precipitation, typically measured over 30 years.

At a divergent plate boundary in the ocean, what type of feature typically forms?

Answer: Mid-ocean ridge

At divergent oceanic boundaries, magma rises to fill the gap as plates separate, forming mid-ocean ridges.

Which type of cloud is associated with continuous, widespread precipitation and forms in low horizontal sheets?

Answer: Nimbostratus

Nimbostratus clouds are dark, layered clouds that produce steady, widespread rain or snow over a large area for extended periods.

What is the name of the boundary between Earth's crust and mantle?

Answer: Mohorovičić discontinuity

The Mohorovičić discontinuity (Moho) marks the boundary between Earth's crust and upper mantle, identified by a sudden increase in seismic wave speed.