01 Earth as a Geological System Free Online FlashCards

What are Earth’s three main compositional layers?

The crust is the thin, solid outer layer; the mantle is thick, hot, and mostly solid; and the metal-rich core has a liquid outer part and a solid inner part.

How do the lithosphere and asthenosphere differ?

The lithosphere is the crust and rigid uppermost mantle, broken into tectonic plates. The hotter, weaker asthenosphere beneath it deforms slowly, allowing plate motion.

What does the absence of shear waves through the outer core show?

Shear waves do not pass through liquids. Their absence through the outer core indicates that it is liquid.

How does a mineral differ from a rock?

A mineral is a naturally occurring inorganic solid with an orderly internal structure and characteristic chemical composition. A rock is an aggregate of one or more minerals, or a mass of mineral matter.

How do igneous rocks form?

Igneous rocks form when molten rock cools and solidifies. Basalt forms from lava at or near the surface; granite forms from magma cooling underground.

Why does the rock cycle have no single starting point?

The rock cycle describes how rocks transform through processes such as weathering, burial, metamorphism, melting, and solidification. It has no single starting point, and rocks can follow different paths.

How does solar energy drive geological change at Earth’s surface?

Solar energy drives weather and climate, evaporation and precipitation, and much of the movement of water and air. These processes weather rock and transport sediment.

What geological processes does Earth’s internal heat help power?

Internal heat, largely from radioactive decay and leftover heat from Earth's formation, drives slow mantle movement and helps power melting, volcanism, metamorphism, and plate tectonics.

What are Earth’s four connected spheres?

The geosphere is solid Earth; the hydrosphere is water, with the cryosphere as its frozen part; the atmosphere is surrounding gases; and the biosphere includes living organisms and their habitats.

How can rainfall connect several Earth spheres?

Rainfall links the atmosphere and hydrosphere. Flowing water can erode the geosphere and carry nutrients that support life in the biosphere.

What can geophysical surveys reveal underground?

Geophysical surveys use seismic, magnetic, gravity, or electrical measurements to infer buried structures and materials without directly exposing them.

What does a fault cutting a rock layer reveal about their relative ages?

Relative dating places events in sequence. A fault that cuts a rock layer is younger than the layer it cuts.