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Harcourt 4th grade science, Unit B, Chap 1.


a physical feature of Earth's surface


the process of breaking rock into soil, sand, or other tiny pieces


the process of moving sediment from one place to another


the process of dropping, or depositing, sediment in a new location

mass movement

the downhill movement of rock and soil because of gravity


the outer layer of Earth made of solid rock


the layer of rock beneath the Earth's crust


Earth's hottest layer; the center layer of Earth


a rigid block of crust and upper mantle


hot, soft rock from Earth's lower mantle


an opening in Earth's crust through which lava flows


a shaking of the ground caused by the sudden release of energy in Earth's crust


a place where pieces of Earth's crust move

continental drift

a rigid block of crust and upper mantle


According to theory this was a "supercontinent" that contained all of Earth's land about 225 million years ag.


the remains or traces of past life found in Earth's crust

Grand Canyon

a mile-deep slice into Earth's history - and a very popular tourist attraction

The oldest rock layer

What rock layer is found at the bottom of the Grand Canyon

How old are the oldest rocks of the Grand Canyon

250 million years old

The southern continent that existed 200 million years ago was


Many strong earthquakes are caused by

plates sliding past each other

How do volcanoes form where oceanic and continental plates collide?

The edge of the oceanic plate pushes under the edge of the continental plate, and then melts as it sinks into the mantle, becomes magma and forces its way up between the plates.

shield volcanoes

broad volcanoes with gentle slopes - they are mostl lava

cinder cone volcanoes

tall and narrow, with steep slopes - mostly ash

composite volcanoes

wide and have fairly steep slopes - they are lava and ash.

What parts of the Earth are solid rock

inner core, crust, upper mantle

A type of mass movement is a


What new landforms are created by erosion and deposition

island, terminal moraines, deltas, lakes, valleys

terminal moraines

they mark the leading edge of a glacier - long ridges of soil and rock.

What are some of the forces that change landforms

water, wind, ice, mass movement

Beginning with the outermost layer, Earth's layers are the

crust, mantle, core

Wind erodes rock and deposits sediments to form


water erodes rock and dposits sediments to form


Ice erodes rock and deposits sediments to form

terminal moraines

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