SOL 5.7 – Changes in the earth’s surface

Scientists think our earth is 4.6 billion years old

Continental drift

Layers of the earth

There are three types of rocks

Sedimentary are formed when particles of sediment are put under a lot of pressure and are stuck together

Igneous Rocks are formed when magma comes to the earth’s surface and cools

Metamorphic rock is formed by great heat or pressure or both

Metamorphic rocks often have stripes in them

Rock Cycle Rock and Roll

The difference between Weathering and Erosion Weathering is the physical breaking down of rocks caused by wind, rain, and ice Erosion is the movement of the broken down rocks

A large chunk of bedrock many hundreds of feet long is broken down into smaller and smaller pieces, until finally there are many tens of thousands of small rocks. Often rocks are broken down so much that they become dirt. Weathering is caused by water, as it freezes and thaws, as well as by chemical reactions that loosen the bonds holding rocks together. Weathering is most common at the surface where exposed bedrock meets the atmosphere. However, weathering can extend many thousands of feet downward into the Earth’s crust, following cracks, fissures, and microscopic holes that allow water to penetrate.

Weathering from ice occurs when the water gets in the cracks of rocks and freezes and expands causing the rock to split apart

Which type of weathering is this?

Which type of weathering does this show?

Erosion – when the landscape is changed by the movement of rocks and soil caused by water

There are Seven major tectonic plates and many smaller ones There are Seven major tectonic plates and many smaller ones. They are always moving. Their movements end up causing huge instantaneous changes in the earth’s surface: volcanoes and earthquakes. There are three types of movements these plates make.

Divergent Oceanic plates

Convergent Plates

Subduction - an oceanic plate & a continental plate

Often where the oceanic plate goes under the continental plate, the pressure causes volcanoes to erupt

Transform Plates

Damage from two plates sliding

The Haiti earthquake occurred at a fault that runs right through Haiti and is situated along the boundary between the Caribbean and North American plates, which are rocky slabs that cover the planet and fit together like a giant jigsaw puzzle. These two plates constantly creep past one another, about 0.8 inches a year, with the Caribbean plate moving eastward with respect to the North American slab.

Fast changes in the earth’s surface

Tsunamis are typically caused by large undersea earthquakes at tectonic plate boundaries. When the ocean floor at a plate suddenly rises or falls, it displaces the water above it and launches the rolling waves that become the tsunami.

Identifying rocks

How we identify rocks color hardness grains grain size layers taste