Possible test responses

1 - Use sentences to describe and explain the following steps and processes that occur to make sedimentary rock

A - Describe what weathering is and how it works. Use one way rock is weathered and describe how it works in detail.

Weathering is the breaking of rock into smaller pieces called sediment. There are 2 types of weathering- Mechanical Weathering where the rock is physically broken into smaller pieces. Chemical weathering is when the minerals that hold the rock sediments together are dissolved.

Examples

1 Rust is a form of Chemical weathering where the iron in the rock is dissolved by oxidation, breaking the rock apart. Oxygen and water combine to disolve (rust ) the iron mineral in the rock, breaking the rock apart.

2. Frost wedging is a form of mechanical or physical weathering. Water can get into cracks in rock. When water freezes it takes up almost 10% more volume (space). If it then freezes and expands on cold nights and thaws out in the warm days repeatedly, this will increase the size of the crack and the pressure. If the water thaws and refreezes over and over, and the constant pressure in the crack will break the rock apart. This process is called FROST WEDGING.

WEATHER IS NOT THE SAME THING AS WEATHERING.!!!!!!!!!!!!!!!!!!!!

1B- Describe how Sediment can be eroded and deposited.

Explain using e examples of different types of erosion.

Description:

Erosion is the process where sediments are moved by things like gravity, water, waves, wind or ice from one location and deposited in another.

EXAMPLES

- A Landslide is a form of erosion.

HOW  Sediments (earth, sand, gravel rocks) on the side of a hill are

loosened (sometimes by rain water) and then, because of gravity, the land slides

down the hill. Water and Gravity work together to erode (move) the

sediment on a hill.

OR - Waves can erode a beach.

HOW  During a storm, the giant waves push and pull the sand, taking it

away from one beach, and depositing it somewhere else.

Sand dunes in the middle of a lake or river can result.

OR - Ice in the form of a Glacier can move rock debris from higher up the mountain.

HOW  As the Glacier moves down the mountain and valley, it takes the

sediments with it, depositing it at the end of the glacier. This is also an example

of mechanical Weathering at the same time as Glacier freezes to the rock, then

slides, breaking off pieces of the mountain stuck in the ice.

OR Gravity: Rocks break up higher up and fall onto rocks lower down, Gravity is

moving (eroding) the rock from one place and depositing it at another.

This is also an example of mechanical Weathering at the same time as the

falling rocks can break apart other rocks into sediments.

1C- What happens after sediments deposit to actually create new rock?

Layers of sediment are eroded frequently by rivers and glaciers, and deposited in

layers often in lakes and rivers.

Over time these layers get very thick.

When deposited in a lake or ocean for thousands of years, the weight of the water can compress the sediment and then the minerals cement (glue it) together to make new sedimentary rock. Frequently, the lake or ocean evaporates, speeding up the cementation and making of the rock. Minerals in the sediment act like a glue, cementing the sediment into new type of sedimentary stone like sandstone.

2. Intrusive Igneous rock is formed when magma cools and hardens within cracks in the crust before it can escape to the surface. Intrusive igneous rocks crystallize (solidify) below the Earth's surface and are not exposed to the atmosphere. The slow cooling that occurs there allows rocks with large crystals to form. “Veins” of metallic minerals like gold and silver are created this way. Granite and quartz are intrusive igneous rocks.

Extrusive Igneous rocks occur when lava erupts onto the surface (volcano, ridge) and are exposed to the atmosphere or ocean water on the earth's surface. They cool quickly to form igneous rocks with small crystals. Basalt, obsidian, and pumice, are extrusive igneous rocks.

3. Convection currents are currents of magma in the mantle that are heated at the core where its

density decreases, rises to the underside of the crust and is either redirected under the crust (pushing/pulling the crust with it). Sometimes it breaks through the crust creating ridges or volcanoes. As the current of magma flows below the crust it cools and begins to descend back to the core because it is now more dense (cooler). At the core it is heated again and repeats the cycle over and over. There many individual pockets of convection currents under the crust we call convection cells.

3B- Convection currents form convection cells. These cells have moving currents of lava going in different directions. As the currents of magma pass below the crust it can pull or push the crust that is above it as it goes. These convection cells- can cause the crust to move and the plates to collide, come apart or slide by each other, causing earthquakes.

4. Extrusive igneous rock to Metamorphic rock

If igneous or sedimentary rock undergoes pressure and/or heating deep in the

earth’s crust, it transforms into metamorphic rock. It could reform into

sedimentary rock. BUT HOW DOES THE EXTRUSIVE IGNEOUS FIND ITS WAY FROM THE SURFACE TO DEEP IN THE CRUST?????????

so.....

Extrusive igneous rock is found on the surface. To become metamorphic rock it must first move location and be deep in the earth's crust. Folding and faulting of the plates can do this. The plates can collide and over ride each other or or mountains get made, folding the crust on its self. This way, the extrusive igneous rock can find its way deep in the crust. Here , heat from the mantle, and pressure caused by the weight of the overlying rock, combine to make metamorphic rock.