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The Rock Cycle

For this lab, you will learn about and use the rock cycle. I recommend that you print the lab, record your answers, and then use those

to input your answers into our online class site so that you can then get credit for the laboratory exercise.

The rock cycle is the repeating events that gradually and continuously change rocks from one type to another. It is often displayed in

diagrams that help to visualize this cycle, such as Figure 1 below. As an example, we will follow one possible cycle of the rock cycle,

although there are many different paths that nature can take on the rock cycle. When magma either rises towards or reaches the

surface, it cools and solidifies, undergoing crystallization to become igneous rock. Once they are at the surface, igneous rocks are

slowly broken down by weathering, forming sediment. This sediment can be eroded and deposited. As sediment accumulates in layers,

lithification begins, as it compacts and cements together, making a sedimentary rock. Over time, sedimentary rocks are buried under

other sediments or are caught in movements of the crust that expose them to high temperatures and pressures, such as subduction. The

heat and pressure causes them to change to metamorphic rock. When metamorphic rock is subjected to still higher temperatures, it can

melt, forming magma. Therefore, we have completed one cycle, but the cycle keeps going. Rock does not need to take this same path,

as there are alternative paths, depending on what is going on in nature in that area.

Figure 1. The rock cycle

Igneous Rock

Magma Sediment

Sedimentary

Rock

Metamorphic

Rock

Key

Crystallization

Weathering

Metamorphosing

Lithification

Melting

Part 1: Practice Using the Rock Cycle

Using the rock cycle in Figure 1, fill in the missing information in order to change one given rock type to another. Ignore the numbers

in parenthesis, as these will just be used to fill in your answers online.

Magma (1)____________________________ into igneous rock. The igneous rock (2)____________________________ into

sediment. The sediment (3)____________________________ to make sedimentary rock. The sedimentary rock becomes

metamorphic rock due to (4)____________________________. The metamorphic rock melts, becoming

(5)____________________________.

Igneous rock (6)____________________________ to become metamorphic rock. The metamorphic rock

(7)______________________ to become magma. The magma crystallizes to make (8)____________________________.

Metamorphic rock (9)____________________________ into sediment. The sediment (10)____________________________ to make

sedimentary rock. The sedimentary rock (11)____________________________ back into sediment.

Igneous rock (12)____________________________ into sediment. Sediment compacts and cements to make

(13)____________________________. Sedimentary rock metamorphoses into (14)____________________________, which is then

weathered to make (15)____________________________.

Igneous rock metamorphoses into (16)____________________________, which then (17)____________________________ to

become magma. The magma crystallizes into (18)____________________________. This material then weathers into

(19)____________________________, which then (20)____________________________ to make sedimentary rock.

The repeating events that gradually and continuously changes rocks from one type to another is called the

(21)____________________________

Part 2: Characterizing Processes and Rock Properties

Indicate what rock group is characterized by each of the listed processes or rock properties in Figure 2.

Figure 2. Characterizing processes and rock properties.

Process or Property Igneous Sedimentary Metamorphic

Lithification of

sediment

Intense heating (but

no melting)

Crystals precipitate

from water

Crystallization from

magma

Crystallization from

lava

Compaction of

Sediment

Cementation of

sediment

Folding, causing

recrystallization

Foliated

Fossils present

Melting of rock

Part 3: Rock Cycle Predictions

For each of the samples in Figure 3, and using the rock cycle diagram in Figure 1, determine where this rock would fall on the rock

cycle. In other words, classify the rock as either igneous, sedimentary, or metamorphic (there are three of each category). Then,

predict changes that the rock could undergo next if left in the natural setting. Answer the questions found on the page after the

pictures.

Figure 3. Photographs of a rock samples for classification, analysis, and prediction.

Sample #1 Sample #2

Sample #3

Sample #4

Sample #5 Sample #6

Sample #7

Sample #8

Sample #9

Sample 1:

Where would this rock fall on the rock cycle? In other words, is this an igneous, sedimentary, or metamorphic rock?