Download LAB - Rock Classification

NAME: ________________________________________
LAB - Rock Classification
Date: _______
Introduction: A rock is any naturally occurring aggregate of minerals, mineral-like solids, glass, or
organic particles. The properties that can be observed in a rock are clues to its origin. These properties are
used to classify rocks.
Objective: You will investigate the properties of different classes of rocks for identification.
Procedure A:
You have been given a “bucket of rocks”. Classify the rocks you have into 3 different groups. Decide
what characteristics you chose to look at when dividing the rocks into the 3 groups. List the characteristics
you chose for each group below.
Group 1
______________________________________________________________________________________
Group 2
______________________________________________________________________________________
Group 3
______________________________________________________________________________________
Procedure B:
After the class discussion (notes) and an introduction to the 3 different classes of rocks, reclassify your
“bucket of rocks” once again into 3 groups. This time, use the classifying characteristics discussed in class
and in your notes and list the characteristics used to identify each class of rock below. Be sure to
name/label each class of rock for each group. Use the list of identifying characteristic provided to help you
as you observe each rock.
Banding
Distorted/Wavy
Flattened Minerals
Fossils
Glassy
Layered
Scattered Intergrown Crystals
Shells
Vesicular (Air Bubbles)
Visible Cemented Fragments
Group 1
______________________________________________________________________________________
Group 2
______________________________________________________________________________________
Group 3
______________________________________________________________________________________
Discussion Questions:
Igneous Rocks
1. How is the size of mineral grains affected by the rate at which molten rock material cools?
2.
How could you tell if an igneous rock has had an intrusive or extrusive origin?
3.
How does the characteristic mineral composition of a light colored igneous rock differ from that of
a dark colored igneous rock?
4.
How does the density of a light colored igneous rock differ from that of a dark colored igneous
rock?
5.
What is the main difference between lava and magma?
6.
What characteristics do you look for to identify igneous rocks?
Conclusion: On what basis are igneous rocks identified?
Sedimentary Rocks
1. What are the maximum and minimum dimensions (the size range) for the following particle sizes?
a. Cobble:
b.
Pebble:
c.
Sand:
d.
Silt:
e.
Clay:
2.
Describe the sequence of events in the lithification of sandstone.
3.
How can you distinguish a clastic (fragmental) sedimentary rock from a chemically formed
sedimentary rock?
4.
What characteristics do you look for to identify sedimentary rocks?
Conclusion: On what basis are sedimentary rocks identified?
Metamorphic Rocks
1. Why are metamorphic rocks formed by contact metamorphism usually not as dense as those
formed by regional metamorphism?
2.
Why do you not find fossils in metamorphic rocks?
3.
Why do minerals in metamorphic rocks rearrange in layers?
4.
What characteristics do you look for to identify metamorphic rocks?
Conclusion: On what basis are metamorphic rocks identified?
The Rock Cycle
Describe the rock cycle and include the processes that occur.
Reading Comprehension: Read the article below on the geology of Fundy National Park and answer the
questions that follow (in complete sentences).
Fundy National Park of Canada
Geology: Fundy's hidden story
http://www.pc.gc.ca/pn-np/nb/fundy/natcul/geolog.aspx
Covered by the soil and the forests or guarded by inaccessible, tide-washed cliffs, the geology of Fundy
National Park is a well-kept secret. There are ways, however, to touch this ancient heart of Fundy.
Exploring the beaches of the Bay of Fundy, hiking along the deep river valleys and even travelling over the
Caledonia Highlands, you can piece together the story which is as rich and varied as that of the Earth itself.
The Bay of Fundy Coast
While exploring the beaches and learning about the amazing Fundy tides, let your eyes wander back to the
land. You will find steep cliffs which are being sculpted by the daily movements of Fundy's giant tides. In
fact, the water has exposed the bedrock of the planet for most of the coastline of the park. This rock has a
story to tell.
Around Alma and Herring Cove the story is one of rivers and jungles. The grey and beige rocks forming
the impressive cliffs of Owls Head are made of sandstone. This rock used to be sand and mud which a vast
and ancient river lay down during the Carboniferous era (about 325 million years ago). Along this river
there was a lush, tropical jungle. You can read this incredible story if you take a walk along the beach near
the town of Alma. The rock has a fine sandy look to it and contains many black plant fossils and thin seams
of coal.
The story is considerably older at Point Wolfe where volcanoes and the movement of the continents have
formed the oldest rocks in the park. Walk down the steps to Point Wolfe beach and as soon as you reach the
beach you will notice some grey, green rocks forming a low cliff along the right side of this inlet. The rock
has been smoothed by the tides but the story can still be deciphered. Volcanoes erupting ash and lava
created off-shore islands during the Pre-Cambrian era (one billion years ago). Afterwards, during a
collision between the continents of Europe and North America, these volcanic islands were bulldozed into
the mainland. Look for the white quartz veins, swirling folds and criss-crossing fractures in the rock, which
tell of this transformation. Rocks, which have undergone changes due to the heat and pressure of
continental collisions, are called metamorphic rocks.
Point Wolfe is a geologist's paradise. Opposite the grey rocks, you will notice rusty, maroon colored cliffs
towering above you. The rusty red cliffs tell a tale of crumbling mountains. These mountains were created
by the ancient Pre-Cambrian volcanoes and by the collision of Europe and North America. At one time
they rivaled the Rocky's in massive splendor. But they were worn down, or eroded, by the passage of time.
Water and gravity piled all of the debris at their feet. These boulders and pebbles were later cemented
together to form a new rock which we call the Hopewell conglomerate. If the name Hopewell sounds
familiar to you, you are probably thinking of the Rocks Provincial Park at Hopewell, where the
conglomerate is also found. You can also find it at Herring Cove. Don't forget to examine all of the rounded
rocks and pebbles that have been cemented together to form this conglomerate. At one time they were the
backbone of towering mountains.
1.
“The rock has a fine sandy look…contains many black plant fossils” refers to what class of rock?
2.
What type of rocks are the oldest rocks in the park? State your evidence.
3.
Why are the rocks rusty? Which element causes this? (think back to minerals and chemical
weathering)