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Rock Labs 2015
Igneous Rock Activity
Name __________________________ Hr__
Igneous rocks are classified by texture (grain size) and composition (ingredients). Igneous rocks are formed from the
crystallization of molten rock deep underground (magma) or from molten material at or near the surface (lava). Magma cools
slowly deep underground, will crystallize, and form large grained (intrusive) rocks. Lava cools quickly near or at the surface,
will crystallize, and form small or no grained (extrusive) rocks.
The color of the rock is a product of its composition. A light colored rock comes from a lava or magma with light
colored minerals in it. A dark colored rock comes from a lava or magma with dark colored minerals in it.
Data and Observation:
1
2
Rock Composition
= Color
light
medium
dark
Take one rock at a time. Do the observations in the numbered order.
3
4
Feel
Texture
Formation
rough
jagged
smooth
coarse
bubbly
fine
glassy
Intrusive
Extrusive
5
Rock name
Refer to
the Reference Guide
on p. 4
1
2
3
4
5
6
7
8
Analyze: See purple book-pages 118-123
1.
Q. Why do you think that obsidian (volcanic glass) differs from the other extrusive igneous rocks?
______________________________________________________________________________________
______________________________________________________________________________________
2.
Q. Do you think pumice is more dense than rhyolite?
Yes / No
(circle one)
Why? _________________________________________________________________________________
3.
Q. How do the intrusive rocks and extrusive igneous rocks differ?
______________________________________________________________________________________
______________________________________________________________________________________
1
Sedimentary Rock Activity
Name __________________________ Hr__
Sedimentary rocks form when rock fragments or organic materials are deposited, compacted, and/or cemented
together. They also can form during evaporation-when minerals crystallize from water, or when organisms remove minerals
from the water to make their shells and then die and fall to the lake or sea bottom.
There are 3 types of Sedimentary rocks: Clastic-made of rocky fragments (clasts), Organic (biochemical)-made of once
living plant or marine life, and Chemical-from when minerals crystalize directly from the evaporation of water.
Data and Observation:
1
2
Take one rock at a time. Do the observations in the numbered order.
3
4
Rock Composition Origin
Grain size (clastics only)
Acid
-Mineral
-Clastic
(rocky)
(rocky)
-Coarse >2.0 mm easily see (gravel/sand) Yes
-Organic
-Fossil
(once living) -Medium 0.06-2mm, still see (like sugar) or
(dead plants
-Chemical
or marine shells) (from water) -Fine <0.06mm, can’t see (like flour)
No
5
6
Rock Name Formation
-See reference
guide
provided
-Compacted
-Cemented
-Both
See guide p. 4
A
B
C
D
E
F
G
Analyze: See purple book-pages 125-131
1.
Q. Why would testing a rock with acid be helpful?
Q. What minerals react with acid?
_____________________________________________ ___________________________________
2.
What is needed in order for sedimentary rocks to form from fragments (aka. clasts)?
_________________________________________________________________________________
3.
Halite forms by evaporation of seawater. Would you classify halite as a clastic, chemical, or organic?
_________________________________________________________________________________
Conclude and Apply
4.
Compare and contrast sedimentary rocks with clastic texture from rocks with non-clastic texture.
_________________________________________________________________________________
5.
List the two ways sedimentary rocks are classified.
_________________________________________ _______________________________________
2
Metamorphic Rock Activity
Name __________________________ Hr__
Title: Metamorphic Rocks
Purpose: To observe rocks that have undergone changes in structure (mineral arrangement), texture
(crystalline shapes), and chemical composition (types of minerals) due to processes of heat & pressure.
Materials: Metamorphic rock samples, rock guide (p. 4 in the packet)
Problem: How do Metamorphic Rocks form?
Hypothesis:
_______________________________________________________________________________________
_______________________________________________________________________________________
Procedures:
1) Make a list indicating the properties of metamorphic rocks vs. those rocks that aren’t metamorphic.
2)
Metamorphic rocks: (see pur bk. pp. 132-137)
Non-metamorphic rocks:
a. have ___________________________
a. don’t have ___________________________
b. have ___________________________
b. don’t have ___________________________
c. have ___________________________
c. don’t have ___________________________
2) Obtain a metamorphic rock samples from your teacher.
3) Examine and observe foliation and grain size for each sample. Record.
4) Refer to the rock guide on pg. 4 on this packet, cross-reference, and name each rock.
Data table:
Foliation type
1
Grain size (texture)
Rock name
2
3
4
5
(Choose foliated or non-foliated)
Conclusion:
(Choose coarse, medium, fine)
See reference guide on p. 4
Analysis questions:
1. Review the characteristics that metamorphic rocks have to those that aren’t metamorphic.
Metamorphic rocks have a. ______________________ b. ______________________c. __________________
2. Match the non-metamorphic “parent” rock with the correct metamorphic they turn into (see packet p. 4).
________________________________________ will turn into ________________________________________
________________________________________ will turn into ________________________________________
________________________________________ will turn into ________________________________________
________________________________________ will turn into ________________________________________
________________________________________ will turn into ____________________________________
3
The Rock Reference Guide
Igneous Rocks - classified by grain size and magma/lava type. (cooling time vs. comp.)
Lava type
Granitic
<---------->
Basaltic
Andesitic <------------->
Chem. Comp.
Siliceous
<------------------------------------------> Metallic: Iron,Magn.
Color:
Light
(felsic)
<----------> Medium
Texture:
Coarse grn.
<---------->
Dark
(mafic)
Cooling
rate
GRANITE
DIORITE
GABBRO
Intrusive
ANDESITE
BASALT
Extrusive
SCORIA
Extrusive
Extrusive
Fine
grn.
RHYOLITE
Bubbly
Glassy
(vesicular)
PUMICE
OBSIDIAN
Quartz
Mineral comp.
(proportions)
Feldspar
Metals:
Mica, Hornblend
Cross color with grain size
Sedimentary Rocks - classified by composition and manner in which they solidified/formed.
(clastic,organic, chem) vs. (compacted, cemented)
Rock name
Composition
Grain Size
Characteristics
(Texture)
Conglomerate
Rounded pebbles of Quartz, Coarse grains Gravel-size particles
Feldspar., Granite., Lmstne
>2mm
Cemented
Breccia
Angular pebbles of Quartz.,
Coarse grains Gravel-size particles
Feldspar., Granite., Lmstne
>2mm
Cemented
Sandstone
Quartz
Medium size Sand size grains
Cemented or compacted
0.06-2mm
Siltstone
Quartz
Fine grained Too small to see well
Some clay
0.004-0.06mm Compacted
Shale
Mostly clay. Some mica
Microscopic
Very fine, compacted
Limestone
Calcite from seawater precip.
NA
Compacted limy mud
Compacted. Salty
Rock Salt
Halite from evaporation
NA
Fossiliferous limestone Whole shells (calcite)
NA
Cemented limy mud
Coquina
Shell fragments (calcite)
NA
Loosely packed and
cemented
Microscopic shell frag. (calcite)
Chalk
NA
Compacted, very fine
Bituminous coal
Carbonized plant remains
NA
Compacted, jet black
Formation
(Origin)
Clastic
Clastic
Clastic
Clastic
Clastic
Chem
Chem
Organic
Organic
Organic
Organic
Coarse=easy to see, Med=still see, Fine=can't see
Clastic-broken fragments or pieces of other rocks.
Chemical-precipitated/settled out of a solution or leftover after evaporation of seawater
Organic-decomposed plants [=jet black] or sea shells [shells are made of Calcite (CaCO3) and fiz in acid]
* Limestone is basically the mineral calcite.
CaCO3 (calcite) + 2 HCl(acid) = CaCl2 + H2O +CO2 (fizzing gas)
Metamorphic Rocks - classified by texture (foliated vs. unfoliated).
Rock
Gneiss
Schist
Slate
Quartzite
Marble
Foliation type
Composition
Foliated
Foliated
Foliated
Unfoliated
Unfoliated
Alt. bands of Qtz. Fldspr, mica
Texture
Coarse
Aligned Quartz and mica
Medium
Clays. Would seem to cleave Fine-cannot see
Quartz sand has recrystallized
Medium
Granular (sugar-y) calcite
Medium
Parent rock. (It use to be…)
Ign.-Granite
Met.-slate, Ign.-basalt/granite
Sed.-shale
Sed.-sandstone
Sed.-limestone
Foliated-layered appearance=may seem to cleave. Has aligned grns=stripes/bands of color from the pressure.
Unfoliated-shiny granular appearance and randomly organized recrystallized grains from the heat. P.4
Now that you are done with all three labs:
1. Design a flowchart in your notebook for identifying rocks that includes
all three rock types (igneous, sedimentary, and metamorphic) and the
characteristics you have used in each of the 3 rock identification labs.
Characteristics may include texture/size of grains or crystals, color,
relative density, and whether it fizzes with vinegar or not.
** For ideas, go to http://www.rockhounds.com/rockshop/rockkey/ or packet p. 4
2. Experiment with your flowchart as you classify rock samples brought in from home.
3. Refine or make changes to the classification flowchart as needed so it works for all samples that you are
given.
4. Identify the unknown samples and include their names in the flowchart that you made.
Lab Hints:
• Remember that the light or dark colors of a rock can lead to the identification
of minerals in the rock.
• Rocks that fizz when acid, such as vinegar, is added to them contain the mineral
calcite. Examples of such rocks include limestone and marble.
Analyze and Conclude
5. Describe how some samples were more difficult to classify than others.
6. Explain which characteristic was the least helpful in your flowchart.
7. The Big Idea What characteristics made it easier to classify rock samples?
Communicate Your Results: Transfer your final flowchart onto a whiteboard to share with your class. Be
sure to label the characteristics and the choices at each step in the chart so it is easy to follow.
Below is a partial flowchart to help ID a couple of sedimentary rocks. Yours need to include all rock types.
5
Rock Collecting and Classifying
**Bring in 2 rocks from around your house—they need to fit in the palm of one hand and be large enough to see the
characteristics!
Try to collect a variety of different types of rocks-- igneous, sedimentary, and metamorphic. Use a data table like the one
below to describe and classify each rock in your collection. Use your flowchart to ID the rock.
Rock Collecting and Classifying Data Table
Sample
& who
brought it
Color
Light/med./dark
Texture
(coarse/med/fine)
Foliated
or Non-
A
B
C
D
E
F
G
H
Pg 6
Fizzes
with
Vinegar?
Rock Type
(ign/sed/meta)
Rock I.D.
Rocks and Rock Cycle Vocabulary:
Vocabulary Word
Sedimentary-
Definition
Clastic Sedimentary RockChemical Sedimentary RockOrganic/Biochemical Sedimentary Rock-
CementationCompactionWeatheringDepositionErosionSedimentStratificationIgneousLavaMagmaExtrusive rockIntrusive rockMetamorphicNon-foliated metamorphic rock-
Foliated metamorphic rockRock Cycle-
Pg. 7