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GEOL 1101 LAB #3 SEDIMENTARY AND METAMORPHIC ROCKS
1. How do clastic (also called detrital) sedimentary rocks form?
What type of texture do all clastic sedimentary rocks have?
Name 2 clastic sedimentary rocks.
2. How do chemical sedimentary rocks form? Name a chemical sedimentary rock.
3. How do biochemical sedimentary rocks form? Name a biochemical sedimentary rock.
4. What happens to the size, shape, and sorting of sediment as transport distance increases?
5. You are hiking in the Franklins and find two rocks: a conglomerate containing mostly large rock fragments and a
well sorted quartz rich sandstone. Which of these 2 rocks would have formed further from the source area (farther
from the area where the sediments originated)? How do you know?
6. Which minerals weather the most quickly?
Which minerals are the most stable?
7. Explain how evaporite chemical sedimentary rocks form. Name an evaporite rock.
8. Explain in words (you don’t need to write chemical formulas), the chemical weathering process of oxidation.
Name the 2 iron oxide minerals discussed in class.
9. Question 9 is optional, for up to 3 pts extra credit on Lab Exam 1. Sedimentary structures are features in
sedimentary rocks that form during the deposition of sediments. For each of the samples name the type of
sedimentary structure and explain how that structure forms.
9A.
TYPE:
METHOD OF FORMATION:
9B.
TYPE:
METHOD OF FORMATION:
9C.
TYPE:
METHOD OF FORMATION:
10. Use the Lecture Notes, your text, and the chart and figure on the next page to determine the sedimentary rock
that forms (resultant rock) in the following environments and then match the rock to the correct sample letter A – F.
ENVIRONMENT
Reefs and Carbonate Platforms
(these are warm, shallow seas like the
Caribbean)
Desert playa lake (these are wetweather lakes)
Stream or river (these are called
“fluvial” environments)
Alluvial fans (where sediments are
deposited next to a mountain)
Deltas
TYPE OF SEDIMENTARY ROCK THAT FORMS
SAMPLE
LETTER
11. Define the following:
lithification:
protolith:
foliation:
recrystallization:
plastic deformation:
12. What is contact metamorphism (also called “thermal metamorphism”)?
Name two metamorphic rocks that form during contact metamorphism and give the protoliths
of each.
13. What is regional metamorphism? In which type of plate boundary does regional metamorphism occur?
What texture in the metamorphic rock results from regional metamorphism?
14. List 5 factors in metamorphism.
15. Match the sample letter to the correct description:
protolith, unmetamorphosed sedimentary rock: ____________
low grade metamorphic rock: _____________
low to intermediate grade metamorphic rock: _____________
intermediate grade metamorphic rock: _____________
high grade metamorphic rock: _____________
igneous rock: ____________________
16. ROCK C in the cross section below is an igneous intrusion. Sedimentary rock A is limestone, sedimentary rock
B is sandstone, and sedimentary rock D is shale.
What metamorphic rock will form when A undergoes contact metamorphism?
What metamorphic rock will form when B undergoes contact metamorphism?
What metamorphic rock will form when D undergoes contact metamorphism?
17. Use the IGNEOUS ROCK IDENTIFICATION CHART, the SEDIMENTARY ROCK IDENTIFICATION CHART,
the METAMORPHIC ROCK IDENTIFICATION CHART, and the MINERAL IDENTIFICATION CHART to identify the
unknown samples. All abbreviations must be understandable!!!!!!
1) determine if the sample is a mineral, igneous, sedimentary, or metamorphic rock.
2) If the sample is a rock, also determine the class: Igneous Rock classes: plutonic or
volcanic; Sedimentary Rock classes: clastic or chemical/biochemical;
Metamorphic Rock classes: foliated or nonfoliated
3) If the sample is a rock, name the texture:
Igneous Rock textures: phaneritic (coarse-grained); aphanitic (fine-grained);
porpyritic; vesicular, glassy
Sedimentary Rock textures: clastic; crystalline; bioclastic
Metamorphic Rock textures: foliated or nonfoliated
4) Name the sample.
ROCK
TYPE OR
MINERAL
1
2
3
4
5
6
7
8
9
CLASS OF
ROCK
TEXTURE, IF
SAMPLE IS
A ROCK
IDENTIFYING CHARACTERISTICS OF
SAMPLE
SAMPLE NAME
10
11
12
13
ROCK
TYPE OR
MINERAL
14
15
16
17
18
19
20
21
22
23
24
25
26
27
CLASS OF
ROCK
TEXTURE, IF
SAMPLE IS
A ROCK
IDENTIFYING CHARACTERISTICS OF
SAMPLE
SAMPLE NAME
28
For up to 5 points extra credit on Lab Exam 1, answer questions 18 – 22.
18. Using the Lecture Notes and your textbook, describe the difference in chemical composition between limestone
and dolostone.
Examine the samples of limestone and dolostone set out for you. How can you distinguish between the two in
hand sample?
19. What was the environment like in the El Paso area during most of the geologic era called the Paleozoic?
How do we know?
20. What was the environment like in El Paso area during the Cretaceous period, about 70 million years ago?
How do we know?
Where in the El Paso area can we find dinosaur tracks?
21. Where is sediment being deposited today in the El Paso area and what type of sediment is being
deposited?
22. Examine the samples of the Castner and Lanoria, the oldest rocks in the Franklin Mountains. What types of
rocks are they now?
How old are they?
What type of rocks were they originally (that is, what is the protolith for each)?