Download Alper Midterm 1 Solution (1)

The American University of Sharjah
School of Engineering
CVE 231: Geology
FALL 2013
1ST MIDTERM EXAM
ALLOCATED TIME = 50 MINUTES
NAME:__________________________________ ID:____________________________
Instructions:
1) Write your name and ID in the space provided above
2) Check for the number of questions and alert if any are missing
3) This is a closed book exam and only calculators and stationary are allowed on top of the desk
4) Use of mobile phones for any reason will result in automatic dismissal from exam
5) Show all work. Partial credit will only be given if all work is clearly explained in steps and units
are shown.
6) Do not detach pages
For Instructor’s USE ONLY
Question
Marks
1
/26
2
/24
3
30
4
/20
Total
/100
PROBLEM 1 (26 Marks)
1) The lithosphere forms the hot, partially molten plates of plate tectonics. (2pt)
a) True
b) False
2) The Asthenosphere is the solid part of Mantle. (2pt)
a) True
b) False
3) The MOHO is the boundary between earth’s crust and mantle. (2pt)
a) True
b) False
4) At divergent boundary, the plates...............each other. (2pt)
a) Move away from
b) Move towards
c) Slide against
5) Divergent boundaries are also known as (2pt)
a) Subduction zones
b) Spreading ridges
c) Reverse faults
6) Mantle is............... (2pt)
a) Partially molten
b) Solid
c) Molten
7) Trenches are formed at subduction zones. (2pt)
a) True
b) False
8) Volcanoes are formed by subduction, rifting and hotspots (2pt)
a) True
b) False
9) Describe each major type of plate boundary. How can these boundaries be recognized at earth's
surface? (2pt)
 Divergent: They occur when the plates at each side of the boundary move away from each other. They
can be recognized via mid-oceanic ridges at the oceans and continental rifts at the land.


Convergent: They occur when the plates at each side of the boundary move towards each other. They
can be recognized at trenches in ocean floors.
Transforming: They occur when the plates at each side of the boundary slide trough each other. They
can be recognized at transform faults.
10) Plates are moved around by underlying....................... (2pt)
a) Outer core
b) mantle convection cells
c) subduction zones
11) Continent -Oceanic crust collision zones are called....................... (2pt)
a) Asthenosphere
b) Subduction zone
c) spreading ridge
b) False
12) Vadoze zone represents the soil with no moisture. (2pt)
a) True
b) False
13) Two most common elements in crust are ___Silica____ and __Oxygen__. (2pt)
PROBLEM 2 (24 Marks)
1) How could cleavage affect the engineering properties of rock composed of minerals with strong
cleavage? (2pt)
Cleavage affects the engineering properties of the rocks since it results in weak planes along the cleavages that
need to be considered during engineering design.
2) Write 5 minerals from Mohs scale from soft to hard. (2pt)
1
Talc
2
Gypsum
3
Calcite
4
Fluorite
5
Apatite
6
Orthoclase Feldspar
7
Quartz
8
Topaz
9
Corundum
10
Diamond
3) Which is not correct for minerals (2pt)
a) Naturally occurring
c) Ordered internal molecular structure
b) Organic solid
d) Definite chemical composition
4) Silicates are the most abundant group, 95% of Earth crust (2pt)
a) True
b) False
5) Which one of the following does not describe a mineral? (2pt)
 Specific, internal, crystalline structure
 They can be a liquid, solid, or gas.
 Specific, predictable chemical composition.
 Identified by physical properties.
6) Which one of the following is not a native element? (2pt)
 Gold
 Diamond
 Silver
 Quartz
7) Ferromagnesian silicates contain magnetite and ferroite and they are clear to light green (2pt)
a) True
b) False
8) What is explored when a mineral is mechanical impacted? (2pt)
A) luster B) cleavage C) streak
D) crystal form
9) Specific gravity of a mineral is related to the atomic structure of the mineral. (2pt)
a) True
b) False
10) Which minerals are formed first in the Bowen’s Reaction Series? (2pt)
a) Minerals of Felsic Rocks
b) Minerals of Mafic Rocks
11) Which of the following minerals crystallize among the last in Bowen's reaction series? (2pt)
A) biotite
B) quartz
C) olivine
D) muscovite
12) Which one of the mineral characteristics is related to its engineering properties? (2pt)
A) luster
B) cleavage
C) streak
D) crystal form
PROBLEM 3 (30 Marks)
1)
2)
3)
4)
5)
6)
7)
8)
9)
10)
11)
12)
13)
a)
b)
c)
d)
What is the dominant mineral in Felsic rocks? (2pt)
SiO2
Igeneous rocks formed from Magma at depth are called __intrusive (plutonic)_rocks. (2pt)
Obsidian has a __glassy___ texture. (2pt)
Which of the physical properties can be similar between Granitic and Basaltic rocks? (2pt)
a) Color
b) texture
c) composition
Match the rock types to rocks below? (4pt)
Granitic
Andesitic
Basaltic
Diorite
Rhyolite
Gabbro
Ferromagnesian silicates contain magnetite and ferroite and they are dark in color. (2pt)
a) True
b) False
Obsidian has a _____glassy___ texture. (2pt)
Granitic rocks are termed as mafic and they are rich in (magnesium and ferrum, for iron) in
composition. (2pt)
a) True
b) False
Which of the following is not fine grained? (2pt)
a) Rhyolite
b) Andesite
c) Basalt
d) Granite
Most abundant rock type in oceanic crust is __Gabbro__. (2pt)
If an igneous rock has phenaritic texture, the origin can be presumed to be volcanic. (2pt)
a) True
b) False
Which of the following criteria is not used to classify the igneous rocks? (2pt)
a) Composition
b) Texture
c) Color
d) Hardness
Which is not one of Wegener's lines of evidence? (4pt)
The same rock types formed under different climatic conditions support the fact that they were one
together.
Earth's crust is thicker under continents.
The structural trends, mountain belts and rock types in different pieces of this puzzle are continuous.
Fossil evidences found connecting pieces also support that they were together once.
PROBLEM 4 (20 Marks)
1) The most important depositional feature in sedimentary rocks is ____Bedding__. (4pt)
2) Clastic sedimentary rocks are named based on ____________ (2pt)
a) mineral content
b) grain size
c) crystal shape
3) Names of three bedding types: (4pt)
parallel, cross and graded
4) Summarize the steps that take place prior to lithification: (4pt)
weatering-erosion-transportation-deposition
5) Shale is a clastic rock. (3pt)
a) True
b) False
6) Limestone is an evaporitic rock. (3pt)
a) True
b) False