Structural Geology

Geology 3263

Structural Geology

Homework 1

Name ______

Homework is not graded. It serves as a partial topic review for Quizzes and Tests. Look in your books, the internet, confer with your classmates, etc.

THIS ONE IS JUST A CHECK. I want to get a feel for what each student was taught in their Introduction to Geology course.

A. Mixed Format

1. In a breccia, the coarse particles are (choose: angular / rounded) .

2. A rounded grain of quartz greater than 0.0625 mm and less than 2mm would be a (choose one: mud particle, grain of sand, pebble)

3. Salt, Gypsum and other chemical sediments that form when a body of water dries up are called (choose: halogens / alluvium / evaporites)

5. In ______bedding, the coarsest grains settle to the bottom first, and grain size decreases gradually toward the top of a layer.

6. Pyroclastic materials that cool and solidify from lava ejected into the atmosphere are called ______.

5. When basaltic lava erupts beneath the sea, it forms a ______structure.

6. A volcano with a composite cone has layers of ______and layers of pyroclastic material within the cone.

B. Match the terms

1. Gabbro ____ a. intermediate silica content

2. Andesite _____ b. coarse grain basaltic

3. Rhyolite _____ c. fine grain granitic

4. Fine-grained texture ____ d. cooled rapidly

C. True or False.

1. The San Andreas Fault is an example of a transform boundary. True or False?

2. Water driven out of a subducting ocean plate causes partial melting in the nearby mantle. The magma that may rise to form volcanoes. True or False?

3. The Himalayan Mountains are an example of a collisional boundary. True or False?

4. When a solid is heated it contracts. True or False?

5. The Andes Mountains are an example of volcanic mountains that formed above a subduction zone. True or False?

6. Smaller plutonic features, such as dikes, generally appear in divergent (rifting) zones. True or False?

7. Oceanic rocks carried by subduction down into the aesthenosphere lose their water, which flows out to surrounding mantle. The mantle can partially melt; this process can generate vast quantities of magma. True or False?

8. Solid rocks that form deep in the Earth's interior may be raised to shallower levels during a continental collision. True or False?

D. Multiple Choice

1) The Great Rift Valley of East Africa contains:

a. divergent plate boundaries

b. basalt rock from lava flows

c. stream and lake sediments

d. All of the above

2) The Triassic and Jurassic lowlands of New Jersey:

a. are the western margin of the rift that opened the Atlantic

b. contain the same rocks and fossils as similar rocks in Morocco

c. contain red shales with occasional dinosaur footprints

d. contain basalt rock formed from lava flows in a rift valley

e. All of the above

3) The Appalacians and other great mountain ranges contain:

a) Divergent plate boundaries

b) Convergent plate boundaries

c) Transform plate boundaries

4) The San Andreas Fault contains:

a) Divergent plate boundaries

b) Convergent plate boundaries

c) Transform plate boundaries

5) The most abundant rock-forming minerals in the lithosphere are

a. Pyrite, Galena, Sphalerite, Halite, Gypsum, Anhydrite

b. Quartz, Feldspars, Micas, Amphiboles, Pyroxenes, Olivine

c. Wulfenite, Franklinite, Zincite, Andalucite, Pyrope

d. All of the above

6. The most important factor controlling igneous rock texture is

a. The composition of the parent magma

b. The rate of cooling of the magma

c. The amount of magma available

d. The amount of pressure on the magma

7. In divergent (MOR, rift) margins, the magmas that rise are typically

a. silica poor (basaltic a.k.a. mafic)

b. silica rich (granitic a.k.a. felsic)

c. intermediate in silica content

8. The term viscosity refers to:

(a) how heat and pressure influence volatiles.

(b) resistance to flow.

9. Which one of the following sedimentary sequences records regression?

a) shale overlain by quartz-rich sandstone with an eroded top

b) Fine sand overlain by abyssal calcareous ooze.

c) Quartz-rich sandstone overlain by shale.

d) all of the above

9) Nappes are:

(a) non-marine foreland basin deposits accompanying the uplift of a mountain belt.

(b) a large body of rocks that has been moved by thrust faulting, often with recumbent folding

10) Flysch is:

(a) non-marine foreland basin deposits accompanying the uplift of a mountain belt.

(b) a large body of rocks that has been moved by thrust faulting, often with recumbent folding

11) Molasse is:

(a) non-marine foreland basin deposits accompanying the uplift of a mountain belt.

(b) a large body of rocks that has been moved by thrust faulting, often with recumbent folding

The Catskill Delta

12) Fossil 1 is a:

(a) brachiopod

(b) crinoid

(d) trilobite

13) If you found fossil 1, you would be certain the

sediments containing it formed in the

(a) Cenozoic

(b) Mesozoic

(d) Precambrian

14) Fossil 2 is a:

(a) brachiopod

(b) crinoid

(d) trilobite

E. Mixed Format

1) On a topographic map, contours mark

lines of equal elevation. True or False?

2) This photograph, taken by Kean University student Andrew Stockum, shows Mt. Vesuvius, near Pompeii and Herculaneum, and east of Naples, Italy. It sits above a subduction zone. Its lavas and tephra are most likely:

a) Basaltic

b) Andesitic

c) Rhyolitic

3) Next to pictures A, B and C, write a corresponding example. Choose from Himalayas, Cascades, and Japan (You must get all three correct)

4) These folds, visible in a hillside, are (choose one: overturned/recumbent)

5) These folds viewed from space are show plunging folds in the Appalachians. This very severe folding was probably due to the (choose: Taconic / Acadian / Allegheny ) Orogeny.

6) Above is a cross-section from a geologic map. Rocks marked O are Ordovician, rocks marked Y are Precambrian.

Which came first (choose one: folding of Ordovician rocks/ a thrust fault)

7) Below is a cross-section from a geologic map. Rocks marked lP are Pennsylvanian, rocks marked P are Permian, rocks marked TR are Triassic,

J Jurassic and K are Cretaceous.

Questions: a. Which came first (choose one: folding of Pennsylvanian through Cretaceous rocks/ the fault)?

b. This is a (choose one: Normal Fault/Reverse Fault/Transform Fault)

8) The cross-section below is from a geologic map. Rocks marked J are Jurassic, K Cretaceous, and Q Quaternary.

Question: In the cross-section, the fault is younger than the Jurassic rocks and the Cretaceous layer marked Kd. True or False?

9) There are ______degrees in a circle, ______minutes in a degree, and ___ seconds in a minute.

10) An arc of half a minute is equal to ______seconds.

11) Which event is younger? (Circle one: the Sevier Orogeny or the Nevadan Orogeny).

12) The mid-ocean ridge separating the Farallon and Pacific plates was subducted during the Cenozoic. True or False?

13) The mid-ocean ridges are made of rocks that are warmed by heat transferred from the mantle below. This heating causes them to expand, and sea-level rises.

Question: During the Cretaceous, the Atlantic mid-ocean ridges were so large that shallow seas covered the interior of North America. True or False?

14) Hot rising mantle rock loses its heat to the lithosphere above. It is forced aside by hotter mantle rock rising from below. The mantle rock spreads out, pulling the lithosphere apart. This causes the lithosphere to crack. The cracks let in water and low pressure, and some mantle minerals ______, forming a new magma body. The new material fills in the cracks in the lithosphere, forming new ocean floor.

15) New ocean floor is made of granite. True or False?

16) When mantle material under the lithosphere cools, it sinks back into the earth's interior, pulling dense ocean lithosphere down with it, forming a subduction zone. True or False?

17) Fact: New ocean floor lava is lumpy, with lots of spaces filled with wet sediment between the lavas. In a subduction zone, water is squeezed out at great depth. The nearby mantle is exposed to water, and partially melts, despite the great pressure.

Question: These melts form new buoyant magmas that can rise to form huge plutons (such as batholiths) deep underground and, if they reach the surface, volcanoes. True or False?

18) During the Nevadan Orogeny, a volcanic arc formed on the west coast of North America. All that remains are the deep batholiths under the arc: huge blobs of magma that cool deep in the Earth.

Question: Batholiths are often made of granite. True or False?

19) When microplates rifted from Africa collided with southern Europe the (choose: Alps / Himalayas / Appalachians) formed.

20) When India collided with Asia the (choose: Alps / Himalayas / Appalachians) formed.