Medium- To Long Answers (5 pts. each)

1. Why do we not have a detailed time scale for the Precambrian? (Why is it not divided like the Phanerozoic?)

2. You are a highway engineer, so you are digging into mountains to make road cuts. In Kendall County, you find a layer of sandstone covered by a layer of siltstone, and then covered by a conglomerate. Next door, in Baker County, you find the same sandstone and conglomerate (you know they are the same because they contain the same fossils), but the intermediate siltstone is missing. Give two explanations how this can be?

3. During some periods of geologic time sea level has been higher than it is today. During other periods of geologic time it has been lower than it is today. Why? How does this happen?

4. Define base level. What is the base level of the Red River?

5. When metamorphosed, some rocks undergo mineralogical changes. Other rocks never seem to change mineralogy no matter how much pressure and temperature they feel. Why the difference?

Multiple Choice (2 pts. each)

1. The radioactive isotopes of uranium and thorium eventually decay to

a. iron     b. argon     c. strontium d    . lead

2. Which answer best characterizes an angular uncomformity?
a. tilted strata lie below the uncomformity; bedding in younger strata above is parallel to the uncomformity
b. horizontal lava flows lie below the uncomformity and horizontal, sedimentary strata lie above
c. the uncomformity is between a granite, or other plutonic rock, and overlying sedimentary strata

3. Which two time-scale period names used in North America are combined into the Carboniferous period in Europe and elsewhere?
a. Triassic, Jurassic                 c. Cambrian, Ordovician
b. Permian, Pennsylvanian    d. Mississippian; Pennsylvanian

4. What fundamental principle states that in a horizontal sequence of conformable strata, each higher bed is younger than the bed below it?
a. law of original correlation   c. theory of correlative deposition
b. law of superposition           d. superstitious theory

5. What is the main focus of paleontology?
a. fossils and evidence of ancient life forms
b. sedimentary rocks and their environments of deposition
c. absolute age determinations on minerals from igneous rocks
d. deformed strata that were once horizontal

6. What is an essential characteristic of an index fossil?
a. the organism live in only specific environments such as beaches or estuaries
b. the organism only lived for a short period of geologicaltime
c. the fossils are exceptionally abundant and well preserved
d. the fossils are rare and difficult to find.

7. Humans have been around on the order of 4,600 years. What fraction of the history of the Earth does this represent?
a. 1/10,000                 c. 1/1,000,000
b. 1/1,000,000,000    d. 1/100,000

8. Which rock forms at the highest grade of regional metamorphism?
a. hornfels      b. schist      c. slate      d. phyllite

9. Which metamorphic rock is really partly an igneous rock since it forms by partial melting?
a. magnetite      b. magma      c. migmatite      d. mangerite

10. Which of these descriptions best describes the conditions of contact metamorphism?
a. pressures are high; deep in the Earth; heat comes from inside Earth
b. pressures are low; upper part of crust; heat comes from nearby magma
c. depths are shallow, but pressures and temperatures are so high that rocks begin to melt
d. heat and pressure come from shearing and faulting along major fault zones

11. Which metamorphic rocks are composed predominantly of a single mineral?
a. garnet schist and hornfels      c. schist and granitic gneiss
b. marble and quartzite                d. phyllite and amphibolite

12. Which response has rocks in the correct order from (left to right) low-grade and fine grain size to high-grade and coarse grain size?

a. slate=>phyllite=>schist      c. phyllite=>slate=>schist
b. schist=>slate=>phyllite      d. slate=>schist=>phyllite

13. As progressive metamorphism occurs
a. hydrous mineral break down to produce lower grade minerals
b. retrograde metamorphism takes place
c. hydrous minerals react to produce higher grade minerals
d. carbonates react to produce quartz and other oxides

14. What term describes the zone of contact metamorphism around an intrusion?
a. pluton      b. shear zone      c. migmatite      d. aureole

15. If a metamorphic rock contains lots of carbonate minerals, what was it before it was metamorphosed?
a. quartzite      b. shale or mudstone       c. a plutonic rock       d. limestone or dolostone

16. Which process is NOT part of the hydrologic cycle?
a. water evaporating from lakes or streams
b. water infiltrating into the soil or bedrock
c. calcium carbonate dissolving in soil water and groundwater
d. water moving into creeks and streams following a rainstorm

17. Which must result in a lower base level for rivers and streams?
a. sea level drops or land subsides
b. sea level rises or land subsides
c. sea level falls or land rises
d. sea level rises or land rises

18. Which constituents make up the suspended load of most streams and rivers?
a. dissolved ions and sand      b. dissolved salts      c. silt and clay      d. sand and gravel

19. A the head of a delta, the major channel splits into many ____________.
a. estuaries      b. distributaries      c. tributaries       d. dendrites

20. The Green River, and some others of the Colorado Plateau, are characterized by incised meanders. How did this happen?
a. original, youthful streams continued to downcut as the land rose
b. original, old-age streams downcut as the land gradually rose
c. as sea level dropped, the original youthful streams matured into old-age streams
d. as sea level rose, the original old-age streams were rejuvenated

21. Which is the only correct response concerning the location and causes of the extraordinarily severe, 1993, flooding on the Mississippi River and tributaries?
a. in the lower basin there were heavy rains in late spring and early summer
b. in the upper basin there was rapid melting of an unusually dep snow pack in early spring
c. in the lower basin there were very heavy late summer rains associated with a severe hurricane
d. in the upper basin there was very heavy, sustained rainfall in the late spring and early summer

22. Which river has the largest discharge in the world?
a. Nile      b. Amazon       c. Congo      d. Red e. Mississippi

23. Which component is generally greatest over an entire year for a stream?
a. bed load       b. dissolved load       c. suspended load       d. saltating load

24. Where is erosion concentrated along a meandering stream?
a. on the straight parts of the channel
b. on the outer parts of the meander loops
c. on the inner parts of the meander loops
d. on the river's bottom

25. The Appalachians of Pennsylvania include several long, parallel, mountain ridges. So, the river drainage pattern is
a. dendritic      b. polygonal       c. circular       d. trellis

Matching (1 pt. each)

For questions 1-9, use the answers below; put answer in "(____)":

a. gradient           d. alluvial fan                    g. graded stream
b. stalagmite        e. infiltration                     h. capacity
c. stalactite           f. evapotranspiration       i. runoff

1. (____) a fan-shaped deposit of sediment formed when a stream's slope is abruptly reduced
2. (____) the icicle-like formation that may hang from the ceiling of a cave
3. (____) the amount of water that a stream can carry without leaving its banks
4. (____) the movement of surface water into the subsurface
5. (____) describing a situation in which erosion and deposition are equal
6. (____) the flow of water downslope across the land
7. (____) the slope of a stream; generally expressed as vertical drop over a fixed distance
8. (____) the loss of water from land, or plants on land, to the atmosphere
9. (____) the column-like formation that grows upwards from a cave floor

For questions 10-15, use the answers below:

a. schist       c. marble       e. gneiss
b. phyllite   d. slate           f. hornfels

10. (____) calcite rich and nonfoliated
11. (____) represents a grade of metamorphism between slate and schist
12. (____) very fine grained and foliated; excellent rock cleavage
13. (____) foliated and composed of more than 50% easily seen platy minerals
14. (____) often composed of alternating bands of light and dark silicate minerals
15. (____) Hard, nonfoliated, a result of contact metamorphism

True-False (circle "T" or "F")

T F 1. Gradients usually decrease downstream in a major river system
T F 2. Artesian wells require pumping to produce water
T F 3. Rapids and waterfalls are characteristic of laterally cutting streams
T F 4. A stream flowing out from a lake cannot downcut below the water surface elevation of the lake
T F 5. With passing time, deposition and erosion gradually shorten the channel length of a meander loop
T F 6. Calcite is the main mineral in most limestones AND in most marbles.
T F 7. High-grade, regional metamorphism produces significant and recognizable changes in textures and minerals in most kinds of rocks.
T F 8. Metamorphic facies are specific regions of pressure-temperature space.
T F 9. The geological time scale was devised BEFORE absolute dating using radioactivity was invented.
T F 10. After three half lives, 1/9 of an original, radioactive, parent isotope remains and 8/9 has decayed to the daughter isotope.
T F 11. The term Paleozoic describes the era of ancient life forms.
T F 12. The Paleocene is the oldest epoch of the Tertiary Period.