geol 2 mid term i · 2016-03-20 · geol 2: historical geology with lab mid‐term i 3 | page (24)...

GEOL 2: Historical Geology with Lab Mid‐Term I

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Name: ________________________________________________________ Date: _____________ (1) 1 pt. A ________ is a well‐tested and widely accepted view that best explains certain scientific observations. A) law B) hypothesis C) generalization D) theory (2) 1 pt. The currently accepted age of the Earth is ________ years. A) 4.6 billion B) 4.6 thousand C) 6.4 million D) 6.4 trillion (3) 1 pt. Sedimentary rocks that are dipping at an angle A) were always that way. B) have been uplifted/deformed tectonically. C) are younger than the fault that cut them. D) are older than the fault that cut them. E) A & B F) B & C G) B & D (4) 1 pt. What happens to oceanic crust as it gets older, in the correct order? A) crust cools, becomes more dense, and sinks B) crust becomes more dense and sinks C) crust gets more dense, cools, and rises D) crust heats, becomes less dense, and rises (5) 1 pt. Oceanic crust rock composition is ____ and Continental crust rock composition is _____. A) mafic, felsic B) felsic, mafic C) algic, felsic D) mafic, algic (6) 1 pt. Which is the most dense? A) continental crust B) oceanic crust C) core D) mantle (7) 1 pt. Which is the least dense? A) continental crust B) oceanic crust C) core D) mantle (8) 1 pt. In correct order from the center outward, Earth includes which units? A) inner core, crust, mantle, hydrosphere B) core, crust, mantle, hydrosphere C) core, inner mantle, outer mantle, crust D) inner core, outer core, mantle, crust (9) 1 pt. Which of the following best defines a mineral and a rock? A) A rock has an orderly, repetitive, geometrical, internal arrangement of minerals; a mineral is a lithified or consolidated aggregate of rocks. B) A mineral consists of its constituent atoms arranged in a geometrically repetitive structure; in a rock, the atoms are randomly bonded without any geometric pattern. C) In a mineral the constituent atoms are bonded in a regular, repetitive, internal structure; a rock is a lithified or consolidated aggregate of different mineral grains. D) A rock consists of atoms bonded in a regular, geometrically predictable arrangement; a mineral is a consolidated aggregate of different rock particles. (10) 1 pt. A(n) ________ texture represents a single, long period of cooling and crystallization. A) glassy B) pyroclastic C) aphanitic D) phaneritic (11) 1 pt. Which one of the following shows the correct order (left to right) of decreasing magma viscosity? A) rhyolite, andesite, basalt B) andesite, rhyolite, basalt C) basalt, rhyolite, andesite D) basalt, andesite, rhyolite


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(12) 1 pt. Which of the following best describes an aphanitic texture? A) The rock is crystalline; mineral grains are too small to be visible without a magnifying lens or microscope. B) The mineral grains have glassy textures. C) The rock consists of broken, volcanic‐rock and mineral fragments. D) The rock is crystalline; mineral grains are of distinctly different sizes. (13) 1 pt. Extrusive igneous rocks are typically finer grained than intrusive igneous rocks. Why? A) Intrusive magma is cooler because it is well insulated by the surrounding rock. B) Intrusive magma flows onto the Earth's surface and cools very slowly, allowing many small mineral grains to grow. C) The extrusive magma cools quickly so the mineral grains do not have time to grow. D) The extrusive magma, because it is deep below the surface, cools very slowly producing very small mineral grains. (14) 1 pt. Which of the following describes the light reflecting characteristics of a mineral? A) luster B) color streak C) virtual absorption D) fluorescence (15) 1 pt. The strong tendency of certain minerals to break along smooth, parallel planes is known as: A) streak B) cleavage C) cracking luster D) crystal form (16) 1 pt. All silicate minerals contain ________ and ________. A) iron; silicon B) silicon; sodium C) oxygen; carbon D) silicon; oxygen (17) 1 pt. The ion at the center of a silicate tetrahedron is surrounded by ________. A) 4 oxygen ions B) 6 oxygen ions C) 4 sodium ions D) 6 sodium ions (18) 1 pt. Which one of the following is a sodium and calcium feldspar with striations? A) orthoclase B) microcline C) plagioclase (19) 1 pt. Which of the following minerals is a ferromagnesian silicate? A) quartz B) orthoclase C) hornblende D) muscovite (20) 1 pt. Which of the following minerals is in the mineral group known as mica? A) orthoclase B) muscovite C) augite D) olivine (21) 1 pt. The sizes, shapes, and arrangements of mineral grains in an igneous rock are known as ________. A) silica content B) texture C) mineral content D) Bowen's reaction series (22) 1 pt. A ________ is an open cavity in a volcanic rock that was filled by a gas bubble when the lava was still mainly liquid. A) porphyrocryst B) vesicle C) phenocryst (23) 1 pt. Detrital sedimentary rocks are classified (named) based on the ________. A) colors of the cementing minerals B) grain sizes of the detrital particles C) compositions of soluble minerals D) degree of compaction and lithification


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(24) 1 pt. What is the main difference between a conglomerate and a sedimentary breccia? A) Breccia clasts are angular; conglomerate clasts are rounded. B) A breccia is well stratified; a conglomerate is poorly stratified. C) Breccia clasts are the size of baseballs; conglomerate clasts are larger. D) Breccia has a compacted, clay‐rich matrix; conglomerate has no matrix. (25) 1 pt. ________ is a strong, parallel alignment of coarse mica flakes and/or of different mineral bands in a metamorphic rock. A) Rock cleavage B) Foliation C) Stress streaking D) Marbleizing For the following 3 questions, use the figure below. (26) 1 pt. Which type of volcano erupts with lava low in Si? A) L B) N C) O D) J (27) 1 pt. Which has the form of a stratovolcano? A) J B) K C) O D) N (28) 1 pt. Which type of volcano is the source for the Columbia River Flood Basalts? A) N B) J C) L D) O (29) 1 pt. Which volcano type is associated with the correct rock? A) fissure flow – rhyolite B) shield volcano – granite C) caldera – basalt D) shield volcano – basalt (30) 1 pt. In the figure below, match the letter L and M with the correct level of sorting. A) L = poorly sorted, M = well sorted B) L = not sorted, M = well sorted C) L = well sorted, M = poorly sorted


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(31) 1 pt. In the figure at the right, match the letter J and K with the correct description A) J = transported a long distance, K = transported a short distance B) J = transported a short distance, K = transported a long distance C) J = time transported, K = transported a short distance (32) 1 pt. Linear, magnetic patterns associated with mid‐ocean ridges are configured as ________. A) reversed magnetizations along the rift valleys and normal magnetizations along the ridge B) normal and reversed magnetized strips roughly parallel to the ridge C) normal and reversed magnetized strips roughly perpendicular to the ridge axis D) concentric circles about a rising plume of hot mantle rocks and magma (33) 1 pt. An unconformity is a buried ________. A) surface of erosion separating younger strata above from older strata below B) fault or fracture with younger strata above and older strata below C) surface of erosion with older strata above and younger strata below D) fault or fracture with older rocks above and younger rocks below (34) 1 pt. Visualize five horizontal sedimentary strata exposed in a cliff or canyon wall identified by consecutive numbers, 1 being the lowest bed and 5 being the highest. Which of the following statements concerning the strata are TRUE? A) bed 5 is the oldest B) bed 3 is older than beds 2 and 4 C) beds l and 3 are older than bed 4 D) bed 4 is older than bed 2 (35) 1 pt. ________ is an erosional contact between tilted, older strata below and horizontal, younger strata above. A) A disconformity B) Cross cutting C) An angular unconformity D) Inverse bedding (36) 1 pt. Sandstone strata and a mass of granite are observed to be in contact. Which of the following statements is correct geologically? A) The sandstone is younger if it shows evidence of contact metamorphism. B) The granite is older if it contains inclusions of sandstone. C) The granite is older if the sandstone contains pebbles of the granite. D) The sandstone is younger if the granite contains sandstone inclusions. (37) 1 pt. What fundamental concept states that in a horizontal sequence of conformable sedimentary strata, each higher bed is younger than the bed below it? A) theory of correlative deposition B) law of original correlation C) law of superposition D) theory of superstition


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The following 7 questions refer to the following diagram:

(38) 1 pt. Which is younger (more recent)? A) the fault or B) Rhyolite Dike B (39) 1 pt. Which is younger? A) the Haephest Granite or B) Rhyolite Dike B (40) 1 pt. Which is younger? A) the Leif Limestone or B) the Dink‐Dink Sandstone (41) 1 pt. Which is younger? A) the Dink‐Dink Sandstone or B) the Plainview Shale (42) 1 pt. Which is younger? A) Rhyolite Dike A or B) the Killarney Limestone? (43) 1 pt. Which is younger A) Rhyolite Dike A or B) the Haephest Granite (44) 4 pts. Radiometric ages indicate that the Haephest Granite is 85 million years old and Rhyolite Dike A is 30 million years old. a) What can you say about the age of Rhyolite Dike C? A) Rhyolite Dike C is older than 85 million years. B) Rhyolite Dike C is younger than 30 million yrs. C) We cannot tell how old Rhyolite Dike C is. D) Rhyolite Dike C is older than 30 million yrs.


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b) What can you say about the age of the Kings Sandstone? A) Kings Sandstone is older than 85 million yrs. B) Kings Sandstone is younger than 30 million yrs. C) We cannot tell how old Kings Sandstone is. D) Kings Sandstone is older than 30 million yrs. (45) 1 pt. The half‐life of carbon‐14 is about 6000 years. Assume that a sample of charcoal formed by burning of living wood 15,000 years ago. How much of the original carbon‐14 would remain today? A) between 33% and 50% B) between 25% and 50% C) more than 50% D) between 12.5% and 25% (46) 4 pts. In the chart of radioactive decay shown at the right: (a) how many half‐lives have elapsed by this time? _____ (b) how many half‐lives have elapsed by this time? _____ (47) 1 pt. The youngest seafloor rocks are found: A) nearest to the mid‐ocean ridges B) nearest to the continental shelves C) evenly distributed throughout the ocean D) underneath the continents E) where the ocean is the flattest (48) 1 pt. Pull‐apart rift zones are generally associated with a ________ plate boundary. A) convergent B) divergent C) transform D) all plate boundaries (49) 1 pt. The volcanoes and deep valleys of east Africa are related to a ________. A) continental collision zone between Africa and the Zagros Mountains along the southern margin of Eurasia B) transform fault aligned with the Red Sea carrying the Arabian and African blocks in opposite directions C) continental rift along which parts of the African continent are beginning to slowly separate D) fault allowing Arabia to slip westward past east Africa and penetrate into Turkey (50) 1 pt. The ________ is an example of an active, continent‐continent collision. A) westward movement of the South American plate over the Nazca plate B) Arabian Peninsula slamming into North Africa under the Red Sea C) northern movement of Baja California and a sliver of western California toward the Hawaiian Islands D) northward movement of India into Eurasia (512) 4 pts. Sample #A‐1

(a) Describe the distinguishing properties of the mineral: (b) List the mineral name: __________________________________________


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(52) 4 pts. Sample #A‐3

(a) Is this rock intrusive or extrusive? _________ Explain the basis for you answer: (b) List the igneous rock name: __________________________________________


(a) Describe the distinguishing properties of the mineral: (b) List the mineral name: __________________________________________


(a) Is this rock intrusive or extrusive? _________ Explain the basis for you answer: (b) List the igneous rock name: __________________________________________

For the following samples numbers, name the rock and provide at least one characteristic that justifies your interpretation. Also, for some samples, designate how sorted the sediment is (e.g. sorting). (55) 3 pts. Sample B‐1: (56) 3 pts. Sample B‐3: (57) 3 pts. Sample B‐4: (58) 3 pts. Sample B‐5: (58) 3 pts. Sample B‐10: (59) 3 pts. Sample B‐11:

Analyze each fossil specimens (samples 1 through 15) and assign the specimen to one of the taxonomic

classifications below.

Phylum Porifera (including Archaeocyathids)


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Phylum Cnidaria,

Class Anthozoa

Rugose (Order Rugosa)

Tabulate (Order Tabulata)

Scleractinian (Order Scleractinia)

Phylum Bryozoa

Phylum Brachiopoda

Phylum Mollusca

Class Bivalvia

Class Gastropoda

Class Cephalopoda – Subclass Ammonoidea

Class Cephalopoda ‐ Order Belemnitida (Belemnites)

Phylum Arthropoda

Class Trilobita

Class Crustacea

Phylum Echinodermata

Class Crinoidea

Class Echinoidea

(60) 10 pts. (2 pts. each)

1.

2.

3.

4.

5.

geol 2 mid term i · 2016-03-20 · geol 2: historical geology with lab mid‐term i 3 | page (24)...

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