Geology Final (All tests combined)

The lithosphere rides on top of the asthenosphere, but can NOT penetrate the asthenosphere at subduction zones because it is too RIGID.

Based on the Plate Tectonics Theory, the Earth's lithosphere is broken up into approximately a dozen pieces of large plates. Which one of the following statements is FALSE about the Plate Tectonics Theory? A. Lithosphere is the outer rigid shell of the Earth. The dozen pieces of the large plates are composed of the crust and part of the upper mantle B. Asthenosphere is part of the mantle beneath the lithosphere (to ~400km in depth) C. The Plate Tectonics Theory is a Unify Theory in Geology like Evolution by Natural Selection in Biology. D. The lithosphere rides on top of the asthenosphere, but can NOT penetrate the astenosphere at subduction zones because it is too RIGID. (Answer giving only the name, don't give the letter.)

a few cm to ten cm

Based on the Plate Tectonics Theory, the Earth's surface is covered by a dozen big plates. These plates are moving at an averaged speed of approximately __________ a year.

more mafic

Bowen's reaction series tells us that mafic minerals such as olivine and pyroxene crystallize from the magma chamber at higher temperatures than felsic minerals such as K-feldspar and quartz. If a magma undergoes fractional crystallization during cooling, the crystallized materials (crystals) will be __________ than the remaining magma.

6 protons and varying numbers of neutrons

Carbon has an atomic number of 6 and an atomic mass of 12.011. The atomic mass (weight) is the sum of the number of protons and the number of neutrons in the nucleus. We also know that carbon has a number of isotopes. These statements mean that carbon atoms have __________.

quartz

Cleavage is formed because of the tendency of the mineral to break along a flat planar surface to produce geometric patterns. For example, layer silicates tend to break between silica layers as the bonding between the layers is weaker. Therefore, cleavage can be a useful piece of information in identifying minerals. Which of the following minerals does NOT exhibit cleavage because of its structural characters? A. amphibole B. pyroxene C. mica D. quartz (Answer giving only the name, don't give the letter.)

lighter, thicker

Continental and oceanic crusts cover the Earth's crustal surface. The continental crust is __________ than the oceanic crust.

slate, schist, gneiss, migmatite

Foliated metamorphic rocks are classified by the nature of their foliation, crystal size, and segregation of minerals that are all related to the metamorphic grade. Which one of the following orders has an increased intensity of metamorphism? A. slate, schist, gneiss, migmatite B. slate, migmatite, schist, gneiss C. migmatite, schist, gneiss, slate D. migmatite, gneiss, schist, slate (Answer giving only the name, don't give the letter.)

Limestone

Foraminifera, coral, and mollusks all secrete carbonate CaCO3 for protection. What is the dominant sedimentary rock lithified from carbonate sediments?

geologic processes we observe today have operated in the past

Geologist have used the principle of uniformitarianism to understand geological activities preserved in the rock records. According to the principle of uniformitarianism __________.

the rock cycle

Igneous, metamorphic, and sedimentary rocks are the three rock types we have discussed in the class. The concept that identifies that the three basic groups of rocks are all related is called ___________.

increasing pressure and increasing temperature

Lithification in sedimentary rocks include burial, compaction, and cementation. Burial of sediments results in __________.

the Earth's north and south poles flip

Magnetic mapping of the ocean floor revealed a pattern of symmetric "stripes" with alternating polarity, centered along the mid-ocean ridges. These indicate the magnetic reversals of the Earth's magnetic field when __________.

Spreading Center (Mid-Atlantic Ridge)

Mantle upwelling in response to the plate pulling-apart at spreading (divergent) ridges results in decompression melting of the upper mantle peridotite. Partial melting of an ultamafic rock at high temperatures results in melting of mafic minerals with a basaltic composition. In which tectonic setting are you most likely to find abundant basaltic volcanism as a result of the mantle upwelling?

All of the above

Melting occurs when a solid (rock) becomes a liquid (melt; magma). There are a number of pressure, temperature, and compositional conditions that can cause a rock to melt. Which one of the following conditions can cause a rock to melt in the Earth's deep interior? A. addition of volatiles such as water into the rock B. decompression (a decrease in pressure) C. an increase in temperature D. all of the above (Answer giving only the name, don't give the letter.)

continental collisions in plate boundaries where pressure and temperature are high (such as the Himalayas)

Metamorphic Grade refers to the intensity of metamorphism in the formation of metamorphic rocks. Where would you expect to find higher-grade metamorphic rocks?

Suites of minerals

Metamorphic facies are indicative of particular tectonic environments, and can therfore be clues to the (pressure and temperature) history of the rock. Geologists define the metamorphic facies by __________.

Glass

Mineral Definition: A naturally occurring, inorganic element or compound, having an orderly internal structure, and characteristic chemical composition, crystal form, and physical properties. Based on the definition, which of the following substances is NOT considered a mineral? A. Glass B. A natural diamond from a jewelery store C. Quartz D. Olivine (Answer giving only the name, don't give the letter.)

isochrons; ages

On a map of the seafloor such as the Atlantic oceanic crust, the boundaries between normally magnetized oceanic crust and reversely magnetized oceanic crust are called __________ because the represent the same __________ of the rocks.

diamond, graphite

Polymorphism means "many forms." In mineralogy it means that a single chemical composition can exist with two or more different crystal structures; however, each of the structures is only stable at certain pressure and temperature conditions. __________ and __________ are examples of polymorphs.

at or near the Earth's surface

Sedimentary rocks provide a record of ancient tectonic events (e.g. mountain building and erosion), fossil record and evolution of life, the history of the past climate changes, among others. They are commonly found on the Earth's surface because sedimentary processes take place __________.

inner core, outer core, mantle, crust

Seismic studies of the Earth have shown that the planet's interior is made of a few layers with distinct seismic signatures and chemical compositions. The major layers of the planet include (from innermost to the outer most layers) __________.

framework

Silicate minerals are very abundant in igneous rocks, and some silicates contain more SiO2 (or SiO4 tetrahedra) than others. Felsic igneous rocks contain abundant ________ silicate minerals.

pyroxene

Silicate minerals commonly exist in igneous rocks and can be used to classify the compositions of the igneous rocks. Which of the following silicate minerals is commonly found in mafic igneous rocks? A. biotite B. orthoclase feldspar C. pyroxene D. quartz (Answer giving only the name, don't give the letter.)

Both grain size and foliation coarseness increase

Texture (foliation), crystal size, and index minerals can all be used to classify the intensity of metamorphism. How do crystal size and foliation change with increasing intensity of metamorphism?

mafic

The Earth's upper mantle is mainly made of peridotite, an ultramafic igneous rock with lots of olivine crystals. What type of magma forms when the upper mantle undergoes decompression melting at mid-ocean ridges?

at a hot spot (in the intraplate)

The Hawaiian islands are very far away from the continents, but there are active volcanoes in the region. These islands were formed __________ over a period of geological times.

Based on the principle, young rocks are buried under old rocks

The Principle of Original Horizontality was proposed by the Danish geological pioneer Nicholas Steno (1638-1686). The Principle is commonly used in studying sedimentary rocks. Which one of the following statements about the principle is FALSE? A. Gravity is the main driving force in the principle. B. based on the principle, young rocks are buried under old rocks C. the principle is important to the analysis of folded and tilted strata D. the principle states that layers of sediment are originally deposited horizontally under the action of gravity. (Answer giving only the name, don't give the letter.)

Pyroxene is a single-chain silicate and has the chemical fomula of (Mg,Fe)2SiO4

The basic building blocks to all silicates are the SiO4 tetrahedra that are linked in a variety of ways in three dimensions. Which one of the following statements about major silicate minerals is FALSE? A. Olivine is an abundant mineral of the upper mantle and is formed through the isolated SiO4 tetrahedra B. Mica group minerals such as biotite and muscovite are called sheet silicates because they are formed by layered SiO4 tetrahedra. C. Quartz and feldspar are all framework silicates D. Pyroxene is a single-chain cilicate and has the chemical formula of (Mg,Fe)2SiO4. (Answer giving only the name, don't give the letter.)

increase

The mineralogy of terrestrial planets evolves as a consequence of a range of physical, chemical, and biological processes. Based on the statement, the number of minerals on the Earth would __________ as the planet evolves through time.

in order of increasing number of protons

The periodic table is commonly used to understand the properties of elements and their compounds in earth materials. How are the elements organized in the periodic table?

isotopes

The structure of atoms is mainly made of the inner nucleus with protons and neutrons, and the outer orbiting electrons. An element is defined by the number of protons, but can have various numbers of neutrons. What is the name for atoms of the same element that have different numbers of neutrons?

subduction zone

There are three types of plate tectonic boundaries. The convergent plate boundary occurs when two plates collide against each other. Which of the following is a type of convergent plate boundary? A. continental rift B. spreading center C. mid-ocean ridge D. subduction zone (Answer giving only the name, don't give the letter.)

granite

We can classify igneous rocks by their textures and compositions. For example, felsic igneous rocks contain very high amounts of K-feldspar and silica. Which of the following rocks has the highest silica content and is a felsic rock? A. peridotite B. gabbro C. basalt D. granite (Answer giving only the name, don't give the letter.)

Limestone

What is the dominant sedimentary rock lithified from carbonate sediments?

decrease in pressure

What triggers the mantle melting that occurs beneath the Hawaii Big Island that is located above a mantle hot spot?

All of the above

Which of the following statements about the age of the geological even it TRUE? A. The Earth was formed about 4.6 billion years ago B. The oldest rocks on the continental crusts are about 4 billion years old C. The oldest rocks on the ocean floor are about 200 million years old D. All of the above (Answer giving only the name, don't give the letter.)

Gabbro is a coarse-grained, felsic, extrusive rock

Which of the following statements is FALSE about igneous rocks? A. Melts are always more felsic than their parent rocks B. Andesite is a fine-grained, intermediate, and extrusive igneous rock C. Basalt is a fine-grained, mafic, and extrusive rock D. Gabbro is a corase-grained, felsic, and extrusive rock (Answer giving only the name, don't give the letter.)

All of the above

Which one of the following conditions can cause melting or partial melting of rocks? A. Pressure decreases (Ex. Mantle upwelling at mid-ocean spreading centers) B. Temperature increases (Ex. Crustal melting during mountain building) C. Fluids are added that reduce the melting temperature of the rocks (Ex. Addition of water at subduction zones) D. All of the above (Answer giving only the name, don't give the letter.)

Mafic minerals are more stable and can be commonly found in sedimentary rocks.

Which one of the following statements about the three rock types is FALSE? A. Igneous rocks form by crystallization from a magma, a mass of melted rock that originates deep in the crust or upper mantle B. Sedimentary rocks are commonly found on the Earth's surface C. Metamorphic rocks are formed under high pressure-temperature conditions when original rocks change forms (textures and/or mineralogy) D. Mafic minerals are more stable and can be commonly found in sedimentary rocks. (Answer giving only the name, don't give the letter.)

granite is very abundant in the oceanic crust because it contains lots of quartz and feldspar

You find an igneous rock containing large, interlocking crystals of quartz, feldspar, and muscovite. The rock you have found is most likely a granite. Which one of the following statements about granite is FALSE? A. granite is a felsic intrusive rock B. granite is very abundant in the oceanic crust because it contains lots of quartz and feldspar C. granite is more felsic than basalt and peridotite D. granite can be found in the Enchanted Rock State Park in Texas. (Answer giving only the name, don't give the letter.)