Geology Final Exam

What special properties of electrons are there (ie. configuration, filling orbitals, transfer, etc...).

-surround nucleus in specific energy levels -number of electrons in an electrically neutral atom must equal the number of protons -electrons fill orbits/sub-orbits from inside to outside -atoms are only truly stable if they have completed orbits/sub-orbits

The first plagioclase crystals to form as a hot melt cools are high in ______.

calcium

In a(n) __________ the erosional contact represents missing rock strata and separates sedimentary beds that are parallel.

disconformity

Most of the gas released by volcanic eruptions is sulfur dioxide.

false

The ___ of a radioactive material is the time it takes for a given amount of radioactive isotope to be reduced by half.

half life

A silica tetrahedron is composed of four atoms of the element ___ and one atom of __.

oxygen; silicon

_____ are subdivisions of eras.

periods

A(n) _______ is a mix of gas and dust emitted by a volcano that is so dense that it hugs the ground.

pyroclastic flow

In 1902 the port city of St. Pierre on the island of Martinique was destroyed by a ___.

pyroclastic flow

A(n) _______ is an erosional surface that represents a gap in the geologic record.

unconformity

The more _____ the lava, and the greater the amount of gas trying to escape, the more violent the eruption.

viscous

What are the different silicate subgroups? What are some examples?

~Island silicates-olivine garnet (peridot) ~Single-chain silicates-pyroxene ~Double-chain silicates-amphibole ~Sheet (layer) silicates-mica(biotite/muscovite) ~Framework silicates-quarts and feldspar

_____ is a coarse-grained sedimentary rock formed by the cementation of rounded gravel.

Conglomerate

___ is the picking up and physical removal of rock particles by an agent such as wind, flowing liquid water, or glaciers.

Erosion

When the ____ came to a close, dinosaurs became extinct.

Mesozoic era

Imagine two magmas that are identical in all respects (for example, same chemistry, pressure, volume) except that one magma is hotter than the other. Which magma will have the higher viscosity?

The cooler magma will be more viscous.

______ first pointed out that fossil species succeed one another through successive layers of sediment in a predictable order.

W.S. Smith

The ______ group of minerals is characterized by two parallel chains of silica tetrahedra in their structure.

amphibole

What is the definition of a mineral?

any naturally occurring inorganic solid chemical compound with a more or less fixed chemical composition, is homogeneous in its physical and chemical properties and has a regular arrangement of its constituent atoms.

What is the atomic number? The atomic mass number (weight)?

atomic number =number of protons (fixed value) atomic mass #=number protons+number neutrons (varies)

What is an isotope?

atoms with the same number of protons but a different number of neutrons

In order for a particular type of material to be classified as a mineral, it must ____.

be a solid occur naturally have a crystalline structure have a definite chemical composition

Shield volcanoes have ___ bases and ___ inclined slopes.

broad; gently

A _________ is a volcanic depression much larger than the original crater, formed when the volcano collapses into a vacated magma chamber.

caldera

A ______ is a volcano constructed of pyroclastic fragments ejected from a central vent.

cinder cone

A _____ volcano is composed of alternating layers of pyroclastic fragments and solidified lava flows.

composite

Igneous rocks may be either ____ if they form on or near Earth's surface, or ___ if they solidify under ground.

extrusive; intrusive

An angular unconformity is an erosion surface that is tilted from the horizontal.

false

Composite volcanoes are also called cinder cone volcanoes.

false

Extrusive igneous rocks are typically fine grained because they crystallized slowly, deep below the Earth's surface.

false

Rhyolite is considerably more common than granite.

false

Silicic lavas, which are relatively high in silica, tend to be more fluid than mafic magmas.

false

The Mesozoic Era precedes (is older than) the Paleozoic Era.

false

The atomic mass number is equal to the number of neutrons in an atom.

false

The principle of superposition states that in a stack of horizontal layers the oldest layer is on top.

false

Volcanic eruptions have no effect on climate.

false

Viscosity is a property of a fluid that relates to how easily the fluid flows. A material that is viscous __.

flows less easily

What is the silica tetrahedron?

four oxygen atoms and one silicon atom bonded tetrahedrally to each other

The coarse-grained equivalent of basalt is a(n) ______.

gabbro

A(n) _______ fossil is a fossil from a very short-lived, geographically widespread species that existed during a specific interval of geologic time.

index

How does the Si:O ratio change among the various silicate subgroups?

island silicates-1:4 single-chain silicates-1:3 double-chain silicates-2:5.5 sheet silicates-2:5 framework silicates-1:2

_______ of an element are atoms containing different numbers of neutrons but the same number of protons.

isotopes

The principle of ___ states that an original sedimentary layer extends laterally until it tapers or thins at is edges.

lateral continuity

The term ___ is used for molten rock on the Earth's surface.

lava

_____ are tunnel-like caves within a lava flow.

lava tubes

What is a magma? A lava?

magma-silicate liquid below the Earth's surface (intrusive) lava-silicate liquid exiting onto the surface (extrusive)

The Earth's largest mass extinction coincides with _____ in Siberia.

massive volcanism

The _____ group of minerals are sheet silicates.

mica

What is a polymorph?

minerals that have the same chemical composition but different crystal structures

Carbon-14 has eight __.

neutrons

Eruptions of shield volcanoes fed by mafic magma tend __.

not to be explosive or particularly dangerous

The common mineral ___ is an example of an isolated silica tetrahedron structure.

olivine

What is the sequence of crystallization along the discontinuous branch of Bowen's reaction series?

olivine, pyroxene, amphibole, biotite

____ is the most common element in the Earth's crust.

oxygen

The two most abundant elements in Earth's crust are __.

oxygen and silicon

Some minerals have the same chemical composition but different crystal structures, a phenomenon termed _______.

polymorphism

The ____ is based upon the observation that fossil species succeed one another through layers in a predictable order.

principle of faunal succession

The atomic number of an element equals the number of _____ in each atom.

protons

The atomic mass number of an atom is the total number of ___ in the atom.

protons and neutrons

A _____ is a mixture of gas and pyroclastic debris that is so dense that it hugs the ground as it flows rapidly into low areas.

pyroclastic flow

Two examples of framework silicates are _____ and ______.

quartz; feldspar

Because _____ magmas are the most viscous they are associated with the most violent eruptions.

silica-rich

The most common minerals in the Earth's crust are the _______.

silicates

What is meant by an igneous rock texture?

size, shape, and orientation of the minerals that form from the lava or magma

What is an atom? What particles compose it?

smallest particle of matter that still retains the characteristics of an element

The principle of ___ holds that, in a stack of horizontal layers the oldest layer is on the bottom and the layers become younger upward.

superposition

When marine geologists collects a core of undeformed ocean-floor sediment, they know that the youngest layer is on the top of the core and the oldest is at the bottom because of the principle of __.

superposition

A mineral is defined as a crystalline solid that is naturally occurring, has a specific chemical composition and forms through geologic processes.

true

All of the most common rock-forming minerals in Earth's crust are silicate minerals.

true

An index fossil is a fossil from a very short-lived, geographically widespread species known to exist during a specific interval of geologic time.

true

Basaltic magmas crystallize at higher temperatures than granitic magmas.

true

Columnar jointing is a characteristic of basalt lava.

true

Half life is the time it takes for a given amount of a radioactive isotope to decay to half its original amount.

true

Lava is magma on the Earth's surface.

true

Lithification is the general term for the processes that convert loose sediment into a sedimentary rock.

true

Mafic igneous rocks are silica-poor.

true

Minerals that have the same chemical composition but have different crystalline structures exhibit polymorphism

true

Most shale contains both clay-sized and silt-sized particles.

true

Pahoehoe lava flow is characterized by a ropy or billowy surface.

true

Pillow structures, pillow-shaped rounded masses, form where lava is extruded under water.

true

Relative time refers to the time sequence in which events take place rather than the number of years involved.

true

The atomic number of an element is equal to the number of protons in each atom.

true

The islands of Hawaii are essentially a series of shield volcanoes built upward from the ocean floor over millions of years.

true

The original volcano Mount Mazama erupted to form Crater Lake, Oregon.

true

The principle of original horizontality states that beds of sediment are nearly always deposited as nearly horizontal layers.

true

The sequence in which minerals crystallize in a cooling igneous melt is called Bowen's Reaction Series.

true

The term mafic comes from the terms magnesium and ferric.

true

n an unconformity the contact represents a gap in the geologic record.

true

The Earth is approximately _____ years old.

4.5-4.6 billion years old

_____ describes the surface of a basalt flow with a jagged, rubble surface.

Aa

The _______ Era is the Age of Mammals.

Cenozoic

The half-life of the carbon 14 isotope is 5730 years. If there were 4 billion atoms of C-14 in a particular organism at the time it died, how many atoms of C-14 would there be in the remains of that organism 11,460 years after it died?

1 billion

How are igneous rocks named?

1.) texture/where the liquid is: -aphanitic: lava, extrusive,volcanic -phanerific: magma, intrusive, plutonic 2.) composition of lava/magma -high Si:O ratio=sialic-->LOW TEMP -intermediate compositions=intermediate -low Si:O ratio=mafic-->HIGH TEMP

_____ describes the surface of a basalt flow with a smooth ropy surface.

Pahoehoe

The ___ Era began with the appearance of complex life, as indicated by fossils like trilobites.

Paleozoic

The _____ ended with the greatest mass extinction ever to occur on Earth.

Paleozoic era

______ denotes the vast amount of time that precedes the Paleozoic Era.

Precambrian

____ is the process by which sediment grains are selected and separated according to grain size by agent of transportation

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