Test #2

Average oceanic crust is ____ kilometers thick, whereas average continental crust is ____ kilometers thick.

4 to 7, 20 to 40

The mantle makes up about ____ percent of the Earth's volume.

80

What is the difference between a normal and reverse fault?

A fault refers to a displacement of a part of earth as a result of rock movement. Some of the differences between a normal fault and a reverse fault are as follows; (i) A normal fault is caused by tensional forces while a reverse fault occurs due to compressional forces.

Nonconformity

A type of unconformity in which layered sedimentary rocks lie on an erosion surface cut into igneous or metamorphic rocks

Disconformity

A type of unconformity in which the beds above and below are parallel.

Describe the mechanism of elastic rebound that causes an earthquake

Elastic rebound theory. Over time stresses in the Earth build up (often caused by the slow movements of tectonic plates). ... An earthquake rupture occurs and relieves some of the stresses (but generally not all)

What type of igneous rock is most commonly formed from the magma?

Extrusive igneous rocks, also known as volcanic rocks, are formed at the crust's surface as a result of the partial melting of rocks within the mantle and crust. Extrusive igneous rocks cool and solidify quicker than intrusive igneous rocks. They are formed by the cooling of molten magma on the earth's surface.

Eons in order

Hadean, Archean, Proterozoic, Phanerozoic

Describe the two types of volcanic eruptions—explosive and effusive:

Effusive eruptions - magma rises through the surface and flows out of the volcano as a viscous liquid called lava. Explosive eruptions - magma is torn apart as it rises and reaches the surface in pieces known as pyroclasts.

____ waves are the fastest body waves generated by an earthquake.

P

Describe the differences between P waves and S waves

P waves travel faster than S waves P waves travel through any kind of material, whether it is a solid, liquid or gas. On the other hand, S waves only move through solids and are stopped by liquids and gases. S waves are generally larger than P waves

Precambrian refers to all the time before the start of the ____ Eon.

Phanerozoic

What is the difference between brittle strain and plastic strain?

Plastic rocks bend and do not regain their original shape while brittle rocks are broken/shattered

The ____________________ encompasses approximately the first 4 billion years of Earth's history.

Precambrian

What are the principles that can be used to determine the relative age or order of geological features?

Principle of uniformitarianism- physical processes observed today operated in the same way in the geologic past, so modern processes help us understand ancient events. 2) Principle of superposition- in an undeformed sequence of layered rocks: each bed is older than the one above and younger than the one below, so the oldest layer lie at the bottom and the youngest layer lies at the top. 3) Principle of original horizontality- sedimentary rocks were horizontal when originally deposited. If tilted, it is due to a subsequent geologic event. 4) Principle of original lateral continuity- sedimentary beds are originally laterally continuous within their environment of deposition. Faulting, severe folding, and erosion may have separated the originally laterally continuous beds into what now appears to be separate units. 5) Principle of cross-cutting relations- younger features cut across older features, so faults, dikes, erosion, volcanoes etc. must be younger than the material that is faulted, intruded, or eroded. 6) Principle of inclusions- inclusions (a rock fragment within another rock) must be older than the material they are in. 7) Principle of baked contacts- thermal metamorphism occurs when country rock is invaded by a plutonic igneous intrusion. The baked rock must have been there first, so it is older.

Geologists learned that the outer core is liquid because ____ do not travel through the outer core.

S waves

How is a strike-slip fault different from the normal and reverse faults?

Strike-slip faults have a different type of movement than normal and reverse faults. You probably noticed that the blocks that move on either side of a reverse or normal fault slide up or down along a dipping fault surface.

What are the three types of stress? In what plate boundary type would each be associated?

Tension- two opposing forces pull apart Compression- two opposing forces pushing together Shear- two opposing forces dragging past each other

When is it possible to use Carbon-14 to determine a rock's age?

When rocks are younger than 50,000 years

An unconformity in which tectonic activity tilted older sedimentary rock layers before younger sediment accumulated is:

an angular unconformity.

P, or primary, waves:

are characterized by alternate compression and expansion of rock.

The ____________________ is the hot, weak, and plastic uppermost portion of the mantle.

asthenosphere

Oceanic crust is typically of ____ composition.

basaltic

A pluton with an outcrop area of more than 100 square kilometers is a:

batholith

A/An ____ is a crater formed by the collapse of a magma chamber.

caldera

Layers of sedimentary rock are ____ if they were deposited without detectable interruption.

conformable

mountain range

converge

volcanic arc

converge

The Himalayan Mountain Range is an example of a ____ boundary.

convergent

Where two plates move horizontally toward each other, they form a ____ boundary.

convergent

magma

convergent

subduction

convergent

Three plate boundaries

convergent, divergent, transform

A/An ____________________ is an unconformity in which the sedimentary layers above and below the unconformity are parallel.

disconformity

Mid-ocean ridge-

divergent

rift valley

divergent

The ____ is located on Earth's surface directly above the initial rupture point of an earthquake.

epicenter

Pyroclastic bombs, cinders, and ash:

erupt explosively from volcanoes.

Gentle eruptions of basaltic lava from long fissures create ____.

flood basalts

A shield volcano commonly erupts when:

fluid basaltic magma builds a gently sloping mountain.

The initial rupture point of an earthquake (below Earth's surface) is the ____.

focus

How can mountains be created by folding

formed when two plates move together (a compressional plate margin). This can be where two continental plates move towards each other or a continental and an oceanic plate.

A composite cone:

forms by repeated lava flows and pyroclastic eruptions over a long time.

The principle of faunal succession states that:

fossil organisms succeeded one another through time in a definite and recognizable order.

Continental crust is typically of ____ composition.

granitic

The most catastrophic volcanic explosions occur when ____ reaches the Earth's surface.

granitic magma

The outer 75 to 125 kilometers of the Earth, including both the crust and upper mantle, consists of:

hard, strong rock of the lithosphere.

three ways magma can form

heat transfer, decompression melting and flux melting

To measure the distance from a recording station to an earthquake epicenter, geologists evaluate the ____ with a time-travel curve.

interval between the arrival of P and S waves

How is an intraplate earthquake different from most earthquakes?

intraplate earthquakes are caused by stresses within a plate

The magma of andesite and diorite contains ____________________ silica than granite.

less

The ____ includes Earth's crust and the uppermost strong and rigid part of the mantle.

lithosphere

According to the theory of isostasy, the ____ is in floating equilibrium on the ____.

lithosphere, asthenosphere

Granitic magma has a/an ____ melting temperature compared to basaltic magma.

lower

The Mid-Oceanic Ridge is elevated above the surrounding sea floor because it is:

made of the newest, hottest, and lowest-density lithosphere.

The three environments of magma production are ____________________ ____________________, ____________________ ____________________, and ____________________ ____________________.

mantle plumes, spreading centers, subduction zones

The ____ scale measures the total amount of energy released during an earthquake, based on the amount of movement and the fault surface area.

moment magnitude

The metallic core is composed of ____________________ and ____________________.

nickle, iron

The principle of ____ states that most sediment is deposited as nearly horizontal beds.

original horizontality

Melting caused by decreased pressure is called ____ melting.

pressure-release

Explosively erupted rock particles or magma form ____________________ rock.

pyroclastic

Measurement of ____ age refers only to the order in which events occurred.

relative

A mantle plume is a ____.

rising column of hot, plastic mantle rock

At a divergent boundary between spreading tectonic plates in oceanic crust:

rock and magma rise to form the Mid-Oceanic Ridge.

Evidence for plate tectonics

rocks, fossils, climate, puzzle fit, glaciers, sea floor spreading

What is the difference between an anticline and syncline?

Anticlines are folds in which each half of the fold dips away from the crest. Synclines are folds in which each half of the fold dips toward the trough of the fold. You can remember the difference by noting that anticlines form an "A" shape, and synclines form the bottom of an "S."

The earliest fossils have been found from the ____ Eon.

Archean

Eras in order

Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian

How do unconformities form? How do the three varieties of unconformities differ?

Disconformity, nonconformity, angular unconformity

____________________ are atoms of the same element that have the same number of protons but different numbers of neutrons.

Isotopes

What are the layers of the earth?

Lithosphere. Asthenosphere. Mantle. Outer Core. Inner Core.

____ have occurred on average every 500,000 years over the past 65 million years of Earth's history.

Magnetic reversals

how can mountains be formed by erosion?

Many mountains were formed as a result of Earth's tectonic plates smashing together. The Earth's crust is made up of multiple tectonic plates that still move today as a result of geologic activity below the surface.

What is the difference between focus and epicenter?

The focus is the point within the earth where seismic waves originate; it is centered on the part of the fault that has the greatest movement. The epicenter is on the earth's surface directly above the focus.

How did the formation of Pangaea create metamorphic rocks in Piedmont?

The igneous rocks are the roots of volcanoes formed during an ancient episode of subduction that occurred before the formation of the Appalachian Mountains.

What are volcanic products or hazards?

These include lava flows, lahars, ash falls, debris avalanches, and pyroclastic density currents.

how can mountains be formed by faulting?

These mountains form when faults or cracks in the earth's crust force some materials or blocks of rock up and others down. Instead of the earth folding over, the earth's crust fractures (pulls apart). It breaks up into blocks or chunks.

Magma with a high water content has a greater tendency to ____ in the crust, compared with magma with a lower water content.

solidify

Where two lithospheric plates of different densities converge, the denser one sinks into the mantle beneath the other in a process called ____.

subduction

Why is the seafloor age very young near a mid-ocean ridge and gradually become older the further away you go?

subduction destroys old crust

The Ring of Fire, a zone of concentrated volcanic activity encircling the Pacific Ocean basin, is located adjacent to ____.

subduction zones

The fact that sedimentary rocks usually become younger from bottom to top is the principle of ____________________.

superposition

How is the formation of the Appalachian Mountains related to the supercontinent Pangaea?

the direct cause of the creation of the Appalachian Mountains was the merging of all continents into the supercontinent Pangea as the Iapetus Ocean closed 290 million years ago. ...

The likely source of the Earth's magnetism is:

the flow of liquid metals in the outer core.

The half-life of a radioactive isotope is:

the time it takes for half the atoms of the radioactive isotope in one sample to decay.

transform vault

transform

trench

transform

Which of the following tectonic environments does not generate large quantities of magma?

transform boundaires

How is a tsunami created and how does it grow when it reaches the coast?

tsunami leaves the deep water of the open ocean and travels into the shallower water near the coast, it transforms. ... When it finally reaches the coast, a tsunami may appear as a rapidly rising or falling tide, a series of breaking waves, or even a bore.

Why does the seafloor rock have a distinct magnetic pattern that is identical on opposite sides of a mid-ocean ridge?

two plates are moving in opposite directions as in a mid-ocean ridge. 3. Transform boundary - two plates are sliding past each other as in the San Andreas fault of California. A transform boundary is like a tear in the Earth's crust.

At a transform boundary:

two plates slide horizontally past each other.

angular unconformity

where horizontally parallel strata of sedimentary rock are deposited on tilted and eroded layers, producing an angular discordance with the overlying horizontal layers