ESC 1000C - chapter 2

According to the image below, where is new oceanic crust being formed?

A

The image below shows a view of a typical segmented mid-ocean ridge. Which letter below marks the location of the active transform fault?

B

A geologist aboard a deep-sea research vessel has collected several drill cores of oceanic crust from the bottom of the ocean. The cores are collected in order from east to west along the bottom of the basin and are labeled A1, B1, C1, and D1, respectively. Core A1 has 2.88 meters (m) of clay and siliceous ooze covering 4.86 m of pillow basalt. Core B1 has 2.37 m of muddy, clay ooze covering 3.57 m of basalt. Core C1 has 2.11 m of clay and siliceous ooze above 3.2 m of basalt. Core D1 has 1.87 m of siliceous ooze over 2.54 m of basalt. Which core is closest to the mid-ocean ridge?

D1

Which of the following is MOST true of the lithosphere?

It is composed of the crust and uppermost part of the mantle.

Consult the figure below. Abundant swamps led to the formation of coal during the Late Paleozoic in which of the following places?

North America

What would happen if the rate of seafloor spreading was faster than the rate of subduction?

The Earth would grow larger.

Which of these parts of the deep-ocean floor is flat and nearly featureless?

abyssal plain

Seafloor spreading is driven by volcanic activity

along mid-ocean ridges

Beneath a blanket of sediments, oceanic crust is primarily composed of

basalt.

The Himalayan Mountains are the result of

continental collision.

Which basic type of plate boundary is shown in the image below?

convergent

Subduction zones occur at

convergent boundaries.

Slab pull occurs because subducting slabs are __________ and therefore __________ than surrounding asthenosphere.

cooler; more dense

seafloor spreading

creates new oceanic crust.

The density of rocks in Earth's layers is generally related to composition. Which of the following choices places compositions in order of increasing density?

crust, mantle, core

Under the theory of plate tectonics, the plates themselves are

discrete pieces of lithosphere at the surface of the solid Earth that move with respect to one another.

Seafloor spreading occurs at __________ boundaries

divergent

Which basic type of plate boundary is shown in the image below?

divergent

Seafloor spreading is MOST likely to occur at

divergent boundaries

Transform boundaries occur MOST commonly perpendicular to __________ boundaries in order to break the __________ into segments so as to accommodate motion on a sphere.

divergent; mid-ocean ridges

The distribution of __________ across the globe provides the primary indicator of boundaries between all tectonic plates.

earthquakes

At transform plate boundaries,

earthquakes are common but volcanoes are absent

Compared with typical oceanic lithosphere, the thickness of continental lithosphere is

greater.

Regions of the seafloor with positive magnetic anomalies were formed during times when Earth's magnetic field

had normal polarity.

Hawaii is an example of

hot-spot volcanism

Compared with the crust, the mantle is __________ and __________ able to flow

hotter; more

With increasing distance from a mid-ocean ridge, the age of oceanic crust

increases.

During a journey to the center of Earth, one would experience temperature __________ and pressure __________.

increasing; increasing

The densest layer of Earth is the

inner core

Unlike the lithosphere, the asthenosphere

is able to flow over long periods of time

At a subduction zone, the down-going (subducting) plate

is always composed of oceanic lithosphere.

In the geologic past, the polarity of Earth's magnetic field is

known to have experienced numerous reversals, as shown by remnant magnetization of iron-rich minerals in rocks.

The thickness of oceanic lithosphere is

least near the mid-ocean ridges and thickens away from the ridges

As compared to basalt, granite has a

lower density

Molten rock beneath Earth's surface is termed

magma

Continental coastlines that occur within the interior of a tectonic plate are called __________ margins.

passive

In general, the mantle is made of the rock

peridotite.

According to the figure below, marine magnetic anomalies lay roughly __________ to mid-ocean ridges.

perpendicular

The theory of __________ states that the lithosphere is broken into a series of plates that move relative to each other.

plate tectonics

Deformed (bent, stretched, or cracked) lithosphere occurs

primarily on the margins of tectonic plates.

Marine magnetic anomalies can be used to estimate the

rate of seafloor spreading

Geologists are able to study Earth's interior primarily using

seismic waves

Which of the following was NOT used as evidence by Alfred Wegener to support his theory of continental drift?

seismic waves

Globally, the rate of seafloor spreading takes place at the same rate as

subduction

The primary difference between lithospheric and asthenospheric mantle that gives rise to numerous different patterns of physical behavior is

temperature: the lithosphere is cooler than the asthenosphere.

If a geologist discovered coal in a modern-day cold, snowy location, he or she could conclude that

the area was once covered with swamps and/or jungles.

Younger oceanic crust will have __________ ocean sediments, whereas older oceanic crust will have __________ oceanic sediments

thinner; thicker

Measuring the elevation of a mountain means measuring variation in __________, whereas doing the same on a mid-ocean ridge would be measuring variation in __________.

topography; bathymetry

In Wegener's evidence for continental drift, continents were proposed to fit together, such as the east coast of South America with the

west coast of Africa.

Hot spots can occur

within either continental or oceanic plates