Earth Science 1

A typical rate of seafloor spreading in the Atlantic Ocean is?

2 centimeters per year

In the early part of the 20th century, who argued forcefully for continental drift?

Alfred Wenger

Today, what is in about the same place as during the later Paleozoic time?

Antarctica

Where lithosphere sinkis into the mantle.

Convergent

The temperature below which magnetic material can retain a permanent magnetization?

Curie Point

Basaltic volcanoism and seafloor spreading.

Divergent

Plates are moving apart from one another.

Divergent

Pull-apart rift zones are generally associated with what type of plate boundary?

Divergent

What is a fundamental assumption underlying plate tectonic theory?

Earth's diameter has been essentially constant over time

As the south Atlantic basin widens by seafloor spreading, Africa and South America are moving closer together.

False

Average rate of seafloor spreading is 1 meter per year.

False

Earth's radius and surface are slowly increasing to accommodate the new oceanic crust being formed at mid-oceanic ridges.

False

Hawaii is the oldest island in the Hawaiian Island chain.

False

A very long-lived magma source located deep in the mantle?

Hot Spot

Linear, magnetic patterns associated with mid-ocean ridges are configured as?

Normal and reversed magnetized strips roughly parallel to the ridge

The former late Paleozoic super continent is known as?

Panagea

Deep-oceanic trenches are the most abundant around the rim of what ocean basin?

The Pacific Ocean basin

What is the logical evolutionary analog of the African rift valleys 10,000,000 years from now?

The Red Sea

Boundary is normally devoid of volcanoism.

Transform

Plates are sliding past one another.

Transform

At times in the past, the polarity of Earth's magnetic field has been reversed.

True

Rocks of the continental crust are less dense than rocks of the oceanic crust

True

Seafloor spreading rates can be restricted if geologic ages of the magnetic field reversals are independently known.

True

The magnetic field poles have generally been close to Earth's rotational poles.

True

The oldest rocks of the oceanic crust are found in deep oceanic trenches far away from active, mid-ocean ridges.

True

The oldest rocks on the seafloor are much younger than the oldest rocks on the continents.

True

Wenger's continental drift hypothesis lacked a viable mechanism to explain continental movement.

True

Who first related the symmetrical magnetic patterns in seafloor basalts to seafloor spreading at a mid-oceanic ridge?

Vine and Matthews

A transform plate boundary is characterized by?

a deep, vertical fault along which two plates slide past one another in opposite directions

The modern day Red Sea is explained by Plate Tectonics:

a rift zone that may eventually open into a major ocean if Arabia & Africa continue to separate

a. Hawaii b. island arc c. volcanic arc d. subduction

a. Hawaii

a. slab pull b. mantle drag c. ridge pull d. slab suction

b. mantle drag

a. oceanic ridge b. seafloor spreading c. arc volcanoes d. divergent

c. arc volcanoes

All of the following are evidence supporting Plate tectonics except?

changes in the moon's orbit due to shifting plates

The volcanoes and deep valleys of east Africa are related to a:

continental rift along which parts of the African continent are beginning to slowly separate

Arc of stratovolcanoes and deep floor trenches

convergent

West coast of South America

convergent

where a subduction zone occurs

convergent

Aleutian Islands occur at a?

convergent boundary on a volcano arc above a North West subducting Pacific plate

a. curie point b. paleomagnetism c. magnetic poles d. polar

d. polar

mid-atlantic ridge

divergent

New oceanic crust and lithosphere are formed at?

divergent boundaries by submarine eruptions and intrusions of basaltic magma

Which of the following energy sources is thought to drive the lateral motions of the Earth's lithospheric plates?

export of heat from deep in the mantle to the top of the asthenosphere

The continental drift hypothesis was rejected primarily because Alfred Wenger could not?

identify a mechanism capable of moving continents

What was never proposed as evidence supporting the existence of Pangaea?

islands of Precambrian rocks along the mid-Atlantic ridge

What most effectively outlines the edges of the lithospheric plates?

lines of earthquake epicenters

What ancient reptile lived in South America and South Africa during the late Paleozoic?

mesosaurus

What is an example of an active, continent-continent collision

northward movement of India into Europe

Where would you drill to recover samples of the oldest basalts of the oceanic crust, which are Jurassic in age?

oceanic side of the Aleutian trench

a. fossil evidence b. fit of the continents c. paleomagnetism d. paleoclimates

paleomagnetism

Which of the following most accurately describes the Hawaiian Island volcanoes?

shield volcanoes fed by a long-lived hot spot below the Pacific lithospheric plate

Deep ocean trenches are superficial evidence for?

sinking oceanic lithosphere into the mantle at the subduction zone

Cooler, older, oceanic lithosphere sinks into the mantle at?

subduction zones along convergent plate boundaries

Early results of the deep sea drilling project clearly justified what conclusion?

the oceanic basins are relatively young; most ocean based rocks and sediments are Cretaceous or younger in age

Which of the following paleoclimatic evidence supports the idea of the late Paleozoic supercontinent in the southern hemisphere?

tillites (rocks formed by glacers) in South Africa and South America

San Andreas fault

transform

Mount St. Helen and other Cascade volcanoes are:

young, active stratovolcanoes built on a continental margin above a sinking slab of oceanic lithosphere

What applies to the asthenosphere but not the lithosphere?

zone in the upper mantle that deforms by plastic flowage