Final

Which one of the following numerical ages is reasonable for a mammoth bone dated using radiocarbon methods?

17,000 y.b.p.

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

2 centimeters per year Typical rates of seafloor spreading average around 5 centimeters (2 inches) per year. However, comparatively slow spreading rates of 2 centimeters per year are found along the Mid-Atlantic Ridge. Spreading rates along the East Pacific Rise exceed 15 centimeters (6 inches) per year.

What is the temperature above which magnetite loses its magnetization?

800°C is the temperature above which magnetite loses its magnetization. As lava cools, its iron rich grains become magnetized and allign themselves in direction of existing magnetic lines of force. After they solidify, their magnetic lines don't change anymore. The minerals act like a compass and point towards position of magnetic poles at time of their formation. They posses fossil magnetism or PALEOMAGNETISM.

What causes the volcanoes and deep valleys of East Africa?

A continental rift along parts of the African continent beginning to slowly separate As they separate it thins out the see floor below allowing magma to come up from the mantle, creating the volcanoes around the rift region.

What type of boundary occurs along the Aleutian Islands in the North Pacific?

A convergent boundary on a volcanic arc above the northward-subducting Pacific plate

What type of region is the modern-day Red Sea?

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

Which of the following statements applies to the asthenosphere, but not the lithosphere?

A zone in the upper mantle that deforms by plastic flowage

Which of the following will cause melting that produces magma? Choose all that apply. The mantle is composed entirely of magma; it does not need to be "produced." Adding volatiles to the rock Decreasing temperature while keeping pressure constant Removing volatiles from the rock Decreasing pressure while keeping the temperature constant

Adding volatiles to the rock Decreasing pressure while keeping the temperature constant

Which of the following statements are TRUE?

All subduction zones occur at convergent plate boundaries

Where in the ocean does oceanic lithosphere sink into the mantle?

At subduction zones along convergent plate boundaries

Which of Earth's oceans was created by the breakup of the supercontinent Pangaea?

Atlantic Ocean

Which of the following sequences places Earth materials in the correct relative order?

Atoms-Elements-Minerals-Rocks

Why was Wegener's continental drift hypothesis rejected?

Because Wegener could not identify a mechanism capable of moving continents

Which of the following statements describes how metallic bonding occurs?

Each atom donates its valence electrons to a common pool of electrons that are free to move throughout the entire structure. covalent - sharing of valence electrons

Which one of the following is an important fundamental assumption underlying the plate tectonic theory?

Earth's diameter has been essentially constant over time.

Volcanic eruptions affect many populated areas. Which of the following pieces of evidence would a geologists use to predict future eruptions?

Frequency of localize earthquakes

What was the name of the fossil flora that grew on Pangaea during the late Paleozoic?

Glossopteris

Which of the following terms refers to an untested explanation formulated by scientists to describe why something happens?

Hypothesis

Which of the following is true of igneous rock?

Igneous rocks form when magma beneath the Earth's surface cools and solidifies.

Which of the following was never proposed as evidence supporting the existence of Pangaea?

Islands along the Mid-Atlantic Ridge with rocks dating back from 542 million to 2500 million years ago

Which of the following describes the geologic doctrine known as catastrophism?

Large features like mountains and canyons were created by sudden events produced by unknown causes.

What causes the linear patterns associated with paleomagnetism on either side of mid-oceanic ridges?

Normal and reversed magnetized strips roughly parallel to the ridge

Which of the following minerals would be the first to crystallize?

Olivine

What ultramafic rock is thought to be common in Earth's mantle but rare in the crust?

Peridotite

Which of the following minerals would you find in abundance in a granitic (felsic) igneous rock? Choose all that apply. Which of the following minerals would you find in abundance in a granitic (felsic) igneous rock? Choose all that apply.

Potassium feldspar Quartz

What process is evident at oceanic trenches?

Sinking of oceanic lithosphere into the mantle at a subduction zone

Which of the following statements accurately describes the difference between the lithosphere and the asthenosphere?

The lithosphere is a strong outer layer of Earth that sits atop the warmer and weaker asthenosphere.

Which of the following is an example of an active continent-continent collision?

The northward movement of India into Eurasia

Which of the following statements describes the view held by most geologists about the continents and ocean basins prior to the 1960s?

The ocean basins and continents are geologically old features with a fixed geographic position.

What evidence did the Deep Sea Drilling Project find about the dates of rocks in the ocean basins?

The ocean basins are relatively young; most ocean basin rocks and sediments are Cretaceous or younger in age.

Which of the following describes the inner planets of our solar system?

They contain mostly iron, nickel, and rock-forming minerals.

Which of the following paleoclimatic evidence supports the idea of the late Paleozoic supercontinent in the Southern Hemisphere?

Tillites (rocks formed by glaciers) in South Africa and South America

What is an important difference between transform plate boundaries and convergent and divergent plate boundaries?

Transform plate boundaries do not produce volcanic activity.

Which two scientists proved that a symmetrical magnetic pattern existed in seafloor basalts and related those stripes to spreading at a mid-oceanic ridge?

Vine and Matthews

How does water affect the melting temperature of rock?

Water causes rock to melt at lower temperatures.

How does silica content affect the viscosity of magma?

With more silica, magma becomes more viscous, more gel-like.

Which of the following describes the region of the ocean known as the mid-ocean ridge?

a continuous elevated belt that winds underwater for more than 43,000 miles around the Earth

A transform plate boundary is characterized by __________.

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

The event that is hypothesized to have led to the extinction of the dinosaurs on Earth involved a(n) ______________ that occurred about __________years ago.

a meteorite impact; 65 million

The exposure of large granite plutons at the Earth's surface implies that:

a thick section of overlying rock has been removed by erosion

Which of the following would NOT be classified as a mineral?

coal mineral = inorganic

While walking along the Earth's continental surface, you observe a large mountain range composed of layers of strata that have been shortened by folding, which type of tectonic stress is most likely responsible for the strain you observed?

compressional

Which part of Earth's structure would include the Himalayan Mountains?

continental crust

Which of the following is a component of the Earth's biosphere?

coral reefs

Which of the following minerals belongs to the non-silicate mineral group known as oxides?

hematite

A very long-lived magma source located deep in the mantle is called a(n) __________.

hot spot

The __________ proposed by Alfred Wegener to explain the continental shapes and positions is known as _____.

hypothesis; continental drift

While observing a sedimentary rock outcrop, you note that majority of the material cemented in the stratigraphic unit is gravel-cobble in size, but poorly sorted and angular. From these basic observations, what can you infer about the depositional environment represented by the sedimentary characteristics?

located near the headwaters of a mountain reach of a stream

Which of the following is NOT used by researchers to measure plate motion?

magnetic reversal records

When we see sedimentary rock units that are twisted or tilted, we know that some force must have disturbed the strata after they were deposited. The principle upon which we base this inference is the principle of _____.

original horizontality

In addition to silicon, every silicate mineral contains what element?

oxygen

Which of the following is an extrusive igneous rock?

pumice

Most of the information about the interior structure of the Earth (i.e. core, mantle, crust, etc.) has been derived from:

seismic waves generated by earthquakes

Which of the following mechanisms is the largest contributor to plate motion?

slab pull

Which of the following terms refers to a mineral's resistance to deformation like breaking or bending?

tenacity

While hiking in the Grand Canyon of northern Arizona, you stop and observe an outcrop that exposes three different sedimentary rock types. On the bottom is a layer of shale, which is overlain by a layer of limestone, which is in turn overlain by a layer of sandstone. This stratigraphic sequence indicates a _________ or a _________ in sea-level occurred in this location in the past.

transgression; fall

Of what are the North American Cascade Mountains an example?

volcanic arc