Ocean Chapter 2 Questions

Of the following statements about nemataths and volcanic arcs, which is/are true?

-In a volcanic arc, any of the volcanoes can be active at any time. -A nematath is created by hotspot. -A volcanic arc is associated with a convergent plate boundary. -Nemataths and volcanic arcs are both the result of volcanic activity. -In a nematath, the age of the volcanoes progressively decreases as you move closer to the volcanic source.

Iceland is located on what type of plate boundary?

Divergent

Which hypothesis best explains the continuous bend in the Hawaiian Islands-Emperor Seamount chain?

The direction of plate motion shifted over time over a stationary mantle plume (hot spot).

What do all plate boundaries have in common?

They are all associated with zones of earthquakes.

Numerous small, shallow earthquakes tend to occur at _______.

divergent plate boundaries

A researcher interested in the vertical zonation of oceanic lithosphere would want to study __________.

ophiolites

The following set of observations describes an actual body of water. Evaluate these statements and determine the evolutionary stage of an ocean basin based upon the following characteristics: 1. Lacks a mid-ocean ridge 2. Deep ocean basin is present 3. Early signs of mountain formation 4. Volcanic island arc and trench absent

terminal

Compared to the rest of the planet, an unusually high concentration of hot spots and rifting is located on the continent of Africa. A likely explanation for this is that __________.

the African Plate is essentially stationary with respect to Earth's interior and the thick continental crust acts as a "heat blanket"

Of the following statements about ocean crust, which is/are true?

-Ocean crust is created at mid-ocean ridge -Ocean crust is destroyed at deep sea trenches.

Why does the sea floor have a striped pattern of magnetic anomalies that is symmetric with respect to the mid-ocean ridge?

-The igneous rock of the ocean preserves earth's existing magnetic field as the rock cools. -The polarity of Earth's magnetic field experiences reversals. -The ocean floor is spreading apart, and now sea floor is forming.

Of the following statements about Earth's magnetic field, which is/are true?

-The magnetic field is oriented vertical relative to Earth's surface at the south magnetic pole. -The magnetic field is oriented horizontal (parallel) to Earth's surface at the magnetic equator. -Earth's magnetic field has varying dips around the world that range from vertical to horizontal, depending on latitude. -The locations of Earth's magnetic poles have moved through time and have even reversed in polarity. -The magnetic field is oriented vertical relative to Earth's surface at the north magnetic pole.

Which of the following lines of evidence did Alfred Wegener use to support the concept of drifting continents?

-the distribution of species of fossils -the pattern of similar mountain belts on different continents -evidence of glaciers in areas that are now tropical -the way the shapes of the continents fit together like species of a jigsaw puzzle

Sea floor spreading along the axis of an oceanic ridge results in symmetrical patterns of all of the following EXCEPT ______________.

-the paleomagnetic record the age of the sea floor -the depth of the sea floor -the flow of heat through the crust *the location of subduction zones*

If ocean crust forms at a rate of 10 centimeters per year, how much ocean crust can be created in 20 million years?

2,000 km (about 1200 miles)

The cities of Los Angeles and San Francisco, CA, are about 380 miles apart. Plate motion along the San Andreas Fault is about five centimeters per year. If the Los Angeles Dodgers and the San Francisco Giants continue to play at their current locations, how long will it be before their games will constitute a cross-town rivalry?

About 12,230,000 years

Which of the following is the main reason that Earth has a magnetic field?

Convection in the liquid iron-nickel outer core generates a magnetic field.

What piece of evidence supports Wegener's hypothesis of continental drift?

Modern-day species that evolved in isolation share a common ancestor.

Of the following statements about the age of the ocean crust, which one is true?

The oldest ocean crust is about 200 million years old and is located near an ocean trench.

Of the following statements about sea floor magnetic anomalies, which is/are true?

They are oriented parallel to the mid-ocean ridge.

Evidence shows that periodic reversals of Earth's magnetic field have resulted in __________.

a symmetrical pattern of normal and reverse magnetization in ocean crustal rocks

Earthquakes can occur only in the __________.

lithosphere

What type of plate boundary will result in the formation of a volcanic island chain or arc near a deep-sea trench?

oceanic-oceanic convergent boundaries

A trench and a chain of volcanoes known generally as a volcanic arc are always present where there is __________.

subduction

Based on paleogeographic records, _____________.

the North Atlantic opened before India separated from Antarctica.

Loihi

the newest Hawaiian volcano

The flat top of guyot or tablemount in deep water is evidence that _______.

the seamount was once at the surface of the ocean, but is now submerged due to plate movement and erosion when it was near sea level.