Geology Chapter 11 Quizlet

How are island arcs different from Andean-type arcs?

Andean-type arcs have continental lithosphere for the upper plate, so the volcanoes are built upon continental crust.

How is "brittle" deformation different from "ductile" deformation, and why?

Brittle deformation occurs in rocks that are colder, whereas ductile deformation occurs at high temperature where energy is higher.

A good example of a present-day, passive continental margin is the ________.

East coast of North America

Andean-type mountain building involves the convergence of two oceanic plates.

False

Which of the following best describes "deformation" of rocks?

Generally the changes in size, shape, orientation or position of a rock mass

Which of the following is consistent with deformation by "folding"?

Horizontal distance is shortened perpendicular to the fold axis

According to the idea of "isostatic adjustment," what would happen if a weight is added to the top of the crust?

It will respond by sinking the crust downward.

Mountains are not found everywhere, but in distinct linear belts (see the diagram below). Which of the following was an early explanation for the isolated nature of mountain belts, and for how they formed?

Mountains are simple "wrinkles" in Earth's crust, produced as the planet cooled since formation.

Why do continental collisions occur?

Once a continent is pulled into the Andean-type arc, the two continents collide because the arriving continent is too low a density to subduct.

Which one of the following statements about "rock deformation" and "rock strength" is correct as learned from laboratory experiments?

Rupture and plastic deformation occur when stresses exceed the elastic limit of a material.

Below Andean-type arcs, what impedes the ascent of magma such that almost all of it ponds at the base of the crust, and does not make it to the surface?

The continental crust is so thick and rigid, that the magma cannot ascend as easily through it as it can through the mantle.

Convective flow in the mantle accounts for some broad upwarping in the overlying lithosphere.

True

Isostasy is the concept that Earth's crust is "floating" in gravitational balance upon the material of the mantle.

True

One of the best examples of an inactive Andean-type orogenic belt includes the Sierra Nevada and the Coast Ranges in California.

True

The Himalayas are the result of the collision of two plates, each carrying continental crust.

True

What is a "batholith" and what does it mean when a geologist encounters one?

a large plutonic body composed of numerous individual plutons that is the eroded root zone of an ancient continental arc

What do geologists say indicates that a continental arc once existed in a location that currently is not the site of an arc (e.g., the Sierra Nevada mountains of western North America)?

a nearly continuous belt of igneous plutons, now exposed after uplift and removal of the volcanic chain above

A transform fault is _______________.

a strike-slip fault that forms the boundary between tectonic plates

Which of the following is NOT a consequence of "stretching" of the crust during extension to form fault-block mountains?

accretion of terranes

What observation would be a good indicator that the continental crust had been uplifted?

ancient wave-cut platforms now found as terraces at high elevation

Unlike older ideas, according to the Plate Tectonics model, where do most mountain belts occur, and why does the model indicate that fact?

at convergent plate boundaries, where plates collide to produce tectonic forces that would fold and uplift rocks

Using the map of Michigan below, showing Paleozoic strata in roughly circular pattern surrounding a core area of Pennsylvanian rocks, determine the type of structure the strata define:

basin

In the figure below showing the northward migration and collision of India with the Eurasian plate, the feature labeled A represents:

developing accretionary wedge where India will collide with Tibet

In the figure below showing the northward migration and collision of India with the Eurasian plate, the feature labeled C represents:

differentiated magma ascending in the crust

Which of the following is the fundamental difference between "dip-slip" and "strike-slip" faults?

dip-slip faults have motion up or down the fault / strike-slip faults have motion parallel to the horizontal direction

In the figure below showing the northward migration and collision of India with the Eurasian plate, the feature labeled B represents:

future location of Tibet behind the future location of the high Himalayas

In the figure below showing the northward migration and collision of India with the Eurasian plate, the feature labeled D represents:

heating oceanic lithosphere (now completely subducted under Tibet)

Under what circumstances will subduction lead to continental collision, and when will subduction end?

if the subducting plate contains a continent that will eventually end up at the trench - since the continental lithosphere is too low a density to subduct, the subduction zone is blocked

A thrust fault is different from a reverse fault because ___________.

it is lower-angle, and is the structure that transports its hanging wall block many kilometers

What are the components of an "accretionary wedge"?

mud, ash and sediment from both the volcanic mountains and the top of the subducting slab

The term ________ refers specifically to geologic mountain building.

orogenesis

Which of the following is NOT one of the four most important factors that determine how rocks respond to applied stress, e.g., brittle (break) vs. ductile (bend) behavior?

size

What is volcanism in arcs dominated by?

the eruption of lavas and pyroclastic materials of andesitic composition

What is the most important distinction between all three major classifications of faults?

the relative motion direction between fault blocks

Which of the following best describes the term "orogenesis" when referring to mountain building?

the term for the processes that collectively produce a mountain belt

Which of the following is NOT true about "dip-slip" faults?

they are folded layers of rocks

How do compressional mountain belts display striking visual evidence of great tectonic forces that formed them by shortening and thickening the crust?

they contain rocks that have been contorted into folds