Exam 10: Crustal Deformation and Mountain Building

The Peninsular terrane is now part of the crust of North America in southern Alaska.The dominant rock type in this terrane is intrusive igneous rock that ranges in composition from gabbro to granite and volcanic rock with a similar compositional range.Geologic evidence indicates the Peninsular terrane collided with North America during late Mesozoic time.Which of the following would be the most reasonable interpretation for the origins of the Peninsular terrane?

If these mountains formed 50 million years ago,why are they still high?

The higher the temperature,the more likely it is that a rock will deform ________.

Subduction produces mountains because subduction zones are the upwelling zones of mantle convection,which lifts the earth's surface to form mountains.

Most geologists think the elevation of mountains above sea level is limited by earth's gravity because ________.

A region is characterized by numerous anticlines and synclines.There are also several faults present that appear to have formed at the same time as the folding.Without looking at any details,what type of faults would be most likely? Why?

What type of basin would be most likely to contain large amounts of sediments derived from a volcanic source?

The Sierra Nevada Mountains of California,and the Teton Mountains of Wyoming,ranges are examples of ________.

The Appalachians were formed by three phases of ________ orogeny.

Folds are an example of ________.

The ________ is (are)characterized by terrane accretion that has been active throughout most of Mesozoic and Cenozoic time.

The west coast of California is underlain by rocks that represent ________.

A(n)________ fault has little or no vertical movements of the two blocks.

When subjected to a differential stress,a very "brittle" material,like glass,will ________.

In the figure,the stress on block 'Y' is ________.

In the interior of continents the earth's crust is typically about 40km thick and the elevation is near sea level.Most earth materials expand when heated,lowering their density.During rifting continental margins are heated but cool as sea floor spreading moves offshore from the continent.Thus,basic isostasy suggests that after rifting,a continental margin will ________.

Orogenesis refers to the formation of mineral deposits.

________

Folded limestones that are exposed high elevations in the Himalayas were originally deposited as sediments in a ________.

The boundary between two terranes or two continents that have collided is called a ________.