Exam 3: Plate Tectonics: a Unifying Theory

Which type of plate boundary is least likely to contain volcanoes?

Alfred Wegener gave the name Pangaea to the supercontinent of landmasses that later broke apart.

Compare and contrast the concepts of slab-pull and ridge-push. How might mantle plumes influence plate movement?

Features associated with ancient continental rift zones include faults, dikes, and sills.

Pieces of lithosphere with completely different fossil content, stratigraphy, structural trends, and paleomagnetic properties than surrounding rocks are called ____.

The oldest ocean crust is most likely to be found ____.

The first fossil evidence associated with the hypothesis of continental drift was ____ flora.

Although plate boundaries influence the distribution of some metals resources, petroleum geologists cannot effectively use tectonics to explain petroleum concentrations.

The volcanic Emperor Seamount-Hawaiian Island chain resulted from a hot spot.

Mantle convection cells are fueled with heat from the core.

Sequences of deep-sea sediments, oceanic crust, and upper mantle rocks on land-called ophiolites-indicate the presence of an old convergent boundary.

The present-day magnetic polarity of the Earth is called ____________________.

280,000,000 cm/115,000,000 years = 2.4 cm/year A magnetic anomaly that formed 115 million years ago and is 2,800 km away from the present-day mid-ocean ridge. What has the average rate of plate movement been over this time interval? (1 km = 100,000 cm)

At deep sea trenches, ____________________ crust is subducted into the ____________________.

An orogeny is an episode of lithospheric plate downwarping that forms a sedimentary basin.

Harry Hess used oceanographic research data to propose the theory of ____________________.

Earth's magnetic field is strongest at the equator and weakest at the poles.

The most effective method of calculating the rate of tectonic plate movement is to measure the thickness of a rock unit and divide that thickness by the age of the rocks.

The orientation of glacial striations was one piece of evidence supporting continental drift.

The Earth's present magnetic field is described as "normal," meaning that the north magnetic pole is located ____, and the south magnetic pole is located ____.