Exam 12: Plate Tectonics: The Framework for Modern Geology

Provide an example of Wegener's conjectures about continental drift for which there is no evidence.

Iceland is a good example of an island arc, formed from an oceanic-oceanic plate collision.

From the list below, which contribution did J.Tuzo Wilson make to Plate Tectonic theory?

During the first quarter of the twentieth century, ________ was the most vigorous proponent of continental drift.

By the Middle Jurassic, about 150 million years ago, Pangaea had split into Laurasia and Gondwanaland by the rifting that was opening the North Atlantic.

Pangaea was ________.

________ was never proposed as evidence supporting the existence of Pangaea.

Following technologic advances in ocean mapping that came from the Cold War in the 1950s and 1960s the new data from the ocean basins led ________ to propose the first model for seafloor spreading.

A transform plate boundary is characterized by ________.

The longest topographic feature on Earth, at > 70,000 kilometres, is the mid-ocean ridge system.

What are three ways of measuring plate tectonic rates of movement?

As continents drift, they plow through the thinner ocean lithosphere like big rocky "ice breakers" and push it out of their way.

Where lithosphere is sinking into the mantle, it is a ________ plate boundary.

In general, rocks of the continental crust are less dense than rocks of the oceanic crust.

In the early part of the 20th century, ________ argued forcefully for continental drift.

During various times in the geologic past, the polarity of Earth's magnetic field has been reversed.

Which of the following energy sources is thought to directly drive the lateral motions of Earth's lithospheric plates?

Early results of the Deep Sea Drilling Project clearly justified the conclusion that ________.

Of the approximately 40 "fixed" mantle hot spots, 12 of them are actually located on or near mid-ocean ridges and several of these generate symmetric lines of seamounts on both diverging plates.

________ to the south and ________ to the north were the two remaining halves of the Pangaea supercontinent once the Atlantic started to rift open.