Exam 6: The Active Earth: Plate Tectonics

____________ was found in the equatorial regions of Wegener's supercontinent called Pangea.

If a geologist is studying volcanoes on the ocean floor, she or he is examining a _________________.

Explain why the rock evidence that Wegener compiled supported his theory of continental drift.

The entire mantle-lithosphere system circulates in great ______________ cells.

If a geologist was studying oceanic crust, the rock material he or she collected would be primarily composed of __________________.

If you were a geologists studying the Mid-Atlantic Ridge, you would be examining what specific type of plate boundary?

Explain how mantle convection drives continental drift.

The concept that suggests the asthenosphere flows laterally away from a region to make space for a heavy lithospheric mass is known as ___________________.

Scientists theorize that tectonic plate movements formed the first ____________________ between 2 billion and 1.8 billion years ago.

Oceanic crust subduction into the mantle is the reason Manhattan Island is now nine meters farther from London than it was in 1776.

If a scientist discovers beaches that formed when glacier had depressed Scandinavia to sea level during the Last Ice Age, they would see that these beaches now lie well above that elevation because the land rose due to ___________.

Explain why the Hawaiian Island chain represents a mantle plume that wells up from a deeper convection system.

The internal heat from Earth's early melting event and from the continued decay of radioactive isotopes has allowed the interior of the Earth to remain hot even though the surface has cooled off.

The lithosphere floats on the asthenosphere because it is made of continental and oceanic crust that is buoyant rock and of the upper mantle where the temperature is cool and its pressure is low.

Continental rifting occurs when two continental plates pulling apart because basaltic magma works it way through the granitic crust allowing for volcanoes to erupt both basaltic and rhyolitic compositions.

The asthenosphere is deep enough below Earth's surface that the weight of glaciers and mountains can cause the asthenosphere to move laterally away from the depressed region,

If a geologist was studying continental crust, the rock material she or he collected would be primarily composed of ___________________.

Explain why mantle rock becomes weak and plastic in the asthenosphere.

Explain why the ocean crust contains magnetic stripes.

If you were a geologist, where on Earth would you search to find the oldest rocks?