Plate Tectonics and Island Formation

The rock type most likely being formed in Iceland is shown in the diagram is-

• metamorphic

• intrusive

• igneous

• sedimentary

The Hawaiian Islands are positioned over a hotspot in the middle of the Pacific Ocean, which is a location on a tectonic plate where magma pushes up through the crust from the mantle. There is regular volcanic activity on the islands, in which magma erupts as lava, but often parcels of magma rise and remain trapped below the surface of the earth. Which type of rock could a geologist expect to find deep below an inactive volcano on the Hawaiian Islands?

• sedimentary: the rocks would have cooled quickly in the Earth’s crust

• Metamorphic: the rocks would have cooled slowly in the Earth’s crust

• Intrusive Igneous: the rocks would have cooled slowly in the Earth’s crust

• Extrusive Igneous: the rocks would have cooled quickly in the Earth’s crust

A geologist studying volcanic activity is collecting rocks that formed from hot, molten magma. What type of rock is the geologist collecting?

• Clastic Sedimentary

• metamorphic

• Chemical Sedimentary

• Igneous

The horizontal structure shown in the rock formation 3 is called a-

• sill

• inclusion

• extrusion

• dike

Using the shown figure, place arrows to correctly identify the movement of the two plates at a convergent boundary.

• a

• b

• c

• d

Which figure correctly demonstrates the type of plate boundary found at mid-ocean ridges?

• a

• b

• c

• d

• e

A student examines 2 maps which show the distribution of Glossopteris fossils across Pangaea, and across the current location of continents. What is the most likely cause of the separation of the fossils, and the geographic evidence for it?

• the subduction of 1 plate under another caused the separation, & a continuous trench would serve as evidence.

• seafloor spreading caused the separation, & a line of volcanoes along Africa would serve as evidence

• the subduction of one plate under another caused the separation, & a line of islands would serve as evidence

• seafloor spreading caused the separation, & a mid-ocean ridge would serve as evidence

What type of stress is shown?

• uplift

• shearing

• compression

• tension

When the sea floor spreads apart, volcanoes and ridges are formed because-

• sediments are deposited where the floor spreads, building ridges

• ocean water pushes down on the surrounding sea floor, pushing up ridges

• underwater earthquakes lift the sea floor into long ridges

• as the plates pull apart, magma moves to the surface, building ridges

Which city was located the closest to the epicenter?

• New York

• Buffalo

• Boston

• Montreal