Exam 2: Plate Tectonics: A Unifying Theory

The Appalachian Mountains of the eastern United States are thought to have once been joined with mountains located in which other continental regions?

Briefly explain why apparent polar wandering is "apparent".

What were the major lines of evidence for continental drift as presented by Wegener in the early 20ᵗʰ century?

What two features of the magnetic field do magnetic iron-bearing minerals that crystallize out of magma record?

The cause of magnetic reversals is a change in the structure of the Earth's inner core.

Large,high mountain ranges without volcanoes are built at which type of plate boundary?

Features associated with ancient continental rift zones include andesite volcanoes and strike slip faulting.

The type of plate boundary that runs through California is called ____________________,and the name of this plate boundary is the ____________________.

Earth's magnetic field is dipolar,meaning that it has two similar magnetic poles one at the north pole and one at the south pole.

Changes in the Earth's magnetic field have occurred throughout geologic time,and these are called magnetic reversals.

Copper deposits are most commonly found at transform plate boundaries.

Why were glacially deposited strata important in the development of continental drift theory?

Magnetic stripes in oceanic basalts are ____________________ and ____________________ around ocean ridges.

At deep-sea trenches,____________________ is subducted back into the ____________________.

Why were glacially deposited strata important in the development of the continental drift hypothesis?

Aseismic ridges have that name because they do not have earthquakes.

That the northern continents were once joined and located along the equator was shown by the:

Around most of the Atlantic the continental slope descends into an oceanic trench but around the Pacific the continental slope merges with a more gently sloping continental rise.

The process that continues to move Africa and South America apart from each other is ____________________.

Draw a cross-section of an oceanic-oceanic convergent plate boundary.Show the directions of relative plate motion.Put stars for the locations of earthquakes.Put triangles with smoke out the top for the locations of volcanoes.Label the trench,back arc basin,and subduction complex.