PRESENTATION OUTLINE
CONTINENTAL DRIFT-
The movement across the Earth's surface through geological times.
-Alfred Wegener-
MID OCEAN RIDGE-
Any of several seismically active submarine mountain ranges that extend through the Atlantic, Indian, and South Pacific oceans: each is hypothesized to be the locus of seafloor spreading.
-Henry Hess-
SEA-FLOOR SPREADING-
A process in which new ocean floor is created as molten material from the earth's mantle rises in margins between plates or ridges and spreads out.
-Henry Hess-
PANGAEA-
The hypothetical landmass that existed when all continents were joined, from about 300 to 200 million years ago.
-Abraham Ortelius-
PLATE TECTONICS-
A theory of global tectonics in which the lithosphere is divided into a number of crustal plates, each of which moves on the plastic asthenosphere more or less independently to collide with, slide under, or move past adjacent plates.
-Henry Hess-
ABRAHAM ORTELIUS-
1596, the Dutch map maker Abraham Ortelius believed the continents where put together as one big land mass and have since drifted apart "by earthquakes and floods" His "evidence" was the jigsaw fit of the continents. Ortelius's idea helped provide Hess and Wegener with their theories!
ALFRED WEGENER-
In 1912 he purposed the idea of continental drift, which he believed was true because of the different placement of animals, plants, fossils and glacial deposits! Wegener's idea was not accepted by the scientific community at this time because there was little evidence to support his theory. In the 1960s there was a growing amount of evidence to support his idea, which is now widely accepted!
HENRY HESS-
Henry Hess was very influential in setting the stage for the plate-tectonics theory in the early 1960s. Hess believed in many of Wegener's observations made about continental drift, although he had a different idea on the large-scale movements of Earth. Hess idea is largely accepted and confirmed as knowledge of the ocean floor increased dramatically during his lifetime.
