A SUMMARY OF CONTINENTAL DRIFT THEORY AND SUPPORTING DATA

Professor Wegener, University of Nevada-Reno

The theory of continental drift, first formulated in the 1920's, has a rich variety of data supporting it.  These data include patterns of rocks, structures, fossils, and sediments; the jigsaw fit of the continents; and patterns of biological evolution.

Continents drift over time.

PATTERNS OF EARTHQUAKE AND VOLCANO DISTRIBUTION

Dr. Magma, University of Calcutta

Earthquakes and volcanos can occur nearly anywhere on Earth; however, when the largest earthquake events and volcanic eruptions from the last 100 years are plotted on a map, patterns emerge.  The greatest activity occurs near mid-ocean ridges and trenches.

Earthquakes and volcanoes occur most often near mid-ocean ridges and trenches.

THE GEOGRAPHY OF THE OCEAN FLOOR

Dr. Acoustica, Institute for Undersea Mapping

Recent sonar mapping of the ocean floor reveals two outstanding features not previously known:  a mid-ocean valley (rift) and mountain system that runs the length of the Atlantic ocean; and a deep trench system that rings the Pacific Ocean.

Mid-ocean ridges and trenches are the most obvious features of the ocean floor.

AGES OF ROCKS NEAR MID-OCEAN RIDGES

Dr. von Tectos, University of Hamburg

An extensive sampling of rocks on either side of the Atlantic mid-ocean ridge was conducted.  Radiometric dating was used to determine the age of the rocks.  A very clear pattern emerges which indicates that rocks near the ridge are younger, and rocks farther from the ridge are older.

Rocks are younger near mid-ocean ridges and older farther away from those ridges.

SEISMIC PATTERNS AND THE INTERNAL STRUCTURE OF THE EARTH

Professor Seismos, Unversity of Athens

Earthquake waves bend when they go from one type of material to another.  S-waves do not travel through liquids at all.  By examining patterns of earthquake waves on a planetary scale, it is determined that Earth is composed of a relatively thin rigid outer layer (the lithosphere), a viscous plastic layer (the asthenosphere), a liquid outer core, and a solid inner core.

The outer, rigid layer of the Earth rests on a hot, plastic, flow-able layer..

MAGNETIC REVERSALS NEAR MID-OCEAN RIDGES

Dr. Polarski, University of Warsaw

A deep-ocean magnetometer array was towed across the Atlantic Ocean, back and forth across the mid-ocean ridge.  A pattern emerges of reversals in the magnetic polarity on either side of the mid-ocean ridge.  The patterns is symmetrical on either side of the ridge.

Magnetic reversals form a mirror image patter on either side of the Atlantic mid-ocean ridge.

DEEP CORE DRILLING

Profesor Mohorovicic, University of Moscow

Core samples from the drilling ship Soviet Glory have established the depth of the Earth's crust under the oceans.  This depth is considerably less than the thickness of the crust underneath continents, and it is much more iron-rich than continent rocks.

The crust under the ocean is thicker and more iron-rich than continental crust.

EARTHQUAKES AND VOLCANOES NEAR OCEAN TRENCHES

Dr. Fujii, Tokyo University

Recent seismic studies reveal a pattern of earthquake distribution near ocean trenches.  The pattern can best be described as lobe-shaped, moving diagonally underneath the continent.  Very large, violent volcanoes are located in regions inland from these trenches and above the lobe-shaped pattern of earthquake distribution.

Very large earthquakes and violent volcanos are found near ocean trench regions.