THE PLATE TECTONICS THEORY AND HOW IT REVOLUTIONIZED THE EARTH SCIENCE

THE PLATE TECTONICS THEORY AND HOW IT REVOLUTIONIZED THE EARTH SCIENCES

Ms. Shiela Mae L. Balut

Learning Objectives

1. 1.​Explain how the plates originate;

2. ​2.Appreciate the Continental drift and Seafloor spreading theory in supporting the Plate tectonics theory; and

3. 3.Cite the important pieces of evidence at present that support the Plate Tectonics theory.

​

​How these processes in the mantle-core connect and influence the exogenic global processes, operating in the Earth's outermost solid layer?

​

Fill in the Blanks

It is a body of scientific explanations or a theory about how the earth's outer solid layer developed through time, from the past up to the present. It can also predict what will happen to the Earth in the future.

​Did you know that...

​Tectonics

Latin word, tectonicus, Greek word, tektonikos means "building".

​

​In geological sense, it refers to the structure of the earth's crust.

​The lithosphere was broken into irregularly-shaped plates with different surface areas.

Multiple Select

What are the Earth's  major plates?

• Pacific plate

  North American plate

  South American plate

• Nazca plate

  Philippine Sea plate

  Scotia plate

• Eurasian plate

  African plate

  Antarctic plate

  Indian-Australian plate

• Cocos plate

  Caroline plate

  Arabian plate

  Caribbean plate

​major plates- areas >10 million km²

​minor plates- <10 million km²

​German meteorologist

​Continental drift Theory(1912)

Alfred Lothar Wegener 1880-1930

Fill in the Blanks

Wegener explained the striking fit between the continents along their coastlines, for example, between the western coastline of ______ and that of ______.

Fill in the Blanks

Wegener proposed that all of the continents once formed a single supercontinent called _.

Open Ended

Wegener cited observations to support his claim. What are these?

The evidences​

​1. Fossils evidence in the same rock formations of South America and Africa

2.Similarities of rocks between the mountain ranges of Greenland and Scandinavia

​3. The continuity of the shortened rock regions in Europe can be found in North America

​4. Common traces of glaciation in Australia, South Africa, South America and India during the Permian period

​5. Traces of polar wandering during the Tertiary period

Alfred Lothar Wegener

​German meteorologist

The breakup of Pangaea was caused by the equatorial centrifugal force (outward force) that is produced by the Earth's rotation.

Open Ended

Why Wegener's continental drift was rejected by many scientific experts?

Fill in the Blanks

In 1950's onward to the 1970's, Wegener's theory was revived, when substantial data were obtained from the world's oceans due to the heightened interest in exploring these unchartered parts of the world. What is that theory proposed by Harry Hess?

​

Scientists who supported the ideas of Wegener, drew a mechanism of continental drifting from basic scientific disciplines to form multi-disciplinary explanation.

Harry Hess(1906-1969)

​American Petrologist/Geologist

​Rear Admiral of the U.S Navy

​Commander of the U.S. Cape Johnson in the Pacific Ocean World war II

Robert Dietz (1941-1995)

Oceanographer

They discovered the varying intensities of the magnetic field in the oceans and started undertaking echo-sounding surveys of the seafloor.

​Volcanic activity forms a guyot under the ocean. Vents in the seafloor over an area of volcanic activity may produce lava periodically to grow a guyot or other seamount formation. A seamount is any kind of underwater elevated landform.

​The ocean floor spreads apart and travels away from where it forms, becomes colder as it ages, and sinks back into the mantle to be melted again into a mantle material.

​

In 1963, they ​provided the major evidence in favor of this theory that the seafloor spread apart.

​

​Frederick John Vine(1939) & Drummond Hoyle Matthews(1931-1997)

​ (British geophysicists)

​The symmetrical patterns of magnetization of the rocks in the ocean floor

​education.psu.edu/earth520

​

​John Tuzo Wilson (1908-1993)

​Canadian geophysicist

​In 1965, he unified the continental drift and the seafloor spreading theory to become the plate tectonics theory.

​Basic Evidence that supports the Plate Tectonics Theory

​1. The continents fit along their coastlines into one supercontinent, Pangaea, as Wegener's continental drift theory had predicted.

2.The distribution of marker fossils across continents forms a contiguous pattern when the continents are fit together.

​marker fossils serve as indispensable tools in delineating specific time spans in earth's history

3.Geological features, such as mountain ranges, rock formations with the same ages, and rock characteristics of continents, such as North America and Europe, form contiguous bodies when continents fit together.

​4. Contrasting paleoclimate indicators or deposits provide clues that continents, such as Antarctica and Europe, which were once situated in the tropics are now found in arctic and temperate climate environments. The tropical deposits such as coal, coral reefs and evaporites were once situated in the tropics and had migrated to where they are now found.

​Climatic zones do not change locations but continents change locations because of their drifting.

​5.Glacial deposits (tillites) found in South America,Africa,India, and Australia or close to the equator and far from latitudes experience glaciation.

Open Ended

What are the ​Basic Evidence that supports the Plate Tectonics Theory?

​Basic Evidence that supports the Plate Tectonics Theory

​1. The continents fit along their coastlines.

​2.Marker fossils

​3. Geological features, such as mountain ranges, rock formations with the same ages, and rock characteristics of continents

​4.Paleoclimate indicators or deposits

​5. Glacial evidence