This document provides an overview of plate tectonics and types of plate boundaries. It defines plates as large, rigid slabs that move slowly over the asthenosphere. There are 6 major and 20 minor tectonic plates. Plates interact along boundaries where they converge, diverge, or move past each other, causing seismic and volcanic activity. The three main types of plate boundaries are divergence boundaries where plates move apart, convergence boundaries where they move together, and transform boundaries where they slide past each other.
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Plate tectonics
1. Plate tectonics and Types of Plate
boundaries
DEPARTMENT OF GEOLOGY
Guided By Presented By
Prof. Lalsingh Solanki Aakash khede
M.Sc. 1st semester
2. Table of contents
1. Introduction
2. Concept of Plate tectonics
3. What is Plate ?
4. What is Plate tectonics ?
5. What are Tectonic plates made up of ?
6. Types of plate boundaries
6.1 Divergence
6.2 Convergence
6.2.1 Ocean-Continent convergence
6.2.2 Ocean-Ocean convergence
6.2.3 Continent-Continent convergence
6.3 Transform
7. Plate movement
8. Physical features of Plate Tectonics
9. Importance of Plate Tectonics
10. References
3. INTRODUCTION
The concept of plate tectonics was formulated in the 1960s. According to
the theory, Earth has a rigid outer layer, known as the lithosphere, which is
typically about 100 km (60 miles) thick and overlies a plastic (moldable,
partially molten) layer called the asthenosphere. The lithosphere is broken
up into seven very large continental- and ocean-sized plates, six or seven
medium-sized regional plates, and several small ones. These plates move
relative to each other, typically at rates of 5 to 10 cm (2 to 4 inches) per
year, and interact along their boundaries, where they converge, diverge, or
slip past one another. Such interactions are thought to be responsible for
most of Earth’s seismic and volcanic activity, although earthquakes and
volcanoes can occur in plate interiors. Plate motions cause mountains to
rise where plates push together, or converge, and continents to fracture
and oceans to form where plates pull apart, or diverge. The continents are
embedded in the plates and drift passively with them, which over millions
of years results in significant changes in Earth’s geography.
4. CONCEPT OF PLATE TECTONICS
Plate tectonic theory is based on two major scientific concept :
1. The concept of continental drift :- In 1908 , It was F.B Taylor who
propounded the continental – drift hypothesis , incorporating much
other geological evidence . In 1910 and 1912 , Alfred Wegener , a
German meteorologist , advocated the continental had drifted apart
and suggested mechanism by which this might have occurred .
2. The concept of sea floor spreading:- Seafloor spreading is a process
that occurs at mid-ocean ridges, where new oceanic crust is formed
through volcanic activity and than gradually moves away from the
ridge. Professor Harry Hess of Princeton university was first to
formulate the hypothesis of ‘seafloor spreading; in 1960.
5. If you look at a map of the world , you may notice
that some of the continental could fit together like
pieces of a puzzle.
6. What is Plate ?
• Plate term was first used by Canadian Geophysicist J. T.
Wilson in 1965.
• W. J. Morgan and Le Pichon elaborated the various aspects
of plate tectonic in 1968.
• A Plate is a large, rigid slab of rock which move slowly over
the Asthenosphere.
• The thickness of a plate is from ‘ 0 to 10 Kms at the ridges
and 100 to 150 km elsewhere.
• There are 6 major and 20 minor plates present on the world
map.
• The rigid lithospheric slabs or rigid and solid crustal layers
are technically called plates.
• The Earth’s crust and upper mantle are broken into sections
called plates.
• Plates move around on top of the mantle like rafts.
8. What is plate tectonics ?
The whole mechanism of the evolution, nature and
motion of plates and resultant reaction is called
plate tectonic. Or the whole process of plate
motion is referred to as plate tectonic.
Plate boundary- zone of motion between two
plates.
Plate margin- the marginal part of a particular
plate.
9. Plate Tectonics
1. The earth’s crust Is divided into 7 major plates
which are moved in various directions.
2. The Plates Collide, Pull apart or scrape against
each other.
3. Each motion causes different types of features on
the Earth’s crust.
4. The word tectonic refers to the changes in the
crust because of plate interaction.
10. What are Tectonic Plates made up of ?
• Plates are made of rigid lithosphere.
• The lithosphere is made up of the upper
part of the mantle.
What lies beneath the tectonic Plates ?
• Below the lithosphere is the
asthenosphere.
22. • Mariana Trench is located in the Western Pacific
Ocean about 200 km east of the Mariana Islands.
Mariana Trench is 2,550 km long and 69 km wide.
27. Plate movement
Plates of the lithosphere are moved around by the
underlying hot mantle convection cells.
30. Importance of Plate-Tectonic theory
• Origin and distribution of earthquakes.
• Origin of mountain ranges and their
distribution .
• Formation of island arcs and oceanic
trenches.
• Distribution of volcanoes.
• Continental drift.
• Formation of mid-oceanic ridges and
rift valleys.
• Sea-floor spreading, etc.
31. References
1. DR. GHOSH MUKUL & DR. SHRIVASTAV D. K.,
PHYSICAL GEOLOGY, MADHYA PRADESH HINDI
GRANTH ACADEMY BHOPAL ( page no. 113 to
133)
2. MAHAPATRA G.B. , THE TEXTBOOK OF PHYSICAL
GEOLOGY,2014,CBS PUBLISHERS(page no. 128 to
172)
3. https://en.m.wikipeduia.org/wiki/Plate_tectonics
4. Youtube.com