What is the difference between the concepts of the lithosphere and the earth's crust. "lithosphere
The purpose of the lesson: to form an idea about the inner layers of the Earth and their distinctive features, about the movement of lithospheric plates.
Tasks:
1. Introduce students to the inner layers: the earth's crust, mantle, core and their distinctive features. Define the term lithosphere.
2. Demonstrate the result of the movement of lithospheric plates.
3. Develop students' skills to analyze information, read a diagram, highlight the main thing, use additional information, work with a geographical map.
4. Teach students how to work with electronic textbooks.
5. Contribute to the formation of geographical thinking of schoolchildren, geographical culture.
Used in the lesson electronic textbook- an appendix to the textbook by A.I. Alekseev "Geography. Grade 6". M., Enlightenment, 2012
Download:
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Municipal educational institution
"Average comprehensive school No. 85"
city of Taishet, Irkutsk region
Geography lesson in 6th grade.
Topic: " Earth's crust- the upper part of the lithosphere "
Conducted by a geography teacher
Feskova Vera Pavlovna
Taishet, 2014
The purpose of the lesson: to form an idea about the inner layers of the Earth and their distinctive features, about the movement of lithospheric plates.
Tasks:
- To acquaint students with the inner layers: the earth's crust, mantle, core and their distinctive features. Define the term lithosphere.
2. Demonstrate the result of the movement of lithospheric plates.
3. Develop students' skills to analyze information, read a diagram, highlight the main thing, use additional information, work with a geographical map.
4. Teach students how to work with electronic textbooks.
5. Contribute to the formation of geographical thinking of schoolchildren, geographical culture.
Methods . Verbal, verbal-visual, practical.
Form of work: work in pairs.
Lesson type. Combined.
Substantiation and features of the used methods / teaching methods, pedagogical technologies.Leading technology this lesson - developing education using ICT.Within the framework of this technology, active methods learning(AMO): verbal - problem presentation of new material, conversation; illustrative -presentation material, relief globe "Internal structure of the Earth", samples rocks; practical - independent work, filling in the table, working with a physical map of the hemispheres; gaming - to explain the concept of "lithospheric plates", relaxation.
Equipment: interactive board,projector, 15 laptops,atlases, textbook, notebook, electronic supplement to the textbook, embossed globe "Internal structure of the Earth", rock samples:basalt, granite, sulfur, video "Professor Pochemushkin - Earth's crust", physical map hemispheresdispensing didactic material, cards: brown - "Continental lithospheric plate", blue - "Oceanic lithospheric plate", apple.egg, presentation "Earth's crust".
During the classes
Org. moment.
Sl. one
Today we have an unusual lesson.
We have guests.
Turn around. Greet guests with a smile.
Wish each other good luck! Hands!
You are working in pairs today.
Sl. 2
I. Stage initiation.Using the "Let them talk" method.
How do you understand these words?
II. Introduction to the topic:(Message of the topic and objectives of the lesson)
Astronauts flying in outer space say that when viewed from spaceship has an excellent blue color.Looks like a precious blue pearl.
This color is due to the properties of the atmosphere andThe fact that the World Ocean covers 71% of its area. What or who is it about?
About the planet Earth. Right.I show the globe.
What do you know about the Earth? (shape and size)
Ball, geoid, Radius = 6371 km,
Equator length \u003d 40 00 km, the longest parallel
All meridians are the same length = 20,000 km
What shells of the Earth do you know?
Atmosphere
Hydrosphere
Lithosphere
Biosphere
Do shells interact with each other?
Yes
Sl. 3
- Watch the video "Professor Pochemushkina" and say guess what our lesson will be about?
your versions.
- "The Structure of the Earth".
Yes, we will consider the structure of the Earth, but in detail over the course of several lessons we will talk aboutthe earth's crust - the upper part of the lithosphere.
(on the slide is the topic of the lesson).
slide 2
Lithosphere.
What is this shell? - the solid shell of the Earth. "Lithos" - in Greek - stone, (show basalt, granite).
What is the goal, what tasks will we solve in today's lesson?
What is your point of view? (children formulate the purpose of the lesson):
The goal is to form an idea of the internal structure of the Earth,
Learn about the types of the earth's crust,
Learn to establish causal relationships;
Develop the ability to build your speech. You will receive bonuses for this
Understand and accept another position,
Work in pairs, team
- we will continue to learn how to work with an electronic textbook
III Interactive lecture. (Transfer and explanation of information)
You will work on worksheets that you will paste into your notebook at home.
Underline the subject and include the date.
Lesson topic: The earth's crust is the upper part of the lithosphere.
Today you yourself will teach a friend
Sl. four
1. Independent work in rows. Method "Creative Lab".
- The right to work on the head CT and teach others, those who quickly read, quickly find the necessary information, enter it into the table of the working fox and show willingness to answer.
1 row - core
2 row - mantle
3 row - the earth's crust
4 - The composition of the earth's crust
Work according to instructions
Open § 20. Find these terms in the text. Fill in the table only where the term of your series is indicated. Get ready to answer. Paste the worksheet into your notebook at home.
Shell name | What does it consist of | Thickness | Temperature |
1st row Core | |||
2nd row Mantle | |||
3 row. Earth's crust | |||
Structure earth's crust | continental crust= ___ layer: 1_________________________ 2_________________________ 3_________________________ | ||
1._________________________ 2__________________________ |
2. Verification
1 row - Core . Goes to the board and methoddrag and drop inserts:
Made of iron and nickel.The outer core is 2250 km. The inner core is 1250 km. 3500km. 6000°. Solid. Liquid.
Someone from the row complements. The rest are listed on their list. Let's estimate.
I - External relatively light, each cubic cm weighs 14 grams. Presumably composed of sulfur.(show sulfur)
2 row - Mantle. They go to the board and insert by drag and drop:
2800 km. 2000°. Bedspread Plastic
Shell name | What does it consist of | Thickness | Temperature |
Nucleus | |||
Mantle |
- 3 row. Earth's crust. They go to the board and insert by drag and drop:
80km Solid
Shell name | What does it consist of | Thickness | Temperature |
Nucleus | |||
Mantle | |||
Earth's crust |
Sl. ten
3. Teamwork.
- Page 68 last paragraph.
Reading.
One student goes to the head CT and inserts by drag and drop:
2 3 sedimentary sedimentary granitic basalt basalt.
4. Creating a problem situation
BUT. Why is the earth compared to an apple? an egg?
I show you a cut egg.
If we compare the Earth with an apple, then ZK will be only its thin skin. But it is this “skin” that is intensively used by man. Cities, industrial buildings were built on its surface, minerals are mined from its bowels. It gives a person water, energy and many others.
B. - What do you think, is it possible for Professor Pochemushkin to travel to the bowels of our amazing planet?(Not)
- Why? (pressure, temperature)
- I think each of you has a question:how did people know what the Earth has inside?
I show a relief globe and the internal structure of the Earth.
– There are 2 modern methods study. It is cosmic and seismic.
A picture from space.
The space method is based on photographs taken from space. On them you can see faults, as well as the bottom of the ocean to a depth of 700 meters.
Sl. eleven
seismic methodis based on the change in the speed of passage of seismic waves in the lithosphere. In different rocks, the speed is not the same. And the change in speed makes it possible to judge the structure of the lithosphere.
A seismograph is an instrument that records the vibrations of the earth's crust.
(Video clip. The work of a seismograph.
5. Relaxation . Physical pause. Let's depict one of the states " Earth, air, water"
Earth. We must make contact with the ground,ground yourself and feel confident. The teacher, together with the students, begins strongly press on the floor , standing in one place, you can stomp your feet and even a couple of times jump up. Can rub your feet on the floorspin in place. The goal is to have a new sense of your feet, which are farthest from the center of consciousness, and through this bodily sensation to feel more stable and confident.
Sl. 12
Open E.U.
6. Fixing. Performing interactive tasks from the EU.
A.- Let's practice perform interactive tasks in the electronic textbook.
Open EU, § 20
Slide number 6. Complete interactive tasks #6.
Determine the elements of the earth's structure.Well done!!! That's right!
The task is more difficult than the first, so help each other! Who needs my help - a hand.
Let's color the structure of the Earth.Well done!!! That's right!
Let's celebrate each other's success! Let's clap!!!
Close the slide.
Sl. fourteen
B. Open the Trainer . Activity 7
Slide number 7. Work as directed in pairs. Time 2 min. First 5 people get grades.
Give yourself grades: 100% = "5"; 80% = "4"; 60% "3"
8. Lithospheric plates.§ twenty
The lithosphere is not monolithic. It is broken by faults into separate blocks - lithospheric plates. Textbook p.70
In total, seven are distinguished on Earth very large lithospheric plates and several smaller ones.
Lithospheric plates interact with each other in different ways.
Moving along the plastic layer of the mantle, they move apart in some places, and collide with each other in others.
Working with the tutorial map p.70.
Exercise:
Find and show in the figure the boundaries of the expansion and the boundaries of the collision of lithospheric plates.
List the names of the plates.
Determine which lithospheric plate you live on.
9. Practical work. Chips!!
Working with a physical map. Find mountains on the map that stretch along the lithospheric plates and mark them with chips.
Himalayas - Everest-Chomolungma - 8848m
Alps - Mont Blanc - 4808 m
Cordillera - Mack - Kinley - 6194m
Andes – Aconcagua - 6960m
Sl. fifteen
10. Summing up. Reflection
Game "Erudite"
Tell us about the lithosphere, the earth's crust, as much as possible.
It is allowed to speak only one sentence at a time, starting with the words: "I know that ...". Can't be repeated.
Slide I know...
I know that The lithosphere is the shell of the Earth.
I know that the lithosphere is made up of the earth's crust and the upper mantle.
I know that the lithosphere - unites the inner and outer shells of the Earth.
I know that the lithosphere is the stone shell of the Earth.
I know that the earth's crust is divided into continental and oceanic.
Did you answer all the questions posed at the beginning of the lesson?
Yes. Was our work productive?
Has the motto of the lesson been confirmed?
"Argue, be mistaken, make mistakes, but, for God's sake, think and even crookedly, but yourself."
11. Grading. Open diaries!
Sl. 16
12. Homework
1. Study § 20, questions 2,5,7,8
2. Paste the worksheet into your notebook at home.
3. E.U. § twenty - slide 8 "Control".
Application No. 1
Handout for the lesson.
Worksheet
Lesson topic: The earth's crust is the upper part of the lithosphere.
Instruction
Open § 20. Read the material on page 68. Look at Figure 42.Find these terms in the text. Fill in the table only where the term of your series is indicated. At home, paste the sheet into the notebook.
Structure
earth's crust
continental crust= ___ layer:
1_________________________
2_________________________
3_________________________
Oceanic crust = ____ layers:
1._________________________
2__________________________
Used Books:
1. Alekseev A.I. Textbook: “Geography. Grades 5-6 ", textbook for 6 classes general educational institutions.M.Prosveshchenie, 2012.
2. Guseva E.E. Geography. 6th grade. "Current Control Constructor". A guide for the teacher. . M., "Enlightenment", 2012.
3. Nikolina V. V. Geography. 6th grade. My trainer. A guide for students of educational institutions M. Education, 2008.
4. Nikolina V.V. Geography. Lesson developments, grades 5-6. Handbook for teachers of educational institutions. M., "Enlightenment", 2012.
Internet resources used:
1. http://www.nature.com
2. http://nature.worldstreasure.com/ - wonders of nature
4. http://demonstrations.wolfram.com - 3D images
5. http://ru.wikipedia.org/wiki
The state of rest is unknown to our planet. This applies not only to external, but also to internal processes that occur in the bowels of the Earth: its lithospheric plates are constantly moving. True, some parts of the lithosphere are quite stable, while others, especially those located at the junctions tectonic plates, are extremely mobile and constantly shudder.
Naturally, people could not leave such a phenomenon unattended, and therefore, throughout their history, they studied and explained it. For example, in Myanmar, the legend is still preserved that our planet is entwined with a huge ring of snakes, and when they begin to move, the earth begins to tremble. Such stories could not satisfy inquisitive human minds for a long time, and in order to find out the truth, the most curious drilled the earth, drew maps, made hypotheses and put forward assumptions.
The concept of the lithosphere contains the solid shell of the Earth, consisting of the earth's crust and a layer of softened rocks that make up the upper mantle, the asthenosphere (its plastic composition makes it possible for the plates that make up the earth's crust to move along it at a speed of 2 to 16 cm in year). It is interesting that the upper layer of the lithosphere is elastic, and the lower layer is plastic, which makes it possible for the plates to maintain balance when moving, despite constant shaking.
During numerous studies, scientists came to the conclusion that the lithosphere has a heterogeneous thickness, and largely depends on the terrain under which it is located. So, on land, its thickness ranges from 25 to 200 km (the older the platform, the larger it is, and the thinnest is under the young mountain ranges).
But the thinnest layer of the earth's crust is under the oceans: its average thickness ranges from 7 to 10 km, and in some regions of the Pacific Ocean it even reaches five. The thickest layer of the crust is located along the edges of the oceans, the thinnest - under the mid-ocean ridges. Interestingly, the lithosphere has not yet fully formed, and this process continues to this day (mainly under the ocean floor).
What is the earth's crust made of
The structure of the lithosphere under the oceans and continents is different in that there is no granite layer under the ocean floor, since the oceanic crust has undergone melting processes many times during its formation. Common to the oceanic and continental crust are such layers of the lithosphere as basalt and sedimentary.
Thus, the earth's crust consists mainly of rocks that are formed during the cooling and crystallization of magma, which penetrates into the lithosphere through cracks. If at the same time the magma could not seep to the surface, then it formed such coarse-grained rocks as granite, gabbro, diorite, due to its slow cooling and crystallization.
But the magma that managed to get out, due to rapid cooling, formed small crystals - basalt, liparite, andesite.
As for sedimentary rocks, they were formed in the Earth's lithosphere in different ways: clastic rocks appeared as a result of the destruction of sand, sandstones and clay, chemical ones were formed due to various chemical reactions in aqueous solutions it is gypsum, salt, phosphorites. Organic were formed by plant and lime residues - chalk, peat, limestone, coal.
Interestingly, some rocks appeared due to a complete or partial change in their composition: granite was transformed into gneiss, sandstone into quartzite, limestone into marble. According to scientific research, scientists managed to establish that the lithosphere consists of:
- Oxygen - 49%;
- Silicon - 26%;
- Aluminum - 7%;
- Iron - 5%;
- Calcium - 4%
- The composition of the lithosphere includes many minerals, the most common are feldspar and quartz.
As for the structure of the lithosphere, stable and mobile zones are distinguished here (in other words, platforms and folded belts). On tectonic maps, you can always see the marked boundaries of both stable and dangerous territories. First of all, this is the Pacific Ring of Fire (located along the edges Pacific Ocean), as well as part of the Alpine-Himalayan seismic belt (Southern Europe and the Caucasus).
Description of platforms
The platform is practically immovable parts of the earth's crust that have gone through a very long stage of geological formation. Their age is determined by the stage of formation of the crystalline basement (granite and basalt layers). Ancient or Precambrian platforms on the map are always located in the center of the continent, young ones are either on the edge of the mainland, or between the Precambrian platforms.
Mountain-fold area
The mountain-folded region was formed during the collision of tectonic plates, which are located on the mainland. If the mountain ranges were formed recently, increased seismic activity is recorded near them, and all of them are located along the edges of the lithospheric plates (the younger massifs belong to the Alpine and Cimmerian stages of formation). Older areas related to the ancient, Paleozoic folding, can be located both on the edge of the mainland, for example, in North America and Australia, and in the center - in Eurasia.
It is interesting that scientists determine the age of mountain-folded areas according to the youngest folds. Since mountain building is ongoing, this makes it possible to determine only the time frame of the stages of development of our Earth. For example, the presence of a mountain range in the middle of a tectonic plate indicates that the border once passed here.
Lithospheric plates
Despite the fact that ninety percent of the lithosphere consists of fourteen lithospheric plates, many do not agree with this statement and draw their own tectonic maps, saying that there are seven large and about ten small ones. This division is rather arbitrary, because with the development of science, scientists either identify new plates, or recognize certain boundaries as non-existent, especially when it comes to small plates.
It is worth noting that the largest tectonic plates are very clearly visible on the map and they are:
- The Pacific is the largest plate on the planet, along the boundaries of which constant collisions of tectonic plates occur and faults form - this is the reason for its constant decrease;
- Eurasian - covers almost the entire territory of Eurasia (except Hindustan and the Arabian Peninsula) and contains the largest part of the continental crust;
- Indo-Australian - consists of the Australian continent and the Indian subcontinent. Due to constant collisions with the Eurasian plate, it is in the process of breaking;
- South American - consists of the South American mainland and part of the Atlantic Ocean;
- North American - consists of the North American continent, part of northeastern Siberia, the northwestern part of the Atlantic and half of the Arctic Oceans;
- African - consists of the African continent and the oceanic crust of the Atlantic and Indian Oceans. It is interesting that the plates adjacent to it move in the opposite direction from it, therefore the largest fault of our planet is located here;
- The Antarctic Plate is made up of the mainland Antarctica and the nearby oceanic crust. Due to the fact that the plate is surrounded by mid-ocean ridges, the rest of the continents are constantly moving away from it.
Movement of tectonic plates
Lithospheric plates, connecting and separating, change their outlines all the time. This enables scientists to put forward the theory that about 200 million years ago the lithosphere had only Pangea - a single continent, which subsequently split into parts, which began to gradually move away from each other at a very low speed (an average of about seven centimeters per year). ).
There is an assumption that due to the movement of the lithosphere, in 250 million years a new continent will form on our planet due to the union of moving continents.
When the oceanic and continental plates collide, the edge of the oceanic crust sinks under the continental one, while on the other side of the oceanic plate its boundary diverges from the plate adjacent to it. The boundary along which the movement of the lithospheres occurs is called the subduction zone, where the upper and plunging edges of the plate are distinguished. It is interesting that the plate, plunging into the mantle, begins to melt when the upper part of the earth's crust is squeezed, as a result of which mountains are formed, and if magma also breaks out, then volcanoes.
In places where tectonic plates come into contact with each other, there are zones of maximum volcanic and seismic activity: during the movement and collision of the lithosphere, the earth's crust collapses, and when they diverge, faults and depressions form (the lithosphere and the Earth's relief are connected to each other). This is the reason why the largest landforms of the Earth are located along the edges of the tectonic plates - mountain ranges with active volcanoes and deep-sea trenches.
Relief
It is not surprising that the movement of the lithosphere directly affects appearance of our planet, and the diversity of the Earth's relief is amazing (relief is a set of irregularities on earth's surface, which are above sea level at different heights, and therefore the main forms of the Earth's relief are conventionally divided into convex (continents, mountains) and concave - oceans, river valleys, gorges).
It is worth noting that the land occupies only 29% of our planet (149 million km2), and the lithosphere and the Earth's relief consist mainly of plains, mountains and low mountains. As for the ocean, its average depth is a little less than four kilometers, and the lithosphere and the relief of the Earth in the ocean consist of a continental shelf, a coastal slope, an oceanic bed, and abyssal or deep-sea trenches. Most of The ocean has a complex and varied relief: there are plains, basins, plateaus, hills, and ridges up to 2 km high.
Problems of the lithosphere
The intensive development of industry has led to the fact that man and the lithosphere in recent times began to get along extremely badly with each other: pollution of the lithosphere is acquiring catastrophic proportions. This happened due to the increase in industrial waste in conjunction with household waste and used in agriculture fertilizers and pesticides, which negatively affects chemical composition soil and living organisms. Scientists have calculated that about one ton of garbage falls per person per year, including 50 kg of hardly decomposable waste.
Today pollution of the lithosphere has become topical issue, since nature is not able to cope with it on its own: the self-purification of the earth's crust is very slow, and therefore harmful substances gradually accumulate and over time have a negative impact on the main culprit of the problem that has arisen - a person.
In this video lesson, everyone will be able to study the topic "The structure of the Earth." Users will learn about how the earth's crust is studied, what properties it has, what layers our planet consists of. The teacher will talk about the structure of the Earth, how it was studied at different times.
2. Mantle.
As we move deeper into the Earth, temperature and pressure increase. In the center of the Earth is the core, its radius is about 3500 km, and the temperature is more than 4500 degrees. The core is surrounded by a mantle, its thickness is about 2900 km. Above the mantle is the earth's crust, its thickness varies from 5 km (under the oceans) to 70 km (under mountain systems). The earth's crust is the hardest shell. The substance of the mantle is in a special plastic state; this substance can slowly flow under pressure.
Rice. 1. The internal structure of the Earth ()
Earth's crust- the upper part of the lithosphere, the outer solid shell of the Earth.
The earth's crust is made up of rocks and minerals.
Rice. 2. The structure of the Earth and the earth's crust ()
There are two types of earth's crust:
1. Continental (it consists of sedimentary, granite and basalt layers).
2. Oceanic (it consists of sedimentary and basalt layers).
Rice. 3. The structure of the earth's crust ()
The mantle accounts for 67% of the total mass of the Earth and 87% of its volume. Separate the upper and lower mantle. The material of the mantle can move under pressure. Internal heat from the mantle is transferred to the earth's crust.
The core is the deepest part of the Earth. There is an outer liquid core and an inner solid core.
Most of the earth's crust is covered by the waters of the oceans and seas. The continental crust is much larger than the oceanic and has three layers. The upper part of the earth's crust is heated by the sun's rays. At a depth of more than 20 meters, the temperature practically does not change, and then increases.
The most accessible for human study is the upper part of the earth's crust. Sometimes deep wells are made to study the internal structure of the earth's crust. The deepest well is over 12 km deep. Help to study the earth's crust and mines. In addition, the internal structure of the Earth is studied using special instruments, methods, images from space and sciences: geophysics, geology, seismology.
Homework
Paragraph 16.
1. What parts does the Earth consist of?
Bibliography
Main
1. Initial course of geography: Proc. for 6 cells. general education institutions / T.P. Gerasimova, N.P. Neklyukov. - 10th ed., stereotype. - M.: Bustard, 2010. - 176 p.
2. Geography. Grade 6: atlas. - 3rd ed., stereotype. - M.: Bustard, DIK, 2011. - 32 p.
3. Geography. Grade 6: atlas. - 4th ed., stereotype. - M.: Bustard, DIK, 2013. - 32 p.
4. Geography. 6 cells: cont. cards. - M.: DIK, Bustard, 2012. - 16 p.
Encyclopedias, dictionaries, reference books and statistical collections
1. Geography. Modern illustrated encyclopedia / A.P. Gorkin. - M.: Rosmen-Press, 2006. - 624 p.
Literature for preparing for the GIA and the Unified State Examination
1. Geography: an initial course. Tests. Proc. allowance for students 6 cells. - M.: Humanit. ed. center VLADOS, 2011. - 144 p.
2. Tests. Geography. 6-10 cells: Teaching aid/ A.A. Letyagin. - M .: LLC "Agency" KRPA "Olimp": "Astrel", "AST", 2001. - 284 p.
Materials on the Internet
1. Federal Institute of Pedagogical Measurements ().
2. Russian Geographical Society ().
4. 900 presentations for children and 20,000 presentations for schoolchildren ().
The lithosphere is the stone shell of the Earth. From the Greek "lithos" - a stone and "sphere" - a ball
The lithosphere is the outer solid shell of the Earth, which includes the entire earth's crust with part of the Earth's upper mantle and consists of sedimentary, igneous and metamorphic rocks. The lower boundary of the lithosphere is fuzzy and is determined by a sharp decrease in rock viscosity, a change in the propagation velocity of seismic waves, and an increase in the electrical conductivity of rocks. The thickness of the lithosphere on the continents and under the oceans varies and averages 25 - 200 and 5 - 100 km, respectively.
Consider in general view geological structure Earth. The third planet farthest from the Sun - the Earth has a radius of 6370 km, an average density of 5.5 g / cm3 and consists of three shells - bark, robes and i. The mantle and core are divided into inner and outer parts.
The Earth's crust is a thin upper shell of the Earth, which has a thickness of 40-80 km on the continents, 5-10 km under the oceans and makes up only about 1% of the Earth's mass. Eight elements - oxygen, silicon, hydrogen, aluminum, iron, magnesium, calcium, sodium - form 99.5% of the earth's crust.
According to scientific research, scientists were able to establish that the lithosphere consists of:
- Oxygen - 49%;
- Silicon - 26%;
- Aluminum - 7%;
- Iron - 5%;
- Calcium - 4%
- The composition of the lithosphere includes many minerals, the most common are feldspar and quartz.
On the continents, the crust is three-layered: sedimentary rocks cover granitic rocks, and granitic rocks lie on basalt ones. Under the oceans, the crust is "oceanic", two-layered; sedimentary rocks lie simply on basalts, there is no granite layer. There is also a transitional type of the earth's crust (island-arc zones on the outskirts of the oceans and some areas on the continents, such as the Black Sea).
The earth's crust is thickest in mountainous regions.(under the Himalayas - over 75 km), the middle one - in the areas of the platforms (under the West Siberian lowland - 35-40, within the boundaries of the Russian platform - 30-35), and the smallest - in the central regions of the oceans (5-7 km). The predominant part of the earth's surface is the plains of the continents and the ocean floor.
The continents are surrounded by a shelf - a shallow-water strip up to 200 g deep and an average width of about 80 km, which, after a sharp steep bend of the bottom, passes into the continental slope (the slope varies from 15-17 to 20-30 °). The slopes gradually level off and turn into abyssal plains (depths 3.7-6.0 km). The greatest depths (9-11 km) have oceanic trenches, the vast majority of which are located on the northern and western margins of the Pacific Ocean.
The main part of the lithosphere consists of igneous igneous rocks (95%), among which granites and granitoids predominate on the continents, and basalts in the oceans.
Blocks of the lithosphere - lithospheric plates - move along the relatively plastic asthenosphere. The section of geology on plate tectonics is devoted to the study and description of these movements.
To designate the outer shell of the lithosphere, the now obsolete term sial was used, which comes from the name of the main elements of rocks Si (lat. Silicium - silicon) and Al (lat. Aluminum - aluminum).
Lithospheric plates
It is worth noting that the largest tectonic plates are very clearly visible on the map and they are:
- Pacific- the largest plate of the planet, along the boundaries of which constant collisions of tectonic plates occur and faults form - this is the reason for its constant decrease;
- Eurasian- covers almost the entire territory of Eurasia (except Hindustan and the Arabian Peninsula) and contains the largest part of the continental crust;
- Indo-Australian- It includes the Australian continent and the Indian subcontinent. Due to constant collisions with the Eurasian plate, it is in the process of breaking;
- South American- consists of the South American mainland and part of the Atlantic Ocean;
- North American- consists of the North American continent, part of northeastern Siberia, the northwestern part of the Atlantic and half of the Arctic Oceans;
- African- consists of the African continent and the oceanic crust of the Atlantic and Indian oceans. It is interesting that the plates adjacent to it move in the opposite direction from it, therefore the largest fault of our planet is located here;
- Antarctic Plate- consists of the mainland Antarctica and the nearby oceanic crust. Due to the fact that the plate is surrounded by mid-ocean ridges, the rest of the continents are constantly moving away from it.
Movement of tectonic plates in the lithosphere
Lithospheric plates, connecting and separating, change their outlines all the time. This allows scientists to put forward the theory that about 200 million years ago the lithosphere had only Pangea - a single continent, which subsequently split into parts, which began to gradually move away from each other at a very low speed (an average of about seven centimeters per year ).
It is interesting! There is an assumption that due to the movement of the lithosphere, in 250 million years a new continent will form on our planet due to the union of moving continents.
When the oceanic and continental plates collide, the edge of the oceanic crust sinks under the continental one, while on the other side of the oceanic plate its boundary diverges from the plate adjacent to it. The boundary along which the movement of the lithospheres occurs is called the subduction zone, where the upper and plunging edges of the plate are distinguished. It is interesting that the plate, plunging into the mantle, begins to melt when the upper part of the earth's crust is squeezed, as a result of which mountains are formed, and if magma also breaks out, then volcanoes.
In places where tectonic plates come into contact with each other, there are zones of maximum volcanic and seismic activity: during the movement and collision of the lithosphere, the earth's crust collapses, and when they diverge, faults and depressions form (the lithosphere and the Earth's relief are connected to each other). This is the reason why the largest landforms of the Earth are located along the edges of the tectonic plates - mountain ranges with active volcanoes and deep-sea trenches.
Problems of the lithosphere
The intensive development of industry has led to the fact that man and the lithosphere have recently become extremely difficult to get along with each other: pollution of the lithosphere is acquiring catastrophic proportions. This happened due to the increase in industrial waste in combination with household waste and fertilizers and pesticides used in agriculture, which negatively affects the chemical composition of the soil and living organisms. Scientists have calculated that about one ton of garbage falls per person per year, including 50 kg of hardly decomposable waste.
Today, pollution of the lithosphere has become an urgent problem, since nature is not able to cope with it on its own: the self-purification of the earth's crust is very slow, and therefore harmful substances gradually accumulate and eventually negatively affect the main culprit of the problem - man.
Municipal budgetary educational institution
"Pervomaiskaya secondary school"
Lesson summary on the topic:
§ 13. The earth's crust and lithosphere - the stone shells of the Earth
Prepared by a geography teacher
S.N. Antipova
Lesson Objectives:
Educational - to continue the formation of students' knowledge about the "lithosphere" shell, to contribute to the formation of ideas about the reasons for the diversity of the structure of the Earth's crust, methods for depicting lithospheric plates on maps.
Developing - developing the ability and skill to work with physical and contour maps, development logical thinking, memory.
Educational - to increase interest in the study of the subject, to form a scientific worldview.
Forms of organization cognitive activity : individual, pair, group.
Type of lesson (by objectives): lesson learning new material.
Type of lesson: combined.
Equipment: multimedia complex, physical map of the world, atlas for grade 6, textbook.
During the classes:
Organizing time.
I'm glad to meet you guys in class today. I think that our joint work will be interesting and useful. Let's smile at each other, tune in to the search and creativity and start the lesson.
Remember
What inner shells of the Earth stand out? (Core, mantle, earth's crust)
Which shell is the thinnest? The earth's crust is the thinnest, outer shell of the earth.
Which shell is the largest? The mantle is the largest of the inner shells.
How is granite formed?
How are sedimentary rocks formed?
What rocks are called metamorphic?
Riddles about minerals
1. It is very durable and resilient
builders - a reliable friend
houses, steps, pedestals
become beautiful and noticeable. (granite)
2. He is black, shiny,
Real helper for people
He brings warmth to the house,
From him it is light in the houses,
Helps melt steel
Make paints and enamels. (coal)
3. If you meet on the road,
Then the legs get stuck a lot.
And to make a bowl or vase -
She'll be needed right away. (clay)
4. He really needs the kids,
He is on the paths, in the yard,
He is at a construction site and on the beach,
And it's even melted in glass. (sand)
5. They cover the roads with them,
Streets in the village
It's also in cement.
He himself is a fertilizer. (limestone)
6. This master is white - white.
The school does not lie idle:
Runs across the board
Leaves a white trail.
Our ceiling is also white,
After all, he is whitewashed ... (with chalk)
7. They don't eat it alone,
And without it, they eat little. (salt)
8. Mom has an excellent assistant in the kitchen,
It blooms with a blue flower from a match. ( natural gas)
9. Plants grew in the swamp ...
And now it's fuel and fertilizer. (peat)
And we begin to study the new paragraph 13
The Earth's crust and lithosphere are the stone shells of the Earth.
The earth's crust is the uppermost rocky shell of the earth. It consists of igneous, metamorphic and sedimentary rocks. On the continents and under the oceans, the Earth's crust is arranged differently.
Consider (Fig. 42).
how do they differ from each other? They differ from each other in thickness and structure. The continental crust is more powerful - 35-40 km, under high mountains - up to 75 km. It consists of three layers. The top layer is sedimentary. It is composed of sedimentary rocks. The second and third layers consist of a variety of igneous and metamorphic rocks. The second, middle layer is conditionally called "granite", and the third, lower - "basalt".
Rice. 42. The structure of the continental and oceanic crust
The oceanic crust is much thinner - from 0.5 to 12 km - and consists of two layers. The upper, sedimentary layer is composed of sediments covering the bottom of modern seas and oceans. The lower layer consists of hardened basaltic lavas and is called basaltic.
The continental and oceanic crust on the surface of the Earth form giant steps of different heights. More high steps- these are the continents rising above sea level, the lower ones - the bottom of the oceans.
Lithosphere. As you already know, the mantle is located under the earth's crust. The rocks that make it up differ from the rocks of the earth's crust: they are denser and heavier. The earth's crust is firmly attached to the upper mantle, forming a single whole with it - the lithosphere (from the Greek "cast" - stone) (Fig. 43).
Rice. 43. The ratio of the lithosphere and the earth's crust
Consider the relationship between the earth's crust and the lithosphere. Compare their thickness.
Remember why there is a layer of plastic material in the mantle. Determine from the drawing the depth at which it lies.
Find in the figure the boundaries of the expansion and the boundaries of the collision of lithospheric plates.
The lithosphere is the solid shell of the Earth, consisting of the earth's crust and the upper part of the mantle.
Under the lithosphere is a heated plastic layer of the mantle. The lithosphere seems to float on it. At the same time, it moves in different directions: it rises, falls and slides horizontally. Together with the lithosphere, the earth's crust, the outer part of the lithosphere, also moves.
Rice. 44. Main lithospheric plates
The lithosphere is not monolithic. It is broken by faults into separate blocks - lithospheric plates (Fig. 44). In total, seven very large lithospheric plates and several smaller ones are distinguished on Earth. Lithospheric plates interact with each other in different ways. Moving along the plastic layer of the mantle, they move apart in some places, and collide with each other in others.
Questions and tasks
What are the two types of earth's crust?
How is the lithosphere different from the earth's crust?
What lithospheric plate do you live on?