8.2. Rock types
8.2.1. Read the text and find the English equivalent of the following Hungarian terms.
8.2.2. Igneous rocks
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This section of the study material was adapted from Physical Geography. Third Edition by Alan Strahler and Arthur Strahler. 2005. John Wiley and Sons, Inc. |
Igneous rocks are formed from molten rock (magma) rising towards the surface from the astenosphere. Some of the magma never reaches the surface and solidifies under the surface. Rocks formed from magma solidifying under the surface are called plutonic / intrusive igneous rocks. These rocks can be seen on the surface only when the rock layers above them erode. Plutonic / intrusive igneous rocks solidify gradually and slowly under the surface of the earth, and as result of this these rocks are coarse-grained. This means that minerals are clearly visible even to the naked eye.
The second type of igneous rocks, extrusive igneous rocks form when the magma or molten rock reaches the surface. When the magma reaches the surface it is called lava. On the surface lava solidifies rather fast, and as a result, the structure of extrusive rocks is fine-grained.
An example of intrusive/plutonic igneous rocks is granite, and that of extrusive rocks is basalt or andesite.
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Language corner Some of these rock names have verbatim equivalents in Hungarian. However, their English pronunciation is different from the Hungarian one. Listen to the English pronunciation and use that in the CLIL class! granite, rhyolite, diorite, andesite, basalt |
Audio
8.2.3. Sedimentary rocks
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This section of the study material was adapted from Physical Geography. Third Edition by Alan Strahler and Arthur Strahler. 2005. John Wiley and Sons, Inc. |
Sedimentary rocks are formed from sediments of surface rocks. Because of erosion and physical and chemical weathering rocks fragment into smaller particles, the size of particles ranges from boulders to fine sand grains. The sediments are then collected and transported by rivers into lakes, seas or oceans where they are deposited and, during millions of years, solidify into sedimentary rocks. Sedimentary rocks have three types. Clastic sedimentary rocks, for example sandstone or mudstone, are formed from rock and mineral segments. Organic sedimentary rocks are formed from organic material. Some of these rocks are valuable resources, such as coal, petroleum or natural gas. Chemically precipitated sedimentary rocks are formed as a result of chemical precipitation from seawater. An example is limestone.
8.2.4. Metamorphic rocks
Read this description of metamorphic rocks taken from Wikipedia and then rewrite it to make it suitable for primary school pupils.
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Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means "change in form".[1] The original rock (protolith) is subjected to heat (temperatures greater than 150 to 200 °C) and pressure (1500 bars),[2] causing profound physical and/or chemical change. The protolith may be sedimentary rock, igneous rock or another older metamorphic rock. Metamorphic rocks make up a large part of the Earth's crust and are classified by texture and by chemical and mineral assemblage (metamorphic facies). They may be formed simply by being deep beneath the Earth's surface, subjected to high temperatures and the great pressure of the rock layers above it. They can form from tectonic processes such as continental collisions, which cause horizontal pressure, friction and distortion. They are also formed when rock is heated up by the intrusion of hot molten rock called magma from the Earth's interior. The study of metamorphic rocks (now exposed at the Earth's surface following erosion and uplift) provides information about the temperatures and pressures that occur at great depths within the Earth's crust. Some examples of metamorphic rocks are gneiss, slate,marble, schist, and quartzite. Forrás / Source: http://en.wikipedia.org/wiki/Metamorphic_rock (2015. January 26) |
8.2.5. Discussion
What strategies did you follow when rewriting the text? What are the most important changes you had to carry out to the text on word, sentence and text level?
References
Alan Strahler and Arthur Strahler. 2005. Physical Geography. Third Edition John Wiley and Sons, Inc.
http://en.wikipedia.org/wiki/Metamorphic_rock (2015. January 26)