محاضرة أولى الجغرافيا: أنواع الصخور والبراكين PDF

‫كلية اآلداب‬ ‫جامعة المنصورة‬ ‫قسم الجغرافيا‬ ‫الفرقة الثالثة‬ ‫مقرر( نصوص جغرافية بلغة‬ ‫اوروبيه )‬ ‫المحاضرة األولى‬ ‫اعداد‪ /‬د‪.‬عبد الحميد كليو‬ Main Topics of the 1st lecture: 1. Rock Definition. 2. Main types of rocks. 3. Volcanoes definition. 4....

‫كلية اآلداب‬ ‫جامعة المنصورة‬ ‫قسم الجغرافيا‬ ‫الفرقة الثالثة‬ ‫مقرر( نصوص جغرافية بلغة‬ ‫اوروبيه )‬ ‫المحاضرة األولى‬ ‫اعداد‪ /‬د‪.‬عبد الحميد كليو‬ Main Topics of the 1st lecture: 1. Rock Definition. 2. Main types of rocks. 3. Volcanoes definition. 4. Volcanic cone.  ROCKS Rocks are the materials of the earth's solid crust. They are made up of small pieces or minerals packed and cemented together. You can see this if you look at next picture which is a close-up of a rock called granite, showing its minerals. Rocks are very varied. They can be many colors. Some are very hard indeed while others are loose and weak. Again, some rocks are made up of just one type of mineral while others contain many different minerals. Some minerals are large while others are too small for the eye to see. Granite No matter what a rock is like it can be grouped under one of three types depending on how it has been made. Igneous rocks are those that have been formed from cooled, molten rock. Some rocks become solid below the ground and others cool on the surface as lava. As the rock cools, each different mineral makes its own patterns of a particular shape, forming crystals. Sedimentary rocks, as the name suggests, have been formed from deposits or sediments. For the they have been formed as layers or strata under the sea. Often they contain the remains of plants and animals as fossils. Earth movements can produce great pressures. Clearly the great heat of molten rock (magma) must bake the rocks around it. Metamorphic rocks are those igneous and sedimentary rocks that have been changed through such heat and pressure.  The rock pieces and minerals may be rearranged into bands. New mineral may be formed.  Volcanoes As the earth's plates slowly move, strains and stresses are set up in the crust. The rocks can be weakened so much that pressure from below pushes hot, molten rock upwards to reach the surface of the earth. This may be through a crack (called a fissure) or a pipe (called a vent). Molten rock below ground is called magma. When the molten rock comes to the surface it is known as lava. Volcanic cone Many volcanoes are roughly cone- shaped because they have been formed around central vent, from which the lava. flows, cools and becomes solid rock. Volcanic activity can often be dramatic and explosive. The magma may cool and become solid in the volcano's vent. Pressure then builds up below it. When the pressure is great enough the solid plug is blown away in an explosion. Other materials are formed by the explosion. Molten rock is thrown up into the air, where some becomes solid lumps or bombs before it falls back to the ground. These layers build up around the vent to form a conc- shaped volcano. Such a volcano like Etna, made up of a mixture of deposits, is called a composite cone.  ‫التكليف الطالبيه‬ 1. Name some minerals in rocks. 2. How sedimentary rocks are formed 3. What happens to sedimentary and igneous rocks when transferred to metamorphic rocks? 4. Draw a world map of volcanoes. 5. Draw a volcanic cone and illustrate the different parts of it.