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rock cycle and metamorphic rock

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how the rocks forms.
sedimentary rock
igneous rock
metamorphic rock

Publicado en: Ingeniería
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rock cycle and metamorphic rock

  3. 3. What is a rock?  We all know what rocks are right? They are lying on the ground everywhere! They are the mountains, and canyons that you can’t help but notice. We have all thrown them, sat on them, and dug them out of our gardens. However, to pin down an exact definition… that is something not all of us could do.  A rock is:  A solid Naturally occurring Is made up of minerals or mineral like matter. Perhaps the more important question is “why study rocks?” Rocks are the pages in the history book of the earth. They tell stories of times long past. From rocks, we have learned of dinosaurs, trilobites and thousands of other life forms that existed on earth once but are now no more.
  4. 4.  We have learned that the earth is constantly moving, shifting, and changing. Rock is continually being created. It is heated, squeezed, and weathered into new rocks.  Rocks are simply aggregates of mineral grains. Each rock is unique as the composition of a rock varies from specimen to specimen. Understanding rocks is crucial to understand the make up of the earth. Rocks are economically vital, and the minerals extracted from them are used in every aspect of our lives.
  5. 5. From Wikipedia :  In geology, rock or stone is a naturally occurring solid aggregate of one or more minerals or mineraloids. For example, the common rock granite is a combination of the quartz, feldspar and biotiteminerals. The Earth's outer solid layer, the lithosphere, is made of rock.  Rocks have been used by mankind throughout history.  From the Stone Age, rocks have been used for tools. The minerals and metals found in rocks have been essential to human civilization.  So I think this enough for the rocks now lets move on to the rock cycle
  6. 6. ROCK CYCLE: The rock cycle is a basic concept in geology that describes the time-consuming transitions through geologic time among the three main rock types: sedimentary, metamorphic, and igneous.  As the diagram illustrates each of the types of rocks is altered or destroyed when it is forced out of it equilibrium conditions.  An igneous rock such as basalt may break down and dissolve when exposed to the atmosphere , or melt as it is subducted under a continent. Due to the driving forces of the rock cycle, plate tectonics and the water cycle, rocks do not remain in equilibrium and are forced to change as they encounter new environments.
  7. 7. The rock cycle is an illustration that explains how the three rock types are related to each other, and how processes change from one type to another over time.  Most rocks on earth began as igneous rocks. Let's trace a possible rock cycle for newly formed igneous rocks.  Igneous rocks are formed from magma. Magma cools and solidifies into rock.  When igneous rocks are exposed on the surface, time and weather break the rock down into smaller and smaller pieces. This process is called ‘Weathering and Erosion’.
  8. 8. Wind and water carry the smaller pieces of igneous rocks into piles called sediment beds. Over time the sediment beds get buried and the pieces of rock become cemented together to form a new type of rock called a ‘Sedimentary rock’.  If our sedimentary rock is exposed at the surface, it can be eroded away and eventually changed into new sedimentary rock. However, if our sedimentary rock gets buried deep in the Earth, heat and pressure essentially bake the rock, changing it into something new. This process is called metamorphosis, and the new rock is called a metamorphic rock. Metamorphosis can happen to igneous rocks as well.
  9. 9. Metamorphic rocks can also be weathered and eroded and eventually changed into sedimentary rocks. Or, if metamorphic rock is forced deeper into the Earth, the rock can melt and become magma.  If the magma cools and hardens it will form into igneous rock. Igneous rocks and sedimentary rocks can also be forced deep into the earth and melt into magma. Once magma cools it forms igneous rocks. o Now lets see a video so you can imagine what was the slide is trying to tell you (video)
  10. 10.  METMORPHISM, METAMORPHIC ROCK AND THEIR TYPES  Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism, which means "change in form“  The word "Metamorphism" comes from the Greek: meta = change, morph = form, so metamorphism means to change form. In geology this refers to the changes in mineral assemblage and texture that result from subjecting a rock to conditions such pressures, temperatures, and chemical environments different from those under which the rock originally formed.
  11. 11.  What are Metamorphic Rocks?  Metamorphic rocks have been modified by heat, pressure, and chemical processes, usually while buried deep below Earth's surface. Exposure to these extreme conditions has altered the mineralogy, texture, and chemical composition of the rocks. OR  Metamorphic rocks form deep within the Earth when heat and pressure are applied to either igneous rocks or sedimentary rocks. This heat and pressure in essence cooks the rocks, changing their structure substantially.
  12. 12.  Metamorphic rocks are one of the three main types of rocks and are the most common of rock on the continental plates. Fossils may be found in metamorphic rocks, but only if the metamorphic rock was formed from a sedimentary rock that already had the fossil in it. However, the fossil is most likely going to be crushed, warped, or somehow changed because the process that changes sedimentary rock into metamorphic rock will change the fossil, too.
  13. 13. TYPES OF METAMORPHIC ROCK There are two basic types of metamorphic rocks. (1) Foliated metamorphic rock  such as gneiss, phyllite, schist, and slate have a layered or banded appearance that is produced by exposure to heat and directed pressure.  (2) Non-foliated metamorphic rocks  such as hornfels,marble, quartzite, and novaculite do not have a layered or banded appearance.