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Geological mapping

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mapping of earth by contour map etc

Publié dans : Ingénierie
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Geological mapping

  1. 1. What is a Map?  A map is a picture or representation of the Earth's surface, showing how things are related to each other by distance, direction, and size.  Maps are a way of showing many things about a portion of the earth's surface on a flat piece of paper that can be carried and transported easily.  A map is not a photograph of the Earth's surface. It can show many things that a picture cannot show, and as a result, a map looks different in many ways from a photograph of the Earth's surface. 1
  2. 2. What is a Map? 2
  3. 3. What is a Map?  Maps are one of the most important media used to communicate information in exploration geology.  Maps are a two dimensional representation of the surface of the earth and its features.  Maps are a kind of shorthand language media with two main purposes: 1. To convey detailed information about a specific area, and 2. To indicate the position of the specific area relative to other parts of the earth. 3
  4. 4. What is a Map?  The first objective is accomplished by recording information in graphic form, either directly from field observation or indirectly from air photographs or a wide variety of other source  A geologic map records the distribution of rock and soil materials.  It provides to identify and protect valuable resources, avoid risks from natural hazards. 4
  5. 5. What is a Geological Map? Geological map is a special purpose map made to show geological features, Rock units or geologic strata are shown by color or symbols to indicate where they are exposed at the surface. 5
  6. 6. What is a Geological Map?  A geologic map is a map of the different types of rocks or structures that are on the surface of the Earth.  By mapping different rock types and structures, geologists can determine the relationships between different rock formations which can then be used to find mineral resources, oil, and deposits.  Geologic maps are used to interpret the structure,Stratigraphy, mineralogy, paleontology, and the historical record of the Earth's crust.  Geologic maps are our most important and complete compilation of information about the solid Earth we live on, and we cannot understand the Earth without them. We use geologic maps and the fundamental information they provide in many ways. 6
  7. 7. The value of Geological Map  Geologic maps are the single most important and valuable tool we have for understanding and living with the Earth around us. Their usefulness is so broad that geologic maps are the most requested scientific product produced by state and federal geological surveys.  Geologic maps are central to almost any geological exploration projects. 7
  8. 8. Types of Geological Maps Main types of geological maps are:  Topographic Maps, show a 3 dimensional world in 2 dimensions by using contour lines (dashed lines showing the third axis of the map)  Areal Maps, show 2 dimensional view of the location by using XY coordinates, maybe used for showing, and comparing different aspects like lithology, structure etc.  Block Diagrams is not a map actually but sometimes it is also considered as a geological map, because of showing data similar to a geological map 8
  9. 9. A Topographic view using contour lines to show elevation 9
  10. 10. An Aerial Map showing lithology of British Isles 10
  11. 11. A Block Diagram of a structure 11
  12. 12. How Geological maps are prepared?  The aim of geologic mapping is to create a map which summarizes the geologic data gathered in the field.  Every place that an observation is made, a sample is gathered, or any type of data collection takes place, it is positioned on the map at the appropriate X – Y coordinates.  The map can be small scale and show much detail, or be large scale and generalized.  Rock units are typically represented by colors. Instead of colors, certain symbols can be used.  Different geologic mapping agencies and authorities have different standards for the colors and symbols to be used for rocks of different types and ages. 12
  13. 13. Geological Map 13
  14. 14. How Geologists Make a Geological Map  Making a geologic map requires several decisions before the process actually begins.  If one is going to explore some area:  First, all previous geologic maps and data for an area needs to be sought, for a better understanding of that region.  Maps of very large areas, such as states or provinces are commonly made by putting together and compiling more detailed, large scale maps of smaller areas. 14
  15. 15. How Geologists Make a Geological Map 15