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This virtual mapping trip is a video “game” that you to simulate the experience of making a geologic map. You will navigate a virtual landscape to collect outcrop observations and field notes, recording your observations on a paper base map and field book as you go. A pop-up compass and GPS instrument will help you navigate and decide which of the outcrops on the base map you’ve discovered. Having recorded all the outcrop data on the base map and compiled the field notes, you have what you need to complete a cross section and stratigraphic column. Making a geometrically sound map from the very sparse outcrop data is a challenging (and realistic) task. To do it correctly you’ll also incorporate Rule of V’s concepts and strike lines. What to turn in A photograph of your map showing colored unit boundaries and strike and dip marks for the places you’ve visited so far. This image comprises 30% of the grade and isn’t based on how much you have done, rather whether you are making progress and following the instructions (e.g. coloring units and drawing strike and dips while you are at each outcrop). 1. A completed geologic map and map key 2. A N-S geologic cross section from Skyreside Bay to the north end of the map. Supplies needed: · colored Pencils · 0.5 mm pencil and eraser · notebook · protractor · metric ruler · two or more printed copies of the map Instructions Navigate in google Chrome to https://www.see.leeds.ac.uk/virtual- landscapes/schools/index.html. If Chrome doesn’t work well, try Firefox. Gathering field data 1. Get the software running on your computer and become familiar with the navigation keys. Be patient, it can take a while to load. Arrow Keys or WASD keys - Movement Space - Jump Mouse - Look Mouse Key Down - Rotate Map in overview T - Transfer from World to Topographic map G - Toggle gps for position C - Toggle compass 2. Study your base map and make a tentative plan regarding where to go and in what order. Outcrops are indicated by 30+ open circles, and there are trails, stone walls, bridges, a road, rive, a coastline and other features to navigate. You don’t need to visit every outcrop – finding an efficient strategy to make an accurate map is part of the challenge (both here and in the real world). 3. Open the field book at each outcrop. You’ll find a sketch of the outcrop, rock descriptions, and a strike and dip of bedding. While at the outcrop, plot the strike and dip on the base map at the outcrop, then use the appropriate color for that rock unit and shade the open circle with colored pencil. If an outcrop contains a contact between two units, then use the appropriate colors to shade two halves of the open circle. Color (lightly!) as follows: · fine sandstone: orange · coarse sandstone: brown · ammonite limestone: purple · coral limestone: blue · shale: green 4. Place the rock unit, and notes about them, in a properly ordered (oldest at the bottom, youngest at the top) stratigraphic column as you map. 5. Use the GPS and compass when needed to navigate. Do not blithely go from outcrop to outcrop collecting data. Instead, try gradually building a mental image of the geometric and stratigraphic relationships as you record new data on the base map. This is what accomplished field geologists do. a. As you place data on the map ask: What is the stratigraphic sequence so far, from oldest to youngest, based on the notes and dip direction? What do I predict I’ll find at the next outcrops to the north, south, east or west? b. With some data already plotted, what do the Rule of V’s and strike lines predict about what should be found at each outcrop? A strike line is a line connecting two or more points on a geologic surface that are at the same elevation. c. If your predictions aren’t confirmed by your new observations, you need to ask why. Can you discover your error(s) in logic or, if your logic is sound, can you come up with another testable hypothesis that explains the new data? The game is far more interesting once it becomes an intellectual exercise of this sort. For many, the joy and pleasure of geologic mapping comes from solving just these sorts of puzzles. Finish the map At this point you’ll have visited all the outcrops and have spots of color and strikes and dips plotted on the base map. Your next job is to predict where rock unit contacts belong in areas where no rock are exposed, and to draw them in with dashed lines. Examine the data carefully: Where are the oldest rocks? Where are the youngest rocks? Can you see a pattern to the distribution of rocks types perpendicular to strike? What rough pattern does the rule of V’s predict for these north dipping contacts? (you can lightly pencil your hypothesis in) Next, draw in contacts between the beds. To do this, lightly sketch strike lines and use them to extend contacts across the topography. To determine the spacing between strike lines make a triangle in the vertical plane running perpendicular to dip. The dip known, and so is the contour interval. Use these values to calculate the horizontal distance between contour intervals. Contour intervals should be solid lines near outcrops, and dashed lines where contacts were not seen. Color the areas of the map very lightly where outcrops were not observed. The completed geologic map should include: 1. The trace of unit contacts, shown with dashed lines where inferred and solid where exposed. 2. Properly plotted symbols of strikes and dip values for all outcrops 3. Lightly colored units with unit abbreviations. You can create your own abbreviations (e.g. J Ss1 for Jurassic sandstone 1, JLm2 for Jurassic limestone 2, etc.) 4. Neatness and clarity count. 5. The proper location of the windmills 6. An accompanying map key that shows: · a labeled & colored box for each unit, stacked in proper order from oldest at the bottom to youngest at the top · a symbol key for contacts (“dashed where inferred”) and for bedding strike and dip Make a Cross Section The cross section should run in the north-south direction from Skyreside Bay to the north end of the map. Begin by making a topo contour with no vertical exaggeration. If you happen to have metric graph paper, use that, otherwise make your own horizontal reference lines using a ruler. Next, draw in unit contacts and plot 10 tick marks along the surface. Then extend the units into the ground. basemap lighthouse bay CCNY(3).pdf