Embedded Files
So there you have it! You just did a mapping exercise! So is this what you turn in?
(I'll give you a hint — it's not) If you turn this in, any field instructor is going to lose their mind. But, this is a great working map of your observations. At each of these stops, you know what you saw. And what you saw is what’s there (you can't get points taken off for an observation. Interpretations are what’s going to get you in trouble).
So in order to finish this map, you have to color in the rest of it. Now, this is such a huge area, and I only gave you 14 stops- none of which showed a contact (I did see a contact! but as a law of roadside geology states: any roadcut worth stopping at will have nowhere to park your car).
Based on the information I gave you; this could be what your map looks like. You could have chosen to angle the contacts in a different way: as long as they separate all the dots of one unit from another, I didn't give you enough information to really know where they are.
Now for my disclaimer, and explanation:
This is absolutely a flawed map. But the purpose of me giving you this was not to get you to make a 100% precise map of NC. It was to get you to start thinking about how you map-especially when you're in an area where you can't physically walk on the contact that you want to trace. This was a huge, forested area. The outcrops were all along 1 road. But you were still able to see the outcrop and figure out what was there. Some of the rocks that were all a part of 1 unit looked very different, but you were able to figure out ways to identify them and figure out which unit they belonged to. You were also able to figure out that if you see a unit on both sides of an area, unless that unit has been faulted, or folded, you should expect it to be laterally continuous between the two. This was a baby mapping exercise- but it absolutely uses some of the same skills that will be expected of you later.
The only difference between this virtual mapping exercise and an in-person mapping exercise, is when you're in-person YOU get to make the choice of what's important, and where all you want to go (try as you might, you will never be able to cover the whole map area-so you need to figure out what observations you need to make to make an educated assumption and extend units).
So, if this was a mapping exercise for a class, what could you have done to make your map more accurate?
More sampling points. The more observations you make at different points, the more accurate your map will be, and the less assumptions and interpretations you will have to make. With that being said, you will never have a mapping project where you can fill out the whole map with observations. You just won't reasonably have the time to cover that much area, or you physically won't be able to get to some places. But the more observations you can make at different places, the more accurate your map will be.
If you're curious, this is what the official map of the area looks like. You can see, it’s a little different than what we got (don't worry about all the colors, NC breaks the units we mapped into more subunits). But you couldn't have known all the information here from the road cuts I showed you- and the map we made together really isn't that far off.
You guys did well :-). I know mapping isn't easy at first, but practice is what's going to make you better. I'm proud of you for getting through this first one, and if you have questions, please ask me!
If you've done everything up to this point in one sitting, you are encouraged to take a break (you've certainly earned it!). These first 3 stops built on each other, but we're now going to change directions a little.
You've gotten some introductory practice on making hand lens, outcrop, and regional observations. Now that you know how to make these observations, we're going to do some more practice, and focus in on some specific things you might see.
Page updated
Google Sites
Report abuse