Geologic time relative dating

22-Feb-2017 00:31

We begin our focus on the basic part of a topographic map, all those lines. Think of it this way, if you had a tub of water with a big rock in it and you started filling the tub with water but paused every minute to draw a line where the water had risen to - those lines would be like contour lines.If you did this for the entire rock, then drained all the water out, the rock would have lines all over it.Eventually, it would look like a square bull's eye with the center being the smallest square. As you go up in elevation, that circle will get smaller and smaller.Just like lines in the whipped cream, the lines here would completely surround the pyramid.The other rule we need to look at states that contour lines close around hills and depressions.This is probably best explained by going back to our step idea.If you were to run all the way around the base of one of those pyramids, it would make a big square.

For example, below you can see some pink rocks with circles on them from Yosemite National Park. It's not the real color of the rock, just a way to show difference.

This would be a little bit smaller, but the same exact shape.

If you kept doing that, eventually you would you would probably be arrested, but you would end up with a bunch of concentric squares.

Speaking of lines, if you see lines or markings that are black, those are typically geologic markings which contrast the brown contour lines showing elevation.

The most obvious feature here is color, lots of color.

For example, below you can see some pink rocks with circles on them from Yosemite National Park. It's not the real color of the rock, just a way to show difference.This would be a little bit smaller, but the same exact shape.If you kept doing that, eventually you would you would probably be arrested, but you would end up with a bunch of concentric squares.Speaking of lines, if you see lines or markings that are black, those are typically geologic markings which contrast the brown contour lines showing elevation.The most obvious feature here is color, lots of color.Here's a sample of what I mean: If you had a topographic map of a footprint in the sand, it would have hachures like those shown below.