Fossils

A fossil is evidence, in rock, of something that was once alive. These are pictures found online of different types of fossils.

These are cast and mold fossils because the one on the left is a hollow imprint of the swirly thing,  which means whatever living thing it was decayed and only this is left (making a cast);  the one on the right is a mold since it looks the same as the other one  only now the spaces are filled in with minerals.

This one is a trace fossil because it's not the actual remains or imprints of anything,  but it's a footprint preserved in the rock so it still shows proof of something alive.

This is an original remains fossil because the ant thing is completely preserved in amber,  which doesn't let it decay or anything, so it's still in its original state.

Relative dating homework

       

Picture 1 (Rock layers)

          I was asked to put these six rock layers in order. The newest layer would be number three, because it is an intrusion into all of the rock layers, and intrusions are always the newest.

          The second newest layer is number one, because it's the topmost layer. Number six is next because it's the layer directly under number one.

Picture 2

          If you move this section of rock (outlined in red) down, you can see which layers were together before the layers slid sideways.

Picture 3

          The layers outlined in green, blue and purple match up in the different parts. From this you can tell that when the layers were horizontal, number five would have been above number four, and newer.

Picture 4

          Looking at number two (in pink) and the other section of rock (also in pink), you can tell they are the same material. They were probably attached when the bottom layers were horizontal, and they might have slid around a little when the rocks shifted (when I tried to put them back together in the picture, they didn't quite match up). Number two is another intrusion which intruded through both numbers four and five, so it is younger than both of those, making it the fourth newest layer.

         Since number five is newer than four (see picture 3), five is the fifth newest layer and four is the oldest.

NEWEST

3

1

6

2

5

4

OLDEST