I run across this, what I call swamp oil from time to time in the swampy areas that I do a lot of shooting in. I was in the Ann Arbor Art Show years ago, which is held on the grounds of the University Of Michigan, and had some of these images in my booth. One of the students from the Botany Dept. came through and went crazy when she saw the swamp oil prints. She told me she had done a research paper on this oil and gave me some info about it. It has a long Greek name which I couldn’t pronounce and can’t remember, and that is produced by rotting vegetation. It rises to the surface and has all these cool colors, and when it hits the air at the surface it starts to dry out and causes the little wrinkles you can see in the first, or top image. As it continues to dry out the oil starts to lose it colors and turn to a silver color which you see in the third or bottom image. You mainly find it in small pockets in swamps or at the edge of a small stream, and it will look different depending on what stage of the drying out process you find it at.