For more detail go to the link and click on the image for a high definition image. You can then move the magnifying glass cursor then click to zoom in and click again to zoom out. When zoomed in you can scan by moving the side bars on the bottom and right side of the image.
The colors and pattern would make lovely floor tile or linoleum.
I suspect the source of heat is the radioactive decay of Uranium and Thorium. Such decay is enough to keep the Earth’s core hot.
Hillary’s emails? Epstein’s client list? P. Diddy’s client list? excess democratic ballots? All kinds of things could be in that black hole!