Should be easy to determine. Volcanic rock is fairly distinctive. I have a question about the flood leaving a silt layer: what would it look like if you consider the turbulence of the flood waters?
I never bought the 6000 year view...Genesis states the earth itself was a formless void of water before God acted on it....how long it was that was might have been billions of years...before the water...rock heat dust ect. I can buy a 7 day creation, if one is God God can do anything he wants...that adaptations occur within species I have no doubt.
I'm always struck by the stand off commands the Lord makes when he "commands the Earth" to bring forth birds and grass and fishes, ect...but when he decides to make man he TAKES A VERY DIRECT ROLE IN THAT! "Let US make man in our own image and likeness and stating that he forms the man from the very RED DUST(Adam means red dirt man or red mud man) of the Earth. Why was red dust significant...it has to do with the heme molecule of red blood cells being iron based. It was never a skin color issue. The iron oxide in the dust was used to make the very blood of man...as well as the blood of animals and fish.
God may have used and may be using a natural selective process in the world....but man was not a part of this process at least it never was the intent for him to be so!