Expert: John J. Shea - 10/22/2008

Question
Hi Mr. Shea, I'm a truck driver in the USA and I drive all over the US and I notice a formation in the rocks every where I drive especially in the mountains of Interstate 80 in Wyoming where I have noticed in the rocks where they have cleared mountains for the interstates the same distinct 3 layers or stripes in the mountains and in some places vary in their width and even some places have in the inner band a red thick stripe and I think these formations in the rocks or mountains as the K/T boundry and if so why would it vary in color such as the center layer being red in some places and why does it vary in width? I have a digital camera and if you would like photos of these differences I can take them and send them to you and there exact locations.

Answer
Dear Wilburt,
Thank you for your kind offer, but the K/T boundary concerns an event 65 million years ago, much earlier than the focus of my research (last 2 million years).  I suggest you offer these photos to a paleontologist who works on dinosaur evolution/extinction or to the curator of a natural history museum out west.  I bet any high school science teacher would be very grateful for them, too.
As to variation in width, this probably reflects a variety of factors -pressure from overyling sediment, erosion of the layer before burial.  This is really a question for a geologist or a paleontologist, rather than for an archaeologist such as myself.
You clearly know a lot about geology.  I'll bet that being able to see so much of the geological record of USA in your work gives you a real appreciation for the complex history of life on earth. Drive safe.
Cheers,
John Shea