The problem that I have with such glaring miscalculations is that "scientists" evidently don't have evolution-related "facts" down to a science.
1) The age of the Grand Canyon has virtually nothing to do with evolution.
2) Why are you putting the profession of these geologists in quotes? Do you have some reason to believe that they aren't real scientists?
3) You seem to have a problem with everything in science not being a "fact" that's set in stone. I refer you to:
http://en.wikipedia.org/wiki/Science#Scientific_method
Science cannot claim absolute knowledge of nature or the behavior of the subject or of the field of study due to epistemological problems that are unavoidable and preclude the discovery or establishment of absolute truth. Unlike a mathematical proof, a scientific theory is empirical, and is always open to falsification, if new evidence is presented. Even the most basic and fundamental theories may turn out to be imperfect if new observations are inconsistent with them.
There is absolutely nothing sacred in science, which is as it should be. This is a strength, not a weakness.