Giza Pyramid Old?

Dr. J, I have a question as to Dr. Girtwood's class. You said that they had to find trace of civilization before 4000 years ago, but if they quote some evolutionary sources, they could supposedly prove the Egyptian pyramids to be "10,000-12,000" years old. What was there take on this, or did the assignment mean ConTinuous chronology? Thanks! Noah in MD