CompuServe Messages

"Do fossils from one time period ever appear preserved in sediment of a later time period as the rock in which they were originally present erodes or dissolves and is redeposited as sediment? Or is the erosion process so complete that this doesn't happen." I should answer that question the way I answer my students' questions, "We'll have to find out the answer to that one. Where do you think we could start?" But I'll hazard a speculation. A fossil might, through erosion, be transported lower to an older formation, but such out of sequence fossils would probably be easily recognized as such. Fossils are unlikely to "wash down" to younger layers because the younger sediments overlay the older ones. Only in an area where a tremendous upheaval has occurred and inverted the stratigraphy (like the rim rocks around Meteor Crater, AZ) or where faulting has aligned the sequence of adjacent rocks out of order would you be able to find older fossils washing down into younger fossil beds. That's my best guess but if someone knows more (which should be quite a few people here) I'd like to know the answer too. jf