CompuServe Messages

Geologic Time Table

    17-Aug-94 15:14:40
Fm: Jim Ferguson 75766,3357
To: Kamron Kirkconnell 73740,2246
"The average particles in a given layer are consistent within the layer. Each layer is world wide." Neither of these 2 statements is true. There are many layers of water formed sandstones and shales that have very different particle sizes. The differences are accounted for by differential rates of erosion due to flooding and periods of drought over thousands of centuries. The layers of stone are not present worldwide. If they were then here in Indiana we would have all the layers of rock that are found at the Grand Canyon and we don't. We do have some rock layers that were formed during the same time periods as some of the rocks of the Grand Canyon but they are not the same kinds of rocks. Your use of the terms Pre-Cambrian, Cambrian, Ordovician, Silurian for the layers of rocks is unusual. Those terms are time periods. They do not connote or denote anything about the types of rocks formed during that period. They do convey information about the types of fossils, and the geological time-frame during which those rocks were formed. It is quite possible to have a Pennsylvanian coal in one place, a Pennsylvanian sandstone in another place, and a Pennsylvanian limestone somewhere else. "These facts prove the material arrived from outer space (ie from the Sun)." I won't argue the merits or demerits of your suggestion, but your argument has problems because your premises (the statements you call facts) are not true. Therefore any conclusion you would draw from them would only be true by chance not by proof. _The Grand Canyon_ by Jeremy Schmidt (ISBN 0-395-59932-6) is widely available in the travel section of most bookstores and provides a good overview of the geology and ecology of GCNP. Reading it might clear up some of your questions. jf