Keebler@cmu-cs-edu1.ARPA (Keebler) (04/12/85)
___________________________________________________________________ > { from: Lief Sorensen, Hewlett Packard Co. } > > Better be careful about this question. It has been calculated > from the combined effects of suspended particles and dissolved > materials removed by rivers that the surface of the United States > is being stripped away at an average rate of one foot in 9000 > years. Other materials in the stream and riverbeds (i.e. pebbles > and particles which are rolled , slid, and moved bodily along the > bottom by currents) cannot be measured and are therefore not in- > cluded, leaving a conservative calculation. For the 1,265,000 > square miles in the Mississippi River drainage basin, the esti- > mate is one foot per 5000 to 6000 years. Just from reading this paragraph alone, I see a great problem. How are you going to be able to justify using an "average" value, when you have obtained an average for a surface with so many variations, such as the United States. The Mississippi River drainage basin is proof enough, let alone a small topographic map, that your standard deviation is incredibly large. > Assuming that factors accelerating the rate (higher average tem- > perature and rainfall) would be balanced by factors slowing it > down (periods of drought and areas of vegetation cover) at the > minimal average present-day rate of 1 foot per 9000 years, every > trace of land would have washed into the oceans many times during > the 2 billion or more years that life is supposed to have been > present on the planet. That's quite an assumption ... especially, when volcanoes do exist. Recently, there was the creation of an island off the coast of Eas- tern Canada from an underground volcano. (I can't recall the exact date or place. It was well-covered by the following issue of Na- tional Geographic, however.) Then there is the volcano that sprung up in the middle of a farmer's corn field in Mexico. These are not hypothesized events. They are very real and very recent. > At this slow average rate more than 42 vertical miles would be > stripped off the land. Even though the seas are a little more > than twice as extensive as present land area, the deposited sedi- > ments should have caused the oceans to rise nearly 18 miles, mak- > ing a total of sixty miles the continents would have sunk in re- > lation to sea level. > > Your are going to need to develop a theory of intermittent land > uplift and/or sea bottom depression or formation to counterbal- > ance the leveling effects of erosion and deposition. The average > altitude of the continents is only a little more than one half > mile above sea level, or three miles above the average sea bottom > depth. During a 2 billion year period, Mount Everest, it it were > to escape eventual disappearance beneath a shoreless ocean, for > example, would have to be re-elevated to its present height more > than ten times. At the present average elevation of continents, > this figure would be increased to 120 times, all within a time > span less than half of the estimated age of the planet and less > than two thirds of the time often speculated that habitats suit- > able for life existed. Furthermore, the erosion rate used for > these calculations is far slower than is evidently necessary to > account for the high quality of fossil preservation existing in > many rock strata. To be preserved as fossils, most animals and > plants have to be covered quite rapidly or they disintegrate, > leaving no trace. And just WHAT is eroding Mount Everest? Glaciers perhaps. Hardly rain. You cannot apply some continental average of soil erosion to a mountain and expect to get some sensible result. As for the fossil preservation comments: I wonder why creationists gripe so much about gaps in the fossil record if someone like you turns around and yells "... far too many fossils to account for the erosion rates ...". ___________________________________________________________________ Live long and prosper. Keebler { hua@cmu-cs-gandalf.arpa }