Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/18/84; site islenet.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!lll-crg!dual!islenet!bob From: bob@islenet.UUCP (Bob Cunningham) Newsgroups: net.origins Subject: Re: The Scientific Case for Creation: (Part 38) Message-ID: <1410@islenet.UUCP> Date: Sat, 27-Jul-85 18:16:03 EDT Article-I.D.: islenet.1410 Posted: Sat Jul 27 18:16:03 1985 Date-Received: Wed, 31-Jul-85 22:58:55 EDT References: <396@iham1.UUCP> <385@kontron.UUCP> Distribution: net Organization: Hawaii Institute of Geophysics Lines: 66 > > 71. Over twenty-seven billion tons of river sediments are > > entering the oceans each year. Probably, this rate of > > sediment transport was even greater in the past as the > > looser top soil was removed and as erosion reduced the > > earth's relief. But even if erosion has been constant, the > > sediments that are now on the ocean floor would have > > accumulated in only 30 million years. Therefore, the > > continents and oceans cannot be one billion years old [a]. > > [same reasoning, arguing that continents would have been eroded in > > a fairly short time.] Using a slightly-higher figure (based upon sediment flux measurements in major river systems), we're looking at an average rate of erosion of around 6 cm of continental surface (at a density of 2.4 gm/cm^3) per 1,000 years. Deposited oceanic sediments being less dense (say .8 gm/cm^3, dried density) and factoring in the ratio of 3/7 continental surface area/ocean bottom area, this would produce roughly 6 cm of ocean-bottom sediment every 1,000 years. At this rate, the continents (which are, on the average, only 840 meters high) would be worn down in roughly 50 million years. These sorts of back-of-the-evelope calculations are interesting, but completely ignore several different major processes: volcano building, folding & upthrusting (there is a fair amount of limestone on the continents), and isostatic adjustments. In particular, volcanic eruptions around the world produce roughly the same order of magnitude of material that erosion takes away. Nor, can you ignore the extensive variations in erosion (64% of Australia doesn't drain into the sea, although 90% of North America does); and that the major portion of the sedimentary debris ends up on the margins of the continents (only about 6% of the eroded sediment actually makes it to the deep ocean). The work of erosive processes varies considerably over the surface of our world. Extensive evidence indicates that much of the continental material is quite old, while the current ocean bottom is relatively young (a few hundred million years). That's reasonably explained by our current understanding of subduction in plate tectonics. > > 73. The rate at which elements such as copper, gold, tin, > > lead, silicon, mercury, uranium, and nickel are entering > > the oceans is very rapid when compared with the small > > quantities of these elements already in the oceans. There > > is no known means by which large amounts of these elements > > can precipitate out of the oceans. Therefore, the oceans > > must be very much younger than a million years. Reef-building coral incorporates uranium into their CaC02 extensively, providing a "sink" for uranium (and Ca, Sr, Ba, Ra as well). Lead is virtually insoluble in the oceans, and thus they essentially contain none (it stays in particulate form). Elements with a +2 valence (notably Ni, Co, Cu) show up in relatively high concentrations in deep sea sediments, precipitating out rather rapidly. Silicon is quite effectively used by a number of species of diatoms & radiolarians, and the settling of their skeletons is almost certainly the major "sink" in the occeans (for at least some of the species, silicon is bio-limiting: give them more silicon, and they'll glady use it, grow, prosper, and fairly quickly die and deposit it). -- Bob Cunningham {dual|vortex|ihnp4}!islenet!bob Hawaii Institute of Geophysics Computing Facilities Honolulu, Hawaii