Deposition and Erosion of Sediments

I fear you have a very simplified view of what are sediment and sedimentary processes.There are a large number of different sediment types and sedimentary environments. Vast amount of study time has been done on all this, ranging from using a microscope on up. Vast numbers of journal articles and thick books are the result. Whole university courses are devoted to specialized areas of sediments and sedimentation. And here we try to cover it all in an on-line forum.Indeed, a long history of deposition and erosion, repeated over and over, may well be the route to what is seen in the end. The marks of erosion and/or non-deposition may be large (Grand Canyon) or they may be very subtle.One example of a sedimentary environment is that of a river (referred to as the fluvial environment). In a modern river environment, the sediment of the river banks and flood plain continue to be re-eroded and re-deposited. What you see is the current (no pun intended) result, subject to further change. In either a modern example or an old now rock example, evidence of much of the process can be seen.Concerning limestones: The geo-clich is that limestones mean that nothing was happening. They are there because the was no tectonic activity in the area, and thus no detrital (fragmental) sediment was being brought in and deposited. They are the result of a very placid environment. Much of the limestone is directly or indirectly of biological origin - it is a graveyard of past life.Enough for now. Follow up questions welcome. Fellow geologist are welcome to harpoon me.Mellow Moose with a rusty geology degree

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Professor, geology, Whatsamatta U
Evolution - Changes in the environment, caused by the interactions of the components of the environment.
"Do not meddle in the affairs of cats, for they are subtle and will piss on your computer." - Bruce Graham

Depending on the environment, the degree of sediment reworking and movement can vary from little to none, to very extensive.The previously mentioned fluvial environment is, of course, subject to massive reworking. Likewise a wind blown sand deposit (dune). A deep sea turbidite deposit, on the other hand, is much more isolated from erosional forces.Even in the absence of current reworking, there is such a thing as biological reworking (bioturbation). Think of how modern sediments are being churned by the life forms present. On a pre-Cambrian field trip, the professor commented on how someone else had commented that the there present tidal deposits contained the best preserved tidal structures he had ever seen. The reason? No life was present to bioturbate the sediments.A great example of the reworkings of sediments over a long time period, is found in quartzites (near 100% quartz sandstones). Not only is a lot of physical wear required to get rid of the other softer minerals, but the quartz grains themselves show a long history of wear. It take a lot of abrasion to round an originally angular quartz grain. Even more extreme is the example of quartz grains with abraded over growths. The grains were eroded and rounded and deposited and silica cemented into a hard rock. Then they were re-eroded, re-rounded, re-deposited, and re-cemented again into a new hard rock. Individual grains can be found, that show multiple cycles of this process.One question that is rarely touched on is, if vast amounts of the sedimentary rock pile were deposited in the short period of "the great flood", where did these sediments come from? It is a similar problem to "flood geology", as to where did the water come from. While mainstream geologic theory has no problem with the sediment source, "flood geology" seems to have to produce the sediments from who knows where.I once ran the "where's the sediments from" question past Tranquility Base. He proposed the concept of "catastrophic weathering". I likened that concept as being along the lines of two turtles having a catastrophic collision.Moose

I think you threw out a clinker here.I think your sea deposits in Arizona are from sea transgressions onto the continents. The deposits were always continental, not from the ocean basins.Example of oceanic ancient crust are the ophiolite complexes, such a found on Cyprus.Moose {Edited to correct spelling of "ophiolite". Ophiolites are off-topic here.}Second edit: Nice ophiolite linkThis message has been edited by minnemooseus, 03-17-2005 01:28 PMThis message has been edited by minnemooseus, 03-17-2005 01:34 PM

I'm probably the least powerful degreed geologist at this forum, as far as putting arguments forward. Indeed, many of the non-geo-degreed are stronger than me.In addition, I'm pretty slow at preparing responses, and thus would not be the one to overwelm you.I think we have gone away from the "Great Debate" being a judged debate, which is fine with me.In the past, there often has been a parallel "peanut gallery" thread, where others comment on the "GD" topic. In a sense, the others are still participating in the debate, and as of the most recent "GD" the side topic has been prohibited until after the "GD" is completed. As a matter of fact, I think it was Adminnemooseus that suggested (and enforced?) this restriction.Please start a Suggestions and Questions topic, if you wish to discuss a possible "Great Debate" topic further.MooseThis message has been edited by minnemooseus, 03-17-2005 06:30 PM

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Professor, geology, Whatsamatta U
Evolution - Changes in the environment, caused by the interactions of the components of the environment.
"Do not meddle in the affairs of cats, for they are subtle and will piss on your computer." - Bruce Graham

1) Genesis in the Bible.2) The creation itself, which in the case of the Earth's geology, is the Earth's geology.You are dead set on sticking to Genesis, and your interpretations of Genesis. You are determined, in making your interpretations of your very limited knowledge of what the Earth's geology is, to make (2) conform to (1).MooseAdded by edit:JonF expanded on the above in his message at the Is Evolutionist Disparagement of Creationism Justified? topic. It better belongs in this topic, so I will quote it in its entirety. This message has been edited by minnemooseus, 03-21-2005 07:32 PM

The above was extracted from The Talk.Origins Archive Post of the Month: February 2002, where Glenn Morton was awarded a talk.origins "Post of the Month".My impression is that Faith is absolutely in the grips of Morton's Demon. Any further discussion with her is pointless.Mooseps: BTW, Page 1 of Google search for "Morton's Demon".