Mt. St. Helens

(1) I don't know why you call the Grand Canyon "fast". Did you mean to write that the other way round?(2) You should distinguish between the formation of the rocks and the formation of the canyon.(3) The rocks of the Grand Canyon are formed from different materials. Geologist can tell the difference between volcanic ash and tuff and (e.g.) marine limestone, you know. Where they find layers of volcanic ash, naturally they attribute them to the action of volcanoes.

Well, sort of sedimentary. Geologists joke that volcanic ash is "igneous when it goes up and sedimentary when it comes down". (I didn't say it was a funny joke.) I'm not following you, sorry. It depends on what you mean, and on the rock.Volcanic ash can form rock almost immediately if it's hot enough when it falls to weld itself together; this gives us the rock known as "welded tuff". Or it can be slowly cemented together by the usual process that also cememts together such things as sandstone, which takes longer.There are other processes besides volcanism that deposit a relatively thick layer of sediment quickly, such as turbidity currents. That then takes a long time to turn into rock (turbidite).A layer of basaltic lava can be extruded quite quickly and will be baslat as soon as it cools.Other things, such as limestone or chert are deposited very slowly and then take a long time to be compacted into rock.So how long it takes for (a) the original material to be deposited and (b) for the material to be lithified (turned into rock) depends on what sort of rock it is.If you look at No webpage found at provided URL: this page and follow links 2-13 where it says "No webpage found at provided URL: Related articles" you can find out about various sorts of sedimentary rocks and the circumstances under which they're deposited and how we know this.

The hosting provider, a company called "Wiredtree" has been having technical difficulties. It should be working again soon-ish.I wrote the articles myself, and I think they're particularly useful because they repeatedly ask and answer the question "how do we know this?" rather than just treating the subject as information handed down from on high by the Grand Exalted Wizards Of Geology.Edited by Dr Adequate, : No reason given.

There are a few points to ponder here.First, the rocks at the bottom of the Grand Canyon are not sedimentary, they're metamorphic and igneous.Second, look at the cross-section. If the canyon was cut through fresh sediment, is there any way that the wet sand, the mud, and the calcareous ooze wouldn't have slumped forward and downward? Look at the limestone layers. Is there any way you could cut a near-vertical wall in calcareous ooze? If you could, is there any way it wouldn't have squidged out under pressure like toothpaste from a tube?Also, if you're thinking of some sort of YEC "flood geology" model, that means that all that unlithified sediment turned into rock ... how fast?You might also like to have a think about how the angular unconformity was formed.Edited by Dr Adequate, : No reason given.

Well I think I alluded to it, but it's nice to see pictures.So that is the famous creationist "canyon" at Mt. St. Helens?It looks just as I imagined it.