Coastal dominance & catastrophic geology

It's a page72 quote. The other page is a related (unquoted) passage. It's from a CRSQ paper although I've got the book too ..

First, your Horner quote seems to be just quotemining from a popular press book and not peer reviewed literature. The quote appears to be from two different pages and the intervening material is neither shown or referenced. It is possible that is not at all what Horner said but in typical AIG/ICR style, taken out of context.Second, the study I linked you to was from 1998. It would not have been available to Horner back in 1988 or even earlier when he was contributing to the book.Third, Horner could simply have been wrong.That is how Science works. As new observations are discovered, old ideas and understandings are modified or discarded.

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Aslan is not a Tame Lion

Well, you can believe that Horner was that wrong if you want based on one paper containing the word 'inland' but I'll assume that Horner was basically right for 99% of the formations. And we still need to find out how far inland anyway in that one study!Secondly coastal dominance is already understood via sequence stratigraphy which clearly I will have to re-summarize here . . or do you want to concede now? I'm not talking about zero in-land deposition, I'm talking about a large extent of coastal dominance.How do you think the sigmoid shaped sequences of rock that dominate the geo-col were laid anyway? It's universally understood to be due to sea-level cycles!Thirdly, I'll find the red book (Horner) tomorrow.

I have presented evidence. I provided links to the source. The audience can examine what has been presented and make their own decisions.

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Aslan is not a Tame Lion

JarI never claimed 100% coastal. I claimed 'coastal dominance'. One example of paleogeographically inland fossils (for which you don't even know the distance to the paleo-coast) is of little relevance in the light of Horner stating in his book that 'there are no geological formations that preserve inland habitats from the dinosaurs’ time'. It contradicts Horner's '100%' but NOT the dominance of coastal over inland fossilization.So yes, I'm happy to let the record stand too.Tommorrow I'll discuss coastal catastrophes. Edited by Tranquility Base, : Spelling

Here's the 2 full quotes from my personal copy (that I bought for my sister who 'almost' became a paleontologist) of Horner(1990):

quote:

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"The duckbills [dinosaurs] appeared in the late Cretaceous. They were all herbivores and they all had a two-legged gait, although some may have used their forelegs to help them out occasionally - in rough terrain, for example. They also all had the snouts that resembled ducks' bills. By the time they had evolved, the landmass had separated into continents, and the remains of duckbills are found in Europe, Asia and North and South America. We don't know on which continent they first evolved. In whatever part of the globe they were, they lived on the coastal plains of one sea or another. (As did all the dinosaurs.) We don't know whether they, or any other dinosaurs, also lived in inland areas, because there are no geological formations that preserve inland habitats from the dinosaurs' time. Deposition or sedimentation, which is what makes sedimentary rock and what preserves fossils, did not occur to a large enough extent in the inlands." p72

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And the other (new) one is equally emphatic:

quote:

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"I should emphasize once again that when it comes to dinosaur fossils, the only alternative to an upper coastal plain is a lower coastal plain. All over the world, dinosaur fossils are found in one of these two kinds of deposits. Inland areas, if dinosaurs lived in them, were just not preserved by any kind of deposition." p196

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I have no doubt that paleogeographically inland formations exist, but the notion that the last 16 years of research could turn the extent around is quite ridiculous. Not to mention that seismic/sequence stratigraphy reveals that most of the geological column was laid down by sea-level cycles.Edited by Tranquility Base, : Spelling

Hi TB, I'm going to drop into chat for a while, why don't you join us.--Percy

Just a point of clarification: when we're talking coastal dominance that includes all deposition in the seaward and landward 'vicinity' of the coastline. So for example within 5-10km or so. So that takes in (i) the shallow marine depositions and (ii) the terrestrial coastal plain depositions. Percy and Jar thought I might be meaning only non-marine. That's not the case I simply mean any deposition within the vicinity of the coast.Now, Horner's findings (as well as sequence stratigraphy's regional unconformities) mean that there's little inland deposition.But what about off-shore contributions? It turns out there's simply very little deposition off-shore. Why? Because there's no major source of sediment nearby (ie, no rivers). I'll reference this shortly.So all-in-all, shallow marine deposition (with sediment sourced from rivers) dominates the origin of the sedimentary geo-column with COASTAL 'non-marine' beds making a major secondary contribution.

How close to the coast do you think limestone deposits form? Limestone deposits represent a significant proportion of the geologic column. The more pure the limestone, the more it indicates sedimentary deposition beneath a warm, shallow sea far from the contributions of continental run-off.Here's a map of oceanic sedimentation depth from the National Geophysical Data Center: Definitely click to enlarge, it's a huge map. What this shows is that the area of sedimentary deposits within a couple hundred kilometers of the coast in either direction is dwarfed by the area of oceanic deposits around the world. The sedimentary depth increases with increasing age of the underlying sea floor, simply because the older the sea floor the longer sediments have been accumulating. Near mid-oceanic ridges the depth of sea floor deposits is non-existent to minimal. Far from mid-oceanic ridges but still far from continents the depth of sediments is much greater.Sea bottom that is near a coastline has a fair chance of being glommed onto the continent (due to subsidence and uplift and rising and falling sea levels), and it happens so frequently that the vast majority of sedimentary layers that we find on land were deposited beneath the sea near ancient coastlines.Sedimentary layers from mid-ocean are much less frequently available for easy study in the way that coastal and near-coastal sediments are. While the oldest rocks on continents are more than 3 billion years old, the oldest sea floor in the world is only about 200 million years. This is because the ultimate fate of sea floor is subduction. Much sea floor that begins its life at mid-oceanic ridges to begin the conveyor belt journey toward the continents ends it life by being subducted beneath a continent where it is destroyed forever as it is absorbed into the mantle.So while coastal and near-coastal deposits dominate the sedimentary layers that are available for study, they do not dominate the totality of sediments that are laid down around the world. A far greater area is covered by oceanic sediment, simply because the area covered by oceans is far greater than the area near coastlines.--Percy

You also seem to be ignoring Inland Seas, Valley accumulation, marshes, swamps and all other potential inland depository sites.

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Aslan is not a Tame Lion

The other thing being ignored is the effects of erosion taking away deposits over land areas: this doesn't mean that the deposition did not occur or was not significant, just that it is removed from the available data.We also see that different environments favor fossilization to different degrees, and thus we can have inland deposits that occur but are not favorable to fossilization.This is like looking for dropped keys under a streetlight (as that is the area where "visual data" is available) even if the chances are 1% that the keys were dropped there.Enjoy.

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Agreed. In addition it is ignoring any post fossilization transportation, or the fact that coastlines are dynamic.

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Aslan is not a Tame Lion

I don't think he's ignoring that coastlines are dynamic. Someplace in the thread (or maybe it was last night in the chat room) he points out that it is the wandering coastlines that cause such broad regions of coastal sedimentary layers.--Percy

From Percy's chart it's clear that sediment thickness drops off significantly away from the continental shelf. But up to the continental shelves it's still quite thick for hundreds of kilometres out to sea.The question is is that due to (1) diffusion, local production, currents, wind transport or (2) ancient shallow marine deposition at lower sea-level?It's of course both but shallow marine deposition at lower sea-levels is the dominant factor:As mentioned rivers deliver sediment to the shallow marine environment AND sea-level has evolved due to climate and tectonics thus sweeping the strip of deposition on and off the present continents.In the diagram on slide 11 of the PPT:http://www.tulane.edu/...i/Courses/Oceanography/chap%204.ppt.it points out that the continental shelf is comprised of near-coast modern 'terrigenous'=river delivered sediment and off-shore 'relic' terrigenous sediment formed during earlier lowstands of sea level (e.g. during glacials). It's a nice slide.Lime muds can potentially form anywhere that muds form (from ~ a kilometre off-shore onwards where wave/tidal action is absent) but from the thickness of the deep sediment in the chart it's clearly at a far lower rate than shallow marine sedimentation.In the past, at high stand, the continental shelves where flatter, shallower and more extensive.Note in this PSU ref that

quote:

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"Although rare today because of the overall lowstand of sea level, epeiric seas were widespread in the past during highstands of sea level, such as the early and middle Paleozoic, and for many times provide the only record we have of the marine realm."
http://www.geosc.psu.edu/~sling/ORDOVICIAN/patz_summary.html

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Edited by Tranquility Base, : No reason given.

RAZDIt's unlikely that terrestrial erosion removed almost all inland non-marine formations and only left the shallow marine formations that fill our continents.My statements aren't based primarily on fossilization. It is the basis of modern stratigraphy that the geo-col is laid down by sea-level cycles. Anyway, Horner talks about geological formations and habitats, not fossilization per se.