GeologyRocks

What would happen if a global flood occurred? Interesting question. I would expect the following: Assuming the waters "rise" from somewhere, we should see substantial movement of sediment as it floods the land surface; this should create a clear and unambiguous horizon as a marker. Then when the waters have risen over the majority of land (and no longer flow) and sediment in suspension will fall out, creating the largest graded bedding ever! You might then get a layer of chemically precipitated stuff on top (in shallow areas) along with pelagic stuff (deeper areas). As the waters fall, you would again see another erosion surface and deposition of this material in ocean basins (or other sedimentary basin).

You would not see: desert sediment, flame structures, soft sediment deformation, neptunian dykes, cross bedding, bouma sequences, cyclothems, reefs, dropstones, moraines, drumlins, fluvial deposits, crevasse splays, roots, rain pits, dessication cracks, trough cross bedding, ripple marks, flaser bedding, fossils in chronological order, etc, etc, etc, etc.

Not much question really when you actually study the geological column...

At one time, I tried to explain how the detailed depositional environments that is evident in the rocks (i.e., comparitive sedimentology) refutes a single flood event and that the environments often show in cyclical events (like in carbonate platform deposits) within a relatively thin sequence of rock.  This explanation went over their heads (or maybe I didn't explain it well enough), and other folks in the discussion did not grasp the significance of looking at the sedimentary sequence in detail easily refutes the notion that it was deposited in a 1 time event.

Again, assuming there was this world wode flood, would the overall water chemistry be that of fresh water, salt water or brackish water? And wouldn't this lead to a lot of fish fossils all at a distinct horizon depending on which the water chemistry was. Not to mention the deaths among fish when the waters receded again!!

As Eddie Izzard says (or maybe it was Ricky Gervais): a world wide flood isn't much of a problem is you happen to be a duck! Just sitting there floating on the flood water!

 Actually, when you think of the attitude of seagulls and their habit of trying to steal ice cream perhaps the evil ones did survive a flood!

Well, according to one of the more inventive young earth creationists I've spoken to:

Pieces of the exploded planet between Mars and Jupiter (which exploded without reason or warning) hit earth, this caused the opening of the fountains of the deep (mid ocean ridges). This initiated runaway plate tectonics, and released the flood water (as it is a well known fact that magma is 80% water by volume...) and this water was so highly saturated with minerals that precipitation of thousands of feet of carbonates could happen in a very short time.

" and this water was so highly saturated with minerals that precipitation of thousands of feet of carbonates could happen in a very short time. "

This could happen. if a very short time is measured in billions of years!

If this were true, the carbonate should be a massive precipitate (which of course not what we see).  As always, the devil is in the details.

Just for fun, I thought I'd post some volume estimates for a "Flood" scenario.  I'll make some simplifying assumptions, but it should be good for a first go.  Let me know if I have errors in my maths.

Earth Radius (at equator) = 6372 km

Volume of Earth = 4/3 pi R^3 = 1,083,167,633,017 km^3 (I know that this assumes no land mass above sea level, but bear with me)

Highest Point on Earth = 8.848 km

Earth Radius Flooded = 6380.848 km

Volume of Flooded Earth = 1,087,661,563,872 km^3

Volume of Water Needed for Flood = 4,493,900,855 km^3

That's about 3.35 times the volume of the present oceans.  If the salinity of the ocean is about 3.5%, diluting it by 3.35 times gives a salinity of about 1% (i.e., brackish water).  The brackish fish would certainly survive.

I know these are rough and ignore continental volumes above sea level, but remember that the oceans cover >70% of the earth's surface, so I think that the continental volumes would not result in vast improvement in the numbers.

That's a heck of a lot of water to produce and then get rid of.

Am I missing something?

Yes, the thing missing is the aliens with the giant "super-water vacuum cleaner mk4000"

Just for fun, let's take this one step further.

The bible said it rained for 40 days and 40 nights so that is (40*24) = 960hours

Therefore the volume of water that had to fall per hour was: 4,493,900,855 / 960 =4,681,147km^3/hr

Now the surface area of the earth is 5.12*10^14 m2 (taken from http://www.scenta.co.uk/tcaep/nonxml/science/constant/details/Surface%20area%20of%20the%20Earth.htm)

This is equal to 5.12*10^8 km2 or 512,000,000km2

If we divide the volume of rain required by the surface area of the earth we get the per hour volume required to fall on every km2 of the earth's surface per hour.

4,681,147 / 512,000,000 = 0.00914km/h = 9.14m/h

The heaviest recorded rainfall occured at Foc-Foc in Reunion Island where 1.825m fell in 24 hours (http://www.tate.org.uk/modern/exhibitions/eliasson/facts.htm) or this works out as 0.076m/hr or two orders of magnitude lower than that required to fall consistently for 40 days.

I thank you

Cum hoc ergo propter hoc

Superb, I can feel the basis of a lesson coming on here!!

A Young Earther would tell you that the bible refers to all the great springs of the Earth breaking forth at the same time as the rain which would mean more complications...subtract the total of ground water in aquifers around the world from the rain total...does anyone know what the total amount of water in all the aquafers is?

Actually Most Christian Geologists are prety main stream.  there is a theory called the "gap theory" (sometimes the restitution theory), that is actually plausable.  It calls fro two creations....the first one included all the beasties we know of in the earth, and lasted the billions of years we are now comfortable with...this was wiped away and then the Biblical creation took place.  Gen 1: 1-2 indicates to some a condition that lasted an indeterminate amount of time and preceeded the six days of creation.(which could be literal days or even ages..depending on the individual theory) Verse 2 indicates that the world was brought into a state of disorginization and ruin "the Earth BECAME waste and void" (not was)

Many also hold with  a regional flood not a world wide one...Not the "Creationists" however, but they are a very small, but vocal part of what is taught in  a few Christian Universities. 

I attended Calvin College in Grand Rapids for some summer geology courses and it was very much mainline science.  Like one of the professors there said  Faith and Science do not conflict, unless one tries to pass for the other.

I know it is old but referring to a post made some time ago about those carbonates. I am not sure about a massive precipation of carbonates. As posted earlier the ocean water would likely be diluted by a factor of 3 (roughly) and terrestrial water sources are tiny in comparison to the oceanic water supply. The resulting water body would be undersaturated of carbonates and many other minerals that could precipate.

Of course this depends highly on the water source for any flooding and the composition of that water in terms of mineral contents.

 Also, such a massive event might be an extinction event. It could cause the sedimentation of large Phosphate deposits from lots of dead sea and land life. Furthermore such a torrental rainstorm would definitly cause typical flood sediments followed by a very thin, and therefore likely undetectable (due to the limited time of sedimentation), layer of clay.

 Then we should find large run-off and wash-out structures in corresping age to the flood on all continents.

 No?