Cretaceous sea levels

[sculptor]

Seriously? Bwahahahaha

ok
so
tell me
What does adding the prefix bwa to hahahahahaha signify?
................
Is that some sort of pop-culture thing?

 

[origin]

ok
so
tell me
What does adding the prefix bwa to hahahahahaha signify?
................
Is that some sort of pop-culture thing?

It's an attempt to write out the sound of explosive laughter.

 

[billvon]

I had picked up on the deliberate confusing of timescales - that was what I was alluding to in post 22. Sculptor has done this before. From what you say, it's a standard element of the AGW playbook.

It may be worth my starting to compile a mental list of the rhetorical tricks they use, much as I have done over the years with creationists.

Sculptor's favorite trick is whataboutism. "Yeah, the temperatures are rising with CO2 concentrations. And yeah, we're emitting the CO2. But whatabout this anomalous data from the MIS 11 data set? And whatabout the depth of the ocean? And whatabout ice ages? And whatabout the K-T boundary climate changes? Can you explain all of that? No? I thought so - you can't explain AGW."

 

[sculptor]

It's an attempt to write out the sound of explosive laughter.

ok
so
Instead of hahahahahaha, or bwahahahahahaha:
What would you use to indicate a bemused chuckle?

 

[exchemist]

Sculptor's favorite trick is whataboutism. "Yeah, the temperatures are rising with CO2 concentrations. And yeah, we're emitting the CO2. But whatabout this anomalous data from the MIS 11 data set? And whatabout the depth of the ocean? And whatabout ice ages? And whatabout the K-T boundary climate changes? Can you explain all of that? No? I thought so - you can't explain AGW."

Ah yes, whataboutery (as we call it on this side of the pond) is a rhetorical tactic of creationists, too.

 

[sculptor]

It may have escaped your notice, however:
I did not start this thread so that it could be used as a platform for agw mountebanks.
(sigh)

 

[iceaura]

I did not start this thread so that it could be used as a platform for agw mountebanks.

Just one agw mountebank.

The others are embarrassing to agree with, no? Let's see what kind of thread one can launch without making any definite assertions or asking any clear questions or specifying any particular topic at all.

Apparently during the Cretaceous there were sea levels - probably a consequence of having continents or something - and people are having a hard time figuring out what they were, all those millions of years ago. So far so good?

 

[sculptor]

OK
Perhaps, in an attempt to gain other's open minded perspectives, I do leave questions too open ended.
Researchers have found evidence of "milankovitch" cycles dating back many millions of years.
Researchers coring the earth in the desert south west have found evidence of strong 400 kyr cyclicity.
Then we see changes in sea level within the cretaceous ---outside of this ice age.
so
if the volume of water on earth has remained relatively constant for billions of years.
and the volume of water in the ocean basins had been changing before this ice age, by commonly 20 meters, and occasionally by up to 100 meters(almost approximating the changes within this ice age)
Then the trees/plants/soils/lakes/rivers/atmosphere/etc... must have held that water.
ok so far?
Then, as the temperate zones march poleward
Can we approximate the volume of water that will be sequestered in the trees/plants/soils/lakes/rivers/atmosphere/etc... and withheld from the ocean basins?

give it a try?

 

[billvon]

if the volume of water on earth has remained relatively constant for billions of years.
and the volume of water in the ocean basins had been changing before this ice age, by commonly 20 meters, and occasionally by up to 100 meters(almost approximating the changes within this ice age)
Then the trees/plants/soils/lakes/rivers/atmosphere/etc... must have held that water.

Most of it is held in ice.

 

[sculptor]

Most of it is held in ice.

Yes for today.(most----not quantified?)
However:
That is why I went without this ice age to look at sea level fluctuation, and to look for where the rest of the water was during cretaceous sea level lowstands.

None of the sequestered water was held in ice during the cretaceous!
Meanwhile we have at least 20 meter sea level fluctuations.

.........................
do you not find this interesting?

 

[billvon]

That is why I went without this ice age to look at sea level fluctuation, and to look for where the rest of the water was during cretaceous sea level lowstands.

Why do you think the water went anywhere? A 10C change in ocean temperature (on average) would result in a change in sea level of 21 meters due to thermal expansion/contraction. (assuming an average depth of 3600 meters.) That doesn't seem that fascinating.

No doubt there were other small effects (atmosphere holds more water, more lakes when there's more rain etc) but thermal expansion was the biggest effect back then (and even today.)

 

[exchemist]

Why do you think the water went anywhere? A 10C change in ocean temperature (on average) would result in a change in sea level of 21 meters due to thermal expansion/contraction. (assuming an average depth of 3600 meters.) That doesn't seem that fascinating.

No doubt there were other small effects (atmosphere holds more water, more lakes when there's more rain etc) but thermal expansion was the biggest effect back then (and even today.)

There is also the issue of water held in the rocks of the crust and mantle. Volcanoes emit water, while subduction at plate margins entrains it. I can imagine that variations in intensity of tectonic processes could also alter the amount of water in liquid form at the surface, over geological timescales.

 

[iceaura]

do you not find this interesting?

Of course.
So have all the climate researchers for decades now.

No doubt there were other small effects

Ocean basin configuration, continent configuration, also apply - probably: significantly.

They were quite a bit different then - notice that he appears to be trying to measure "sea level" not from the center of gravity but with reference to shorelines.

It is called "sea level rise/fall" rather than "shore level fall/rise" because reasons.

 

[iceaura]

I ask open ended questions because I do not want primary school responses.

You ask the questions you ask as a method of posting innuendo and bullshit on this forum without being responsible for it.

A typical question:

we do not know why we go into an ice age, nor why we come out of one
we do not know how long this one will last
we do not know the signs that could tell us when to expect a change from icehouse to greenhouse climates.
all is speculation

shall we speculate?

A typical justification:

What I was looking for was a comparison of modern topography/elevation of shorelines and coastal plains to those of the cretaceous, incorporating an ice free, and more equable earth's climate.
And, just how much water would be stored in the trees and soils of a temperate rainforest which would likely cover the arctic and antarctic(replacing the arctic desert). Adding in an estimation of the change in atmospheric moisture should round the information nicely.

and so forth.

By the fourth or fifth post of that nature, the meaning of the term "sea level" itself has been obscured - is it mean distance from the gravitational center? Median? Is it instead measured as a shoreline isocline, with some complications regarding tides necessary? Is floating ice part of the sea or the shore? Does it vary from place to place? Are we to include such concepts as a virtual sea level in analyzing the Cretaceous, as we do when analyzing the Holocene? and so forth - - -

None of this matters. The poster has not defined "sea level" in the first place, and the absence of any solid notion of what the thread is about is clearly irrelevant.

 

[Hipparchia]

I've found several conflicting estimates of Cretaceous sea levels.
darned confusing your thoughts?

As suggested by other members you seem to have over-simplified your question to the point it is meaningless. This is my attempt to raise the background to a level where fruitful discussion can follow.

First, lets note, as simply as possible, what can alter sea level. There are only two things:

• A change in the volume of water
• A change in the volume of the oceans and seas that contain those volumes

What can change these volumes? First, the volume of water:

• Thermal expansion or contraction
• Changes in the amount of water in lakes, rivers, vegetation and sub-surface reservoirs (including groundwater)
• Evaporation from, or influx into, marginal seas
• Subduction of water bearing sediments and (often associated with this) the eruption of H2O bearing magma
• Changes in the amount of ice tied up in continental ice bodies.

(The latter is the major contributor to changes.)

What changes the volume of the oceans and seas?

• Sea floor spreading rates
• Mid-ocean ridge length variation
• Continental collision
• Fluctuations in sedimentation rates
• Mantle convection (including super plumes)
• Eruption of submarine LIPs (Large Igneous Provinces)

I think most of these points have been raised previously, either directly or implied, but laying them out here may provide a better framework for discussion. Now my first question to you, in two parts is, do you agree with all of these; do you think any are missing?

You speak of confusion, implying ambiguity and contradiction in the data, but you are not specific. All scientific data contains ambiguity and contradiction. (If you think otherwise you probably aren’t looking closely enough.) Hence my second question, what specifically do you find ambiguous, or contradictory, or confusing in the Cretaceous sea level data?

In a related (and final) question are you disputing the methodology or the results of backstripping in determining Cretaceous sea levels? If so, why and on what basis?

I also note what has been remarked on by others: you seem to lack an awareness of the different time frames over which these various controls on sea level operate (and the magnitude of changes they may cause). Thus variations in continental ice produce large changes, rapidly - 200m within several thousand years. In contrast sedimentation rate changes produce much smaller changes over 10 My or more, while sea floor spreading may generate changes at a similar rate (10m/My), but of much greater magnitude, equal to or exceeding that occasioned by ice fluctuation. You seem indifferent to, or ignorant of these contrasts. You may want to comment. (Even if you don’t, I think you should.)

 

[iceaura]

Detail factor: large slow changes can hit tipping points after which catastrophes (in the Thom sense) occur suddenly and very rapidly. We also know that aspects of earth's climate, especially in local manifestation, are both close to such tipping points and moving toward them. Different thread.

So: very rapid changes in the past do not conflict with, instead are predicted effects of, a combination of large slow changes that has been stable for a very long time. Also, directly: as with some earthquake classes, in many systems (especially chaotic ones) the longer the time of stability the quicker and larger the change (the farther from the new equilibrium range the change began the larger the difference likely to be covered in one of the jumps, stochastically. With exceptions, of course).

Pertinently: homeostatic mechanisms for stabilizing a dynamic but bounded system, especially a nested one (climate of Australia, say) are likely to maintain it on one side of the equilibrium, fairly close to the tip in one direction only. That's where the minimum {per quantum of benefit} cost of a given "amount" of stability shows up - it's a hidden or cryptic factor, difficult to quantify or even locate. Information becomes key, and who has what information significant.

Enter politics - in or out of its extraordinary euphemism camo.

By subtle (to the unfamiliar) control of deceptive rhetoric the media pro on the vulnerable political side acts to rail the public discussion away from that tipping point (the immediate danger, the too likely catastrophe) and toward some other destination (however unlikely, long in the future, or even impossible) that covers up their past blunders and crimes. In doing that they trash ('in communication'* so to speak) enough hard data and past record to prevent consensus formation outside the firsthand circles of discovery rumors and raw data processing.

Unfortunately, they are unable to rearrange physical reality for their convenience in that way - and agw is not that slow or smooth a train this close to so many tips (even over a couple).

So the physical realities of Cretaceous sea levels would be meaningful often, regardless of or even specifically motivating the particular choice of definition. Knowing them by way of several definitions or measurements of "sea level" would be useful in many situations. They might even enlighten us about agw's likely future effects - just not as much as they would about other matters, such as socially imposed gene flow or the ecological effects of indigenous people's fire regimes, that at least a bit share their timeline scale.

First, lets note, as simply as possible, what can alter sea level. There are only two things:

There is immediately a third - configuration of those basins and seas. The absolute change and difference in surface area, if any, largely determines the absolute level rise from a given increase in water volume).

Several more factors emerge as one specifies the thing to be measured and requires greater precision as well as accuracy - in absolute as well as relative variance, in locality as well as both relative and absolute quantity, and so forth
- partly depending on one's intended employment of "sea level", which will remain mysterious here (my prediction) this time as in the past.
The gravitational attraction of nearby high-density and high-volume land-ice masses, for example, (which is especially significant around Greenland, Iceland, et al) the arctic region coastlines in general, as included in a plurality of Sculptor's agw aimed innuendo settings here.

* Unable to find a term pair belonging to the taxon {in vitro / in vivo}. 'Incommunicado'and such suspend the mud in the river.

 

[Write4U]

This may be pertinent to the OP.

Giant tsunami from dino-killing asteroid impact revealed in fossilized ‘megaripples’
By Akila RaghavanJul. 12, 2021 , 3:35 PM

Some 66 million years ago an asteroid slammed into what is now the Gulf of Mexico, triggering the dinosaurs’ extinction—and a massive tsunami.
MARK GARLICK/SCIENCE SOURCE

When a giant space rock struck the waters near Mexico’s Yucatán Peninsula 66 million years ago, it sent up a blanket of dust that blotted out the Sun for years, sending temperatures plummeting and killing off the dinosaurs. The impact also generated a tsunami in the Gulf of Mexico that some modelers believe sent an initial tidal wave up to 1500 meters (or nearly 1 mile) high crashing into North America, one that was followed by smaller pulses. Now, for the first time, scientists have discovered fossilized megaripples from this tsunami buried in sediments in what is now central Louisiana.

“It’s great to actually have evidence of something that has been theorized for a really long time,” says Sean Gulick, a geophysicist at the University of Texas, Austin. Gulick was not involved in the work, but he co-led a campaign in 2016 to drill down to the remains of the impact crater, called Chicxulub.

To look for ancient buried structures, researchers rely on seismic imaging techniques to “see” underground. They set off explosives or use industrial hammers to send seismic waves into the earth, and listen for reflections from the layers of sediment and rock below. Companies use the technique to search for oil and gas, and they have mountains of data—especially in areas such as the Gulf of Mexico.

https://www.sciencemag.org/news/202...eroid-impact-revealed-fossilized-megaripples?

 

[sculptor]

Hi Write:

This may be pertinent to the OP.

Giant tsunami from dino-killing asteroid impact revealed in fossilized ‘megaripples’
By Akila RaghavanJul. 12, 2021 , 3:35 PM

Some 66 million years ago an asteroid slammed into what is now the Gulf of Mexico, triggering the dinosaurs’ extinction—and a massive tsunami.
MARK GARLICK/SCIENCE SOURCE
https://www.sciencemag.org/news/202...eroid-impact-revealed-fossilized-megaripples?

related
(I read this a couple years ago)
took awhile to find the link
here it is (but first a taste)

A meteor impact 66 million years ago generated a tsunami-like wave in an inland sea that killed and buried fish, mammals, insects and a dinosaur, the first victims of Earth’s last mass extinction event. The death scene from within an hour of the impact has been excavated at an unprecedented fossil site in North Dakota.

(Graphics and photos courtesy of Robert DePalma)
and(the link):
https://news.berkeley.edu/2019/03/29/66-million...
oops(try this one)
66-million-year-old deathbed linked to dinosaur-killing meteor (phys.org)

 

[sculptor]

Wow
talk about your average resurrected post................................3 days be damned

But at least one thing is clear: he was lying through his teeth in post 21.

Gee dad
That was a tad harsh

and

seemingly proclaimed quite loudly from abyssal ignorance?

...............................
or
Is that your(lame?) attempt at humor?

 

[Write4U]

What would you use to indicate a bemused chuckle

hehe.......