Uniformitarianism or catastrophism?

[Mr-Vaquero]

Hello,
Uniformitarianism and catastrophism are 2 ways to look at Earth's geologic history.

Uniformitarianism suggests for example that surface features we see on Earth are caused by long term uniform processes such as weathering or plate tectonics.

Catastrophism suggests that features on Earth can be explained by sudden, short events. Such as Noah's flood or a meteorite impact.

So, what theory do you like best and why?

[EarthScienceguy]

[Replying to The Barbarian in post #85]


"Also, gully-headed side canyons and amphitheater-headed side canyons in the breach resemble side canyons in the Grand Canyon. The breach did not occur straight through the obstruction but has a meandering path, which reminds us of the meandering path of the Grand Canyon through the high plateaus of northern Arizona. The “Little Grand Canyon of the Toutle River” is a 1/40th-scale model of the real Grand Canyon of Arizona."

Steve Austin
B.S. (Geology), University of Washington, Seattle, WA,1970
M.S. (Geology), San Jose State University, San Jose, CA, 1971
Ph.D. (Geology), Pennsylvania State University, University Park, PA, 1979

This geologist does not agree with you.

[EarthScienceguy]

[Replying to DrNoGods in post #90]

Presumably it was present in the accretion disk material and therefore became part of Earth during its formation. That is, it was part of the original material that formed the planet. It didn't "arrive" via impacts after the primary formation event.

It was only present in 2 ppb. That is my point.

[The Barbarian]

[Replying to The Barbarian in post #85]


"Also, gully-headed side canyons and amphitheater-headed side canyons in the breach resemble side canyons in the Grand Canyon. The breach did not occur straight through the obstruction but has a meandering path, which reminds us of the meandering path of the Grand Canyon through the high plateaus of northern Arizona. The “Little Grand Canyon of the Toutle River” is a 1/40th-scale model of the real Grand Canyon of Arizona."

Steve Austin
B.S. (Geology), University of Washington, Seattle, WA,1970
M.S. (Geology), San Jose State University, San Jose, CA, 1971
Ph.D. (Geology), Pennsylvania State University, University Park, PA, 1979

This geologist does not agree with you.

Steve Austin is a creationist, who seems to have his own definition of "meandering." I assume you are a geologist, and you wrongly thought the gullies at Mt. St. Helens had meanders. So there is that.

Austin is also the guy who submitted a sample of dacite from Mt. St Helens for dating. Although the lab told him that their equipment could not accurately date such recent material, he submitted it anyway, and got a very ancient date as a result. Which is consistent with tiny traces of argon gas remaining in the test equipment and the presence of xenocrysts in the sample he submitted. So not the best geologist in the world. There's more, if you want.

[DrNoGods]

[Replying to EarthScienceguy in post #92]

It was only present in 2 ppb. That is my point.

Where does that number come from? And is it ppb by weight or by volume? This makes a big difference for something as heavy as uranium. The sun would contain about 0.27% of the Earth's mass of uranium at 8 ppb by volume (same as meterorites). The Earth's crust is estimated to contain about 40 trillion tons of uranium. So there is a decent amount of it floating around. But what does this have to do with density of the core relative to the mantle and crust?

INNER CORE: Density ~ 12.9 g/cm^3.
OUTER CORE: Density ~ 11.0 g/cm^3.
LOWER MANTLE: Density ~ 5.0 g/cm^3.
UPPER MANTLE: Density of 3.9 g/cm^3.
Average for planet ~ 5.5 g/cm^3.
(from any Google search)

The inner and outer core are believed to be composed of an iron-nickel alloy. possibly ε-iron which is a crystalline form iron. There doesn't seem to be any mystery about density of the core and other layers, or why uranium would need to be in the core in any significant levels at all.

[The Barbarian]

These are meanders:


These are not meanders:


Any questions?

[EarthScienceguy]

[Replying to The Barbarian in post #95]

Both pictures are meanders and other geologists do agree with me. Not you.

[EarthScienceguy]

[Replying to The Barbarian in post #93]

Steve Austin is a creationist, who seems to have his own definition of "meandering." I assume you are a geologist, and you wrongly thought the gullies at Mt. St. Helens had meanders. So there is that.

Are you saying that a man with his doctorate in Geology does not know what a meander is?

Are you saying the other geologist who do not agree with you also do not know what a meander is?

[The Barbarian]

[Replying to The Barbarian in post #93]

Steve Austin is a creationist, who seems to have his own definition of "meandering." I assume you are a geologist, and you wrongly thought the gullies at Mt. St. Helens had meanders. So there is that.

Are you saying that a man with his doctorate in Geology does not know what a meander is?

I'm pointing out that gullies formed by floods do not have meanders. As you saw with Mt. St. Helens. You were wrong to identify the gullies as meanders. That's not how they form.

Are you saying the other geologist who do not agree with you also do not know what a meander is?

From: A Complete List Of Fluvial Landforms
Meander
A river or stream never flows completely straight but snakes its way through the various undulations on the surface of the Earth. The river or stream thus forms a series of loops, curves or bends along its course and these features are called meanders. At the meander, the river erodes the outer convex bank and deposits the eroded material at the inner concave bank.
https://craftstaging.worldatlas.com/art ... forms.html

It would seem that the sinuosity index of the gullies at Mt. St. Helens is well under 1.5. I could check on that for you in Google Earth. Do I need to do that? The gullies as well as the Toulle River, show a braided channel structure, typical of young, fast-moving streams.

[EarthScienceguy]

[Replying to DrNoGods in post #94]

The inner and outer core are believed to be composed of an iron-nickel alloy. possibly ε-iron which is a crystalline form iron. There doesn't seem to be any mystery about density of the core and other layers, or why uranium would need to be in the core in any significant levels at all.

I have a legitimate question for you.

Ok, I get how compression can increase the density of Iron. (I should have thought of that before I started this argument. I have studied supercritical water so I understand how compounds can have different properties under high heat and pressure. And that fact that it there was that much uranium in the core so as to offset the density difference the earth would be nothing but a liquid rock.)

But it seems as if there is a conflict in the literature about whether there is uranium in the core. One paper I read said that uranium IV oxide could not be in the mantle because it is not soluble in iron. But uranium IV oxide has a density of 10.97 g/mL. Why would it not just layer like immiscible liquids? Do you think the structure of uranium IV oxide at high pressure keeps the density lower than iron? It has the same structure as Flourite tetrahedral cubic.

[DrNoGods]

[Replying to EarthScienceguy in post #99]

But it seems as if there is a conflict in the literature about whether there is uranium in the core. One paper I read said that uranium IV oxide could not be in the mantle because it is not soluble in iron. But uranium IV oxide has a density of 10.97 g/mL. Why would it not just layer like immiscible liquids? Do you think the structure of uranium IV oxide at high pressure keeps the density lower than iron? It has the same structure as Flourite tetrahedral cubic.

This paper:

https://agupubs.onlinelibrary.wiley.com ... 06GL027508

suggests that U4+ can be bound up in aluminous CaSiO3 perovskite in the lower mantle. It can replace Ca+2 ions efficiently in the presence of Al. But there is too little U overall in the mantle, and similarly for the core people seem to believe, that it would not contribute much to the overall density of the core.