Chickenheads and Knobs on Snow Creek Wall

[G-spotter]

I had no idea that the Little Ice Age was a period of significant glacial advance relative to proceding 2,3,4 eons.

 

What do they TEACH in American schools these days

[David Trippett]

 

What do they TEACH in American schools these days

 

[JayB]

I had no idea that the Little Ice Age was a period of significant glacial advance relative to proceding 2,3,4 eons.

 

What do they TEACH in American schools these days

 

"There were no substantial advances from 10,000 until 5,000 years ago. That is when the neoglacial began. The neoglacial has featured advances at 3000 years ago and during the LIA that were nearly identically sized. You can see the moraine overlap from these two by Lyman Glacier for example."

 

 

"Glacial History

 

According to Madole (1976), during the latter part of the Pleistocene (~1.8 million years before present - 10,000 years BP) and into the early Holocene (10,000 years BP - present) large valley glaciers were present across most of the higher mountain ranges of Colorado and a small icecap even formed in the northwest part of Rocky Mountain National Park. Valley glaciers in the Front Range were typically 15-25 km long and 1-3 km wide, reaching down to elevations of 2440 to 2745 m. These valley glacier ranged in thickness from 215 to 460 m and the longest was 45 km long (located in the valley of the Cache la Poudre River and fed by the icecap). In Colorado only two Pleistocene glacial advances are recorded on the landscape: Bull Lake and Pinedale (The names come from the Wind River Range where these glacial advances were first identified.). The Bull Lake glaciation is thought to have occurred 125,000 to 50,000 years BP, while the Pinedale glaciation has been dated to 29,000 to 7,600 years BP. Generally the Bull Lake glaciation was more extensive. Additionally there have been three small Holocone (10,000 years BP to present) glacial advances termed, from oldest to youngest, Triple Lakes, Audubon, and Arapaho Peak advances. Collectively these minor advances are termed Neoglaciation, and the largest glacier during these advances was only 1.6 km long. The Arapaho Peak advance is local evidence for the Little Ice Age (the popular name for a period of cooling in the northern hemisphere lasting approximately from the 14th to the mid-19th centuries). Most of the glaciers and perennial ice patches in Colorado today are the tattered remnants of these small Little Ice Age glaciers."

 

I'm new to the topic, but the term "advance" in conjunction with the Little Ice Age seems to suggest that glaciers were adding, rather than losing, mass relative to some interval of time that predated the LIA.

[G-spotter]

We learned that in highschool. Maybe while you were taking a class in saluting the flag?

[olyclimber]

[Cobra_Commander]

I was busy getting a cow up onto the third floor of my highschool. and grating an apple into someone's locker

[JayB]

"We learned that in highschool. Maybe while you were taking a class in saluting the flag?"

 

The inclusion of that topic is clearly responsible for the string of scientific triumphs that you and your countrymen have been responsible for.

 

I wasn't aware of the LIA until a couple of years ago, and kind of assumed that most Alpine glaciers had been undergoing a steady decline, with brief periods of relatively insignificant advance and retreat, since about 10,000 years ago.

[G-spotter]

Maybe your President kind of assumed something similar. Carbon dioxide is good in Pepsi, right, why not in the atmosphere?

[G-spotter]

I was busy getting a cow up onto the third floor of my highschool.

 

Why didn't you just miniaturize it and hide it in some Christmas presents for GI Joe?

[Dechristo]

it's our effort to support the rain forests

[JayB]

Besides, in between using what little math we learned to calculate the precise arrival of the rapture, and how the fossil record was created by larger and more nimble creatures climbing uphill to avoid the Noachian floods, there really wasn't any time for much else.

[JayB]

Maybe your President kind of assumed something similar. Carbon dioxide is good in Pepsi, right, why not in the atmosphere?

 

Just imagine if he knew so little about biology that he fell for bunch of bogus claims about a fat-virus on the basis of some pop-science articles in publications like "Men's Journal."

 

 

[G-spotter]

Hey, adenoviruses have been proven to cause fat accumulation in chickens. It's repeatable science. Could be a good science fair project.

[JayB]

Still worse, imagine if he often showed an inability to distinguish between correlation and causation, and couldn't spot some of the glaring methodological flaws in the original study either.

 

If only he'd attended Canadian schools....

[G-spotter]

If it was correlation, not causation, the chickens would have been fatter to begin with. They weren't. You didn't read the original paper, did you?

[catbirdseat]

The call goes out for bona fide glaciologists and we get Dru and JayB.

[JayB]

Glad to see that we've stayed on topic here. Chickenheads to chickenfat.

 

I think I still have the PDF of the original paper, and if you use your vaunted Canadian education in conjunction with the search function I'm sure that you'll be able to dig out the thread that contains my critiques of it.

 

"If it was correlation, not causation, the chickens would have been fatter to begin with. They weren't."

 

Not necessarily. You could take your favorite hypothesis about bacteria living beneath the earths surface, and claim that they harbor a virus that causes obesity, and then argue that the tight connection between per-capita crude-oil consumption and obesity proves your claim that the said virus is the causal agent for obesity. More crude oil a society consumes, the fatter it gets, so....this must mean that crude oil consumption causes obesity, right?

 

HIV often produces dramatic weight loss in the people who get infected with it, so per-your logic (Infect with virus -----> change in weight) you could argue that the simple presence of the virus in their system is what mediates the weight loss, rather than the opportunistic infections that occur when a specific subset of white blood cells is depleted.

 

Let me know if you need any more examples, otherwise I'll be busy getting ready for the rapture and saluting the flag.

[Stonehead]

I don't see why a biotic influence would be discounted. Given enough time, the influence of microbes and other life such as lichens could contribute to the formation of rock features.

 

These chemical weathering actions could be made more amenable by compositional changes in the plutonic rock.

 

Differences in chemistry (mineralogy) lead to a range in crystallization temperatures such that xenoliths begin to form before the final mass has cooled. Shouldn't there also be compositional changes from top to bottom as the mass cools?

 

Personally, I believe in multiple working hypotheses. Maybe it's that our biases in worldview taint our ability to perceive objectively. Wasn't it Aristotle who created a fictional opponent who questioned him in dialogue so that he could logically create a better argument? Then there's that other fellow who talked about synthesis. And there's also another fellow named Paracelsius who once said that learning occurs outside of the university and you needn't necessarily only look to the given experts (the ones with letters behind their names) of a particular field to formulate ideas of how the world operates.

[ScottP]

The call goes out for bona fide glaciologists and we get Dru and JayB.

 

Titanically overinflated egos, both.

[MarkMcJizzy]

it's all beside the original point if Snow Creek canyon or Icicle Ck canyon were never glaciated. were they?

There are what I have interpreted as small roches moutonnees near Bruce's Boulder. I made this interpretation more that twenty years ago, but I must have seen glacial polish there. I have also shown this site to other geologists, including professors, and no-one has disagreed. The Snow Creek valley is often used in field trips as an example of a hanging glacial valley.

 

See at the bottom of a continental glacier the pressure is enough to plasticize both the rocks in the ice and the rock the ice is resting on.

This is an insane statement. Almost by definition, the plasticization of rocks is metamorphic deformation. The conditions under any glacier are minor in geologic terms. For instance, the rocks immediately under the South Pole should be under ~4.4Kpsi, or ~.29Kbar. Dru's statement is laughable, and shows that his knowledge of crystalline rocks is pathetic, as is Dru.

[Alpinfox]

 

Mark,

So what do YOU think causes those longitudinal striations in glacially polished bedrock. Rocks embedded in the glacier or silty water?

 

What are the differences between "flutes", "furrows", "grooves", and "chattermarks"?

 

The Glacier Glossary I found has the following:

 

grooves/grooving:

As the glacier moves forward, rocks imbedded in the ice scratch the underlying materials. If small, these linear features are called striations. Grooves are larger features which may be regular or irregular and may be helpful in establishing direction of glacial flow.

[olyclimber]

Xenu (also Xemu) is an alien ruler of the "Galactic Confederacy" who, 75 million years ago, brought billions of people to Earth in DC-8-like spacecraft, stacked them around volcanoes and blew them up with hydrogen bombs. Their souls then clustered together and stuck to the bodies of the living, and continue to wreak chaos and havoc today. Then they scratched rocks and created chickensheads, which many people today incorrectly attribute to glaciers or glacier melt or glacier runoff.

[archenemy]

Xenu (also Xemu) is an alien ruler of the "Galactic Confederacy" who, 75 million years ago, brought billions of people to Earth in DC-8-like spacecraft, stacked them around volcanoes and blew them up with hydrogen bombs. Their souls then clustered together and stuck to the bodies of the living, and continue to wreak chaos and havoc today. Then they scratched rocks and created chickensheads, which many people today incorrectly attribute to glaciers or glacier melt or glacier runoff.

Thanks to the flight data recorder recently being recovered, we now have proof.

[G-spotter]

you say plastic, i say viscous

[MarkMcJizzy]

you say plastic, i say viscous

 

Nice backsliding, you said them both

 

Mark,

So what do YOU think causes those longitudinal striations in glacially polished bedrock. Rocks embedded in the glacier or silty water?

 

I think that imbedded rocks cause stria, and polish is caused by a combination of imbedded rock, and rock flour. My main argument with Dru is his intransigence in believing that liquid water does the bulk of the erosion. I believe the old models, and Dru's arguments do not convince me. If he was right, then polar glaciers would do no eroding.