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Drought in Brazil's Amazon reveals ancient engravings

phys.org

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Re: Drought in Brazil's Amazon reveals ancient engravings

#71

Post by defrost »

verisimi wrote: post #69
defrost wrote: post #62

Earlier quoted context omitted.

Doesn't follow. Eg: the pictured carvings are on collapsed rock shelves, presumeably these were above normal river level when carved and in a two thousand year period the river has undercut the rock shelf and they've colapsed to below the usual river level. In fact there are many possible reasons why your apparent smug bad faith poo poo climate change comment isn't well considered.

I'm downvoted, but why? I'm simply making the obvious observation - that the river got this low 2000 years ago, but today the drop is blamed on climate change. > the pictured carvings are on collapsed rock shelves, presumeably these were above normal river level when carved and in a two thousand year period the river has undercut the rock shelf and they've colapsed to below the usual river level. You presume somethin…

> I'm downvoted, but why?

No idea, I was also downvoted by someone, it's not something I fuss about; you'd have to ask the downvoters.

> You presume something that is not expressed in the article.

It's right there in the pictures, layered strata, rock shelf, carvings on rock collapsed off of the shelf.

It's a pretty basic geological observation.

> I'm simply making the obvious observation - that the river got this low 2000 years ago,

That's a shallow conclusion, geologically speaking .. a leap of "can't think of anything else".

There are many possible reasons strata | water relationships might alter over the course of two thousand years. I've fleshed out one.

> take out the political, environmental slant (out of the article, and your mind)

There you go with the poor reasoning and shoddy conclusions based on projected assumption again.

My background is geophysics and my two comments are related to geology and timescales.

Re: Drought in Brazil's Amazon reveals ancient engravings

#72

Post by rocketbop »

verisimi wrote: post #69
defrost wrote: post #62

Earlier quoted context omitted.

Doesn't follow. Eg: the pictured carvings are on collapsed rock shelves, presumeably these were above normal river level when carved and in a two thousand year period the river has undercut the rock shelf and they've colapsed to below the usual river level. In fact there are many possible reasons why your apparent smug bad faith poo poo climate change comment isn't well considered.

I'm downvoted, but why? I'm simply making the obvious observation - that the river got this low 2000 years ago, but today the drop is blamed on climate change. > the pictured carvings are on collapsed rock shelves, presumeably these were above normal river level when carved and in a two thousand year period the river has undercut the rock shelf and they've colapsed to below the usual river level. You presume somethin…

I didn’t downvote you but I assume it’s because you’re saying a drought is evidence of climate change. Regular droughts might be visible effects of climate change but they can happen during a period of general stability too.

Re: Drought in Brazil's Amazon reveals ancient engravings

#74

Post by 7thaccount »

cmrdporcupine wrote: post #56
irrational wrote: post #27

Earlier quoted context omitted.

We had a Mayan guide when we were in the Yucatan on vacation. He spent quite a bit of time pointing out proofs (as the native Mayans see them) of horses being around the entire time. He claimed to have a college degree in archaeology, but went on a rant about non-Mayan archealogists and their bias against native Mayans. Basically, he saw the disbelief against horses being around the whole time as racially motivated.…

It's pretty dubious because horses themselves -- the kinds of horses we domesticated and ride -- are descendants from a pretty isolated genetic pocket in the Pontic-Caspian steppe, potentially all descended from a single male even. The kind of horse that could be domesticated and ridden was not widespread, and in fact were really just hunted for meat until maybe 6500 years ago, and actually riding them came even late…

Camels are crazy and work well in both cold and hot climates. I saw something (I think a PBS documentary) that said they originally weren't adapted to the desert, but the artic of northern Canada or something crazy like that (many many millenia ago).

Edit: more like millions of years

https://en.m.wikipedia.org/wiki/Paracamelus

Re: Drought in Brazil's Amazon reveals ancient engravings

#75

Post by AlecSchueler »

asimpletune wrote: post #21
ldjkfkdsjnv wrote: post #8

People generally dont know it, but the facts/debate around the sophistication of populations thousands of years ago, and how those vary across geographies, is extremely political. There is generally an unseen hand that dictates the narrative around the distant human past. You can pull the facts together, but the full picture is almost never presented cohesively to the non academic population.

I don’t think it’s political, but rather a matter of record. There is much more writing from Greece than the Amazon. Having the Iliad amounts to a cheat code in archaeology.

Though in the cases of colonial history our access to the records are based in politics. Many texts were destroyed and our connections to the cultures that produced them were destroyed along with them.

Re: Drought in Brazil's Amazon reveals ancient engravings

#77

Post by AlecSchueler »

isk517 wrote: post #35
skylurk wrote: post #17

Earlier quoted context omitted.

and on the inside of that shell, we're all pretty much the same...

Looking at Roman graffiti from 2000 years ago does pretty much confirm this.

We're basically still living in the cultural mileu formed in Rome, though. I would expect to have much more cultural connection to someone in Rome in 0AD than someone in the Amazon in the 14th century.

Re: Drought in Brazil's Amazon reveals ancient engravings

#78

Post by secondcoming »

TaylorAlexander wrote: post #45
asimpletune wrote: post #21

Earlier quoted context omitted.

I don’t think it’s political, but rather a matter of record. There is much more writing from Greece than the Amazon. Having the Iliad amounts to a cheat code in archaeology.

There are certainly political threads. American westward expansion had to be justified, for example, by claiming cultural superiority over the people who were being displaced.

What has this got to do with archaeology?

Re: Drought in Brazil's Amazon reveals ancient engravings

#79

Post by verisimi »

defrost wrote: post #71
verisimi wrote: post #69

Earlier quoted context omitted.

I'm downvoted, but why? I'm simply making the obvious observation - that the river got this low 2000 years ago, but today the drop is blamed on climate change. > the pictured carvings are on collapsed rock shelves, presumeably these were above normal river level when carved and in a two thousand year period the river has undercut the rock shelf and they've colapsed to below the usual river level. You presume somethin…

> I'm downvoted, but why? No idea, I was also downvoted by someone, it's not something I fuss about; you'd have to ask the downvoters. > You presume something that is not expressed in the article. It's right there in the pictures, layered strata, rock shelf, carvings on rock collapsed off of the shelf. It's a pretty basic geological observation. > I'm simply making the obvious observation - that the river got this lo…

> It's right there in the pictures, layered strata, rock shelf, carvings on rock collapsed off of the shelf.

It isn't.

The article says:

> The rock carvings are not usually visible because they are covered by the waters of the Negro River, whose flow recorded its lowest level in 121 years last week.

There is no mention of "collapse", "strata" or "shelf". Are we looking at the same info?!?

Re: Drought in Brazil's Amazon reveals ancient engravings

#80

Post by verisimi »

rocketbop wrote: post #72
verisimi wrote: post #69

Earlier quoted context omitted.

I'm downvoted, but why? I'm simply making the obvious observation - that the river got this low 2000 years ago, but today the drop is blamed on climate change. > the pictured carvings are on collapsed rock shelves, presumeably these were above normal river level when carved and in a two thousand year period the river has undercut the rock shelf and they've colapsed to below the usual river level. You presume somethin…

I didn’t downvote you but I assume it’s because you’re saying a drought is evidence of climate change. Regular droughts might be visible effects of climate change but they can happen during a period of general stability too.

I'm not saying that a drought is evidence of climate change - I'm saying the opposite.

The article ties climate change into this, when it says:

> According to experts, the dry season has worsened this year due to El Niño, an irregular climate pattern over the Pacific Ocean that disrupts normal weather, adding to the effect of climate change.

but there is no reason to think climate change has anything to do with this. The article itself also says:

> The rock carvings are not usually visible because they are covered by the waters of the Negro River, whose flow recorded its lowest level in 121 years last week.

ie 121 years ago, the river was recorded as being this low. ie before climate change.

For me this is another 'climate change' article, but is interesting as not all the claims the article makes can all be true.

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