
Amazon rainforest was transformed over 2,000 years ago by mysterious earthworks - Thevet
http://www.exeter.ac.uk/news/featurednews/title_568689_en.html
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cossatot
Amazonian earthworks such as these are discussed quite a bit in Charles Mann's
_1491_ , mostly in the context of dual hypotheses that the Amazon (and much of
N. and S. America) was both far more heavily populated, and far more
ecologically managed, than previously thought. It's a great and fascinating
book, although not as data rich and scholarly as it could be.

I don't recall Mann having much description of what the earthworks were used
for, although there were suggestions of some of them being fish corrals during
high water events, I believe.

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mirimir
Thanks!

Yes, "both far more heavily populated, and far more ecologically managed", and
for a far longer time. Perhaps for as long as 40 kiloyears. But relatively
isolated, with just "low-bandwidth" communication with northeast Asia.

I wonder why things went so differently in Eurasia. Maybe bronze and iron
technology? Jared Diamond stuff?

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kneath
He does go into this a bit. Due to the ecology in the Amazon (a giant mud-
filled floodplain), tools and buildings tended to be made of organic materials
like wood & fiber rather than rock & metal as was more common in other areas
of the world. As such, much of the evidence of these people would have rotted
away by the time we started looking. Organic materials rot away real quick in
a warm, wet climate.

~~~
mirimir
OK, right. So ecology and terrain are the only records. Do we have any idea
when populations crashed? Could it have been smallpox etc epidemics from
European explorers?

Edit: Yes, Mann does indeed argue that. And also that isolation prevented tech
spreading. I must read that book!

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yummyfajitas
Mann mentions several instances of the following scenario, happening at
various times across the Americas:

Year X: European explorer #1 sails up a river/crosses mountains/etc and
discovers a vast empire, huge cities, and marvelous civilizations that his
European nation might trade with. He brings pigs with him and trades them to
the natives for their cool stuff.

Year X+20: European explorer #2 follows the path of explorer #1. Then he's all
"WTF, there's nobody here." But explorer #2 does discover, e.g., the giant
earthworks that explorer #1 said were there - it's just the city on top of the
earthworks doesn't exist.

He postulates that in years X+1 to X+19, the smallpoxalypse occurred and
civilization collapsed. The remaining survivors are just roving tribal bands
trying to survive in the remains of their old civilization.

(To make a fictional analogy, consider the current civilization in Georgia and
then consider the civilization depicted on the Walking Dead. Mann's hypothesis
is that most of what we know about American Indians consists of observing the
Walking Dead and then drawing conclusions about their pre-apocalyptic
civilization.)

~~~
vanderZwan
> _(To make a fictional analogy, consider the current civilization in Georgia
> and then consider the civilization depicted on the Walking Dead. Mann 's
> hypothesis is that most of what we know about American Indians consists of
> observing the Walking Dead and then drawing conclusions about their pre-
> apocalyptic civilization.)_

Which is oddly fitting given the history of siphylis, which was likely carried
over from the Americas and sometimes hypothesised to be the inspiration for
zombies

[https://en.wikipedia.org/wiki/History_of_syphilis](https://en.wikipedia.org/wiki/History_of_syphilis)

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contingencies
Nice meme: _#prehistoricsupermarket_

Reminds me of the Terence McKenna quote: _The scene opens on a world that
appears totally primitive. People are naked, people are orgiastic, people are
nomadic. But when they close their eyes there are menus hanging in space.
Culture has been internalized. Culture is supposed to be internalized. All
this talk about virtual reality - people don 't seem to notice - this is a
virtual reality. These are all ideas - ideas that have been forced into matter
so that we could live in a reconstruction of our imagination. And de-
constructing these virtual realities in which we live is the only way to get
back to some sort of baseline of what it is to be human._

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joshuaheard
These remind me of the circular homesteads I saw when flying over Africa.
These homesteads were made of huts with a yard circled by a fence for
protection and penning the domestic animals. In a rain forest, it would make
sense to dig a small drainage pit around the whole yard, and for added
protection like a moat.

~~~
arethuza
I guess that's just the natural shape for a small fort - circular to enclose
as much area with the least wall and ditch/wall because you need to dig the
earth to build/reinforce your wall from somewhere and a ditch adds to the
effectiveness of your wall?

They look very like the ancient settlements/enclosures that you get all over
the UK - there are loads of them here in Scotland.

~~~
irrational
Except they mention that there are few to no artifacts found in them, thus
indicating that they weren't used as settlements/enclosures.

~~~
gus_massa
IANAA. I remember that it's very difficult to find ancient tools near China,
because they probably used bamboo to build them.

In other places, the people used stones that are more archeological friendly.
So it's possible to find the tools and even the shard of stones discarded
while building the tools.

Is it possible that they can't find the tools here because they were made with
some king of wood?

~~~
sulam
Tools might rot, but in general you'd expect to at least find middens,
skeletal remains, teeth, scorched layers indicating a hearth of some sort,
etc. There's non-tool markers for communities that will survive even in the
rain forest.

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danielsiders
See also:

[https://en.wikipedia.org/wiki/The_Lost_City_of_Z_(book)](https://en.wikipedia.org/wiki/The_Lost_City_of_Z_\(book\))

~~~
e40
That is an excellent book. I read almost exclusively Sci Fi, but I found this
book enthralling. Highly recommended.

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source99
Need to get the team that analyzed Cambodia using LIDAR to analyze Brazil.

~~~
glenneroo
Is it too much to ask NASA/ESA to launch a constellation of CubeSATs with
LIDAR? Alternately let Google do it and add it as an overlay to Google Maps.

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ZenoArrow
I had expected the article would mention terra preta:

[https://en.m.wikipedia.org/wiki/Terra_preta](https://en.m.wikipedia.org/wiki/Terra_preta)

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Neliquat
Strongly reminds me of primitive animal pens/trapping yards. Used in the
ancient middle east to trap wandering animals.

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jcoffland
I would guess that these were used to contain game.

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alisson
I would guess it is to hold/route rain water, like a swale.

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yread
> The structures are ditched enclosures that occupy roughly 13,000 km2

So, they have a radius of 65km ?! How did they make the picture then? Can't be
right

EDIT: why should a reader care what is the total space occupied by 450 ditched
enclosures?

~~~
randallsquared
> why should a reader care what is the total space occupied by 450 ditched
> enclosures?

Sense of scale.

~~~
pbhjpbhj
I'd say it gives a sense of the type of occupation of the land it is, city vs.
village vs. local farmsteads, and thus an idea of the type of land use and
cooperation that might have taken place?

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JoeAltmaier
Sports fields?

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sdld
i thought Amazon Rainforest (R) was some kind of a new platform..

~~~
pgkl
I had the exact same thought when I read the first two words

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momentmaker
Aliens

