Posted on 07/10/2014 12:35:30 PM PDT by BenLurkin
Carson and his colleagues wanted to explore the question of whether early Amazonians had a major impact on the forest. They focused on the Amazon of northeastern Bolivia, where they had sediment cores from two lakes nearby major earthworks sites. These sediment cores hold ancient pollen grains and charcoal from long-ago fires, and can hint at the climate and ecosystem that existed when the sediment was laid down as far back as 6,000 years ago.
An examination of the two cores — one from the large lake, Laguna Oricore, and one from the smaller lake, Laguna Granja — revealed a surprise: The very oldest sediments didn't come from a rainforest ecosystem at all. In fact, the Bolivian Amazon before about 2,000 to 3,000 years ago looked more like the savannas of Africa than today's jungle environment.
The question had been whether the early Amazon was highly deforested or barely touched, Carson said.
"The surprising thing we found was that it was neither," he told Live Science. "It was this third scenario where, when people first arrived on the landscape, the climate was drier."
The pollen in this time period came mostly from grasses and a few drought-resistant species of trees. After about 2,000 years ago, more and more tree pollen appears in the samples, including fewer drought-resistant species and more evergreens, the researchers report today (July 7) in the journal Proceedings of the National Academy of Sciences. Charcoal levels also went down, indicating a less-fire-prone landscape. These changes were largely driven by an increase in precipitation, Carson said.
The earthworks predate this shift, which reveals that the diggers of these ditches created them before the forest moved in around them
(Excerpt) Read more at livescience.com ...
That part of the article was very unclear. The extent of the rainforest ebbs and flows with climactic conditions. The rainforest in Bolivia has been there for a few thousand years but the rainforest as a whole has been there for millions of years.
First Paragraph mentions: “A series of square, straight and ringlike ditches scattered throughout the Bolivian and Brazilian Amazon were there before the rainforest existed, a new study finds.”
This seems to indicate a larger area was previously not rainforest. The article is confusing.
Having studied the Sahara and Arabian deserts for a number of years now I can say with a good deal of confidence that no matter what you read on the internet the provenance of the quartz grains that form the deserts in unknown (the same would apply to the deserts, beaches, sandstone deposits, etc. worldwide). Pretty amazing given they both contain vast oceans of sand. Some say the underlying Nubian sandstone (almost pure quartz sand) may be the source but then they cannot say where this originated. Volcanism largely produces basalt which is mainly devoid of quartz altogether, so this cannot be the source.
I’m in the middle of writing my third book “Extraterrestrial Desert Sands” in which I proposed the deserts (& quartz sand globally) were formed VERY recently. In short: Cosmic chaos involving mainly Mars (once home to humans the same as you and I) created unfathomable quantities of vaporised rock - this condensed as it fell to earth, precipitating out of the atmosphere to form quartz crystals. In other words it rained sand! Vast swaths of it - this is the origin of the deserts (beaches, dune sand, etc.) of the world! All this occurred in the last few thousand years. Prior to this the Sahara was a green savanna, as too were vast regions of the Arabia peninsular.
I’m in favour of the ‘green glass’ the result of a bolide event... as follows.
“The latest research almost proves that Libyan desert glass is the terrestrial by-product of a massive bolide impacting in desert sands. Analysis shows rapidly quenched molten silica with signs of molecularly altered zircon crystals, shocked quartz and metals such as nickel and iron. The only force that can produce this material is really a cosmic impact. Nuclear blasts come close, but the material is very low quality and frothy. Fulgerites from lightning impact is even more frothy and grainy, and looks more like cemented sand.”
http://www.abovetopsecret.com/forum/thread960470/pg2
But I would ignore any “gazillion years old” dates. Everything we see today in geological terms occurred mainly in the last few thousand years (catastrophist not creationist!). Earth is still simmering down as a result of recent planetary encounters.
Loads more on my web.
Apologies if I appear illusive, it’s all eyes down in trying to get book completed!
Turns out, sand formation may be more complex than one might originally suspect. And, after doing some more looking around I discovered there are actually several different types of sand that make up the Sahara itself. It's not uniform at all. Never thought about it but I suppose it makes sense.
I gather you're also a follower of many of Velikovsky's ideas and his interpretations of Biblical an other ancient scripts. Have you looked at the 9th plague, the plague of darkness in Egypt? Utter darkness, a darkness that could be felt??? A cloud of sand cold be felt. Not to mention it had to have been exceedingly thick. Lasted either three days or nine days depending on the source.
The rainforest/jungle I that area is young but that does not imply there was no existing rainforest or jungle species in adjacent regions.
In short, the jungle encroached when rainfall permitted it, and birds and other animals followed the advance of the plant growth.
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