Ancient lake holds secrets to Mayan civilization's mysterious collapse


spaminator
#1
Ancient lake holds secrets to Mayan civilization's mysterious collapse
Washington Post
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Published:
August 4, 2018
Updated:
August 4, 2018 12:18 PM EDT
Oval Palace at the archaeological site of Ek'Balam - a complex built by the Mayan civilization in the Yucatan Peninsula, in the Mexican state of Yucatan, taken on December 2, 2010. (Cris Bouroncle/AFP/Getty Images)
The sediment under a lake in Mexico contains some of the long-sought answers to the mystery of the Mayan demise.
Ancient Mayans, primarily concentrated in what is now the Yucatán Peninsula, were among the most advanced civilizations of their time. Mayans were some of the first to build cities. They used astronomy to advance agricultural production, and they created calendars and used advanced mathematics. But despite all of their progress, the Mayan empire, built over thousands of years, may have crumbled in just a few hundred.
Scientists have several theories about why the collapse happened, including deforestation, overpopulation and extreme drought. New research, published in Science Thursday, focuses on the drought and suggests, for the first time, how extreme it actually was.
While analyzing sediment under Lake Chichancanab on the Yucatán Peninsula, scientists found a 50 percent decrease in annual precipitation over more than 100 years, from 800 to 1,000 A.D. At times, the study shows, the decrease was as much as 70 percent.
While the drought was previously known, this study is the first to quantify the rainfall, relative humidity and evaporation at that time. It’s also the first to combine multiple elemental analyses and modeling to determine the climate record during the Mayan civilization demise.
Climate scientists commonly use sediment cores to determine the conditions of the past, like geological time capsules. Each layer of sediment buried deep underground contains evidence of rainfall, temperature and even air pollution. Via chemical processes and interactions, the climate conditions are “recorded” in the surface soil at the time, and eventually buried. Scientists can bore a deep core of dirt, and carefully analyze it layer by layer, year by year to reconstruct a timeline.
For this study, scientists painstakingly examined the layers of mud and clay in the cores from under Lake Chichancanab. During dry periods, the lake volume would have shrunk, said Nick Evans, a graduate student studying paleoclimatology at Cambridge University and first author of the study. As the water evaporated, lighter particles would have evaporated first, leaving behind heavier elements.
If the drought was intense and long-lasting, gypsum crystals formed and incorporated existing lake water directly into their structure. The “fossil water” inside the crystals allowed Evans and his co-authors to analyze the properties of the lake water during each period.
“It’s as close as you’ll ever get to sampling water in the past,” Evans said.
The chemical composition of the fossil water indicated periods of drought in the Mayan timeline, and revealed how long and intense this particular drought was.
Many theories about the drought triggers exist, but there is no smoking gun some 1,000 years later. The drought coincides with the beginning of the Medieval Warm Period, thought to have been caused by a decrease in volcanic ash in the atmosphere and an increase in solar activity. Previous studies have shown that the Mayans’ deforestation may have also contributed. Deforestation tends to decrease the amount of moisture and destabilize the soil. Additional theories for the cause of the drought include changes to the atmospheric circulation and decline in tropical cyclone frequency, Evans said.
Matthew Lachniet, a professor of geosciences at the University of Nevada Las Vegas, who was not involved in the study, said the quantification of the drought is important because it illustrates the power of natural climate variability alone.
“Humans are affecting climate. We’re making it warmer and it’s projected to become drier in Central America,” Lachniet said. “What we could end up with is double whammy of drought. If you coincide drying from natural causes with drying from human causes then it amplifies the strength of that drought.”
Evans and his team hope their research will help archaeologists understand how the ancient drought may have impacted Mayan agriculture at a critical time in their history.
Currently, vast areas of North America, northern Africa, the Middle East, Southwest Asia and most of Australia are in significant drought, according to the National Oceanic and Atmospheric Administration’s Global Drought Information System. Sociopolitical research suggests that drought may cause war, famine and large human migrations. And many countries affected lack the resources to cope.
“Drought does have the potential to be a driving force for a lot of the issues that can cause civilization stress,” Evans said.
He noted, though, that today’s globalized economy and modern technology have the potential to prevent a Mayan-style, world-ending drought. Probably.
http://torontosun.com/news/world/anc...rious-collapse
 
Blackleaf
#2
For reasons unknown, they built huge cities in the middle of dense jungle.
 
Danbones
#3
or maybe just planted gardens in their cities...

I mean, who would do such a thing?
 
Blackleaf
#4
Quote: Originally Posted by Danbones View Post

or maybe just planted gardens in their cities...

I mean, who would do such a thing?

The people of Welwyn Garden City.
 
MHz
#5
Quote: Originally Posted by Blackleaf View Post

For reasons unknown, they built huge cities in the middle of dense jungle.

You sure it was dense jungle back then, perhaps the tops of the clouds were at the height the temples were at. Weather conditions changed from what it was during the last ice-age. They were 175M above sea level rather than the 25 they are at today, wind/temp could have made those places 'above the clouds so they would be 'deserts' and the 'lake would be ice rather than water'.


That is not taking into account that man is a 'recent arrival' and before that immortal being that could fly were the highest lifeforms on the planet.
 
bill barilko
#6
While cities did indeed collapse the Maya themselves just melted into the jungle thereto farm their milpas as best they could-they never left the area and indeed still live there today-posters here would know that if they ever visited the area-note that I have a number of times.

As to this drought it's been documented for decades now there's nothing new in this story.
 
MHz
#7
I'm more the type that transcends time and the beginning has more appeal to me than how it ended. Stone structure in a arid place fit the story-line better once you take the Nazca Lines into being created about the same time as all the other ancient megaliths around the globe

Being from 'soggy places' I can assure you moving heavy rocks around on roads made of wet black dirt is a program doomed to failure. We can get away with it because the frost in the winter makes it like a concrete parking lot and you can go in any direction you want with as many heavy things as you can carry/pull.

If visiting a place was the only way to get the facts right then every person that visited any site should be telling the same story. They aren't.
 
bill barilko
#8
Quote: Originally Posted by MHz View Post

I'm more the type that transcends time and the beginning has more appeal to me than how it ended. Stone structure in a arid place fit the story-line better once you take the Nazca Lines into being created about the same time as all the other ancient megaliths around the globe

Being from 'soggy places' I can assure you moving heavy rocks around on roads made of wet black dirt is a program doomed to failure. We can get away with it because the frost in the winter makes it like a concrete parking lot and you can go in any direction you want with as many heavy things as you can carry/pull.

If visiting a place was the only way to get the facts right then every person that visited any site should be telling the same story. They aren't.

Drunk again, eh?!
 
MHz
#9
Just pointing out sea level back in the day it was constructed was 100M lower than it is today so the 100% humidity level may not have reached that high.


Going out of your way to show you cannot follow a theory would be considered to be a flaw in most societies. Mud on the bottom of the lake might be all that is needed to show rain-forest like conditions so save your woodie for something big.
 
Curious Cdn
+1
#10  Top Rated Post
See what happens when you drain the swamp.
 
Bar Sinister
#11
Quote: Originally Posted by MHz View Post

Just pointing out sea level back in the day it was constructed was 100M lower than it is today so the 100% humidity level may not have reached that high.


Sea level was 100M lower a thousand years ago? So Britain was joined to Europe by a land bridge and much of the Caribbean was a single land mass?
 
Curious Cdn
#12
Quote: Originally Posted by Bar Sinister View Post

Sea level was 100M lower a thousand years ago? So Britain was joined to Europe by a land bridge and much of the Caribbean was a single land mass?

Maybe, 10,000 years ago?

"The Case of the Missing 0"
 
Bar Sinister
#13
Quote: Originally Posted by Curious Cdn View Post

Maybe, 10,000 years ago?

"The Case of the Missing 0"




The article did stipulate AD, not BC.