Featured Research

from universities, journals, and other organizations

New drought record from long-lived Mexican trees may illuminate fates of past civilizations

Date:
February 3, 2011
Source:
American Geophysical Union
Summary:
A new, detailed record of rainfall fluctuations in ancient Mexico that spans more than twelve centuries promises to improve our understanding of the role drought played in the rise and fall of pre-Hispanic civilizations.

A 1100-year old Montezuma baldcypress from Barranca de Amealco, Queretaro, Mexico. A University of Arkansas researcher and his colleagues used evidence from this tree with 30 other trees for the reconstruction of Mesoamerican droughts over the past millennium.
Credit: David Stahle

A new, detailed record of rainfall fluctuations in ancient Mexico that spans more than twelve centuries promises to improve our understanding of the role drought played in the rise and fall of pre-Hispanic civilizations.

Related Articles


Prior evidence has indicated that droughts could have been key factors in the fates of major cultures in ancient Mexico and Central America (Mesoamerica). But there have been many gaps in the paleoclimate record, such as the exact timing and geographic extension of some seemingly influential dry spells.

The new, 1,238-year-long tree-ring chronology, the longest and most accurate of its kind for Mesoamerica, is the first to reconstruct the climate of pre-colonial Mexico on an annual basis for more than a millennium, pinning down four ancient megadroughts to their exact years.

One large ancient drought previously confirmed for the Southwest of the United States is shown to have extended into central Mexico (1149-1167 AD) by the new dendrochronology, or tree-ring reconstruction. There it may have devastated the local maize crops, potentially giving a fatal blow to the declining Toltec culture, says David Stahle, a paleoclimatologist at the University of Arkansas at Fayetteville and lead author of the new study. Stahle and his colleagues present their new findings in a paper that has been accepted for publication in Geophysical Research Letters, a journal of the American Geophysical Union.

The new record also pins down more precisely than ever before the time periods of two other extended and severe dry periods, possibly leading to new insights into the Aztecs's rise to power, and into the spread of exotic diseases that Spanish Conquistadores brought to America.

This far-reaching rainfall chronology also provides the first independent confirmation of the so-called Terminal Classic drought, a megadrought some anthropologists relate to the collapse of the Mayan civilization. This decades-long dry period had been previously determined by analysis of lake and basin sediments in other areas of Mexico and the Caribbean. But Stahle's team has narrowed the event's timing to 897-922 AD and confirmed that it had a wider geographical impact than previously thought, extending into the highlands of Central Mexico, where other classic period cultures were located.

"Certainly these cultural changes were very complicated -- probably not one single explanation can account for the collapse of the Mayan civilization," Stahle says. "[But] our study will allow other scientists to more thoroughly investigate and understand the impact of these droughts."

Stahle and his team used data from 74 core samples extracted from 30 specimens of millennium-old Montezuma baldcypress trees (Taxodium mucronatum) growing in the canyon of Amealco, Queretaro -- only 90 kilometers (56 miles) away from Tenochtitlan, capital of the Aztec empire, and 60 km (37 miles) northeast from Tula, the Toltec state's main city. Stahle says this tree species, related to North American sequoias, is the only plant in Central America that frequently lives up to one thousand years or more.

"This is the national tree of Mexico, and it tells such an interesting story of the decline of the Mexican empires," says Stahle, adding that previous tree chronologies for Mexico were only three to four centuries long. "This is the first one that goes back into pre-Hispanic times,"

The researchers determined the year of formation for each tree ring and analyzed what the rings' growth patterns had to say about how soil moisture varied from growth season to growth season over the years, a parameter directly associated with rainfall. "The beauty of tree rings is that they're annual: you get an estimate for wetness for every single year -- you don't get it from other archives, not as precisely," Stahle says.

"This research… highlights the role fine-grained climate data can play in helping us understand the trajectories of past human societies," says David Anderson, an archaeologist at the University of Tennessee, Knoxville who was not involved in the new study. "This study will prompt a great deal of follow-up research by archaeologists and paleoclimatologists alike, and offers lessons for our own civilization -- specifically how vulnerable complex societies may be to drought-induced crop failures."

This research received funding from the National Science Foundation's Paleoclimatology Program and the Inter-American Institute for Global Change Research.


Story Source:

The above story is based on materials provided by American Geophysical Union. Note: Materials may be edited for content and length.


Journal Reference:

  1. Stahle, D. W., J. Villanueva-Diaz, D.J. Burnette, J. C. Paredes, R. R. Heim Jr., F. K. Fye, R. A. Soto, M. D. Therrell, M. K. Cleaveland, and D. K. Stahle. Major Mesoamerican Droughts of the Past Millennium. Geophysical Research Letters, (in press) DOI: 10.1029/2010GL046472

Cite This Page:

American Geophysical Union. "New drought record from long-lived Mexican trees may illuminate fates of past civilizations." ScienceDaily. ScienceDaily, 3 February 2011. <www.sciencedaily.com/releases/2011/02/110203124816.htm>.
American Geophysical Union. (2011, February 3). New drought record from long-lived Mexican trees may illuminate fates of past civilizations. ScienceDaily. Retrieved November 23, 2014 from www.sciencedaily.com/releases/2011/02/110203124816.htm
American Geophysical Union. "New drought record from long-lived Mexican trees may illuminate fates of past civilizations." ScienceDaily. www.sciencedaily.com/releases/2011/02/110203124816.htm (accessed November 23, 2014).

Share This


More From ScienceDaily



More Plants & Animals News

Sunday, November 23, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Anglerfish Rarely Seen In Its Habitat Will Haunt You

Anglerfish Rarely Seen In Its Habitat Will Haunt You

Newsy (Nov. 22, 2014) — For the first time Monterey Bay Aquarium recorded a video of the elusive, creepy and rarely seen anglerfish. Video provided by Newsy
Powered by NewsLook.com
Birds Around the World Take Flight

Birds Around the World Take Flight

Reuters - Light News Video Online (Nov. 22, 2014) — An imperial eagle equipped with a camera spreads its wings over London. It's just one of the many birds making headlines in this week's "animal roundup". Jillian Kitchener reports. Video provided by Reuters
Powered by NewsLook.com
Could Your Genes Be The Reason You're Single?

Could Your Genes Be The Reason You're Single?

Newsy (Nov. 21, 2014) — Researchers in Beijing discovered a gene called 5-HTA1, and carriers are reportedly 20 percent more likely to be single. Video provided by Newsy
Powered by NewsLook.com
Raw: Baby Okapi Born at Houston Zoo

Raw: Baby Okapi Born at Houston Zoo

AP (Nov. 20, 2014) — The Houston Zoo released video of a male baby okapi. Okapis, also known as the "forest giraffe", are native to the Democratic Republic of the Congo in Central Africa. Video is mute from source. (Nov. 20) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Plants & Animals

Earth & Climate

Fossils & Ruins

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins