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Research team all set to explore sacred Maya pools of Belize

September 14, 2009 By admin Leave a Comment

Washington, September 14 (ANI): A team of expert divers, a geochemist and an archaeologist is all set to become the first to explore the sacred pools of the southern Maya lowlands in rural Belize.

The expedition, made possible with a grant from the National Geographic Society and led by a University of Illinois archaeologist, will investigate the cultural significance and environmental history and condition of three of the 23 pools of Cara Blanca, in central Belize.

Called ‘cenotes’, these groundwater-filled sinkholes in the limestone bedrock were treated as sacred sites by the Maya, according to University of Illinois archaeologist Lisa Lucero, who will lead the expedition next spring.

“Any openings in the earth were considered portals to the underworld, into which the ancient Maya left offerings,” said Lucero. “We know from ethnographic accounts that Maya collected sacred water from these sacred places, mostly from caves,” she added.

Studies of shallow lakes and cenotes in Mexico and Guatemala have found that the Maya also left elaborate offerings in the sacred lakes and pools.

Items found on the bottom of lakes in these regions include masks, bells, jade, human remains, figurines and ceramic vessels decorated with animals, plants and the gods of fertility and death.

“Diving the sacred pools of Cara Blanca, in central Belize, is necessary to determine if they have similar sacred qualities,” Lucero said.

“Once underwater, we will first have to cut out some of the jungle wood so that we can even reach the bottom,” said Patricia Beddows, a lecturer of earth and planetary sciences at Northwestern University and an expert diver who has explored cenotes on the Yucatan Peninsula of Mexico.

“After mapping for fragile Maya artifacts, we will also take water data and manually drill sediment cores,” she added.

“The sediment samples will provide a record of changes in surface and water conditions,” Beddows said.

“Were the Maya challenged by droughts in the area? Did the water quality suddenly go bad due to sulfur or other geologic factors? We hope these cenotes will provide a rich story of linked human and environmental conditions,” she said.

One of the three pools the researchers will explore has a substantial Maya structure on its edge, likely ceremonial.

Preliminary investigations of the structure conducted by archaeologist Andrew Kinkella, of Moorpark College, turned up a lot of jars and the fragments of jars.

“This could indicate that the site was important for collecting sacred water,” Lucero said. (ANI)

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Current CO2 levels higher than last 2.1 million years

June 20, 2009 By admin Leave a Comment

Washington, June 19 (ANI): A new study has shown that current CO2 levels are higher than the last 2.1 million years.

The study is the latest to rule out a drop in CO2 as the cause for earth’s ice ages growing longer and more intense some 850,000 years ago.

But it also confirms many researchers’ suspicion that higher carbon dioxide levels coincided with warmer intervals during the study period.

The authors show that peak CO2 levels over the last 2.1 million years averaged only 280 parts per million; but today, CO2 is at 385 parts per million, or 38 percent higher.

This finding means that researchers will need to look back further in time for an analog to modern day climate change.

In the study, Barbel Honisch, a geochemist at Lamont-Doherty Earth Observatory, and her colleagues reconstructed CO2 levels by analyzing the shells of single-celled plankton buried under the Atlantic Ocean, off the coast of Africa.

By dating the shells and measuring their ratio of boron isotopes, they were able to estimate how much CO2 was in the air when the plankton were alive.

This method allowed them to see further back than the precision records preserved in cores of polar ice, which go back only 800,000 years.

The planet has undergone cyclic ice ages for millions of years, but about 850,000 years ago, the cycles of ice grew longer and more intense-a shift that some scientists have attributed to falling CO2 levels.

But, the study found that CO2 was flat during this transition and unlikely to have triggered the change.

A global drawdown in CO2 is one theory proposed for the transition.

“The low CO2 levels outlined by the study through the last 2.1 million years make modern day levels, caused by industrialization, seem even more anomalous,” said Richard Alley, a glaciologist at Pennsylvania State University.

“We know from looking at much older climate records that large and rapid increase in C02 in the past, (about 55 million years ago) caused large extinction in bottom-dwelling ocean creatures, and dissolved a lot of shells as the ocean became acidic. We’re heading in that direction now,” he added. (ANI)

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Scientists solve mystery of Earth’s leaky mantle

May 28, 2009 By admin Leave a Comment

Washington, May 28 (ANI): Researchers at Rice University and Harvard University, US, have developed a new model to explain how noble gases – elements like helium, neon and argon – are lost from the Earth’s interior during mantle convection.

The research takes aim at a question that has vexed geoscientists for years: how to reconcile leading theories about the convection of Earth’s mantle with observations of ancient noble gases in volcanic rocks.

“Most existing models find that convection should have left the mantle extensively depleted in ancient noble gases, unless part or all of the lower mantle has been somehow isolated,” said study co-author Helge Gonnermann, assistant professor of Earth science at Rice.

“We set out to see if there was a mechanism that could both preserve ancient noble gases in the lower mantle and still be consistent with the existing framework for whole mantle convection,” he added.

In the new research, Gonnermann and longtime collaborator Sujoy Mukhopadhyay, a Harvard geochemist, developed a model that could reconcile convection involving the lower mantle with the helium-3 measurements found in ocean island basalts.

The model suggests that both the upper and lower mantle are involved in convection, but it affects them in different ways.

Whereas the upper mantle has been extensively degassed through repeated tectonic cycling, the lower mantle has been recycling approximately once during the past 4.5 billion years.

Continuous mixing of subducted plates into the lower mantle has been diluting the concentrations of ancient noble gases there.

Instead of extracting ancient noble gases at their original concentrations, progressively smaller amounts are extracted at any given rate of tectonic cycling.

Consequently, about 40 percent of the ancient helium-3 can still be present in the lower mantle, even though it may have undergone one complete tectonic cycling over the past 4.5 billion years.

“Contrary to the conventional view that tectonic cycling of the lower mantle should result in extensive mixing between the lower and upper mantle, thereby erasing any differences in helium-3, we find that much of the tectonic cycling of the lower mantle essentially bypasses the upper mantle,” Mukhopadhyay said.

“What goes down must come up: Slabs that subduct and mix into the lower mantle are balanced by mantle plumes, rich in helium-3, which rise from the lower mantle to the Earth’s surface without mixing significantly as they traverse the upper mantle,” he added. (ANI)

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Glaciers in Southern Hemisphere are growing out of step with those in North

May 3, 2009 By admin Leave a Comment

Washington, May 2 (ANI): A new study has found that for the last 7,000 years, glaciers south of the equator in South America and New Zealand have often moved out of step with glaciers in the Northern Hemisphere, pointing to strong regional variations in climate.

“This research should provide much more accurate reconstructions of glacial advances worldwide, allowing us in turn to make climate models more accurate,” said Paul Filmer, program director in the National Science Foundation’s (NSF) Division of Earth Sciences, which funded the research.

Conventional wisdom holds that during the era of human civilization, climate has been relatively stable.

The new study is the latest to challenge this view, by showing that New Zealand’s glaciers have gone through rapid periods of growth and decline during the current interglacial period known as the Holocene.

“New Zealand’s mountain glaciers have fluctuated frequently over the last 7,000 years, and glacial advances have become slightly smaller through time,” said Joerg Schaefer, lead author of the paper and a geochemist at Columbia University’s Lamont-Doherty Earth Observatory.

“This pattern differs in important ways from the northern hemisphere glaciers. The door is open now towards a global map of Holocene (a geological time period that began about 11,700 years ago and continues to the present) glacier fluctuations and how climate variations during this period impacted human civilizations,” he added.

By refining the analysis of a method called cosmogenic dating, Schaefer and colleagues were able for the first time to assign precise ages to young Holocene moraines.

They accomplished this by measuring minute levels of the chemical isotope beryllium 10 in the rocks, which is produced when cosmic rays strike rock surfaces, and builds up over time.

The researchers were thus able to pinpoint exactly when glaciers in New Zealand’s Southern Alps began to recede, exposing the rocks to the cosmic rays.

From the results, they constructed a glacial timeline for the past 7,000 years and compared it against historic records from the Swiss Alps and other places north of the equator.

They found that within that timeframe, the glaciers around Mount Cook, New Zealand’s highest peak, reached their largest extent about 6,500 years ago, when the Swiss Alps and Scandinavia were relatively warm.

That’s about 6,000 years before northern glaciers hit their Holocene peak during the Little Ice Age, between 1300 and 1860 AD.

That finding was a surprise to some scientists who assumed that the northern cold phase happened globally.

The record in New Zealand shows other disparities that point to regional climate variations in both hemispheres. (ANI)

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Indian origin scientist finds active African volcano to have most fluid lava in world

March 15, 2009 By admin Leave a Comment

Washington, March 15 (ANI): A geochemist of Indian origin has determined that an active African volcano possesses the most fluid lava in the world, which points toward its source being a mantle plume that is in complete pristine condition.

The lava composition indicates that a mantle plume-an upwelling of intense heat from near the core of the Earth-may be bubbling to life beneath Nyiragongo, an active African volcano, in the emocratic Republic of the Congo.

“This is the most fluid lava anyone has seen in the world,” said Asish Basu, professor of earth science at the University of Rochester, the geochemist who conducted the research.

“It’s unlike anything coming out of any other volcano. We believe we’re seeing the beginning of a plume that is pushing up the entire area and contributing to volcanism and earthquakes,” he added.

Basu analyzed the lava, which resides in the world’s largest lava lake-more than 600 feet wide inside the summit of Nyiragongo-and found that the isotopic compositions of neodymium and strontium are identical to ancient asteroids.

“This suggests that the lava is coming from a place deep inside the Earth where the source of molten rock is in its pristine condition,” said Basu.

“Because the Earth’s crust is undergoing constant change via tectonic motion, weathering, and resurfacing, its chemical composition has been dramatically altered over its 4-billion-year lifespan, but the Nyiragongo magma source in the deep mantle has not,” he added.

That magma source is thought to retain some of the solar system’s original make-up of elements, and this is what Basu and his colleagues believe they have detected in Nyiragongo’s lava lake.

Scientists believe mantle plumes can last hundreds of millions of years, and that their heat can create phenomena such as Yellowstone National Park or the string of Hawaiian Islands.

According to Basu, Nyiragongo’s frequent eruptions may be the birthing pains of a similar plume and the possible beginning of new large-scale geological formations in the region.

Basu said that other well known features of the region also point toward the idea of a growing plume.

“This is a very troubled region of the world, and we hope to be able to help better understand the conditions under which the people of that area must live,” said Basu.

Nyiragongo last erupted in 2002, sending its super-fluid lava down its slopes at more than 60 miles per hour toward the nearby town of Goma, destroying 4,500 buildings and leaving 120,000 homeless. (ANI)

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Huge CO2 releases may have amplified global warming at end of last ice age

March 13, 2009 By admin Leave a Comment

Washington, March 13 (ANI): A new research has suggested that natural releases of carbon dioxide from the Southern Ocean due to shifting wind patterns could have amplified global warming at the end of the last ice age, and could be repeated as manmade warming proceeds.

The research was conducted by a team of scientists at Columbia University’s Lamont-Doherty Earth Observatory, US.

Many scientists think that the end of the last ice age was triggered by a change in Earth’s orbit that caused the northern part of the planet to warm.

This partial climate shift was accompanied by rising levels of the greenhouse gas CO2, ice core records show, which could have intensified the warming around the globe.

Now, the team from Lamont-Doherty Earth Observatory has offered one explanation for the mysterious rise in CO2.

According to them, the orbital shift triggered a southward displacement in westerly winds, which caused heavy mixing in the Southern Ocean around Antarctica, pumping dissolved carbon dioxide from the water into the air.

“The faster the ocean turns over, the more deep water rises to the surface to release CO2,” said lead author Robert Anderson, a geochemist at Lamont-Doherty. “It’s this rate of overturning that regulates CO2 in the atmosphere,” he added.

In the last 40 years, the winds have shifted south much as they did 17,000 years ago, said Anderson.

If they end up venting more CO2 into the air, manmade warming underway now could be intensified.

Two years ago, J.R. Toggweiler, a scientist at the National Oceanic and Atmospheric Administration (NOAA), proposed that westerly winds in the Southern Ocean around Antarctica may have undergone a major shift at the end of the last ice age.

This shift would have raised more CO2-rich deep water to the surface, and thus amplified warming already taking place due to the earth’s new orbital position.

Anderson and his colleagues are the first to test that theory by studying sediments from the bottom of the Southern Ocean to measure the rate of overturning.

According to the scientists, changes in the westerlies may have been triggered by two competing events in the northern hemisphere about 17,000 years ago.

The earth’s orbit shifted, causing more sunlight to fall in the north, partially melting the ice sheets that then covered parts of the United States, Canada and Europe.

“Now I think this really starts to lock up how the CO2 changed globally,” said Toggweiler. “Here’s a mechanism that can explain the warming of Antarctica and the rise in CO2. It’s being forced by the north, via this change in the winds,” he added. (ANI)

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