Posts Tagged "Peru"

Ice-core Evidence of Copper Smelting 2700 Years Ago

Posted by on Feb 28, 2017 in All Posts, Featured Posts, Science | 0 comments

Ice-core Evidence of Copper Smelting 2700 Years Ago

Spread the News:ShareThe mysterious Moche civilization originated on the northern coast of Peru in 200-800 AD. It was known for its metal work, considered by some to be the most accomplished of any Andean civilization. But were the Moche the first Andean culture to originate copper smelting in South America? While the Moche left comprehensive archaeological evidence of an early sophisticated use of copper, the onset of copper metallurgy is still debated. Some peat-bog records (records of spongy decomposing vegetation) from southern South America demonstrate that copper smelting occurred earlier, around 2000 BC. The question motivated Anja Eichler et al. to launch a massive study of copper emission history. The details of the findings were subsequently published in a paper in Nature. Eichler, an analytical chemistry scientist at the Paul Scherrer Institute in Switzerland, and her team presented a 6500-year copper emission history for the Andean Altiplano based on glacier ice-core records. This is a new methodology applied to trace copper smelting. “Copper is often referred to as the ‘backbone of Andean metallurgy – the mother of all Andean metals,’” Eichler explained to GlacierHub. “However, in contrast to the early copper metallurgy in the Middle East and Europe, very little information existed about its onset in the Andes.” The ice-core they used for their research was drilled at the Illimani Glacier in Bolivia in 1999, nearby sites of the ancient cultures. It provides the first complete history of large-scale copper smelting activities in South America and revealed extensive copper metallurgy. Illimani is the highest mountain in the Cordillera Oriental and the second highest peak in Bolivia. When asked about how she started her research, Eichler told GlacierHub, “I got involved in the project in 2012. At that time, PhD students and a post-doc had already obtained exciting findings and secrets revealed by ice-core records. We started looking at copper and lead as traces from copper and silver mining and smelting in the Andes.” The results of Eichler et al.’s study suggest that the earliest anthropogenic copper pollution occurred between 700–50 BC, during the central Andean Chiripa and Chavin cultures, around 2700 years ago, meaning that copper was produced extensively much earlier than people originally thought. “For the first time, our study provides substantial evidence for extensive copper metallurgy already during these early cultures,” said Eichler. One of the most challenging parts of the research is that copper can show up in the ice core from natural as well as human sources. Eichler’s team accounted for this by calculating the copper Enrichment Factor, which is applied widely to distinguish the natural and anthropogenic origin of metal. The principle of this methodology is to measure the occurrence of different metals. If copper appeared naturally due to wind erosion, it would be found in association with other metals that co-occur with it naturally. However, according to Eichler’s findings, there was only copper in central Andean Chiripa and Chavin cultures, without cerium or the other metals that occur with it in natural deposits. Hence, it was anthropogenic. The Chiripa culture existed from 1400 BC to 850 BC along the southern shore of Lake Titicaca in Bolivia,  near Illimani Glacier. Soon after the Chiripa, came the Chavin culture, a prehistoric civilization that developed in the northern Andean highlands of Peru from 900 BC to 200 BC, named for Chavín de Huantar, the principal archaeological site where their artifacts have been found. Copper objects from these earlier cultures are scanty. The reason why there is no sufficient archaeological evidence of copper usage, according to Eichler, is that very often artifacts were reused by subsequent cultures. “It is known that metallic objects cast by civilizations were typically scavenged from artifacts of their predecessors,”...

Read More

Photo Friday: The Melting Andean Glaciers

Posted by on Feb 3, 2017 in All Posts, Featured Posts, Images | 1 comment

Photo Friday: The Melting Andean Glaciers

Spread the News:ShareIn South America, the tropical glaciers of the Andes have been shrinking at an alarming rate, leaving the local communities at risk of losing an important water source. In Bolivia, for example, an Andean glacier known as the Chacaltaya Glacier disappeared completely in 2009, cutting off a valuable water resource to the nearby city of La Paz during the dry season. In total, the Andes Mountains are home to nearly 99 percent of the world’s tropical glaciers, with 71 percent located in Peru’s Cordillera Blanca and 20 percent in Bolivia, according to UNEP. Other tropical glaciers are found in the equatorial mountain ranges of Venezuela, Colombia and Ecuador. Over the past 30 years, scientists estimate that the glaciers of the tropical Andes have shrunk by 30 to 50 percent. This rate of decline predicts that within 10 to 15 years many of the smaller tropical glaciers will have completely disappeared. Take a look at GlacierHub’s collection of images of the rapidly retreating Andean glaciers.                                   Spread the...

Read More

Climate Change Increases Flood Risk in Peru

Posted by on Dec 28, 2016 in All Posts, Featured Posts, Images, News, Policy and Economics, Science | 0 comments

Climate Change Increases Flood Risk in Peru

Spread the News:ShareThe rising danger of glacial lake flooding in a warmer climate has important implications for humans and animal populations in Peru’s Cordillera Blanca. A recent study in CATENA by Adam Emmer et al. examined a large swath of nearly 900 high altitude Peruvian lakes in the mountainous Cordillera Blanca region, studying their susceptibility to outburst floods in light of modern climate change. An outburst flood occurs when the dam containing glacial meltwater, usually comprised of either glacial ice or a terminal moraine (glacial debris lying at the edge of the glacier), fails. Glaciologist Mauri Pelto commented in the American Geophysical newsletter that the moraine dams are “just comprised of gravel, sand and clay dumped by the glacier” and “high water levels caused by upstream floods, avalanches or landslides can cause failure,” leading to major damage of the landscape. The team’s research elucidated that the incidence of glacial lake outburst flooding (GLOF) is increasing and the general distribution of alpine lakes is shifting upward in the region as temperatures warm.  Knowing a lake’s size, configuration and type allows local water management in the Cordillera Blanca to be improved, according to Emmer et al. By mapping lakes with the classification of either moraine-dammed or bedrock-dammed, the team’s analysis can help local hydrological experts improve water management techniques for the changing distribution of alpine water. It also contributes to the scientific community’s overall understanding of ongoing environmental change. By studying the Cordillera Blanca region’s alpine lakes through a combination of remote sensing (high resolution aerial imagery and measurements) and field observations, Emmer’s team categorized 882 lakes by their size and altitude, ultimately referencing their findings with historical data to observe water redistribution over the last 60 years. Emmer et al. established that glacial lakes had expanded in size and number at higher elevations and disappeared at lower elevations since the 1951 study by Juan Concha in the same region. This finding confirms that environmental change and glacier retreat are strongly correlated in the high alpine. Results from the analyses showed that from 1948 to 2013, lakes that remained in already deglaciated areas tended to be resilient and generally maintained water levels throughout the 65-year examination. Moraine-dammed lakes in particular resisted disappearing despite glacial retreat, suggesting that bodies of water dammed by materials other than ice were more adaptable to recently warmer temperatures.  The team also noticed that despite the recent resiliency of moraine dammed lakes, glacial lake outburst flooding was caused predominantly by these dams in the early portion of the Cordillera Blanca’s glacial retreat, in the 1940s and 1950s. Flooding in more recent years has occurred in bedrock-dammed lakes. Although glacial lakes were recorded to have shifted from 4250-4600m in the late 1940s to predominantly above 4600m today, no statistically significant trend was established relating outburst flooding to any particular elevation. In order to reduce the risk of flood damage in local communities, Emmer et al. suggested continuous monitoring of young, developing proglacial lakes, using extensive flood modeling and outburst susceptibility assessments to account for future changes in the glacier. Understanding that the melting of glaciers is accelerating in a warming world, the need for more intensive local efforts in response to the threat of flooding is apparent.   The Peruvian government has responded to high lake levels in the mountains of the Cordillera Blanca by “building tunnels and concrete pipes through the [weakest] moraines to allow lake drainage to safe levels,” according to Pelto. The government then rebuilds the moraines over the drainage system to strengthen it. By incorporating the monitoring techniques suggested by Adam Emmer, the government has the...

Read More

Roundup: Tragedy in Antarctica, Antimony and Glacier Risks

Posted by on Oct 31, 2016 in All Posts, Featured Posts, Roundup | 0 comments

Roundup: Tragedy in Antarctica, Antimony and Glacier Risks

Spread the News:ShareRoundup: Tragedy, Antimony and Risk   Prominent Climate Scientist Dies in Antarctica New York Times: “Gordon Hamilton, a prominent climate scientist who studied glaciers and their impact on sea levels in a warming climate, died in Antarctica when the snowmobile he was riding plunged into a 100-foot-deep crevasse. He was an associate research professor in the glaciology group at the Climate Change Institute at the University of Maine. He was camping with his research team on what is known as the Shear Zone, where two ice shelves meet in an expanse three miles wide and 125 miles long. Parts of the Shear Zone can be up to 650 feet thick and ‘intensely crevassed.’ Dr. Hamilton’s research, aided by a pair of robots equipped with ground-penetrating radar instruments, focused on the impact of a warming climate on sea levels. He was working with an operations team to identify crevasses.” Learn more about the tragedy here.   Antimony Found in the Tibetan Glacial Snow Journal of Asian Earth Sciences: “Antimony (Sb) is a ubiquitous element in the environment that is potentially toxic at very low concentrations. In this study, surface snow/ice and snowpit samples were collected from four glaciers in the southeastern Tibetan Plateau in June 2015… The average Sb concentration in the study area was comparable to that recorded in a Mt. Everest ice core and higher than that in Arctic and Antarctic snow/ice but much lower than that in Tien Shan and Alps ice cores… Backward trajectories revealed that the air mass arriving at the southeastern Tibetan Plateau mostly originated from the Bay of Bengal and the South Asia in June. Thus, pollutants from the South Asia could play an important role in Sb deposition in the studied region. The released Sb from glacier meltwater in the Tibetan Plateau and surrounding areas might pose a risk to the livelihoods and well-being of those in downstream regions.” Read more about the research here.   Managing Glacier Related Risks Disaster in Peru The Climate Change Adaption Strategies: A recently edited book, “The Climate Change Adaptation Strategies – An Upstream – Downstream Perspective,” edited by Nadine Salzmann et al., has several chapters on glaciers. The chapter “Managing Glacier Related Risks Disaster in the Chucchún Catchment, Cordillera Blanca, Peru” discusses some of these glacier related risks: “Glacial lakes hazards have been a constant factor in the population of the Cordillera Blanca due their potential to generate glacial lake outburst floods (GLOF) caused by climate change. In response, the Glaciares Project has been carried out to implement three strategies to reduce risks in the Chucchún catchment through: (1) Knowledge generation, (2) building technical and institutional capacities, and (3) the institutionalization of risk management. As a result, both the authorities and the population have improved their resilience to respond to the occurrence of GLOF.” Explore more related chapters here. Spread the...

Read More

New Study Offers Window into Glacial Lake Outburst Floods

Posted by on Aug 11, 2016 in All Posts, Featured Posts, Science | 0 comments

New Study Offers Window into Glacial Lake Outburst Floods

Spread the News:ShareA recent geological study has shed some light on the cause of a major, yet elusive destructive natural hazard triggered by failed natural dams holding back glacial lakes. The findings show how previously unrecognized factors like thinning glacier ice and moisture levels in the ground surrounding a lake can determine the size and frequency of Glacier Lake Outburst Floods, or GLOFs. The risks of these glacial floods are generally considered increasingly acute across the world, as warming atmospheric temperatures prompt ice and snow on mountain ranges to retreat and to swell glacial lakes. Landslides in moraines as triggers of glacial lake outburst floods: example from Palcacocha Lake (Cordillera Blanca, Peru), published in  Landslides in July 2016, centers its study on Lake Palcacocha in the Cordillera Blanca mountain region of central Peru.  Since Palcacocha is one of almost 600 lakes in the Cordillera Blanca mountain range dammed by glacial moraines, the population of the region lives under serious threat of GLOFs. The Landslides article is a step in understanding a previously understudied geological phenomenon.  As little as five years ago scientists acknowledged the lack of research on the subject. “We don’t really have the scientific evidence of these slopes breaking off and moraine stability… but personal observations are suggesting there are a lot of those…” said Ph.D. environmental historian Mark Carey in a 2011 video where he describes GOLFs.   Glacial Lake Outburst Flood risks do not always emanate from mountain glacier meltwater that flows downstream. As this study shows,  in some instances, trillions of gallons of water can be trapped by a moraine, a formation of mixed rock, which forms a natural dam.  A weakening over time, or a sudden event, such as a landslide, could then result in the moraine dam’s collapse. The massive amount of water is suddenly then released, and a wall of debris-filled liquid speeds down the mountainside with a destructive force capable of leveling entire city blocks. GLOFs have presented an ongoing risk to people and their homes dating back to 1703, especially in the Cordillera Blanca region, according to United States Geological Survey records.  In December of 1941, a breach in the glacial moraine restraining Palcacocha Lake led to the destruction of a significant portion of the city of Huaraz and killed approximately 5,000 people. Scientists and government agencies, like the Control Commission of Cordillera Blanca Lakes created by the Peruvian government following the 1941 GLOF, have recognized the need to better understand and control GLOFs.  The study found that as global temperatures rise and glaciers retreat, greater amounts of glacier melt water will continue to fill up mountain lakes, chucks of ice will fall off glaciers, and  wetter moraines will become  more prone to landslides. The team of mostly Czech geologists and hydrologists (J. Klimeš; J. Novotný; I. Novotná; V. Vilímek; A. Emmer; M. Kusák; F. Hartvich) along with Spanish, Peruvian and Swiss scientists (B. Jordán de Urries; A. Cochachin Rapre; H. Frey and T. Strozzi) investigated the ability of a glacial moraine’s slope to stay intact, called shear strength, and modeled the potential of landslides and falling ice to cause GLOFs. After extensive field investigations, calculations and research into historical events, the study found several causal factors that can determine the severity of a GLOF.  These include size and angle of entry of a landslide,  shape and depth of the glacial lake, glacier thickness and human preventative engineering such as canals and supporting dams.  Frequency and size of a landslide is determined by the stability of surface material, a characteristic called shear strength, which can be influenced by something as subtle as the crystalline shape of the predominant mineral in the rock. The scientists determined that waves caused...

Read More