Roundup: Pre-Columbian Land Use, Trump in Tongass, and Greenland’s Ice Sheet

The Inca’s sustainable land use practices

From Quaternary Science Reviews:

“The extent of pre-Columbian land use and its legacy on modern ecosystems, plant associations, and species distributions of the Americas is still hotly debated. To address this gap, we present a Holocene palynological record (pollen, spores, microscopic charcoal, SCP analyses) from Illimani glacier with exceptional temporal resolution and chronological control close to the center of Inca activities around Lake Titicaca in Bolivia. Our results suggest that Holocene fire activity was largely climate-driven and pre-Columbian agropastoral and agroforestry practices had moderate (large-scale) impacts on plant communities. Unprecedented human-shaped vegetation emerged after AD 1740 following the establishment of novel colonial land use practices and was reinforced in the modern era after AD 1950 with intensified coal consumption and industrial plantations of Pinus and Eucalyptus. Although agroforestry practices date back to the Incas, the recent vast afforestation with exotic monocultures together with rapid climate warming and associated fire regime changes may provoke unprecedented and possibly irreversible ecological and environmental alterations.”

Read the article here.

Lake Titicaca (Source: Wikimedia Commons)

Trump proposes logging nearby Alaskan glaciers

From the Washington Post:

“Politicians have tussled for years over the fate of the Tongass, a massive stretch of southeastern Alaska replete with old-growth spruce, hemlock and cedar, rivers running with salmon, and dramatic fjords. President Bill Clinton put more than half of it off limits to logging just days before leaving office in 2001, when he barred the construction of roads in 58.5 million acres of undeveloped national forest across the country. President George W. Bush sought to reverse that policy, holding a handful of timber sales in the Tongass before a federal judge reinstated the Clinton rule.

Read the article here.

A view of Mendenhall Glacier, which lies in Tongass National Forest (Source: Wikimedia Commons)

Greenland ice sheet mass balance

From GEUS Bulletin:

“The Programme for Monitoring of the Greenland Ice Sheet (PROMICE) has measured ice-sheet elevation and thickness via repeat airborne surveys circumscribing the ice sheet at an average elevation of 1708 ± 5 m (Sørensen et al. 2018). We refer to this 5415 km survey as the ‘PROMICE perimeter’ (Fig. 1). Here, we assess ice-sheet mass balance following the input-output approach of Andersen et al. (2015). We estimate ice-sheet output, or the ice discharge across the ice-sheet grounding line, by applying downstream corrections to the ice flux across the PROMICE perimeter.”

Read the article here.

A helicopter takes off from the Greenland Ice Sheet. (Source: Wikimedia Commons)

Read More on GlacierHub:

What the 2018 State of the Climate Report Says About Alpine Glaciers

The Funeral for Iceland’s OK Glacier Attracts International Attention

Park Officials Remove Signs Warning That Some Glaciers Will Disappear by 2020

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Ice-core Evidence of Copper Smelting 2700 Years Ago

The 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.

Art craft of Moche culture in Lambayeque, PERÚ (source: Douglas Fernandes / Flickr).
Moche mask from Lambayeque, Peru (source: Douglas Fernandes/Flickr).

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.

Location of Illimani (source: Eichler et al.).
Location of Illimani (source: Eichler et al.).

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.

The sculpted head represented the Chavín culture, considered one of the oldest "civilizations" in the Americas [BSO explain this--sculpted head of mythological being at Chavin.](source: Boring Lovechild / Flickr).
A sculpted head at  Chavín de Huantar (source: Boring Lovechild/Flickr).
“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.

Moche copper funeral mask with shell ornaments from Ucupe, Peru (source: University of North Carolina)
Moche copper funeral mask with shell ornaments from Ucupe, Peru (source: University of North Carolina).

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,” Eichler explained. “Furthermore, ancient metallurgical sites are difficult to find because of the lack of substantive remains, particularly smelting installations. Prehistoric smelting furnaces tended to be small or smelting was performed on open fires and thus left little permanent remains.”

Mount Illimani from Aimara, meaning "Golden Eagle" (source: Arturo / Flickr).
Mount Illimani, seen across the Bolivian Altiplano (source: Arturo/Flickr).

The two major sources of copper in the atmosphere— and hence in ice cores from glaciers, where the atmosphere deposits copper compounds— are smelting activities and natural mineral dust. The contribution of Eichler and her team has been to distinguish these and document the creativity of early cultures who developed means to smelt copper.

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