Easter Island in Polynesia is famed for its mysterious carved figures known as Moai, which the indigenous Rapanui people believed helped food grow on the land.
Now new analysis of the quarry where more than 90 per cent of the monoliths were created – Rano Raruko – suggests that they may have been right.
In a five-year study of two Moai monuments at the centre of Rano Raruko, experts at UCLA found that the carving process itself, which took place in during the 13th–16th centuries, turned the quarry into an agricultural oasis.
Creating hundreds of the heads churned up layers of soil and brought nutrient-rich bedrock to the surface.
This, together, with an abundant freshwater supply, allowed banana, taro and sweet potato to flourish on the the land.
Analysis of chemicals in the soil around the Moai revealed the soil was far more fertile than anywhere else on the Polynesian island.
Scroll down fro video
The two Moai analysed in the study were carefully selected due to where they were and how they were placed. Both were upright, with one on a pedestal and one in a deep hole, indicating they were meant to remain there, the researchers say (pictured)
Creating hundreds of Moai in the quarry of Rano Raruko (pictured) replenished the soil with nutrients from the bedrock which worked alongside fresh water supplies to fertilise the land
The Moai were made at Rano Raruko before being moved elsewhere on the island, except for a few which stayed in the quarry for ceremonial purposes.
Two Moai that remained in the quarry were excavated as part of a five-year project by UCLA researcher Jo Anne Van Tilburg, director of the Easter Island Statue Project on Rapa Nui.
‘Our excavation broadens our perspective of the Moai and encourages us to realise that nothing, no matter how obvious, is ever exactly as it seems. I think our new analysis humanises the production process of the Moai,’ Dr Van Tilburg said.
Excavations at Rano Raruko are highly restricted, with the digs for this study being the first to get the go-ahead since 1955.
Soils in the quarry were already thought to be the richest on the entire Polynesian island thanks to a fresh water supply.
But it received a significant boost as the carving of the Moai themselves increased its richness, the researchers believe.
Excavations at Rano Raruko are highly restricted, with these digs the first to get the go-ahead since 1955. the soil received a significant helping hand as the carving of the Moai themselves increased its richness, the researchers believe
Bedrock was unearthed by workers as they toiled in the quarry, was rich in clay which was then returned to the topsoil, providing essential nutrition to crops. The Moai studied in the research were almost completely buried under soil and rubble
Carving of the famed Easter Island heads helped turn a quarry on the Polynesian island into an agricultural oasis where banana, taro and sweet potato flourished
Bedrock unearthed by workers as they toiled in the quarry was rich in clay and then returned to the topsoil, providing essential nutrition for crops.
Extensive chemical testing of the soil around the heads revealed the presence of calcium and phosphorous – key chemicals for plant growth.
Professor Sarah Sherwood, from the University of the South in Tennessee, was involved in the chemical analysis of the soul.
‘When we got the chemistry results back, I did a double take,’ Professor Sherwood said.
‘There were really high levels of things that I never would have thought would be there, such as calcium and phosphorous.
‘The soil chemistry showed high levels of elements that are key to plant growth and essential for high yields.
‘Everywhere else on the island the soil was being quickly worn out, eroding, being leeched of elements that feed plants, but in the quarry, with its constant new influx of small fragments of the bedrock generated by the quarrying process, there is a perfect feedback system of water, natural fertiliser and nutrients.’
The two Moai analysed in the study were carefully selected due to where they were and how they were placed.
They had been almost completely buried by soil and found in the inner quarry between 1510 and 1645, it is thought.
Both were upright, with one on a pedestal and one in a deep hole, indicating they were meant to remain there, the researchers say.
‘We chose the statues for excavation based on careful scrutiny of historical photographs and mapped the entire Rano Raraku inner region before initiating excavations,’ Dr Van Tilburg said.
WHAT ARE THE STATUES ON EASTER ISLAND AND WHAT DO THEY MEAN?
What are the statues?
The Moai are monolithic human figures carved by the Rapa Nui people on Easter Island, between 1,250 and 1,500 AD.
All the figures have overly-large heads and are thought to be living faces of deified ancestors.
The 887 statues gaze inland across the island with an average height of 13ft (four metres).
Nobody really knows how the colossal stone statues that guard Easter Island were moved into position.
Nor why during the decades following the island’s discovery by Dutch explorers in 1722, each statue was systematically toppled, or how the population of Rapa Nui islanders was decimated.
Shrouded in mystery, this tiny triangular landmass, stranded in the middle of the South Pacific and 1,289 miles from its nearest neighbour, has been the subject of endless books, articles and scientific theories.
All but 53 of the Moai were carved from tuff , compressed volcanic ash, and around 100 wear red pukao of scoria.
What do they mean?
In 1979 archaeologists said the statues were designed to hold coral eyes.
The figures are believed to be symbol of authority and power.
They may have embodied former chiefs and were repositories of spirits or ‘mana’.
They are positioned so that ancient ancestors watch over the villages, while seven look out to sea to help travellers find land.
But it is a mystery as to how the vast carved stones were transported into position.
In their remote location off the coast of Chile, the ancient inhabitants of Easter Island were believed to have been wiped out by bloody warfare, as they fought over the island’s dwindling resources.
All they left behind were the iconic giant stone heads and an island littered with sharp triangles of volcanic glass, which some archaeologists have long believed were used as weapons.