Academics restart work to unlock secrets of mystery medieval civilization with links to Persia on edge of the Siberian Arctic.
The 34 shallow graves excavated by archeologists at Zeleniy Yar throw up many more questions than answers. But one thing seems clear: this remote spot, 29 km shy of the Arctic Circle, was a trading crossroads of some importance around one millennium ago.
The medieval necropolis include 11 bodies with shattered or missing skulls, and smashed skeletons. Five mummies were found to be shrouded in copper, while also elaborately covered in reindeer, beaver, wolverine or bear fur. Among the graves is just one female, a child, her face masked by copper plates. There are no adult women.
Nearby were found three copper masked infant mummies - all males. They were bound in four or five copper hoops, several centimeters wide.
Similarly, a red-haired man was found, protected from chest to foot by copper plating. In his resting place, was an iron hatchet, furs, and a head buckle made of bronze depicting a bear.
The feet of the deceased are all pointing towards the Gorny Poluy River, a fact which is seen as having religious significance. The burial rituals are unknown to experts.
Artifacts included bronze bowls originating in Persia, some 3,700 miles to the south-west, dating from the tenth or eleventh centuries. One of the burials dates to 1282, according to a study of tree rings, while others are believed to be older.
The researchers found by one of the adult mummies an iron combat knife, silver medallion and a bronze bird figurine. These are understood to date from the seventh to the ninth centuries.
Unlike other burial sites in Siberia, for example in the permafrost of the Altai Mountains, or those of the Egyptian pharaohs, the purpose did not seem to be to mummify the remains, hence the claim that their preservation until modern times was an accident.
The soil in this spot is sandy and not permanently frozen.A combination of the use of copper, which prevented oxidation, and a sinking of the temperature in the 14th century, is behind the good condition of the remains today.
Natalia Fyodorova, of the Ural branch of the Russian Academy of Sciences, said: 'Nowhere in the world are there so many mummified remains found outside the permafrost or the marshes.
'It is a unique archaeological site. We are pioneers in everything from taking away the object of sandy soil (which has not been done previously) and ending with the possibility of further research.'
In 2002, archeologists were forced to halt work at the site due to objections by locals on the Yamal peninsula, a land of reindeer and energy riches known to locals as 'the end of the earth'.
The experts were disturbing the souls of their ancestors, they feared. However, work is underway again, including a genetic study of the remains headed by Alexander Pilipenko, research fellow of Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences.
Fyodorova suggests that the smashing of the skulls may have been done soon after death 'to render protection from mysterious spells believed to emanate from the deceased'.
With work underway again, archeologists hope for clearer answers.