Image caption The type of rocks that are a signature of diamond deposits have now been identified in Antarctica

Scientists say they have discovered compelling evidence that diamonds exist in the icy mountains of Antarctica.

The researchers have identified a type of rock in the permanently frozen region that is known to contain the precious stones.

However recovering any Antarctic mineral resources for commercial purposes is currently forbidden.

The research is published in the journal Nature Communications.

Diamonds are formed from pure carbon under extreme heat and pressure at depths of about 150km in the Earth's crust.

Ice under ice

Volcanic eruptions bring the valuable crystals to the surface, usually preserved in another type of bluish rock called kimberlite.

The presence of kimberlite has been a clue to significant deposits of diamonds in several parts of the world, including Africa, Siberia and Australia.

Now researchers have, for the first time, found evidence of kimberlite in Antarctica.

The team found three samples on the slopes of Mount Meredith in the northern Prince Charles Mountains.

Image caption Diamonds are usually transported from deep within the earth in a rock called kimberlite

"The fact they are reporting Group One kimberlites is an important one as diamonds are more likely to be found in this style of kimberlite eruption," said Dr Teal Riley, a survey geologist with the British Antarctic Survey.

"However even amongst the Group One kimberlites, only 10% or so are economically viable, so it's still a big step to extrapolate this latest finding to any diamond mining activity in Antarctica."

Even if diamonds were plentiful in this inhospitable region, there are still some significant legal barriers to their extraction.

The Protocol on Environmental Protection to the Antarctic Treaty, added in 1991, explicitly bans any extraction activity relating to mineral resources, except for scientific purposes.

However it is up for review in 2041 and could be subject to change.

"We do not know what the Treaty Parties' views will be on mining after 2041 or what technologies might exist that could make extraction of Antarctic minerals economically viable," said Dr Kevin Hughes from the Scientific Committee on Antarctic Research.

"An additional issue is that nations outside the Protocol are not bound by its provisions, including the ban on mineral resource activities."

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