New Caledonia votes on independence from France in landmark test. Vote in New Caledonia being closely watched as test of support for France in its many territories around the world

New Caledonia, which is 18,000 kilometres (11,000 miles) from France, is home to a quarter of the world’s known supplies of nickel – a vital electronics component – and is a strategic foothold for France in the Pacific.

Off-topic, but how does such a small island in the middle of the Pacific have that much nickel? The Nickel mining in New Caledonia Wikipedia article focuses mostly on the mining process and pollution problems with nothing on the "how" part of the equation.

edit: Found some interesting stuff about it, although it's not properly sourced/attributed so I have no idea how reliable it is:

Geology of New Caldonia

Grande Terre and smaller islands extending northward and southward, are emerging parts of a folded arc (Grande Terre Arc on the map). East of this arc, Loyalty islands are on a volcanic arc (Loyalty Is. Arc).

They are set on the Australian Plate which drifts eastward under (subduction) the Pacific Plate. East of this subduction line Vanuatu is on another volcanic arc, the New-Hebrides Arc.

Grande Terre arc consists mostly in sedimentary, volcanic and ultrabasic rocks from Permian (225-280 millions years) to Tertiary (1,5 - 65 MY). Some geological formations in the main central ranges could be older than Permian but their age has not been established yet. The important group of ultrabasic rocks of Tertiary age relate to a mantle sheet (mantle is a thick layer located under the Earth crust and above its core) overthrust on the other geological formations (obduction). Vast areas of volcanic rocks (basalt), on the West Coast, are spatially associated with the ultrabasic rocks. They are remnants of an oceanic floor obducted before the overthrust of ultrabasics. Several ages of folding have been established. The last one occurred during Eocene to Oligocene (26-53 MA) and created the actual island. These folding and obductions are the result of colliding plates. These plate collisions generated temperatures and pressures which led to a transformation of sediments and volcanics. Such metamorphism has formed schists, micaschists and the interesting glaucophane and garnet bearing blue rocks in the North of Grand Terre. This blueschist metamorphism requires very high pressure and is seldom occurring so extensively in other parts of the world.

New Caledonia economy - Nickel - the resource

Nickel ore deposits are originating from the ultrabasic rocks or peridotites. The ultrabasic rocks come from the mantle (mantle is located under the Earth crust - see "geology, ultrabasic rocks"). They form large massifs in the South and on the West Coast.

Geology - The massifs of ultrabasic rocks or "massifs miniers"

The very large occurrence of ultrabasic rocks is the original feature of the folded arc of Grande Terre. These rocks make large and high massifs in the South and along the West Coast.

They cover an area of 5500 km² (1/3 of Grande Terre). For a long time the large ultrabasic massif of the South was the largest ultrabasic body known on Earth. It has been superseded in the seventies by an ultrabasic massif in Oman.

Ultrabasic rocks originate from the mantle (deep layer under the crust and above the earth core). When plates collided generating the last New Caledonian folding, a large sheet of mantle was upraised and overthrust above other terrains. Erosion then divided it in several massifs.

Ultrabasic rocks are iron and magnesium rich and also contain nickel, cobalt and chromium. They are the source of the nickel, cobalt and chromite deposits in New Caledonia, hence their name of "terrains miniers" (mining grounds). This name was extended to the ultrabasic massifs then named "massifs miniers".

So apparently the islands were formed by a rather unique geological process which resulted in a tremendous amount of mantel material (where high concentrations of nickel are found) being brought to the surface there.