Grand Tour of Argentera and Vallée Merveilles - Stage 5

1 point of interest

  • Geology

    The eclogite of Lac Niré

    Just above Lac Niré, on the right bank of the mountain stream, among the migmatite, can be found very dark rocks which take the shape of huge lentils (geologists call them “black puddings”).
    When you look closely at these one of these lentil, you can see very different minerals to the ones you find in migmatite. The rusty red coloured ones are garnet and the darker ones are amphibole.
    This very distinctive rock with characteristic fine and very dense crystals is eclogite; it is quite rare and a remainder from oceans which have disappeared. It is a metamorphic rock which springs from the transformation of basalts, ancient lava from the oceanic crust.


Go west around the upper lake and head up Vallée des Merveilles along GR52, towards Baisse de Valmasque (2549m – m94) which overlooks the huge lake of Basto; this is where you need to get to. Take GR52 with its red and white markers (m95) and you will reach Baisse du Basto (2693m – m401). Heading downhill, the path will lead you pas boulders and screes until you reach a series of lakes at an altitude of between 2379m and 2353m. Continue alongside Lac Niré’s spillway until you reach the Nice refuge (2221m), which has recently been renamed Refuge Cessole.
  • Departure : Les Merveilles refuge
  • Arrival : Nice refuge
  • Towns crossed : Tende and Belvédère

Altimetric profile


Is in the midst of the park
The national park is an unrestricted natural area but subjected to regulations which must be known by all visitors.

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