Suivre ce blog
Administration Créer mon blog

Earth of fire

Actualité volcanique, Article de fond sur étude de volcan, tectonique, récits et photos de voyage

Fogo Island has other volcanic landscapes than caldera and Pico do Fogo .

On the north coast of the island, the black sand beach of Ponta das Salinas is one of the most beautiful . A succession of creeks bordering basalt cliffs sculpted by wind and sea erosion. It dug a bridge in a basalt flow .
The place is popular for fishermen who shelter their boats. Protected from currents, Ponta das Salinas also has a natural pool where swimming is safe.
A cemetery is perched on the cliff overlooking the surf.

F - 3 - CHB
  Fogo - Ponta das Salinas , creeks lined with basalt cliffs - photo © Carole and Frederic Hardy 2013.

F - 5- CHB                                                
Photo © Carole and Frederic Hardy 2013.

Fogo - Ponta das Salinas, an arch that gave its name to the place - photo © Carole and Frederic Hardy 2013.

Fogo - 2 - CHB
            Fogo - basalt cliff with prismation - photo © Carole and Frederic Hardy 2013.

Sao Vicente has vertical dykes with a
characteristic horizontal prismation.

After complete solidification , the lava flow continues to cool . This results in thermal shrinkage,  a reduction in volume and the genesis of fracture. These fractures start with the edges of the mass of lava to progress towards his heart .
The prisms formed end up perpendicular to the top and the base of the flow, with the possibility of heterogeneity .

In dykes against, by the cooling rate identical on both sides of the vein makes the prismation
homogeneous with formation of continuous prisms through the dyke.

Sao Vicente - 1 - CHB
              Sao Vicente - basaltic dyke and prismation - photo © Carole and Frederic Hardy 2013.

Articles récents

Hébergé par Overblog