Pico do Fogo
Pico do Fogo with Pico Pequeno (right)
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The Pico do Fogo on the island of Fogo is the highest peak of the Cape Verde islands with a height of 2829 m and after the Pico del Teide, the second highest in the Atlantic.
Geography
The layer of volcanic cone rises 1200 m above the east side of the Cha das Caldeira, which represents a semi-circular rock basin at an altitude of 1600 m and 1700 m above the sea with a diameter of about 9 km. However, Cha das Caldeira is not a classical collapse crater ( caldera ), he was created by a massive landslide, then built up on the east side of the layer of volcanic cones. In the south and west of Cha is the Caldeira of nearly vertical 1000 m high rock walls, the Bordeira de Fogo, surmounted. A violent eruption from the central crater of Pico in 1680 was the then " São Filipe " said the island to this day retained the name Fogo (German: "Fire "). In the years 1785, 1799, 1847, 1852, 1857 and 1951 was followed by further outbreaks. The last eruption on April 2, 1995, the lava flow, the Caldeira confined to the interior of the Cha, a small tributary volcano emerged ( Pico Pequeno 1,950 m) at the western foot of the Pico. In the Caldeira is the town of Cha das Caldeira. After the outbreak of Pico Pequeno large parts of the cultural landscape were destroyed in the Caldeira, 2000 residents were temporarily evacuated. As before, the living conditions are simple, there is no public water and power supply. Budding Tourism and winegrowers are the main sources of income. The Pico is part of a nature reserve. For the strenuous, but not particularly difficult hike to the summit accompaniment is prescribed by a mountain guide. With São Filipe, the capital of the island of Fogo, the place Cha is the Caldeira connected by a road over Salto and Monte Largo and by taxi, car as well as collective taxis ( " Aluguer ", 1 times daily) to achieve. At the north- eastern slopes of the island is, inter alia, Coffee, beans, oranges, bananas and corn grown. The eastern side of Pico is not accessible. There is a road along the shoreline at the volcano over after Mosteiros through a very barren landscape. The volcano can be seen almost on the entire route well.
Geology
With the 30 eruptions since its discovery in the 15th century, the Pico do Fogo is one of the most active volcanoes in the world oceanic layer. The outbreaks occurred until 1769 the central vent, since 1785, however, based on a north-south oriented columns on the flanks of the volcano. Geologic be expected the development products of Pico do Fogo youngest stage Fogos, the stage of Cha -das- Caldeira's group. Follow on the deposits of the Monte Amarelo Group, with the gigantic upper pleistocene flank collapse around 123,000 before - found their catastrophic end 62,000 years BP. Since that time, the Cha was the Caldeira gradually filled by the slowly growing Pico do Fogo.
Petrological is in the mining products of Pico do Fogo to undersaturated alkaline volcanics of Differentiationsreihe Basanit / tephrite / Phonotephrit. Also some alkali -rich Foidite are uncommon. The last two eruptions of 1951 and 1995 also provided these rocks. Mineralogical are these porphyry ( with 15-20 vol % phenocrysts in a glassy to microcrystalline groundmass ) volcanics of clinopyroxene, amphibole, magnetite and olivine as phenocrysts or Mikrophphänokristalle and clinopyroxene, magnetite and subordinate feldspar, melilite, leucite ( rarely) and amphibole in the matrix. Rarely occurring crystals of olivine and plagioclase are interpreted in the Phonotephriten as Xenokristalle. Apatite occurs as inclusions in clinopyroxene and columnar Amphibolphänokristallen. Rare mafic Xenolitheinschlüsse are pyroxenite and pyroxenführende hornblendites.
Detailed Thermobarometric studies of E. Hildner et al ( 2011) by means of fluid inclusions in clinopyroxene and olivine crystals were for the last two eruptions of Pico do Fogo following results: the main magma chamber is located in about 16 to 24 km depth, ie the top- Lithosphärenmantel only slightly below the oceanic crust. In it, the differentiation of the stem basanitic magma by fractional crystallization took place. The development towards the Phonotephriten should have probably taken place in a separate area, which allows greater fractionation. When Magmenaufstieg then it came in the oceanic lower crust 10 to 12 km depth to a short-term stagnation (English magma ponding ) from several hours to days.
Swell
- Pitt riding Maier, Lucete Fortes: Travel Guide Cabo Verde, Cape Verde Islands Publishing Reise Know How; ISBN 978-3-8317-1547-3
- Susanne Lipps, Oliver Breda: Hiking in the Cape Verde Islands; Dumont Verlag; ISBN 3-7701-5368-5
- Attila Bertalan, Lucete Fortes Pitt riding Maier Gold City Hiking Map of Fogo - Brava; Gold City - Verlag; ISBN 3-89550-471-8