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Antisana VulkanSchichtvulkan 5753 m / 18,874 ft
Ecuador, -0.48°S / -78.14°W Aktueller Status: nicht aktiv (1 von 5)
Typische Aktivität: Explosiv
Ausbrüche des Antisana: 1801-02, 1728(?), 1590(?) Beschreibung:Antisana volcano was built in at least 2 phases: an older volcano was built above the basement of granitic and metamorphic rocks and forms the SE part of the massif, and still covers two-thirds of the volcano. It is composed of lava flows, numerous volcanic breccias and pyroclastic flow deposits. The activity culminated with 2 large eruptions which formed 2 calderas to the south and east, and the edifice was eroded by glaciers.The younger volcanic cone, present-day Antisana, forms the NW flank of the massif and is composed by numerous lava flows radiating from the summit. The region of the North Volcanic Zone around Antisana volcano has a striking lack of intermediate depth seismicity, and the depth of the subducted slab of the Nazca plate underneath Antisana is not known. Lavas at Antisana are highly porphyritic (contain often >40% modal phenocrysts). Sources: - Smithsonian / GVP Antisana volcano information - Bourdon et al (2002) "Adakite-like Lavas from Antisana Volcano (Ecuador): Evidence for Slab Melt Metasomatism Beneath the Andean Northern Volcanic Zone", J Petrology, v. 43 (2), pp.199-217 1801-02 eruption
The eruption occurred from 2 lateral fissures 15 km west of the base of the cone, which erupted the Antisanilla and Potrerillos lava flows of 10 and 15 km length, respectively. |