Topo Volcanic Complex Explained

Volcanic Complex of Topo
Type:Volcanic complex
Map:Portugal Azores São Jorge
Location:Eastern Group, name=Azores, Portugal
Coordinates:38.574°N -27.862°W
Elevation M:-->
Surface Elevation M:-->
Geology:Alkali basalt

Volcanic Complex of Topo (Portuguese: Complexo Vulcânico do Topo) is a complex of scoria cones and volcanic structures, located near the village Topo in the southeastern part of the island of São Jorge, in the Portuguese archipelago of the Azores.

History

The base of the Topo complex originated in numerous shield volcanoes, erupting from primordial fissural faults that ran along a northwest to southeast and east-southeast to west-northwest alignment.[1] These structures are only observed in the curvature of the higher turf cones, as far as 700m (2,300feet) above sea level. These activities initiated around 600,000 years ago.[1] [2] [3] The island of São Jorge had its initial formation from the rising of magma along these fractures through the Earth's crust, resulting in effusive volcanism from the area east of Ribeira Seca until Topo (from which it got its name).

Owing to age, continuous effusive eruptions occurred simultaneously with the eruption on the island of Faial, along the Volcanic Complex of Ribeirinha.[1] Volcanism in this zone continued, with some interruptions over the next 500,000 years approximately.[1] But, continuous erosion, from coastal action, humidity and rainfall, wind and thermal amplitudes, resulted in an interior relief forming a more gently appearing landscape, in comparison to the western areas of Ribeira Seca.[1]

Geography

The volcanic complex occupies the eastern part of the island and consists of basalt lavas, hawaiite and mugearite (aa) lavas, from explosive pyroclastic rocks and cinder cones originating from Strombolian eruptions.

Its features around the complex includes the Pico do Brejo do Cordeiro and several others.

References

Notes
  • Sources
  • Notes and References

    1. Web site: A História Geológica de São Jorge I: O Início . 17 September 2008 . Portuguese . Ponta Delgada (Azores), Portugal.
    2. G. Féraud et al. (1980), p.276
    3. Web site: São Jorge: Vulcanismo Historico . entro de Vulcanologia e Avaliação de Riscos Geológicos da Universidade dos Açores/Centro de Informação e Vigilância Sismovulcânica dos Açores . Portuguese . Ponta Delgada (Azores), Portugal.