PICO Island - Gruta das Torres

The Gruta das Torres (Grotto of Towers), is a lava cave, a geological formation of volcanic origin formed from the flow and cooling of subterranean magma rivers. This formation is located outside the parish of Criação Velha, in the municipality of Madalena, on the western flanks of the island of Pico. The cave system formed from a series of pāhoehoe lava flows which originating from the Cabeço Bravo parasitic cone about 500 to 1500 years ago. The caves are a group of interconnected lava tubes between 0.5–22 metres (2–72 ft) width, created from both pāhoehoe and ʻaʻā types of lavas generated during different geological periods. It has a height between 1.1 and 15 metres (3.6–49 ft) and is located at an elevation of300 metres (980 ft). With an estimated length of over 5.2 km (3.2 mi) it is the longest lava cave in the Azores. Access to the cave was managed by the Mountaineering Association (“Os Montanheiros” – Núcleo da Ilha do Pico). 

The cave doesn't have a date of discovery but the first scientific exploration was in 1990. The cave's uniqueness lies in its impressive drainage pattern, which can be shown by the presence of more than seven layers on the walls, with lateral benches and three cornices. Gruta das Torres is one of the 17 caves (out of 28 found here) in Pico Island of the 30 caves chosen for Azores as a whole (from an overall list of for inscription under the UNESCO List of World Heritage Sites proposed by the Government of Azores.

Going down the caves..
At the main entrance, after passing through the ‘Algar da Ponte’ ("Algar Bridge"), there is an avenue of trees. Some forms of plant life like ferns, mosses and lichens are also noted at the portal, floor and walls of the cave opening.

Lava gutters are also seen. A number of secondary tunnels also have impressive geological formations. The lava tubes have picturesque formations of stalactites (lavacicles), stalagmites, lava, lava benches and side balls or balls of lava. Considering the large size of the cave, with further scientific studies more faunal species may be discovered.
The liquid lava that dripped from the roof of Gruta das Torres has formed into picturesque stalactite and stalagmite and also in several other formations and shapes. Inside the tunnel, it is humid as water drips from the roof and a constant temperature of 16 °C (61 °F) is recorded throughout the year. 
The tunnels formed within a pāhoehoe type lava flow. The top of the flow cooled against the air and formed a solid crust, while beneath it the liquid lava continued to move. As the amount of liquid lava passing through them decreased, the tunnels emptied. Silica oxide is also seen in walls of the cave in some stretches of the cave. 
Deep inside, in the darker regions of the cave, mold, bacteria and insects have been identified. The troglobite faunal species found, typical of such caves, are the endemic species of Trechus Pico Machado and Cixius azopicavuz Hoch.

(c) Chavanitas