Quetrupillán – the headless ghost   Leave a comment

There is a legend of three volcanoes in Chile. They form a line, with the tall and proud ice-capped peak of Lanín volcano at one end, and the gently smoking, demure, and shapely ice-capped volcano of Villarrica at the other end. In between the two is the stunted Quetrupillán, and which has a somewhat beheaded look about it. As if someone has removed the top of a once proud peak.

Image

Lanín volcano (3,747 m high). The proud warrior….

Image

Villarrica volcano. The demure and smoking lady….

The legend is that Lanín was a proud warrior who loved to gaze upon his lovely smoking lady of Villarrica. But growing between them was a warrior called Quetrupillán, and as Quetrupillán grew larger Lanín became frustrated that his view of the lovely Villarrica was becoming blocked. Frustration grew into anger and in his rage Lanín cut off the head of Quetrupillán.

Quetrupillán means ‘the headless ghost’ and this could be either a quaint story invented by indigenous tribes to explain to their children why these three volcanoes have different shapes, or perhaps it is a story passed down through time by ancestors who witnessed the eruption at Quetrupillán that destroyed the summit cone.

Image

Quetrupillán volcano, showing the ice-filled summit crater with remnants of the original cone flanking the ice.

This is something myself and my Chilean colleague are investigating. Actually we are investigating quite a lot about Quetrupillán. But for now I’ll say a little about the trip we did back in March of this year (2012).

Quetrupillán has a famous neighbour – the smoking volcano of Villarrica. It is understandably famous because the ‘smoke’ is a noxious cocktail of magmatic gases escaping from an active lava lake that occupies the summit crater. And because it’s a fairly easy hike up to the summit to look down into the lava lake. Everyone who goes up there comes away moved if not awed by the volcano, as for most this is a truly unique and weird experience. But turn away from the summit and gaze around and the eye is drawn to the superb ice-capped volcano of Lanín, which lies on the border of Chile and Argentina. (In fact the border goes over the summit.) Lanín looks higher and in fact it is, because it sits on a separate (higher) crustal block, but this is not the place to delve into the vagaries of basement geology and discriminating between the little that is known and the large that is speculation.

Image

Lanín in the background, with ‘beheaded’ Quetrupillán in the middle ground. Taken from the summit of Villarrica. Volcanologist colleague is wearing mask due to noxious magmatic gases escaping from the summit lava lake. Photo courtesy of Jose-Luis Palma.

Looking down from the rim of Villarrica into the lava lake. Taken in 2004, the level of the lava lake is quite low, so only occasional splashes of glowing lava were seen.

Few pay any attention to the less obvious and shorter volcano that lies between Lanín and Villarrica. But this is a rather special volcano. This is Quetrupillán.

My Chilean colleague Andres knew of my work on Icelandic volcano-ice interactions, and that I had worked on another Chilean volcano. So he asked me to go on a recce to Quetrupillán to see if there were interesting volcano-ice interactions.

Image

The author on his trusty steed. There is no vehicle access to Quetrupillán, so the choice for those who cannot afford a helicopter is either horseback or walking. Photo courtesy of Beth McGarvie.

Riding on horseback through forests of Araucaria Araucana was rather special, as the trees exude an enduring and timeless air. The wreaths of cloud added to the feelings of otherworldliness. Photo courtesy of Beth McGarvie.

Now I’m not going to give too much away as there’s a grant proposal being written to do further research in this fabulous place! So I’m going to restrict myself to leaving you to enjoy a few images that reveal some of Quetrupillán’s beauty, and hopefully the captions accompanying the images below will say what needs to be said.

Image

Imagination time. Imagine a lava flow creeping slowly through a circular tunnel tunnel melted into the ice. Cool down the lava flow, then remove the ice. This is what we have here. The giveaway evidence is the radial columnar joints (indicating cooling against ice walls and ice roof) and the sinuous shape of the lava flow showing that it was confined (by ice).

Image

Laguna Azul lies south of Quetrupillán’s summit, and our camp was in the woods. The twin peaked volcano in the distance in Volcan Mocho-Choshuenco.

Image

One for the the volcanology geeks. These top-bottom ridges on this chunk of dacite lava column represent staggered cooling of the lava, as columns don’t form smoothly – they form in increments or steps. The fracture pattern on the surface (when preserved, as here) indicates development of the fracture from solid into ductile (hot) lava, and so gives the direction in which the column was forming. In this case from left to right.

Lanín in the background, with one of the young dacite lava flows from Quetrupillán damming the outflow of Laguna Azul.

Image

Laguna Blanca on the south side of Quetrupillán is fed by glacial streams and so has a milky appearance. In the backround is one of the young (Holocene) andesite lavas from Quetrupillán. The pale-coloured block is an example of ‘peperite’ where a lava has flowed over wet unconsolidated sediment and steam action during lava-sediment interactions has aided mixing between the two components.
Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

%d bloggers like this: