The final week - The Labs!

So this is my last post for the Canaries fieldwork.

The last week of the internship we spent in the InVolcan labs at ITER (the Institute for Technology and Renewable Energy).

This is where we learnt about the equipment used to analyse all the samples we had spent the last three weeks collecting, how to run samples for ourselves and how the data is used to generate diffuse degassing maps referred to as sequential Gaussian simulations (sGs). These maps can be used to highlight the locations of fractures and faults that are actively used as gas conduits.

At InVolcan they use micro-Gas Chromatography as this is more sensitive to CO2 and Quadrupole Mass Spectrometry as this is more sensitive to Helium. In both cases these are quantitative analyses, simply looking for the overall values of these two gases within the total gases that are rising to the surface - providing information about the total gas composition. At InVolcan they also use Isotope Ratio Mass Spectrometry to analyse CO2 in more detail. This fancy bit of kit determines the ratio between two different Carbon isotopes 13C/12C. With this information, it is possible to determine the source of the carbon dioxide rising to the surface - is it's main source of a biogenic nature or a magmatic nature. As InVolcan monitor and analyse in this way every year, they can also compare past results and study any notable changes.

Running samples through the micro-gas chromatography system

Island residents and visitors alike can be safe in the knowledge that Mount Teide, along with many other volcanic systems in the Canaries and other locations including Cape Verde, Iceland and Nicaragua are regularly monitored, so any changes will be identified, monitoring will be increased accordingly, and, if needs alert levels will be changed.

Of course, it is not just the monitoring of diffuse degassing that is monitored. There are many more techniques used to monitor the behaviour of a volcanic system that ultimately contribute to what happens with alert levels and the safety of the islanders. 

Buenas Noches or I really should once again say Lala Salama!

Day 22 - 24 - A few extra curricular adventures

Firstly, please let me take a moment to apologise for the very late finishing of this blog! The last week in the Canaries was quite a busy one and on my return to the UK, the following five weeks were very busy with plans for Kenya fieldwork - from where I now write this, one week in!

So after arriving back on Tenerife after a very early sailing from La Palma, I spent Thursday recovering from the lack of sleep and catching up on some of my own work. And Friday ended up being an unplanned beach day because the Tenerife interns had not yet finished their sampling due to a bad tyre blow out that also damaged the wheel!

So Saturday we finally went on a little Tenerife based adventure that led me to climb my third 'Decade Volcano' - summiting Mount Teide.

The decade volcanoes are 17 volcanoes listed as being worthy of detailed studies in light of their large, explosive and destructive pasts and their proximity to populated areas. The other two decade volcanoes are Mount Vesuvius and Mount Etna (with many others climbed, but not included on this list.

So, the day started at 9am when Ignacio collected us from the apartment, followed by a winding climb through the mountains, stopping at a fossilised pine tree and of course for a Barrachito!

Fossilised pine tree in lava

Once arriving at Mount Teide's cable car station we met with David Calvo from InVolcan who would be our guide, and a camera crew who would be filming the Tenerife interns as we were on La Palma. I suppose using a cable car to take us most of the way is cheating, but it was incredibly hot.

The ride was only about 5 minutes, and once out and grouped together, we started the final 'permit only' ascent. Once we had all reached the top, we continued beyond the barriers across the steaming crater to the top of the west flank where we could see Pico Viejo from above, a view not seen by many.

About half way up the final leg with Las Canadas caldera behind me

Once the filming commitments were completed, we had a wander around inside the crater, paying particular attention to the incredibly hot fumaroles

A view across the summit crater of Mount Teide

The view of Pico Viejo as seen from the west flank

Once the filming commitments for the Tenerife interns was completed, we had a walk across the crater where there are high temperature fumaroles and sulphur deposits - nice smell of rotten eggs that clings to everything. David explained the temperatures have gradually increased in very recent years and along with soil gas sampling across the Canary Islands, the temperatures and the composition of the fumarole discharge is also monitored. 

Once climbing back down to the upper cable car station, we went to have a look at one of the geochemical monitoring stations. Although Mount Teide is part of the annual Volcanic Risk programme, the monitoring station also monitors remotely, the composition of the diffuse degassing on a regular basis, concentrating on the gases that are not always included in the annual monitoring programme. 

A sceond adventure took place on MOnday evening after a day in the labs. We finally got to visit one of the many huge lava tubes. 

The original plan was to visit a tube that is open to the public, but we would have had most of the time in the tube to ourselves as we would have been visiting after hours. However, Ignacio and Sharon thought it would be more fun to visit one that was not on the tourist trail.

So after our day in the labs, off we went on a little drive for about an hour we arrive at our destination where two cavers are waiting to kit us out with hard hats, head torches (to be expected), followed by gloves, knee pads and elbow pads! 

A small climb down a steep bank and we are ready to go. After having to step on the knee of one of the cavers in order to reach a narrow ledge, it was an almost commando style crawl through the entrance that then opened up above our heads by several meters, very impressive!

All kitted out and ready to go caving. In a lava tube!

The cavers know the lava tube well, so we were in safe hands. They were telling us about how the caves are sometimes used to drain away waste water which is a problem for the island as the aquifer is just below. They also spoke of how new species of animals and insects were being discovered in the network of lava tubes sometimes on a daily basis! But as so little is still known about the caves, the government are very reluctant to invest in the protection of the caves. Yet this place is well deserving of SSSI (Site of Special Scientific Interest). We were in the lava tube for about 2 hours, moving approximately 300m in under Mount Teide.

Inside the lava tube - at this section the roof was in the region of 10 meters above our heads. Yet other areas we had to crawl along on our fronts!

We spent about 10  minutes sat with all our head torches switched off, which was really odd. It was so dark that if it wasn't for brain signals that tell us our eyes are open or shut, there would be no way of knowing - does that make sense?

By the time we came back out of the lava tube, it was dark and we were all hungry! Time for some food and to head back to our apartment ready for tomorrow in the labs.

As I have been so busy the past 2 months, I am finishing this off from my new field location, Menengai caldera in the East African Rift Valley. so it is not Buenas Noches, but Lala Salama!

Day 18, 19, 20 and 21 - Finishing off and heading back to Tenerife

So the last two days of sampling are here and they were both shorter days as we had made good time in the last week, covering areas with time to spare and both days went off without any major hitches. The last day I was on soil gas sampling and although nothing went wrong with the day, all but three sites were very difficult to sample from, indicating poor permeability of the soils we were sampling from.

The main geological feature observed on the last day were by the coast and consisted of many fine layers of fin e ash - airfall deposits.

Finely laminated airfall deposits

The day has finally arrived. Though the ferry is tomorrow morning, we are leaving today. Luggage packed, equipment packed, samples packed, house clean and off we go. We are heading to Santa Cruz, La Palma's capital, where the ferry back to Tenerife leaves from at 4am tomorrow. We are taking the long way round by taking the road over the north of the island via the geochemical station in Tazacorte. 

The road takes views over Tazacorte and parts of El Paso, it has been cut in to the Taburiente strato- volcano and passes through some spectacular pyroclastic deposits that contained evidence of base surge sedimentary structures. 

The road became quite 'zig-zaggy' with some very tight corners to get around, but it was well worth it. We pulled in to the car park at the top and went for a very short walk to see the caldera over 2000 meters below our feet, we were down there collecting samples just a week or so ago! Roques de Los Muchachos, the highest point of La Palma.

The highest point on La Palma

A beautiful clear day, again above the clouds, we could see Tenerife, La Gomera and El Hierro. Much closer, peering through the clouds we could see our filed area, Cumbre Vieja. 

From the top of Roques de Los Muchachos with Cumbre Vieja rising above the clouds over my left shoulder

A little cheeky Dream Team selfie at the summit (front to back: me, Samara and Hannah)

Also at the summit is the IAC; the Instituto de Astrofisica de Canarias. La Palma is known for its perfectly clear night skies perfect for star gazing and galaxy hunting.

Just a handful of the IAC telescopes

Well the time has come to say good-bye to La Isla Bonita. La Palma you are truly beautiful and magical and I can't wait to come back. But for now it is Adios!

The 4 am ferry called at La Gomera and on approaching Tenerife we were greeted by a sunrise over Mount Teide.

Sunrise over Teide, she looks so small!

We have today off and due to a tyre blow out, so do the Tenerife interns, which is great as we can have a day of catching up. This does mean however, they have to go out in to the field to complete their sampling tomorrow, so we had an extra day off - much needed after pretty much travelling through the night and getting next to no sleep for the best part of 36 hours. But its all part and part of fieldwork, those little tests, trials and tribulations. 

Every day is an adventure!

Buenos noches de Tenerife!

Day 17 - Volcan de Teneguia and Llano del Banco flows (at last!)

Today was a great day. I was responsible for the soil gas sampling and our main area to sample was on and around the volcano responsible for the 1971 eruption, Teneguia.

The first image Doesn't show Teneguia from her best angle but it does show the clear contrast between the colour of the young lavas of Teneguia (and some of San Antonio) and Roque Teneguia.

It's more a moonscape but with Blue skies. Teneguia has three craters and covers the field of view with the contrasting pale Roque Teneguia to the far right.

Roque Teneguia is much older than the surrounding landscape at ~56,000 years. This pale colour is due to the lava responsible for forming this rock having a much greater evolved composition. This outcrop is what remains of a phonolite dome, now devitrified and spherulitic due to chemical weathering.

This site is of importance for other reasons also. It is only one of two sites, not just within the Fuencaliente municipality, but the island as a whole, where the plant species centaurea (Cheirolophus junoianus) is found. Evidence suggesting this area may have been a sacred place for the pre-Hispanic population of the island is presented in funeral remains and rock carvings. This area would have appeared very different during these times.  

The two main highlights of today were sampling/climbing to the top of Volcan de Teneguia and walking around the Llano del Banco lava flows. 

Volcan de Teneguia, 1971 eruption, second active crater

Teneguia has 3 craters, all of which contributed to the 1971 eruption. The eruption began with the smallest crater in the northwest of the volcanic field and progressively moved south with the second crater that in the above image and the third below. 

The first crater is towards the top of this image among the black lavas, taken from above the second crater, looking roughly north west. The reddy-brown colour in the foreground is due to oxidisation of  some of the individual minerals in the lavas at this location on the volcano

Crater three

Our final sample site on the volcano was the end of the crater rim in the upper right of this image. From this point looking inland, there is a great view of San Antonio volcanic cone.

San Antonio volcanic cone as seen from the rim of crater three of Teneguia

Soil gas sampling on the rim of Teneguia crater three

Making our way back to crater two for the climb back to the car, we found a great example of a small fossil fumarole. We took a small sample of the white rock back to the car with us and put a small amount of 10% dilute HCl on it. If it effervesces (fizzes) the rock, or at least the alteration minerals within the sample, contain CaCO3. This proved to be absent of CaCO3, meaning the white is likely to be associated with chemical weathering to clay containing magnesium - probably the smectite group. 

Fossil fumarole (hammer for scale) on the rim between crater two and three

The next highlight of the day involved finally having a walk around the Llano del Banco (1949) lava flow. As stated in an earlier post, the flow started high up on the western flank of Cumbre Vieja, just below Pico de Birigoyo, it flowed all the way to the sea just over 7 kilometers away, before effusion rates dropped, resulting in the formation of an ocean platform, adding more land to the west of the island. 

I have to admit, after seeing just a tiny snippet of these stunning flows on filming day, I was pretty desperate to find time to go back and explore just a little.

The flows combine blocky, a'a' and pahoehoe morphologies and there are channels, collapsed tubes, windows, tubes that become channel and channels that become tubes everywhere you look. In previous posts I have already presented images of pahoehoe lava from this flow, but below there are examples of some of the other features observed.

 This is probably a lava tube that has collapsed simple because the debris on the surface within the channel is broken up, but not in the style of block/a'a' morphology, with pahoehoe below the debris

 The sunlight made photographing some of the features a challenge. In the centre of the image is a window. These are often seen in Hawaii. They are small areas of a lava tube where the roof is yet to form. It is possible to look through (carefully) and watch molten lava move beneath

This is one of many examples observed of a lava tube transitioning to a channel

 In some areas the lava has formed small topographic highs that we were soon to discover indicated the location of lava tubes larger than previously seen.

Walking to the end of the constructed walk way, Hannah got to a point before me and excitedly called back to tell me to hurry up. We were looking down on a pretty big opening - a lava tube.

A large lava tube, the photo doesn't really do it justice

We walked down in to the lava tube following the constructed route where it became apparent that this was in fact an area where the lava tube started as a channel and a tube roof had started to develop, but due to a drop in effusion rate had never completely formed. This appears to have happened at least three times during the eruption phase, with the final drop in effusion remaining consistent for a long enough period to form a tunnel roof. 

The lava tube was thiisssss biiggggggg......

We were not expecting this!

Every day is an adventure!

Buenos noches de La Palma!

Day 16 - Filling in the gaps

Day 16 was a business as usual day. I was on CO2 efflux and soil temperatures today. A lot of today's sampling involved filling in gaps - areas that we had for various reasons been unable to sample on our first visit to the location in question.

We returned to the Llano del Banco lava field where we both were filmed earlier on in the internship. We collected some soil gas samples and had the opportunity to take pictures if the source location of the lava flow high in the hills - wishing just a little that we could actually go and see the locality. 

  Source of the Llano del Banco lava flow up in the hills to the right of the image - taken from the lower part of the flow. 

There were also some great examples of pahoehoe flow at this locality.

Pahoehoe of the Llano del Banco flow, San Juan eruption, 1949

Today's sampling also took us high in to the hills, sampling on the flow of the El Charco eruption of 1712.

El Charco lava field, taken just below the crater looking west

We also spent sometime today, and on other days, sampling among the banana plantations, where there is often a strong smell of sulphur, though this is not related to any volcanic activity but rather dilute sulphur is used to feed the banana plants (as well as the grapes for the wine)

Bananas!

And among the pine forests that three years ago were damaged by a forest fire, but are recovering well.

Fire damaged pine forest

Every day is an adventure!

Buenos noches de La Palma!

Day 15 - Pilot Whales. In the wild. Where they belong!

As Paulo left last night for the 4am ferry this morning and Samara had driven him to the port and returned at almost 5am, we took they day off so she could snooze and do some work on her final PhD presentation.

We decided to treat ourselves to a boat trip, that had a high success rate of seeing whales and dolphins (though never guaranteed). We went out on the Inia Ocean Explorer, a purpose built R. I. B. (Rigid Inflatable Boat) it emits little noise as it is equipped with low-noise and low-vibration motors. The company adheres to the directives of gentle whale watching by keeping a minimum of 60 meters away from any sighted animals and engines off to drift should they approach us, which often happens with the dolphins as they are familiar with the boats and enjoy playing in the waves.

The Inia is the small yellow boat (12 seats)

My life is a little complete, as we got to see a family pod of pilot whales with young. In the wild. Where they belong! We also saw a small pod of Atlantic Spotted Dolphins, but these guys were too fast to get any good pictures of.

Pilot Whales

After seeing the whales and dolphins we headed out approximately 4 miles at a speed of ~21 knots (~45 mph land speed), jumping the waves and bouncing around, which was great fun!

We then headed back in towards land at a slower speed. We were taken past a small village that had been built on a wave cut lava platform at the very base of the cliffs, a location used during the summer months by locals. Further along we were taken in to a sea cave, the entrance to which was surrounded by columnar joints.

The geology of the cliffs was quite interesting with networks of high dykes and deposits of pyroclastics cut by lava channels (I shall add pictures when I have rectified a technical issue with my camera).

We headed back to the port passing the Taburiente caldera opening on the way.

After disembarking, we headed for a tapas lunch, then relaxed on the beach for a while before getting the bus back to Los Canarios.

Every day is an adventure!

Buenos noches de La Palma!

Day 14 - San Antonio volcano

Today is Paulo's last day with us before heading home to Cape Verde.

Though today is a day of sampling, business as usual, there is a feature we sampled around that is worth discussing a little, so here I go!

Along with the most southerly volcanic centre of Teneguia, responsible for the 1971 eruption, there is a much larger volcanic cone immediately above Teneguia that was responsible for the 1677 eruption. Together these two volcanic centres are responsible for extending the land mass of the island of La Palma in a southerly direction.

San Antonio crater taken from the western crater rim

The eruption of San Antonio was a Strombolian style eruption that resulted in minimal destruction to the area. However, the lava flows were responsible for burying Fuente Santa, the hot spring that is the namesake of the municipality of Fuencaliente. 

Fuente Santa, or Holy Fountain, was a hot spring whose waters were believed to hold healing properties by European travellers and the ancient inhabitants of the island alike. The waters were even shipped to South America, bringing some wealth to the area. Its powers were so amazing to the people that it was also referred to as Fuente Caliente - Holy Source. 

In writings by Nicholas Sotomayor "On November 13, 1677, a quarter of an hour before sunrise, the Earth shook and the underworld opened at the foot of the Mount of Los Corrales. Several lava flows were diverted away from the hot springs, but on November 23, a large flow moved towards the spring and no more could be done to stop the inevitable. This lava flow was coupled with the collapse of part of the cliff where the source of the hot spring was located. Despair among the people of the area raged as the spring was buried and the land was extended to the sea by 400 meters. 

Fuente Santa (image from canariesactual.com)

Recently, the Ministry of Public Works of the canary Islands Government in collaboration with the City of Fuencaliente has discovered the location of the springs and established access. Analysis of the waters reveals high salt an CO2, as well as water temperatures of 60 degrees Celsius. It is hoped that in the near future, these waters will once again be used in a spa that will bring additional wealth back to the region. 

Down near the coast, among the lava flows of this eruption, where roads now cut the flows, it is possible to observed some good examples of lava flows in cross section that demonstrate the rubbly top and base and a solid core with vesicles elongated with the flow direction. 

Cross section through a lava flow

The rubbly at the top and base of the lava flow is due to these surface coming in to contact with the cooler underlying deposit and the atmosphere. The outer edges of the flow begin to cool but the core of the flow continues to move. The friction generated between the still flowing lava and the cooled and partially crystalized outer edges causes the outer edges to break up in to small blocks, resulting in the rubble. 

Every day is an adventure!

Buenos noches de La Palma!