Volcanic Island Hopping – GeoWorld Travel Diaries

For those of us in the northern hemisphere, our winter trip to the Canary Islands offers a rare (and very welcome!) glimpse of the sun and temperatures well into double-figures. And, of course, it offers the chance to view some of the spectacular geology that these islands have to offer. We were delighted to welcome along a group of guests from the UK, the USA and Ireland for our trip in February 2024. We also ran our modified itinerary for the first time, which gave us an extra day on La Palma, so that the extent and effect of the most recent volcanic eruption (in 2021) could be properly witnessed and understood.

GeoWorld Travel’s “Canary Islands: Volcanic Island Hopping” route map

Click on the photos to enlarge

Day One: Monday 19th February

Our group gathered together today, meeting up at the first hotel of the trip in El Médano, just a few miles from Tenerife South Airport. The group had met on a Zoom meeting just a few days before, so it was great to finally meet in person and to get to know each other over a group dinner.

Day Two: Tuesday 20th February

We started our first full touring day with a morning visiting various geological stops on Tenerife. First up was the Chinyero Cone, site of Tenerife’s most recent eruption, in 1909AD. We then moved on to briefly view Mña Reventada, which displays a mix of basanitic and phonolitic magma within a single flow. Our next stop was at Mirador de Chahorra, where an eruption in 1798AD formed along a 1.2km long radial fracture on the south-west flank of the Pico Viejo stratocone. The eruption was mainly Strombolian but it also had violent phreatomagmatic (interaction with water) pulses. Following this, we viewed radial dykes (as shown in the first photo below) which formed in the ancestral Las Cañadas Volcano which existed before Mount Teide formed. Next was Los Azulejos, coloured rocks consisting of clays, chlorite, micas, zeolites, adularia and epidote, formed as part of the Las Cañadas volcano. We still had time for another couple of stops before lunch, so we headed for the Mirador Roques de Garcia and then on to the Minas de San Jose pumice. Pumice, which was erupted 2,000 years ago in a sub-Plinian eruption from a phonolite dome called Montaña Blanca, was mined at this location until the 1970s, when it was suspended due to the environmental impact.

We then headed to the jewel in Tenerife’s geological crown – Mount Teide. Teide Volcano is of global geological importance and it is a UNESCO World Heritage Site. The volcano was once believed to the highest mountain in the world, but today you can ride the cable-car to an altitude of 3,555m, just 200m below the summit. The latest activity from the Teide stratocone occurred from 660-940AD and the eruption built the 220m summit cone, increasing Teide from c.3,500m to 3,718m. A number of lava tongues that erupted during this time cover the strato one with thick flows of glassy phonolite (obsidian). Their intense black gives them their name: Lavas Negras. Some of our group completed the additional climb from the cable-car station to the summit before descending back to the lower cable-car station. We then returned to our hotel, taking in a view of some phonolote lava balls en route back.

Above left: Ring dykes exposed in the wall of the Caldera de Las Canadas at Boca de Tauce, Tenerife. These were intruded as the original Las Cañadas volcano inflated and contracted. The Las Cañadas volcano collapsed 200,000 years ago and the current volcano, Teide, grew inside the caldera.

Above top right: The Roques de Garcia in the foreground with Mt Teide in the background on Tenerife. The Roques de Garcia consist of volcanic necks, dykes, sill and landslide debris sediments.

Above bottom right: A cable car arrives at the upper cable car station on Mt Teide, Tenerife, which is 3,555m above sea level.

Above left: Sue walks the extra 180m from the upper Teide cable car station to its summit. The path leads through a phonolite lava channel that has levees on either side.

Above right: Some of the GeoWorld Travel group on the summit of Mt Teide. At 3,718m above sea level this is the highest point in the Canary Islands and the highest point in Spain. The latest activity from the Teide stratocone occurred from 660-940AD.

Above left: Looking into the summit crater of Teide, which was once had a higher rim but was mined away for its sulphur in the First World War.

Above right: Looking down a phonolite lava channel from the summit of Teide to the upper cable car station below. In the background the rim of the Las Cañadas caldera can be seen.

Day Three: Wednesday 21st February

Our day started with visits to more sites on the island of Tenerife, heading first for the Amarilla Cone, to the west of El Médano. The Amarilla Cone is a phreatomagmatic tuff cone which formed around 1 million years ago. This tuff cone is morphologically different to other tuff cones on Tenerife because the initial eruption was rich in seawater before evolving into a subaerial Strombolian eruption. The name of the volcano, Mña Amarilla, means Yellow Mountain; it is yellow because of palagonite tuff which has formed due to the seawater hydrating the volcanic ash. Our next stop was the Montaña de Guaza dome where we observed a section of the trachytic pyroclastic flow and ash deposits. Our final two stops on Tenerife were Adeje and Caldera del Rey. At Adeje, we viewed ignimbrite overlain by a place, creamy white lapilli tuff (formed by the Las Cañadas volcano) in a road section, and in the town itself, we had views of the oldest rocks in Tenerife, which were formed by a Miocene volcano. Caldera del Rey is a rare example of a felsic phreatomagmatic eruption which can be very explosive (such as the Laacher See eruption in Germany 12,000 years ago). Caldera del Rey, which erupted 953 ka. was less explosive than the Laacher See but was still subplinian.

These were our final stops in Tenerife and in the mid-afternoon, we made our way to the ferry port at Los Cristianos to catch the ferry to the island of La Gomera. On arrival, we headed straight for a couple of geology stops in the vicinity of the port at San Sebastián de La Gomera. Our first stop was at a massive ‘Taparucha’ – this is the local name for a dyke. This particular example (in the photo below) can be traced for hundreds of metres and it intruded the Miocene basalts. We also stopped at a new road cut through a former quarry where scoria and lapilli beds buried under Miocene basalt flows were visible. The lapilli have been baked together forming an excellent building stone, and the baked scoria is cut by photogenic dykes. Having completed our geological itinerary for the day, we headed to our hotel in San Sebastián de La Gomera.

Above left: The group at Mña Amarilla (The Yellow Mountain). They are examining fossilised beach dunes. The yellow cliffs behind are palagonite. The palagonite was formed when a volcanic eruption began under the sea and the ash was hydrated. As the eruption continued it became subaerial and built the Amarilla tuff cone.

Above top right: A fossil shell found in the fossilised beach dunes at the Amarilla Cone.

Above bottom right: An erosional channel near the base of Mña. de Guaza is filled with pyroclastic flow deposits (likely from Guaza) and with fall deposits from Caldera del Rey. Note the thickening of the upper deposit inside the channel in the centre of the photo, thus moderating topography, a characteristic feature of pyroclastic flow deposits.

Above left: Caldera del Rey is a rare example of a felsic phreatomagmatic eruption. These can be very explosive. The eruption occurred 953 ka and was sub-Plinian. Caldera del Rey has two shallow tuff rings that are like a figure of 8. The southern ring is 675m in diameter, while the northern ring is 1100m in diameter. Currently, bananas are grown inside the crater.

Above right: In the afternoon of our second touring day we left the island of Tenerife and took the ferry to the island of La Gomera. The view here is the of the arrival port – San Sebastián de La Gomera.

Above left: A huge Basaltic dyke on La Gomera, up to 5m thick and several kilometres long. The dyke contains cooling joints.

Above right: Sue points to a dyke that cuts through beds of baked red scoria and lapilli. These beds were buried under Miocene basalt flows and experienced ‘burial metamorphism’. They make an excellent building stone, and many buildings on La Gomera are built from it.

Day Four: Thursday 22nd February

We had hoped to take a boat trip to see Los Organos on La Gomera’s north-west coast today, but unfortunately we were thwarted by the weather. However, we reverted to our back-up itinerary and visited a number of other stops on the island instead. Our first port of call was the Roque de Agando (pictured below), a striking trachyte dome intrusion which rises 100m above the road, with its south face towering 200m above the valley below. This was a place of worship for the aboriginal Guanch people. Our second stop was another ‘roque’; roques are trachytic or phonolitic domes that didn’t break the surface. We then moved on to view the distinctive ‘La Fortaleza’ (pictured below), which is a is a 4.36 ma trachytic intrusion with an unusual flat top, which may be due to near surface ballooning, but the intrusion lacked the energy to break through to the surface. It is 300m high and is one of the most important archaeological sites on La Gomera, having been used as a refuge for aboriginal people during the Spanish conquest. The next stop was La Laguna Grande where we took a walk in the stunning forest, which is part of the Garajonay National Park, also a World Heritage Site. From here, we travelled on to see cone sheets and a dyke swarm (pictured below) before having a lunch stop in Vallehermoso. After lunch, we visited the Roque Cano, a trachyte intrusion of Pliocene age (~4.5 Ma) which has pronounced columnar jointing, and the Juego de Bolas Visitor Centre. We then had to head to the ferry port to get our late afternoon ferry over to La Palma, our destination for the next four days of the trip.

Top left: Roque Agando is a trachyte dome intrusion, it rises 100m above the road and the south face is 200m above the valley. It was a place of worship for the aboriginal Guanch people, and there was a shrine on the summit which was looted by a film crew in the 1980s.

Top right: La Fortaleza is a 4.36ma trachytic intrusion with an unusual flat top, which may be due to near surface ballooning, but the intrusion lacked the energy to break through to the surface. La Fortaleza is 300m high and is one of the most important archaeological sites on La Gomera. It was the last refuge for aboriginal people during the Spanish conquest.

Middle right: Garajonay National Park was declared a national park in 1981 and a World Heritage Site by UNESCO in 1986. It occupies 40 km2 (15 sq mi). The park provides the best example of Canarian laurisilva, a humid subtropical forest that in the Tertiary covered almost all of Southern Europe. It is also found on the Azores and the Madeira Islands. Laurus azorica, known as Azores laurel, can be found in the park, as well as Laurus novocanariensis, known as Canary laurel.

Bottom right: A dense swarm of inclined parallel felsic (Trachytic) dykes. These dykes are cone sheets of the Vallehermoso volcano. The Vallehermoso stratovolcano grew 7.5-6.5 million years ago, it would have been as high as Teide, but now only its eroded roots remain.

Bottom left: A dyke swarm Parque Maritimo, La Gomera. The intrusive density is very high in this location and the rock mass consists almost exclusively of dykes intruded into sheets or dykes. This dense, intrusive complex marks the heart of the main Miocene shield volcano, which must have once existed above our current position.

Day Five: Friday 23rd February

Today we were joined by Lotte von Lignau of Graja Tours, an excellent local guide who was able to lead us through a landscape completely changed by the 2021 eruption of the Tajogaite volcano. We spent the morning hiking in the area around the Tajogaite volcano and hearing about Lotte’s personal experiences of the eruption. The eruption lasted from 19th September to 13th December 2021, making it the longest recorded eruption in the island’s history at 85 days. Many buildings were destroyed by the lava and infrastructure was severely impacted, as shown in some of our photos below. After our hike we then visited the Caños de Fuego Lava tubes & Visitor Centre, although unfortunately the lava tubes were not fully open on the day of our visit. The lava tubes here are formed within lava flows from the lower vent, Llano del Banco, of the 1949 eruption of the San Juan volcano. This eruption occurred from three vents along a 2km long fissure. The western lava flow reached the coast and constructed a wide coastal lava platform, whereas the eastern lava flow stopped a few hundred metres short of the coast.

Above left: A pristine lunar like landscape which consists of volcanic ash from the 2021 eruption on La Palma.

Above right: Buildings buried by the 2021 lava flows. In this eruption over 3,000 buildings were destroyed.

Above left: Our local guide, Lotte, shows pictures of the 2021 Cumbre Vieja eruption that formed the new cone Tajogaite. She is standing in exactly the same place as where the pictures were taken. The pictures show fire fountains and lava flows, flowing from the craters.

Above right: Our group and the new Tajogaite volcanic cone that was produced in the 2021 eruption.

Above left: The 2021 lava flows cut a pre-existing road. The Tajogaite cone is seen in the background.

Above right: The GeoWorld Travel group examine 2021 lava flows, that flowed along the wall of a pre-existing building.

Above left: Some of the GeoWorld Travel group and James inside the lava cave at Caños de Fuego Visitor Centre. This cave is part of a longer lava tube that formed inside the 1949 lava flows.

Top right: The Caños de Fuego Visitor Centre in the foreground. In the background on the hill side the 1949 lava flows can be seen as can the Llano del Banco vent from which they were emitted.

Bottom right: A brand new road that has been built across the 2021 lava flows.

Day Six: Saturday 24th February

Our touring day started at the St Martin lava flow, towards the south of the island, where several massive lava beds are separated by top and bottom breccias, suggesting that a stack of individual ‘tongues’ make us this lava deposit. Following this, we headed to the San Antonio Visitor Centre to learn about this volcano. It actually formed more than 3,000 years ago, although it is commonly believed that it formed in 1677. In fact, the 1677 eruption had 2 vents, one at the top of the prehistoric cone and the other at its base, and these covered the pre-existing cone with younger material. Our next stops took us to the southern tip of La Palma, where we visited the Teneguia lava flow and the Fuencaliente lighthouse. At both locations, we were able to get a close-up view of the 1971 Teneguia eruption lavas. Prior to the 2021 Tajogaite eruption, these were the youngest lavas on La Palma. Moving up the west coast of the island, we saw the Caldereta del las Indias, a small cinder cone likely to be related to the San Antonio phreatomagmatic eruption, and evidence of the El Charco Volcano eruption of 1712. We then headed to Jedey, with many more examples of earlier lava flows visible from our vehicle window, and then on to Mirador de Las Hoyas. At the mirador, we got a good view of the coastal platforms formed by lava flows; here we could see 2021 and 1949 lava flows and, further down the coast, lava platforms from the 1585 and 1712 eruptions. The penultimate stop of the day was at El Remo, where a deep flow channel, some 50m wide, bounded by enormous levees, 10m high, could be seen (pictured below). To round the day off, we stopped at the stunning Mirador de La Concepción and enjoyed the views of La Caldereta. La Caldereta is one of the largest tuff cones in the Canary Islands, with a base measuring approximately 1.5km and a crater diameter of 1km. It is composed of highly compacted yellow (palagonitic) tuffs.

Above left: Sue and Charlotte at the San Antonio volcano. Contrary to popular belief, the San Antonio Volcano didn’t form in 1677. It formed more than 3,000 years ago, in a phreatomagmatic eruption. In 1677 a far smaller eruption occurred at the same site.

Top right: The Tenequia cone and the 1971 lava flows that flowed from it.

Bottom right: Sue, Ellen and our coach driver examining pumice embedded in lava at the La Caldereta de Las Indias.

Above left: A partially buried house in the 2021 lava flows.

Above right: Partially buried house in the 2021 lava flows.

Top left: The end of the road. Some of the GeoWorld Travel group view the 2021 lava flows that buried the pre-existing roads and buildings.

Top right: Mirador de Las Hoyas. At this stop, the 2021 and 1949 lava flows can be seen forming new land as coastal platforms. The 1949 lava platforms are covered in banana plantations. It would naturally take 900-1,200 years for the lava to break down into soil in warm moist conditions. Therefore, the spoil for the banana plantations has artificially been brought in from elsewhere.

Middle right: The GeoWorld Travel group examine lava flows from the 1712 eruptions. At this site the lava flow has very large levees.

Bottom: La Caldereta is one of the largest tuff (volcanic ash) cones in the Canary Islands. In the background is the town of Santa Cruz de La Palma.

Day Seven: Sunday 25th February

We started our third day on La Palma with a visit to the Taburiente Caldera Visitor Centre, which gave us a great overview of the geology, geomorphology, plant life and wildlife of the caldera. Once we had enjoyed the displays and the informational video at the visitor centre, we headed to our first field stop of the day, at Mirador de la Cumbrecita. From here, we had a very good view of the Bejenado volcano, which formed on the floor of a collapse basin, which itself had been created when a landslip removed part of the Taburiente volcano. It was here, at the Caldera de Taburiente, that Leopold van Buch first coined the term ‘caldera’ during his visit to La Palma in 1815. This was his prototype of an elevation crater. After a hike at Mirador de la Cumbrecita, we headed to Barranco de las Angustias. Having enjoyed a picnic lunch, we then set off on another hike, this time along the barranco to study the growth of an underwater volcano. The Barranco de las Angustias offers an extraordinary opportunity to do this, as the submarine volcano has been uplifted by intrusive growth to 1,500m above sea level and tilts 50° to the southeast (toward the mouth of the caldera), meaning that the route toward the interior of the caldera brings us deeper and deeper into the submarine volcanic edifice. The route through the caldera runs through breccias and shallow submarine lavas, with traces of oceanic sediments, including warm-water fauna in the form of coral and foraminifera-bearing hyaloclastites that are interlayered with pillow lavas. Further on there are more shallow pillow lavas and then, progressing into the caldera, there is an increase in dykes and hydrothermal metamorphism. After our hikes, we returned to our La Palma hotel for our final night on the island.

Above left: A cliff that is a huge fault scarp, it formed in a massive landslip when part of the Taburiente volcano broke off and slid into the sea forming a huge tsunami.

Top right: The view looking south from the Mirador de la Cumbrecita. On the left of the fault scarp of the massive landslip, on the right is the younger Bejenado volcano which grew after the slip. In the background the sea of clouds can be seen.

Bottom right: Sarah with two different generations of dykes cutting through submarine breccia. This breccia formed when the seamount was emerging, and the water was too shallow to form pillow basalts.

Above left: Our group in front of an outcrop of pillow basalts. These pillows formed on the summit of the seamount that later grew to become the island of La Palma.

Top right: Charley with an outcrop of pillow basalts. These pillows formed on the summit of the seamount that later grew to become the island of La Palma.

Bottom right: Marcus, Charley and Nathaniel in the Barranco de Las Angustias in the base of the Taburiente Caldera on La Palma. Inside this Barranco submarine rocks of the seamount are seen.

Day Eight: Monday 26th February

Our final day on La Palma and our final full touring day arrived and we started by heading into the eruptive centres of the Taburiente volcano. Near the summit of the Taburiente volcano, we were able to view black and red scoria overlain by lavas, pictured below. There was also a good view of the submarine volcano basement, the Bejenado volcano and the 2021 Tajogaite volcano. Our next stop was the Roque de los Muchachos, although en route, we drove past the Tamagantera section, where a plateau of horizontal lava could be seen. On arriving at the Roque de los Muchachos, we got a great view from the caldera rim into the depths of the caldera and we were also able to see Teide in the far distance. The lavas and scoria deposits of the caldera wall here are cut by numerous dykes of variable orientation. We were also lucky enough to witness the meteorological phenomenon of a ‘cloud waterfall’, where the colder, denser air on top of the summit rim cascades like a waterfall down the slope due to gravity and cold air sinking (pictured below). Our final stop of the tour was the Roque de los Muchachos Visitor Centre, a fascinating place focussing on the astronomical research carried out on the rim of the Taburiente crater and demonstrating the importance of astronomy on the island of La Palma. The year-round, dark, clear skies here make La Palma arguably one of the best places in the world for astronomical observation. After finishing the tour on a high note, we made our way back to the ferry port in Santa Cruz de la Palma for our late afternoon ferry back to Tenerife, where we spent the final night of the tour.

Above left: Here, near the summit of the Taburiente volcano, black and red scoria is overlain by lavas. Scoria changes from black to red when heat causes oxidation. This suggests the scoria were deposited very close to a vent or eruptive centre.

Above right: The new Tajogaite cone that formed in the 2021 Cumbre Vieja eruption viewed from the summit rim of the Taburiente caldera.

Above left: A cloud waterfall seen from the summit rim of the Taburiente caldera.

Above right: Mt Teide on Tenerife viewed from the Roque de los Muchachos (2,423m) the highest point on the island of La Palma.

Above left: The Roque de los Muchachos. At 2,423m high, this is the highest point on the island of La Palma.

Top right: Sue, Nathaniel and Charley at the Roque de los Muchachos (2,423m) the highest point on the island of La Palma.

Bottom right: Our group being given a guided tour in the Roque de los Muchachos Visitor Centre, here we learnt all about La Palma’s telescopes and observatory.

Day Nine: Tuesday 27th February

Having enjoyed a varied and exciting seven days of touring, it was time to say goodbye! The group dispersed this morning, with many people travelling home, but others taking the opportunity to stay on for a couple of days to enjoy the Canarian sunshine! Another great trip with great company! A big thank you to all the participants for making it such an enjoyable trip, a special thank you to Lotte von Lignau for her invaluable help with the logistics and huge kudos to the local drivers who negotiated the narrow Canarian roads so effortlessly in their coaches – amazing!

This trip will be running again in the future, so if you are interested in joining us, please check out this page for details of upcoming dates and prices: https://www.geoworldtravel.com/Canary-Islands.php

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