Day 4 - Casa de los Coroneles and El Cotillo

This was an official day off and a car full of people who hadn't been to Lanzarote before decided to go over for the day on the car ferry.
Our car, plus one, went back up to the north of the island to explore. First off we stopped in La Oliva to see what else was there and found the Casa de los Coroneles - the original 'governor's residence. This has fallen into poor repair over the years but now the main house has been restored although the outbuildings are still in disrepair - hopefully there are plans for those too. There's no admission charge, something that rankles with some of the local people who feel that if tourists paid a small fee more work could be done for the benefit of La Oliva.

Casa de los Coroneles, La Oliva

The house itself is a lovely example of Spanish colonial architecture and when we visited we saw an art exhibition and one of photography as well as a set of exhibits themed around La Olivan life in past years.

Photo exhibition gallery

Patio

Morro Tabaiba

Trousers of ascending shortness

Thinking about lunch we headed over to the coast at El Cotillo where we enjoyed prawns with garlic and a crema catalan before going for a walk to see the castle.

A molino in Lajares

El Cotillo from the castle

 And not a halloween ghoul or ghost in sight!

Day 3 - Cueva de Los Llanos, Bayuyo and Corralejo dunes

We headed north to an area where some of the youngest volcanoes on the island have not only produced a line of scoria cones but also a long lava tube with interesting archaeology and fauna.
The Cueva de los Llanos north of La Oliva was our first 'proper' stop though since it didn't open until 10 we diverted to a cafe in La Oliva first.

La Oliva church plaza

Refreshed we headed back to the cave again where we had a chance to visit the exhibition before our tour. Then, after being fitted out with protective hair covers (much laughter), hard hats and head torches we were guided down through the jameo (skylight) and along some 400 m of one branch of the tube. The cave is important for palaeontology (vertebrate and gastropod fossils) and is unusual in preserving palaeoenvironmental changes well in the infilling sediment. It is also inhabited by an endemic arachnic, Maiorerus Randoi. Recently it was used as an arsenal and graffiti dating from this time decorate the walls at the far end. After we had eaten our lunch Julie the guide - having learned of our geological interests - showed us the palaeontological dig which isn't open to the public

The jameo that gives access to the tube

Maiorerus Randoi

Cute!

In the tube - we were able to see 'tide marks' left by flows moving through

Between here and Corralejo is a line of lava cones, Bayuyo, the highest, in the north. We found our way to a track that runs along the NW side of these and, to our delight, it was a good graded track. We stopped a couple of times to check out the ejecta which included a number of small mantle xenoliths of peridotite. At the second stop we were able to climb up to the lip of the breach.

The line of scoria cones north of Los Llanos

Looking for mantle xenoliths in the scoria

Returning we had good views from Corallejo to Lanzarote and the Isla de Lobos before stopping to check out the carbonate sands that form the extensive dune field to the south.

Isla de Lobos with Lanzarote behind

Corralejo carbonate sand dunes - formed from sand deposited when sea level was higher, and also from sand blown onshore when sea level was lower

Ajui and more of the Vega Ring Complex

Day 2 of the F-island trip we went over to the west coast at Ajui/Puerto de la Pena where, as soon as we got out of the cars we were greeted by the sight of some splendid dykes cutting Mesozoic ocean floor sediments!
A well made path from the northern end of the beach leads up the cliff, past the overlying Pleistocene shallow water sands and marls, onto a ledge which we walked along to Caleta Negra, the next bay north. The sequence in the cliffs on the far side of the bay is stunning: upended Jurassic sediments cut by dykes as before at Ajui, then planed off by an erosion surface and then, above the unconformity, beach/coastal sediments and a lava flow, including a mass of pillow lavas in a channel!

The northern end of Ajui beach - vertical Mesozoic sediments at the bottom, intruded by dykes, then above that are Pleistocene sediments

Close view of the northern end of Ajui beach.

Sediments dipping steeply into the cliff are cut by a mafic dyke and both then cut by a trachyte dyke

Path up Ajui cliff makes it easy to walk upwards through the succession

Shallow water sediments at the top of the cliff

Caleta Negra

The cliff section at Caleta Negra

Originally we'd planned to walk on over the cliffs to the next bay and then up the barranco to investigate some more exposures of ocean crust but with temperatures climbing decided to leave that for another day. Instead we went back through Pajara and turned left to take the top road through the Vega Ring complex, stopping at miradors on the way.

A pebble of pyroxenite from the Tierra Mala instrusion just inland of Ajui, and south of the Vega ring complex

Mal Paso at the southern end of the Barranco below Vega de Rio Palmas: the white spot is the hermitage below the dam. An annular intrusion of syenite forms the hill in the centre and the slopes to the right.

From the mirador above the dam, we are standing on the crest of the syenite ridge looking north to a ridge formed of trachyte

From the second mirador, looking south over the dam between the two syenite hills. The embalse (reservoir) is currently dry and full of fine orange silt.

 Tomorrow - to the north of the island!

The Betancuria Massif

Looking north from Morro de Veloso

We began the day with a trip up to the mirador at Morro de Veloso where we managed to kill 3 birds with one stone - we saw some stupendous views  across much of the island.

Spotting dyke trends along a track

We found evidence of the NNE-SSW trending dyke swarm ...

and we had a coffee!


Then we went on to see more evidence of dykes on the road south of Betancuria where the syenite dykes in a road cutting also contained blobs of darker, more mafic material

Cutting south of Betancuria

Syenite dyke with mafic blebs

.. as well as some stunning Liesegang ring patterns and manganese dendrites!

Liesegang rings and manganese dendrites

Vega de Rio de Palmas

From there we headed down into Vega de Rio de Palma where the track down towards the gorge promised a section through part of the igneous 'ring complex' - the heart of the shield volcano that existed here some 20 Ma ago.
The best was along the first part of the path where there were exposures of a beautiful pale gabbro with clumps of mafic minerals, all crosscut by  at least 2 sets of dykes. Finally the high afternoon temperatures kicked in and we turned back and headed for the pool at Caleta de Fuste!

Gabbro in the Vega ring complex

Mafic and felsic dykes cutting the gabbro

Shade!

Fuerteventura

... otherwise known as the F-island. A group of 12 OUGS 'Shoestringers' is due to arrive on Wednesday for 1-2 weeks DIY exploration of this fascinating island. Well it sounds fascinating anyway!
Unlike the ocean island volcano of Tenerife, with its shield and stratocone volcanoes and recent scoria cone eruptionsm which we know well by now, the F-island has remnants of submarine sediments deposited off the African coast in the Jurassic and Cretaceous as the Atlantic began to split apart. These are mixed in with submarine mid ocean ridge volcanics. Seamount(s) built up and, eventually, broke surface and built up as a shield volcano or three. An erosional phase followed, exposing much of the earlier seamount series including a ring complex of the associated plutonic rocks.
We are going to be based in Caleta de Fuste halfway down the east coast and close to the airport since that is a good jumping off point for both north and south parts of the island.

More when I get back