Photos
Our trusty, reliable, first stop (Granadilla ignimbrite at Los Blanquitos) has, sadly, been built on - 2 years ago we found it a building site but Alejandro wheedled our way in; now there is a high wall and solid gates across. This is a great shame as it very clearly showed a fall deposit of angular pumice clasts topped off with a flow of ash, pumice and lithics with fine cross stratified ash at the base. The scouts had been out though and we had two alternatives: one that Alejandro had found for us, and one we had reccied last year. Both good sites, with parking, but the second fitted into the itinerary a tad better this time round and we were pleased with it. Probably try Ale's next time round though. The stop was actually better than the old one as it extended the length of a road cutting, both sides of the road, and included a good channel eroded in the fall deposit by the later flow.
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| Granadilla Formation |
We went on from here to a stop where the old main road crosses the Barranco del Azucar south of Arico: here the Arico ignimbrite is handily exposed on the abandoned section of road where it crosses the ravine. This is a spectacular rock with a welded mid section and massive vertical jointing. There are obsidian and pumice fiamme and with a bit of searching Eileen was the first to find a vivid blue crystal of nosean - a feldspathoid that indicated this is an alkaline igneous rock.
On down the old road from Arico Viejo towards Poris we walked down a side lane past an exposure of the Wavy Bed and ate our lunch while thought about it, then walked back up and got it sorted! There are some enormous solar arrays down this road now - making the most of the sunshine in this sunny corner of the island. Just where the road goes under the autopista is a quarry where the La Caleta ignimbrite is exposed, and a nice band of accretionary lapilli conveniently accessible so we stopped for a quick look at that before going on through Poris and back up the hill a mile or so towards Arico Viejo where there is a really large quarry with excellent sections through a number of different ignimbrites and palaeosoils and a lava flow at the base (and, guess what, that ubuquitous Wavy Bed part way up the side!). This year I tried it as a 'matching exercise' with photos of the exposures on the ramp and in the quarry itself, labelled up with the relevant formations and this works really well: better than trying to sort it out from scratch. We began going here 5-6 years ago now after the car parking area at the quarry by Tajao PIRS was barred off.
Back down through Poris again and onto the autopista for a last stop at La Caleta just south of S Miguel de Tajao where there are soem very photogenic cliffs of pale buff ignimbrite topped off with a much more lithic rich ignimbrite which has sagged down into the underlying bed in metre scale load structures. There's a good exposure by the steps to the beach where you can identify the different lithic clasts and then the fun of finding your very own piece of syenite on the beach itself. Some guys tried to persuade us that the next beach was better but we reckoned it was just because they wanted that one to themselves!
Tomorrow an early start to get parked in Masca before the tourists arrive
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