#VolcanoThursday penitentes near Teide top teleferico station. Tenerife #VolcanoesOnAShoestring #OUGS

Hydrothermally altered Miocene volcanic ashes and breccias on the edge of the Rodalquilar caldera, Las Negras, Almeria, Spain.
#VolcanoThursday #OUGS #VolcanoesOnAShoestring

#VolcanoThursday Volcàn de Bayuyo, Fuerteventura, a monogenetic cone that erupted some 10 000 years ago. #OUGS #VolcanoesOnAShoestring 2010s

#MountainMonday Tindaya, Fuerteventura, is a Majo sacred site and, unusually on the island, a trachyte volcanic plug which stand out from the surrounding basalt hills because of its pale colour. #VolcanoesOnAShoestring 2010s

Just noticed that today is the proposed International Volcano Day: enjoy Montaña Negrita bends/Curvas del Pastel/La Tarta, interbedded mafic scoria and phonolitic tephra from separate sourdes, Tenerife's Dorsal Ridge.
Visited every OUGS #VolcanoesOnAShoestring trip
Do you have a favourite volcano?

#VolcanoThursday the eroded remnants of Fuerteventura's southern shield volcano, in Spain's Canary Islands. Talus cones around the base are coated with sand and dust from the Sahara Desert blown across to the islands by the easterly "calima" wind. #OUGS #VolcanoesOnAShoestring

#mineralisation to brighten up a Monday morning. At the southern end of the Roques de Garcia (Tenerife) my #VolcanoesOnAShoestring group walking up from the Ucanca caldera to Los Azulejos. Stunning green-blue and cream coloured alteration to clay minerals

The syenite texture with those randomly orientated, thin laths of feldspar reminds me of syenite I've seen on Tenerife and Fuerteventura. #OUGS #VolcanoesOnAShoestring 1990s/2000s/2010s

#VolcanoThursday The most recent eruption on Tenerife: the monogenetic scoria cone of Mta Chinyero (1909). There's been seismic activity on that ridge since, but no more eruptions. #VolcanoesOnAShoestring #OUGS

Not exactly #urbangeology as some is rural! But it is building stone...
On #OUGS Tenerife trips #VolcanoesOnAShoestring looked at building stone use as a sideline. Here's some ignimbrite, unwelded (L) and welded, uncommon on the island (R). See ALT text for more detail.
More to follow ...