Tenerife December 2009 Day 4
May 25, 2012Public
Photo: The south-facing section at Tajao quarry.
Photo: South-facing section at Tajao quarry.
Photo: Abades Ignimbrite - a deposit from a pyroclastic flow. Clast supported, with lithic fragments up to 10cm long. Friable matrix, grainsize about 1mm and a red, weathered horizon at the top.
Photo: Base of the Granadilla Pumice at Tajao quarry. From the top of the red Abades Ignimbrite, there is a 5cm thick light grey, slightly fused layer with a 1-5 mm grain size and about 5% lithics. Above this, there is a 1cm light yellow, fused, fine-grained layer, with some larger lithics at the top.
Photo: The Granadilla Pumice. In all, around 215 cm of, on average 3cm pumice lapilli, with smaller grey lithic clasts, making up about 5% of the rock. There is very little ash. This is a Plinian air-fall deposit.
Photo: The weathered top of the Abades Ignimbrite and base of the Granadilla Pumice.
Photo: Three layers in the Granadilla Pumice at Tajao Quarry. The total thickness of the pumice layer is about 215cm. We speculated that the red iron-staining above the hammer may be from the location of a tree root - like the ones we saw at Chimiche Quarry.
Photo: Red iron-stained ash towards the top of the Granadilla Pumice. Could this be an infilled hole left from a tree trunk or root?
Photo: The top of the Granadilla Pumice and broken Granadilla Ignimbrite layer. The red, weathered layer seems to extend through the cracks in the ignimbrite layer, to spread out at the top of the pumice.
Photo: The broken fragments of the Granadilla Ignimbrite, which lenses out to the east. This red colouration indicates sub-aerial weathering before the Lower Grey Lithic Ignimbrite was deposited on top.
Photo: The Lower Grey Lithic Ignimbrite would appear to be a block and ash flow, since it contains large lithic clasts, which are matrix-supported in grey, hard ash, with small angular lithic fragments.
Photo: A black pumice clast at the southern end of the west-facing section in the Abades Ignimbrite. It is clearly visible from Google Street View, but by the time we returned in 2010, someone had hacked away about half of it. We concluded that it was black pumice, not scoria, because of the density of the fragments on the floor beneath it.
Photo: Lower Grey Lithic Ignimbrite - a block and ash flow deposit.
Photo: The Lower Grey Lithic Ignimbrite. Red weathered Granadilla Formation, 5 cm, laminated ash layer, 45 cm coarse ignimbrite layer, then a 35 cm layer which fines up to the top.
Photo: An ignimbrite layer, overlying the Lower Grey Lithic Ignimbrite and cut at the top by the Poris Ignimbrite. Probably part of the Fasnia Formation, but not mentioned in the field guide.
Photo: At the bottom of the hammer handle, a 10 cm thick clast-supported pumice-rich ignimbrite, overlain by a 20 cm thick, more lithic-rich (10-15%), well-cemented ignimbrite layer, with black lithics. The hammer head is next to a 5 cm thick pale ash layer with elongated pumice fiamme, above which is a 60 cm thick ignimbrite with 2-3 cm pumice fragments.
Photo: The Poris Ignimbrite, matrix-supported, with a white, fused matrix. The pumice content increases and lithics decrease from the bottom to the top. Approximately 10-15% lithics near the base. The layer is about 130 cm thick here.
Photo: Top of the Poris Ignimbrite, a pumice and ash-rich rock, deposited by a pyroclastic flow.
Photo: Poris Ignimbrite. The hammer head is next to a fine laminated layer, with isolated 1mm matrix-supported lithics. The layer varies from 2-4 cm thick.
Photo: Poris Ignimbrite at Tajao Quarry.