There are interesting pinnacles of lithic breccia on the bottom of the Las Cañadas caldera which is surrounding Mount Teide — the highest peak of Tenerife. They are known as Roques de Garcia. This formation involves more than just breccia. There are also dikes, necks, lava flows and other interesting phenomena. By far the most famous of these formations is The Cinchado which is considered by some to be the most photographed rock. I plan to write a longer post with pictures of these beautiful landforms. Today I am showing just one pinnacle as an appetizer. Here is the longer post: Roques de Garcia.

Here it is. A pinnacle of lithic breccia on top of the caldera floor some 2100 meters above sea level. I don’t know how high it is but to give you a scale I would guess that perhaps 30 meters or so.

It is not fully understood whether this material represents volcanic debris avalanche deposit or is it even laharic in origin. It is generally believed that the former is more likely because the matrix is not muddy enough for it to be lahar and volcanic debris avalanches are quite common in the Canaries. The Las Cañadas caldera itself is a result of a lateral flank collapse of the Las Cañadas volcano which most likely was higher structure than the edifice of Mount Teide is today. These pinnacles are the remnants of the collapse of the Las Cañadas volcano. Pahoehoe-like lava in the foreground has a composition of trachybasalt¹.

References

1. Gill, Robin & Thirlwall, Matthew (2012). Tenerife Canary Islands: Geologists’ Association Guide: No.49. The Geologists’ Association.