La Palma is geologically young (less than 2 Ma¹) and noticeably three-dimendsional island in the Canary archipelago. La Palma is 2426 meters high (Roque de los Muchachos) although the total area of the island is only 706 km². Numbers like that are hard to visualize. Since most of the readers of this blog are from the US, I will give you the following example: imagine an island which is only one fifth of the size of Long Island but has highest point that is more than six times higher than the highest skyscrapers in New York.

The land area is surely going to change in the future because La Palma is volcanically active. There were several eruptions during the 20th century. Last one so far took place in 1971. Some islands in the Canary archipelago have a desert climate (Lanzarote and Fuerteventura which are located close to the African continent). Islands in the middle (Tenerife, Gran Canaria) are moderately dry and La Palma is the rainiest. No wonder that most inhabitants live in the middle islands and tourists also prefer to go to Tenerife and Gran Canaria.

Tourism infrastructure is weakly developed in La Palma. This island seems to be mostly visited by people who like scenery, mountain trekking, beautiful nature, and perhaps geology as well. La Palma is known as Isla Bonita (beautiful island) and in my opinion it deserves that name.

Here is my selection of some memorable scenes. This is how I remember La Palma.

Barranco de las Augustias is a deep ravine connecting Caldera de Taburiente with the ocean. River running on the bottom of the barranco is the only perennial river in the Canaries. While I hiked in the caldera I had to cross it on foot because there is no bridge, just a flooded road. It was not too dangerous, though. Water was about 40 cm deep. Here I am standing on a rock in the river. I was first looking for a place to cross the river with dry feet. I even found one place where I only needed to jump little more than two meters but it seemed too dangerous to attempt such a foolish jump on slippery rocks. So I just did it like in good old times during my military service when we just crossed rivers straight without hesitation and time wasting. It takes about 7-10 km of walking until boots are dry again. Unfortunately, I had to cross the same damn river again when I came back.

Coastline of La Palma is usually rocky and lots of it is inaccessible because of high cliffs. Here is the best swimming beach (Puerto Naos) on the island. Sand on La Palma is universally black.

Artificial salt pans near the southern tip of La Palma. This beautiful coloration is due to extremophile microorganisms (alga Dunaliella salina) that can tolerate very high salinity. They are photosynthesizing organisms that produce bright-colored pigment carotenoid that also gives bright coloration to shrimps who feed on algae and also to many birds who feed on shrimps.

Lots of lower areas near the coast are occupied by huge banana plantations.

Bananas grown in the Canaries seem to be smaller than those I am more familiar with in grocery stores.

Canaries have their very own native date palms (Phoenix canariensis) but their small fruits are not worth eating.

There are many fresh-looking lava flows on La Palma. Here is an edge of aa lava flow. Lava flows on La Palma are almost universally of this type although most of them are composed of smaller clinkery chunks of solidified lava.

Higher parts of the island were surrounded by clouds.

Cross-section of a lava flow. Aa lava has crumbly upper and massive lower part. There are two flows on the picture.

Waves on the western coast. It is a fine place for swimming but getting in may be somewhat difficult.

I saw a fair number of rainbows there. They occur often because La Palma has lots of sunshine and frequent light rain showers in winter. This particular rainbow was very intense and it formed a complete bow. For me it is unusual to see a rainbow in front of mountains. Usually it seems to be behind physical objects.

There were lots of porphyritic rocks. Here is basanitic rock with pyroxene (black) and weathered olivine (yellow) phenocrysts.

Volcanism on La Palma is alkaline in character. It means that magma is often enriched in potassium and sodium. As a result of this, rocks like phonolite occur on La Palma. Phonolite is not flowing as easily as basaltic lava does. It tends to form lava domes instead. Here is a green phonolitic lava dome formed in 1585.

Aa lava near the southern tip of La Palma. This lava flow formed in 1971.

Fault scarp that most likely formed in 1585. Had this fault movement resulted in a collapse of a part of the volcano, violent pyroclastic flows could have been triggered.

Most lava flows on La Palma are crumbly aa lavas but not always. Here is a beautiful example of smooth pahoehoe.

Volcanoes on La Palma produce lots of pyroclasts which are almost always lapilli in size (2…64 mm). Here is a field of lapilli more than a kilometer above sea level.

Older flanks are deeply dissected by ravines which are locally known as barrancos. Here is a relatively small barranco on the northwestern part of the island. Southern part of the island is geologically so young that no deep barrancos have had time to cut themselves deeply into the rocks. Northern part of the island is green and wet because of trade winds that blow from northeast.

Poinsettia is a pretty common plant on La Palma.

Fresh aa lava flow in the foreground. Behind that is a phonolitic Bejenado volcano (green mountain) and between Bejenado and the aa lava flow is Valle de Aridane (one of the most populous regions of La Palma). This is a valley that formed when the southern part of the Taburiente volcano collapsed into the sea (the rim of the Taburiente is visible behind Bejenado). Bejenado volcano formed after the collapse of Taburiente. Between Bejenado and Taburiente volcanoes is Caldera de Taburiente after which all calderas got their name.

Bejenado volcano looks green because it is covered with pine forest. These are native pines of the Canaries (Pinus canariensis).

An outcrop of pillow lava. These rocks formed when La Palma was only a seamount. They crop out because of Caldera de Taburiente — two kilometer deep erosional scar in the middle of the island and they are uplifted as well.

Aa lava flows occur in many parts of the island.

Basaltic rocks on the southern coast.

Lapilli tuff near the eastern coast. Lapilli tuff is a lithified mixture of fine-grained volcanic ash and coarse lapilli.

References

1. Hoernle, Kaj & Carracedo, Juan-Carlos (2009). Canary Islands, Geology. In: Encyclopedia of Islands (Encyclopedias of the Natural World) (Ed. Gillespie, Rosemary G. & Clague, David A.). University of California Press. 133-143.