The Galapagos are small volcanic islands about 600 miles off the South American coast, almost due west of Ecuador. They were formed, and are still forming, from an active hot-spot area on the edge of a tectonic plate moving to the southeast. Thus the oldest islands are in the east and the newer ones in the west. The eastern islands are worn and low where the western islands are still geologically raw and much more elevated. The islands are mostly lava or tuff; both of these materials are products of volcanic activity. The whole area is a national park and access is restricted. Even Ecuadorian residents can’t have boats and cruise around the islands. There are some local fishing permits allowed and used, but commercial fishing is kept outside the boundaries of the concurrent National Marine Sanctuary that surrounds the islands. It is not a recreational site.
You arrive in the Galapagos by airplane and then travel by boat. There are many tourism boats in the islands and arrangements should be made well ahead of a visit. There are boats that sleep 10-20 and then a few larger boats that sleep as many as 90 people. The larger boats are faster and can reach the western islands and those smaller islands that are open to visitation in the north. The smaller boats can get into shallower bays and inlets but the bigger boats offer much broader coverage. The Ecuadorian government regulates the routes the boats follow. There are outings of varying lengths and the routes for each outing is predetermined by the NP people. It is wise to look into your desires and then choose an outing that gets you to the places you most want to visit. Not every outing will see all the highlight creatures or habitats that are the Galapagos.
Much of the area is coast, as you might guess, and landing is both restricted and often difficult. In many cases the lava dives into the ocean. In other spots it is a layering of volcanic ash that forms the land. In a few spots the ocean has deposited broken shell, urchin bits, and fish-chewed coral on to what might pass for a sandy beach. These “sandy” bits are where the Marine Iguanas deposit their eggs; it is valuable and delicate turf. The animals above are Sally Lightfoot Crabs. The male has his back to us and the female, a bit more colorful, is facing him. They are on lava that is covered by high tide.
Like the animals of these far flung young islands, the vegetation has arrived from elsewhere. Insects and birds can fly or drift but most plants, or their seeds, cannot. However the birds often carry seeds in their feathers or on their feet or inside themselves as food stuff. These seeds then find themselves deposited either in the ocean (a dead end) or (the lucky ones I suppose) on land some distance from where they started. Over time the plants have adapted to the various islands. The Opuntia cactus (above) and the Scalesia (a daisy turned into a tree) have developed many forms (species, types, populations) in the isolation of this archipelago
The lava is both aa and pahoehoe. The aa lava is chunked and angular where the pahoehoe lava is either ropey or smooth. Both occur in the Galapagos. The lava is not suitable for most plants but it is there on barren lava that the Lava Cactus seems to do quite well. The scientific name, genus name actually, for this cactus refers to its being short and candle-like; Brachycereus (nesioticus).
In many places it is ash or layered tuff that forms the light layered rock. Ash is the name for stuff blown out of a volcano, but it is not light and fluffy like wood ash. It is often hard and crystalline. Volcanic ash is like sandpaper grit. It will pile up and compress into a rocky sort of sedimentary layer. Over time the layers build up and, as here in the Galapagos, form the basis for much of the island geology. In the image above there are a few small Marine Iguanas on the rock catching the warming sunshine.,
In the western islands there are some impressive layers, and layering, of tuff. They speak to older volcanic bursts and give us a clue as to the comings and goings of marine islands. The islands form as tuff, ash, or lava accumulates. And they erode into the sea as waves and gravity take their toll. Unto everything there is a season; and the earth itself adheres to that adage.