The Islander is a yacht size catamaran outfitted with 24 guest cabins. This trip has 33 guest aboard. Paula and I were fortunate and have one of the two staterooms overlooking the bow. We have a large cabin with windows wrapping around two sides.
We left the harbor and sailed for Cerros Brujo. On the way we sailed past a magnificent tuff cone called Kicker Rock.
The entire time we were accompanied by dozens of frigate birds surfing along the ship and diving for fish in the wake.
We put into Cerros Brujo by zodiac along another tuff escarpment. The cliffs are riddled with caves
and blue footed boobies dive vertically from the cliffs into the water. None of the animals; birds or mammals showed any fear but, for the most part, ignored us like this brown pelican.
We made a wet landing on a green, olivine beach among a number of slumbering sea lions. A few of the mammals barked and snorted but, for the most part, ignored us completely.
Small yellow warblers and Darwin finches flitted about everywhere and would walk up so close it was difficult to photograph them.
The geology of the islands is fascinating and plays an important role in the unique nature of the islands. For anyone interested, I will insert a short description at the end of this blog on the geology of the Islands.
Galapagos Geology
"I scarcely hesitate to affirm, that there must be in the whole archipelago at least two thousand craters ...Nothing could be less inviting than the first appearance. (Darwin 1845)
The Galapagos Islands are volcanic but, unlike 99% of the world's volcanoes, the Galapagos are not associated with tectonic plate margins. The Galapagos Islands are believed to be associated with a hot spot, a place where the Earth's crust is being melted from below by a mantle plume. This is the same process believed to have formed the Hawaiian Islands. As the Nazca Plate drifts west, new volcanoes are formed over the hot spot resulting in a chain of islands with the oldest, Espanola, in the southeast with rocks above sea level aged at three and one quarter million years. The youngest island, Fernandina in the west, is still being formed and is less than seven hundred thousands years old. The most recent eruption on Fernandina was in April 2009.
The islands sit atop the Galapagos Platform; a huge underwater plateau that rises up from ten thousand feet of water to less than one thousand feet in just a few miles. The platform stretches for more than 300 miles east to west and less than 150 miles north to south. The extent of the platform is easily seen using Google Earth.
Each major island consists of a single shield volcano with the exeption of Isabella which is formed from six volcanoes that have joined above sea level.
The magma, as in Hawaii, is basaltic. Basaltic lavas have a lower water content and flow more easily than silica-rich lavas. This means, for the most part, that the gas can escape from the more liquid basaltic lava and not result in explosive eruptions. This results in smooth, shield shaped volcanoes. The other type, andesitic lavas, are less fluid and result in explosive eruptions such as Mount Saint Helens, Mount Fuji, and Volcan Cotopaxi. Andesitic lava is associated with geologic activity at plate subduction zones.
While volcanoes dominate the landscape, layers of shell bearing rocks have been found at elevations greater than three hundred feet. It is believed these were uplifted. In 1954 part of Urbina Bay, Isabella Island was raised twelve feet so quickly it stranded marine life including turtles, fish, and lobsters. In 1975 another, smaller, uplift occurred between Isabella and Ferdnandina resulting in the kill- off of mangroves and barnacles.
For those of you that suffered through my geology lesson, here is a picture of the Islander taken from Cerros Brujos with Kicker Rock in the back ground.
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Location:Cerros Brujos
Fascinating!
ReplyDeleteThanks for the wonderful descriptions and pictures.
Love you,
Debbie