Monday we visited Bartolome
Island and Sullivan
Bay on Santiago. These two islands show how barren
and desolate the islands can be before they are colonised. The Galapagos Islands are a series of nineteen large islands,
nearly fifty small islands, and many submerged sea mounts. Each formed in a
conveyor-belt fashion by the Pacific plate slowly moving over the Galapagos hot
spot. This hot upwelling of mantle is now directly underneath Fernandina Island
at the western edge of the Galapagos islands,
with smaller older islands carried to the east by tectonic shift, and the
oldest islands now submerged as sea mounts to the far east.
Bartolome Island was still
at the desolation stage.
It was barren and rocky, with only a few pioneer
plants (the ones able to live on rock and slowly turn it into soil) and lava
lizards living on the island. We were still able to see the lava flows, lava
tubes, tuff cones and splatter cones from the island’s birth. The most surreal
vision from seeing these same volcanic swirls and loops from underneath the water,
with white-tipped reef sharks, sea lions and manta rays gliding over shiny
Pottering around in the bay on the boat we
were able to watch storm petrels hopping on the surface of the water, red
swallow tails flying above us, and a solitary Galapagos Penguin sitting on the
After lunch we landed in Sullivan Bay
This shelf of the island was only born 120 years ago from a fresh lava flow, so
we were able to walk over the tinny metallic surfaces and see the pahoehoe
(ropelike formations from rapidly cooled lava) and aa (rough and ragged
formations formed as gas bubbled out of the lave during cooling) lava flows.
The plain was cracked and buckled due to the expansion of the rock after
cooling, and the high iron and magnesium content of the basalt made it feel
like we were walking on an alien planet made from contorted steel. Even this
metallic bed was not sterile though, with lichens and lava cactus growing in
isolated spots and starting the process of breaking the rock down into soil.