Darwin Island
Encyclopedia
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
, and is among the smallest in the Galapagos Archipelago
Galápagos Islands
The Galápagos Islands are an archipelago of volcanic islands distributed around the equator in the Pacific Ocean, west of continental Ecuador, of which they are a part.The Galápagos Islands and its surrounding waters form an Ecuadorian province, a national park, and a...
with an area of just one square kilometer. With no dry landing sites, Darwin Island's main attractions are found in the Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
, which is teeming with a spectacular variety of marine life
Marine biology
Marine biology is the scientific study of organisms in the ocean or other marine or brackish bodies of water. Given that in biology many phyla, families and genera have some species that live in the sea and others that live on land, marine biology classifies species based on the environment rather...
. Darwin Island and Wolf Island
Wolf Island
Wolf Island or Wenman Island is a small island in the Galapagos Islands and was named after the German geologist Theodor Wolf, who also has the volcano Wolf on Isabela Island named after him...
sometimes are referred to as Darwin and Wolf or Darwin Wolf.
Although the island had been marked on maps, and initially had been given the name Culpepper Island on Admiralty charts, the first visit onto Darwin Island was not until 1964 using a helicopter.
Geology
Darwin Island is the remains of an extinct volcano that reaches 165 meters above sea level, it is situated north west of the main Galapagos Island group on the Wolf-Darwin Lineament that extends from the Galapagos Platform to the Galapagos Spreading Center, a mid ocean ridge separating the NazcaNazca Plate
]The Nazca Plate, named after the Nazca region of southern Peru, is an oceanic tectonic plate in the eastern Pacific Ocean basin off the west coast of South America. The ongoing subduction along the Peru-Chile Trench of the Nazca Plate under the South American Plate is largely responsible for the...
and Cocos
Cocos Plate
The Cocos Plate is an oceanic tectonic plate beneath the Pacific Ocean off the west coast of Central America, named for Cocos Island, which rides upon it.-Geology:...
tectonic plates. The formation of Darwin Island is different from the formation of the main Galapagos Islands. There are currently two theories on the formation of the lineament: the first is that magma rising from the mantle plume forming the main Galapagos Islands has been channelled towards the Galapagos Spreading Center; alternatively there has been a separate rise in magma caused by stress in the ocean lithosphere by a transform fault.
Darwin Island is the most northerly of the two peaks on the Wolf Darwin Lineament that reach above the surface, the other island Wolf Island
Wolf Island
Wolf Island or Wenman Island is a small island in the Galapagos Islands and was named after the German geologist Theodor Wolf, who also has the volcano Wolf on Isabela Island named after him...
is approximately 40 km away, although there are other sub surface peaks. The volcano that forms the island is extinct, with the last eruption believed to have been approximately 400,000 years ago, making it younger than Wolf. The lava flows around Darwin are homogenous, believed to be because of its young age and have a similar chemical composition to those of the Galapagos Spreading Center.
Darwin is believed to have had at least two eruptive periods in its history of two tuff layers separated by plagioclase
Plagioclase
Plagioclase is an important series of tectosilicate minerals within the feldspar family. Rather than referring to a particular mineral with a specific chemical composition, plagioclase is a solid solution series, more properly known as the plagioclase feldspar series...
ultraphyric basalt
Basalt
Basalt is a common extrusive volcanic rock. It is usually grey to black and fine-grained due to rapid cooling of lava at the surface of a planet. It may be porphyritic containing larger crystals in a fine matrix, or vesicular, or frothy scoria. Unweathered basalt is black or grey...
. Evidence also exists to suggest that Darwin Island is the remains of what was once a much larger edifice. Since the eruptive phase this would have been eroded.
Darwin Arch is a natural rock arch would at one time been part of this larger structure is located less than a kilometre from the main Darwin Island is a well known landmark to the few visitors to the island.
Wildlife
Darwin Island is not open to land visits. As a result the only visitors are those that come to scuba dive, even here due to the distance from the main island only a limited number of liveaboard ships cruise here.The marine life at Darwin is diverse with large schools of fish. The island’s waters attract Whale Shark
Whale shark
The whale shark, Rhincodon typus, is a slow-moving filter feeding shark, the largest extant fish species. The largest confirmed individual had a length of and a weight of more than , but unconfirmed claims report considerably larger whale sharks...
s from June to November, as well Hammerhead
Hammerhead shark
The hammerhead sharks are a group of sharks in the family Sphyrnidae, so named for the unusual and distinctive structure of their heads, which are flattened and laterally extended into a "hammer" shape called a "cephalofoil". Most hammerhead species are placed in the genus Sphyrna while the...
, Galapagos
Galapagos shark
The Galapagos shark is a species of requiem shark, family Carcharhinidae, found worldwide. This species favors clear reef environments around oceanic islands, where it is often the most abundant shark species...
, Silky
Silky shark
The silky shark is a species of requiem shark, family Carcharhinidae, named for the smooth texture of its skin. It is one of the most abundant sharks in the pelagic zone, and can be found around the world in tropical waters. Highly mobile and migratory, this shark is most often found over the edge...
and Blacktip
Blacktip shark
The blacktip shark is a species of requiem shark, family Carcharhinidae. It is common to coastal tropical and subtropical waters around the world, including brackish habitats. Genetic analyses have revealed substantial variation within this species, with populations from the western Atlantic Ocean...
sharks. In addition Green Turtles, Manta ray
Manta ray
The manta ray is the largest species of the rays. The largest known specimen was more than across, with a weight of about . It ranges throughout waters of the world, typically around coral reefs...
s and dolphin
Dolphin
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...
s can be found.
The island also supports a large bird population, including Frigate Birds and Red-footed Booby
Red-footed Booby
The Red-footed Booby, Sula sula, is a large seabird of the booby family, Sulidae. As suggested by the name, adults always have red feet, but the colour of the plumage varies. They are powerful and agile fliers, but they are clumsy in takeoffs and landings...
birds and the Vampire Finch
Vampire Finch
The Vampire Finch is a small bird native to the Galápagos Islands. It is a very distinct subspecies of the Sharp-beaked Ground Finch endemic to Wolf and Darwin Islands....
.