Galápagos Islands

The Galápagos Islands are an archipelago of volcanic islands in the Eastern Pacific, located around the equator, west of the mainland of South America. They form the Galápagos Province of the Republic of Ecuador, with a population of slightly over 33,000. The province is divided into the cantons of San Cristóbal, Santa Cruz, and Isabela, the three most populated islands in the chain. The Galápagos are famous for their large number of endemic species, which were studied by Charles Darwin in the 1830s and inspired his theory of evolution by means of natural selection. All of these islands are protected as part of Ecuador's Galápagos National Park and Marine Reserve.
There is no firm evidence that Polynesians or the Indigenous peoples of South America reached the islands before their accidental discovery by Bishop Tomás de Berlanga in 1535. If some visitors did arrive, poor access to fresh water on the islands seems to have limited settlement. The Spanish Empire similarly ignored the islands, although during the Golden Age of Piracy various pirates used the Galápagos as a base for raiding Spanish shipping along the Peruvian coast. The goats and black and brown rats introduced during this period greatly damaged the existing ecosystems of several islands. British sailors were chiefly responsible for exploring and mapping the area. Darwin's voyage on HMS Beagle was part of an extensive British survey of the coasts of South America. Ecuador, which won its independence from Spain in 1822 and left Gran Colombia in 1830, formally occupied and claimed the islands on 12 February 1832 while the voyage was ongoing. José de Villamil, the founder of the Ecuadorian Navy, led the push to colonize and settle the islands, gradually supplanting the English names of the major islands with Spanish ones. The United States built the islands' first airport as a base to protect the western approaches of the Panama Canal in the 1930s. After World War II, its facilities were transferred to Ecuador. With the growing importance of ecotourism to the local economy, the airport modernized in the 2010s, using recycled materials for any expansion and shifting entirely to renewable energy sources to handle its roughly 300,000 visitors each year.

Names

The Galápagos or Galapagos Islands are named for their giant tortoises, which were more plentiful at the time of their discovery. The Spanish word derives from a pre-Roman Iberian word meaning "turtle", the meaning it still has in most dialects. Within Ecuadorian Spanish, however, it is now also used to describe the islands' large tortoises. It is usually read in British English and in American English. The name is first attested as the Spanish/Latin hybrid Insulae de los Galopegos on the map of the Americas in Abraham Ortelius's Theater of the Lands of the World, first published in 1570.
The islands were also previously known as the Enchanted Isles or Islands from sailors' difficulty with the winds and currents around them; as the Ecuador Archipelago or Archipelago of the Equator following their settlement by Ecuador in 1832; and as the Colon or Columbus Archipelago in 1892 upon the quadricentennial of Columbus's first voyage.
The islands were mapped by the English buccaneer William Ambrosia Cowley in 1684 and by the British captain James Colnett in 1793. The names they chose to honour British kings, nobles, and naval officers of their eras continued to be used for the major islands until recently and are still used for many of the smaller islets. The Spanish names have varied over time, but the current official names have gradually supplanted the English ones for most of the major islands.

Geology

has been continuous on the Galápagos Islands for at least 20 million years, and perhaps even longer. The mantle plume beneath the eastward-moving Nazca plate has given rise to a 3-kilometre-thick platform under the island chain and seamounts. Besides the Galápagos Archipelago, other key tectonic features in the region include the Northern Galápagos volcanic province between the archipelago and the Galápagos Spreading Center to the north at the boundary of the Nazca plate and the Cocos plate. This spreading center truncates into the East Pacific Rise on the west and is bounded by the Cocos Ridge and Carnegie Ridge in the east. Furthermore, the Galápagos Hotspot is at the northern boundary of the Pacific Large Low Shear Velocity Province while the Easter Hotspot is on the southern boundary.
The Galápagos Archipelago is characterized by numerous contemporaneous volcanoes, some with plume magma sources, others from the asthenosphere, possibly due to the young and thin oceanic crust. The GSC caused structural weaknesses in this thin lithosphere leading to eruptions forming the Galápagos Platform. Fernandina and Isabela in particular are aligned along these weaknesses. Lacking a well-defined rift zone, the islands have a high rate of inflation prior to eruption. Sierra Negra on Isabela Island experienced a uplift between 1992 and 1998, most recent eruption in 2005, while Fernandina on Fernandina Island indicated an uplift of, most recent eruption in 2009. Alcedo on Isabela Island had an uplift of greater than 90 cm, most recent eruption in 1993. Additional characteristics of the Galápagos Archipelago are closer volcano spacing, smaller volcano sizes, and larger calderas. For instance, Isabela Island includes six major volcanoes, Ecuador, Wolf, Darwin, Alcedo, Sierra Negra and Cerro Azul, with most recent eruptions ranging from 1813 to 2018. The neighboring islands of Santiago and Fernandina last erupted in 1906 and 2009, respectively. Overall, the nine active volcanoes in the archipelago have erupted 24 times between 1961 and 2011. The shape of these volcanoes is tall and rounded as opposed to wide and smooth in the Hawaiian Islands. The Galápagos's shape is due to the pattern of radial and circumferential fissure, radial on the flanks, but circumferential near the caldera summits. It is the circumferential fissures which give rise to stacks of short lava flows.
The volcanoes at the west end of the archipelago are in general, taller, younger, have well-developed calderas, and are mostly composed of tholeiitic basalt, while those on the east are shorter, older, lack calderas, and have a more diverse composition. The ages of the islands, from west to east are 0.05 Ma for Fernandina, 0.65 Ma for Isabela, 1.10 Ma for Santiago, 1.7 Ma for Santa Cruz, 2.90 Ma for Santa Fe, and 3.2 Ma for San Cristobal. The calderas on Sierra Negra and Alcedo have active fault systems. The Sierra Negra fault is associated with a sill below the caldera. The caldera on Fernandina experienced the largest basaltic volcano collapse in history, with the 1968 phreatomagmatic eruption. Fernandina has also been the most active volcano since 1790, with recent eruptions in 1991, 1995, 2005, and 2009, and the entire surface has been covered in numerous flows since 4.3 Ka. The western volcanoes have numerous tuff cones.

Physical geography

The islands are located in the eastern Pacific Ocean, off the west coast of South America. The majority of islands are also more broadly part of the South Pacific. The closest land mass is that of mainland Ecuador, the country to which they belong, to the east.
The islands are found at the coordinates 1°40'N–1°36'S, 89°16'–92°01'W. Straddling the equator, islands in the chain are located in both the northern and southern hemispheres, with Volcán Wolf and Volcán Ecuador on Isla Isabela being directly on the equator. Española Island, the southernmost islet of the archipelago, and Darwin Island, the northernmost one, are spread out over a distance of. The International Hydrographic Organization considers them wholly within the South Pacific Ocean, however. The Galápagos Archipelago consists of of land spread over of ocean. The largest of the islands, Isabela, measures and makes up close to three-quarters of the total land area of the Galápagos. Volcán Wolf on Isabela is the highest point, with an elevation of above sea level.
The group consists of 18 main islands, 3 smaller islands, and 107 rocks and islets. The islands are located at the Galápagos triple junction. The archipelago is located on the Nazca plate, which is moving east/southeast, diving under the South American plate at a rate of about per year. It is also atop the Galápagos hotspot, a place where the Earth's crust is being melted from below by a mantle plume, creating volcanoes. The first islands formed here at least 8 million and possibly up to 90 million years ago.
While the older islands have disappeared below the sea as they moved away from the mantle plume, the youngest islands, Isabela and Fernandina, are still being formed. In April 2009, lava from the volcanic island Fernandina started flowing both towards the island's shoreline and into the center caldera.
In late June 2018, Sierra Negra, one of five volcanoes on Isabela and one of the most active in the Galapagos archipelago, began erupting for the first time since 2005. Lava flows made their way to the coastline, prompting the evacuation of about fifty nearby residents and restricting tourist access.

Main islands

The 18 main islands of the archipelago shown alphabetically:
File:Alvaro Sevilla Design Isla Santa Cruz Galapagos foto tomada desde el avión.jpg|thumb|right|250px|From an aircraft flying out of Baltra Island and the Santa Cruz, the Itabaca Channel is the waterway between the islands.

Baltra Island – Baltra is a small flat island located near the centre of the Galápagos. It was created by geological uplift. The island is very arid, and vegetation consists of salt bushes, prickly pear cacti and palo santo trees. Until 1986, Seymour Airport was the only airport serving the Galápagos. Now there are two airports which receive flights from the continent; the other is located on San Cristóbal Island. Private planes flying to Galápagos must fly to Baltra, as it is the only airport with facilities for private planes. On arriving in Baltra, all visitors are immediately transported by bus to one of two docks. The first dock is located in a small bay, where the boats cruising Galápagos await passengers. The second is a ferry dock, which connects Baltra to the island of Santa Cruz. During the 1940s, scientists decided to move 70 of Baltra's land iguanas to the neighboring North Seymour Island as part of an experiment. This move proved unexpectedly useful when the native iguanas became extinct on Baltra as a result of the island's military occupation in World War II. During the 1980s, iguanas from North Seymour were brought to the Charles Darwin Research Station as part of a breeding and repopulation project, and in the 1990s, land iguanas were reintroduced to Baltra. As of 1997, scientists counted 97 iguanas living on Baltra, 13 of which had hatched on the islands.
Bartolomé Island – Bartolomé Island is a volcanic islet just off the east coast of Santiago Island in the Galápagos Islands group. It is one of the younger islands in the Galápagos archipelago. This island, and neighbouring Sulivan Bay on Santiago island, are named after lifelong friend of Charles Darwin, Sir Bartholomew James Sulivan, who was a lieutenant aboard HMS Beagle. Today Sulivan Bay is often misspelled Sullivan Bay. This island is one of the few that are home to the Galápagos penguin which is the only wild penguin species to live on the equator. The green turtle is another animal that resides on the island.
Darwin Island – This island is named after Charles Darwin. It has an area of and a maximum altitude of. Here fur seals, frigates, marine iguanas, swallow-tailed gulls, sea lions, whales, marine turtles, and red-footed and Nazca boobies can be seen. The remnants of Darwin's Arch, a natural rock arch which would at one time have been part of this larger structure, are located less than a kilometre from the main Darwin Island, and it was a landmark well known to the island's few visitors. It collapsed in May 2021. The two remaining stumps are now nicknamed the "Pillars of Evolution".
Española Island – Its name was given in honor of Spain. It also is known as Hood, after Viscount Samuel Hood. It has an area of and a maximum altitude of. Española is the oldest island at around 3.5 million years, and the southernmost in the group. Due to its remote location, Española has a large number of endemic species. It has its own species of lava lizard, mockingbird, and Galápagos tortoise. Española's marine iguanas exhibit a distinctive red coloration change between the breeding season. Española is the only place where the waved albatross nests. Some of the birds have attempted to breed on Genovesa Island, but unsuccessfully. Española's steep cliffs serve as the perfect runways for these birds, which take off for their ocean feeding grounds near the mainland of Ecuador and Peru. Española has two visitor sites. Gardner Bay is a swimming and snorkelling site, and offers a great beach. Punta Suarez has migrant, resident, and endemic wildlife, including brightly colored marine iguanas, Española lava lizards, hood mockingbirds, swallow-tailed gulls, blue-footed boobies, Nazca boobies, red-billed tropicbirds, Galápagos hawks, three species of Darwin's finches, and the waved albatross.
Fernandina Island – The name was given in honor of King Ferdinand II of Aragon, who sponsored the voyage of Columbus. Fernandina has an area of and a maximum altitude of. This is the youngest and westernmost island. On 13 May 2005, a new, very eruptive process began on this island, when an ash and water vapor cloud rose to a height of and lava flows descended the slopes of the volcano on the way to the sea. Punta Espinosa is a narrow stretch of land where hundreds of marine iguanas gather, largely on black lava rocks. The famous flightless cormorants inhabit this island, as do Galápagos penguins, pelicans, Galápagos sea lions and Galápagos fur seals. Different types of lava flows can be compared, and the mangrove forests can be observed.
Floreana Island – It was named after Juan José Flores, the first President of Ecuador, during whose administration the government of Ecuador took possession of the archipelago. It is also called Santa Maria, after one of the caravels of Columbus. It has an area of and a maximum elevation of. It is one of the islands with the most interesting human history, and one of the earliest to be inhabited. Flamingos and green sea turtles nest on this island. The patapegada or Galápagos petrel, a sea bird which spends most of its life away from land, is found here. At Post Office Bay, where 19th-century whalers kept a wooden barrel that served as a post office, mail could be picked up and delivered to its destinations, mainly Europe and the United States, by ships on their way home. At the "Devil's Crown", an underwater volcanic cone and coral formations are found.
Genovesa Island – The name is derived from Genoa, Italy, the birthplace of Christopher Columbus. It has an area of and a maximum altitude of. This island is formed by the remaining edge of a large caldera that is submerged. Its nickname of "the bird island" is clearly justified. At Darwin Bay, frigatebirds and swallow-tailed gulls, the only nocturnal species of gull in the world, can be seen. Red-footed boobies, noddy terns, lava gulls, tropic birds, doves, storm petrels and Darwin finches are also in sight. Prince Philip's Steps is a bird-watching plateau with Nazca and red-footed boobies. There is a large Palo Santo forest.

File:PtoVillamilMuro.jpg|thumb|right|250px|The Wall of Tears at Puerto Villamil on Isabela, the largest of the Galapagos

Isabela Island – This island was named in honor of Queen Isabella I of Castile. With an area of, it is the largest island of the Galápagos. Its highest point is Volcán Wolf, with an altitude of. The island's seahorse shape is the product of the merging of six large volcanoes into a single land mass. On this island, Galápagos penguins, flightless cormorants, marine iguanas, pelicans and Sally Lightfoot crabs abound. At the skirts and calderas of the volcanoes of Isabela, land iguanas and Galápagos tortoises can be observed, as well as Darwin finches, Galápagos hawks, Galápagos doves and very interesting lowland vegetation. The third-largest human settlement of the archipelago, Puerto Villamil, is located at the southeastern tip of the island.
Marchena Island – Named after Fray Antonio Marchena, it has an area of and a maximum altitude of. Galapagos hawks and sea lions inhabit this island, and it is home to the Marchena lava lizard, an animal endemic to Marchena.
North Seymour Island – Its name was given after an English nobleman, Lord Hugh Seymour. It has an area of and a maximum altitude of. This island is home to a large population of blue-footed boobies and swallow-tailed gulls. It hosts one of the largest populations of frigate birds. It was formed from geological uplift.
Pinzón Island – Named after the Pinzón brothers, captains of the Pinta and Niña caravels, it has an area of and a maximum altitude of and has no permanent population. Home to giant Galápagos tortoises of the subspecies Chelonoidis duncanensis and Galápagos sea lions, the island has no visitor facilities and a permit is required for legal visits.
Pinta Island – Named after the Pinta caravel, it has an area of and a maximum altitude of. Sea lions, Galápagos hawks, giant tortoises, marine iguanas, and dolphins can be seen here. Pinta Island was home to the last remaining Pinta tortoise, called Lonesome George. He was moved from Pinta Island to the Charles Darwin Research Station on Santa Cruz Island, where scientists attempted to breed from him. However, Lonesome George died in June 2012 without producing any offspring.
Rábida Island – It bears the name of the convent of Rábida, where Columbus left his son during his voyage to the Americas. It has an area of and a maximum altitude of. The high amount of iron contained in the lava at Rábida gives it a distinctive red colour. White-cheeked pintail ducks live in a saltwater lagoon close to the beach, where brown pelicans and boobies have built their nests. Until recently, flamingos were also found in the lagoon, but they have since moved on to other islands, likely due to a lack of food on Rábida. Nine species of finches have been reported in this island.
San Cristóbal Island – It bears the name of the patron saint of seafarers, "St. Christopher". Its English name was given after William Pitt, 1st Earl of Chatham. It has an area of and its highest point rises to. This is the first island in the Galápagos Archipelago Charles Darwin visited during his voyage on the Beagle. This island hosts frigate birds, sea lions, giant tortoises, blue- and red-footed boobies, tropicbirds, marine iguanas, dolphins and swallow-tailed gulls. Its vegetation includes Calandrinia galapagos, Lecocarpus darwinii, and trees such as Lignum vitae. The largest freshwater lake in the archipelago, Laguna El Junco, is located in the highlands of San Cristóbal. The capital of the province of Galápagos is Puerto Baquerizo Moreno, which lies at the southern tip of the island, and is close to San Cristóbal Airport.
Santa Cruz Island – Given the name of the Holy Cross in Spanish. It was originally named Norfolk Island by Cowley, but renamed after the British frigate HMS Indefatigable after her visit there in 1812. It has an area of and a maximum altitude of. Santa Cruz hosts the largest human population in the archipelago, the town of Puerto Ayora. The Charles Darwin Research Station and the headquarters of the Galápagos National Park Service are located here. The GNPS and CDRS operate a tortoise breeding centre here, where young tortoises are hatched, reared, and prepared to be reintroduced to their natural habitat. The Highlands of Santa Cruz offer exuberant flora, and are famous for the lava tunnels. Large tortoise populations are found here. Black Turtle Cove is a site surrounded by mangroves, which sea turtles, rays and small sharks sometimes use as a mating area. Cerro Dragón, known for its flamingo lagoon, is also located here, and along the trail one may see land iguanas foraging.
Santa Fe Island – Named after a city in Spain, it has an area of and a maximum altitude of. Santa Fe hosts a forest of Opuntia cactus, which are the largest of the archipelago, and Palo Santo. Weathered cliffs provide a haven for swallow-tailed gulls, red-billed tropic birds and shearwater petrels. Santa Fe species of land iguanas are often seen, as well as lava lizards.

File:20180808-Galápagos sea lion-2 at Santiago.jpg|thumb|right|250px|A Galápagos fur seal on Santiago Island

Santiago Island – Its name is equivalent to Saint James in English; it is also known as San Salvador, after the first island discovered by Columbus in the Caribbean Sea. This island has an area of and a maximum altitude of. Marine iguanas, sea lions, fur seals, land and sea turtles, flamingos, dolphins and sharks are found here. Pigs and goats, which were introduced by humans to the islands and have caused great harm to the endemic species, have been eradicated. Darwin finches and Galápagos hawks are usually seen, as well as a colony of fur seals. At Sulivan Bay, a recent pahoehoe lava flow can be observed.
Wolf Island – This island was named after the German geologist Theodor Wolf. It has an area of and a maximum altitude of. Here, fur seals, frigatebirds, Nazca and red-footed boobies, marine iguanas, sharks, whales, dolphins and swallow-tailed gulls can be seen. The most famous resident is the vampire finch, which feeds partly on blood pecked from other birds, and is only found on this island.