The Galapagos Islands, located about 1000 km off the coast of Ecuador in the Pacific Ocean, are of volcanic origin. Most of the Galapagos Archipelago is located just below the equator. A unique fauna developed on this archipelago.
Location, size, name and origin of the Galapagos Islands
The Galapagos Islands (Fig. 1) are located approx. 1000 km from the coast of Ecuador in the Pacific Ocean. They are located at the equator between 1 ° 40 ‘north and 1 ° 30’ south latitude and 89 ° 15 ‘and 92 ° 05’ west longitude.
This archipelago consists of a large number of islands, 13 larger islands (over 10 km²), 6 smaller islands (1 to 10 km²) and numerous (40 to 50) smallest, often unnamed islets and reefs. The entire land area of the islands covers approx. 7900 km².
The islands were discovered in 1535 by the Bishop of Panama (TOMAS DE BERLANGA), who sailed south along the Peruvian coast and reached the islands due to ocean currents. Legend has it that the Inca TUPAC YUPANQUI is said to have reached “fire-breathing mountains” on a sea voyage.
The name Galapagos Archipelago dates back to 1570. The Flemish cartographer ABRAHAM ORTELIUS named the archipelago after the giant tortoises found there (Spanish: galapagos = German tortoise). In 1892, on the occasion of the 400th birthday of CHRISTOPH KOLUMBUS, the archipelago received the official name “Archipiélago de Colón”. However, this name is rarely used.
The Galapagos Archipelago has been a national park since 1959, and in 1970 it was included in the UNESCO World Heritage List.
The Galapagos Islands are oceanic islands because they were built by volcanism from the sea floor to the sea surface. A combination of two phenomena is the cause of their emergence: the displacement of the continental plates with weak zones at their borders, where volcanoes arise, and the “hot spots”, magma chambers fed from the earth’s interior, which form stationary in the earth’s mantle and discharge when there is excess pressure, whereby volcanoes are also heaped up. The Galapagos Islands are on the border of several plates. These drift predominantly in an easterly direction towards the South American continent (5 cm / year). How to get to the volcanic islands out of the area of influence of the hot spots and sink back into the sea, also under the effect of the surf erosion. Therefore, we find the youngest volcanoes in the west on the islands of Fernandina and Isabela, which are still located directly above the hot spots (Fig. 2). The Galapagos volcanoes belong to the shield volcano type. They were created from individual layers of lava that flowed over each other and in the summit region usually have a caldera (Spanish for “cauldron”), a collapse funnel in the chimney area.
Only a few of the volcanic islands are inhabited, e.g. B. Floreana, Isabela, San Christobal, Santa Cruz.
The islands of the Galapagos Archipelago (selection)
Area 27 km²; Port and airport as starting and ending points for island cruises; Territory of the Ecuadorian military
Area 1.2 km²; untouched volcanic landscape (Fig. 3); Pinnacle Rock (remnant of a tuff cone is the island’s landmark); Bartolomé volcano (114 m); Remains of lava tunnels; Welding slag cone (around the conveyor chimney, huge lava clumps, some 40 m high, are stacked, partially welded together)
Area 60 km²; flat, hardly overgrown lava plateau; near the southern cliff is a “blowhole” (Fig. 4), a crevice through the opening of which the surf water shoots up 20–30 m
Area 643 km²; third largest island of the archipelago, mighty, over 1200 m high stratovolcano with enormous lava flows (block lava and knitted lava); white sandy bays, mangrove vegetation
Area 173 km²; Dry vegetation; some parasitic cones (secondary volcanoes); since 1793 from engl. “Post office” set up for whalers (a wooden barrel, Fig. 5) that was entered on nautical charts
Area 4588 km²; largest island in the archipelago; 5 stratovolcanoes, including the highest point in the archipelago: Wolf (1660 m), Darwin (1330 m), Alcedo (1125 m), Sierra Negra (1490 m), Cerro Azul (over 1000 m); Dry vegetation; inhabited in the south
Area 558 km²; Settlement in the southwest, airport; only island with abundant fresh water resources (crater lake El Junco); The north-east part of the island is dry, the south-west part has a lot of rainfall, lush vegetation with guava monoculture, guava (trees with lemon-like fruits that are processed into fruit juice and jam) displaced the native plants
Area 986 km²; second largest island in the archipelago; Charles Darwin Research Station (since 1964) and National Park Administration (since 1968) in the town of Puerto Ayora (Fig. 6); tourist center; Turtle reserve in the mountains
Area 585 km²; fourth largest island in the archipelago; in the northwest rises the main volcano Cerro Cowan (920 m), which is densely overgrown on its slopes ; there are high tuff cliffs on the west coast; the flat eastern and southern parts of the island are covered with dark knitted lava (Pahoehoelava) (Fig. 7)
The wildlife in the Galapagos Islands is unique. Many of the species found only exist here, they are endemic species. There is a special diversity in the reptiles and birds. Examples of this are the giant tortoises (Fig. 8), marine iguanas, Galapagos penguins and the immobile cormorant.