History
Birth of Chichijima, Mukojima, Hahajima, and Kazan Island Groups (source: “Japan’s On-Going Nature Conservation Efforts On the Ogasawara Islands”)
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The Ogasawara Islands are crucial to advancing our understanding of the history of the Earth’s evolution as the processes of island birth and growth can visibly be seen aboveground through rare types of rocks that are usually hidden at the bottom of the ocean.
Around 48 million years ago, the Pacific Plate began to subduct under the Philippine Sea Plate, causing volcanic eruptions to create the Chichijima and Mukojima Island groups. The cooled and solidified magma created boninite rocks, which contain rare minerals that are found in meteorites. As the Pacific Plate continued to subduct, the temperature decreased and the area where the magma was erupting was deeper and moved to the west. This created the Hahajima Island Group around 44 million years ago. The Pacific Plate has continued to subduct in the present day and has moved even further west creating the Kazan Island Group, with active volcanoes. The Ogasawara Islands are believed to have been discovered by a man named Sadaoyri Ogasawara in 1593, although there is limited evidence that supports this claim. However, the islands were uninhabited until 1830, causing it to be named the “Bonin Islands” before its first immigrants arrived (“bonin” in Japanese means “no people”). The islands were accidentally found by a wrecked Japanese ship that was delivering oranges to Edo in 1670, which led to the investigation of the islands by the Edo Government in 1675. In 1823, a British whaling ship landed on the Ogasawara Islands and in 1826, another British ship found refuge on the island after being wrecked on shore. Many of the crew were rescued, however, two sailors stayed on the island and cultivated the land and raised pigs. In 1830, two Americans, one Dane, one Italian, one Briton and fifteen Hawaiian islanders came to the island and brought corn, pumpkin, potato, bean, melon, banana, sugarcane, pineapple, pigs, chicken, turkeys, ducks, goats, and deer with them. The number of immigrants increased greatly when the Ogasawara Islands became a Japanese territory in 1876. The increased human settlement in the Ogasawara Islands caused great degradation through deforestation, field cultivation, fuel collecting, and hunting. However, in 1944 the islanders were forced to evacuate when the Ogasawara Islands came under the United States’ control. This allowed the island to nearly return back to its previous uninhabited condition. The Ogasawara Islands were occupied by the United States until after the war in 1968, when the islands were returned to Japan and initiated the beginning of the construction of a new village. The construction of roads, bridges, parking lots, houses and fields once again destroyed forests and disrupted the many native species. Currently, there are approximately 2,440 residents on Chichijima and Hahajima Island and limited access through a single passenger ship that embarks once a week. |