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The National Park of American Samoa lies in the South Pacific, more than 4,200 km (2,600 mi) southwest of Hawaiʻi — the only National Park Service unit in the Southern Hemisphere. Authorized on October 31, 1988, it gained its land in September 1993 through a 50-year lease between the American Samoa Government and the Park Service.
The park covers approximately 3,341 hectares (8,257 acres) and protects paleotropical rainforests, coral reef ecosystems and Samoan cultural traditions dating back 3,000 years. It is spread across three of American Samoa’s seven islands — Taʻū, Ofu and Tutuila — with rainforests, cloud forests, coastal forests, coral communities, lagoons, wetlands and beaches.
Islands built by volcanoes
American Samoa’s islands are shield volcanoes: broad volcanoes rising thousands of meters from the Pacific floor. They are built of alternating lava flows and pyroclastic debris that hardened into tuff, volcanic breccia, lapilli and cinder layers.
Geologic map of the National Park of American Samoa. Image from NPS’s page.
The rocks of each island
| Park unit | What’s there |
|---|---|
| Ofu | some of the park’s oldest rocks — volcanic breccias and plugs of the Pliocene Asaga Formation — plus younger Pleistocene and Holocene limy sediments and alluvium |
| Taʻū | the Pleistocene Lata Formation, split into lavas that filled the volcano’s caldera and those that came after it; on the island’s northeast, ponded lavas and pāhoehoe flows of the Pleistocene Luatele Formation and lava flows of the Holocene Fitiʻuta Formation |
| Tutuila | volcanic rocks of the Pliocene–Pleistocene Pago Volcanics, trachyte pumice, plugs and dikes, and younger Holocene sand, talus and alluvium |
Fringing coral reefs at Ofu Island, American Samoa. Image from NPS’s page.
Mapping the park’s geology and soils
Geodiversity is the full variety of a park’s rocks, minerals, sediments, fossils, landforms, soils and the processes that shape them. This page draws on the NPS Geodiversity Atlas, a product of the Geologic Resources Inventory, which produces digital geologic maps and reports for more than 270 natural resource parks to support education, geoconservation and the management of living and non-living resources together. For this park, a geologic resources evaluation report (Thornberry-Ehrlich, 2008) and a completed Soil Resources Inventory are available through the NPS DataStore.
Sources
Based on "NPS Geodiversity Atlas—National Park of American Samoa, American Samoa," National Park Service; a work of the United States government in the public domain.
En estas publicacionesNational Park of American Samoa
Licencia: CC0 1.0 (dominio público) · Adaptado de www.nps.gov
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