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Channel Islands National Park lies off the coast of southern California, in Santa Barbara and Ventura Counties — close to the mainland, yet worlds apart. It takes in five of the eight Channel Islands — Anacapa, Santa Cruz, San Miguel, Santa Rosa and Santa Barbara — and the one nautical mile of ocean around them.
| National monument | April 26, 1938 |
| Biosphere Reserve | 1976 |
| National park | March 5, 1980 |
| Area | 100,994 hectares (249,561 acres) |
| Life | more than 2,000 plant and animal species |
| People | hundreds of archeological sites, some as old as the late Pleistocene |
Visitors come to explore history, hike, camp, snorkel, kayak, watch birds, take photographs, sketch — or simply listen.
Built by colliding plates
The islands' rocks record a history driven by plate tectonics. The northern Channel Islands have been caught up for some 30 million years in the complex collision of the North American and Pacific plates, which shifted and rotated the Transverse Ranges and set off volcanism.
Each island has its own geologic story:
| Island | What it's made of |
|---|---|
| Anacapa and Santa Barbara (the two smallest) | mostly Miocene volcanic rock, with a little interleaved sedimentary rock, under a thin cover of Quaternary sediment |
| San Miguel and Santa Rosa | mainly Eocene and Miocene units; San Miguel's oldest rocks date to the Late Cretaceous |
| Santa Cruz | the most varied geology and the longest rock record at the surface, beginning with Jurassic metamorphic and intrusive igneous rock |
The park belongs to the Los Angeles Ranges section of the Pacific Border Physiographic Province, and shares its history and some of its characteristic formations with a region far larger than the park.
Geodiversity
Geodiversity is the full range of a park's natural geologic and soil resources and processes — rocks, minerals, sediments, fossils, landforms and the forces that shape them. The Park Service's Geodiversity Atlas, a product of the Geologic Resources Inventory, gathers this information to support education, geoconservation, and management of the living and non-living parts of each ecosystem together.
Maps and data
The Geologic Resources Inventory makes digital geologic maps and reports for more than 270 natural resource parks:
- scoping summaries — the meetings where park staff and local geologists planned the mapping and the report;
- digital geologic maps for GIS software (newer ones also for Google Earth and online map services);
- reports on the park's setting and significance, notable features and processes, management issues and geologic history;
- posters — PDF views of the map data.
Channel Islands' products are in the NPS DataStore (saved search 2806), and a completed Soil Resources Inventory is there too (saved search 2757).
More
- Channel Islands: geologic formations · paleontological resources · physical resources · coastal resources · park home
- National Park Service: geologic time · regional geology · Geodiversity Atlas
Sources
Based on "NPS Geodiversity Atlas—Channel Islands National Park, California," National Park Service; a work of the United States government in the public domain. It cites Anderson (2017), Tweet and others (2020) and Weigand and others (2002).
In queste pubblicazioniChannel Islands National Park
Licenza: CC0 1.0 (pubblico dominio) · Tratto da www.nps.gov
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