Channel Islands (California)

The Channel Islands are an eight-island archipelago located within the Southern California Bight in the Pacific Ocean, off the coast of California. They define the Santa Barbara Channel between the islands and the California mainland. The four Northern Channel Islands are part of the Transverse Ranges geologic province, and the four Southern Channel Islands are part of the Peninsular Ranges province. Five of the islands are within the Channel Islands National Park. The waters surrounding these islands make up Channel Islands National Marine Sanctuary. The Nature Conservancy was instrumental in establishing the Channel Islands National Marine Sanctuary.
There is evidence that humans have lived on the Northern Channel Islands for thousands of years. Analysis of radiocarbon dating data indicates a continuous human presence starting between 8,000 and 11,000 years ago. The islands were inhabited primarily by two different Native American groups, the Chumash and the Tongva. The Channel Islands and the surrounding waters house a diverse ecosystem with many endemic species and subspecies. The islands harbor 150 unique species of plants.
Two of the islands, San Clemente Island and San Nicolas Island, are used by the United States Navy as training grounds, weapons test sites, and strategic defensive locations.

Characteristics

The eight islands are split among the jurisdictions of three California counties: Santa Barbara County, Ventura County, and Los Angeles County. The islands are divided into the Northern Channel Islands and the Southern Channel Islands. The four northern Islands used to be a single landmass known as Santa Rosae.
The archipelago extends for between San Miguel Island in the north and San Clemente Island in the south. Together, the islands' land area totals, or about.
Five of the islands were made into the Channel Islands National Park in 1980. The Channel Islands National Marine Sanctuary encompasses the waters off these islands.
Santa Catalina Island is the only one of the eight islands with significant permanent civilian settlements—the resort city of Avalon and the unincorporated community of Two Harbors. University of Southern California also houses its USC Wrigley Institute for Environmental Studies marine lab in Two Harbors.
The Channel Islands National Park mainland visitor center in Ventura Harbor received 342,000 visitors in 2014. The islands attract around 70,000 tourists a year, mostly during the summer. Visitors can travel to the islands by boat or airplane. Camping grounds are available in the Channel Islands National Park in Anacapa, Santa Rosa, Santa Cruz, San Miguel, and Santa Barbara Islands. Attractions include whale watching, hikes, snorkeling, kayaking and camping.
Natural seepage of oil occurs at several places in the Santa Barbara Channel. Tar balls or pieces of tar in small numbers are found in the kelp and on the beaches. Native Americans used naturally occurring tar, bitumen, for various purposes, including roofing, waterproofing, paving, and some ceremonial purposes.
The Channel Islands at low elevations are virtually frost-free and constitute one of the few such areas in the 48 contiguous US states. It snows only rarely on higher mountain peaks.

Islands

Geology

The Channel Islands consist mainly of sedimentary rock, which lies on a deep platform of volcanic rock. This, in turn, lies atop the eastern margin of the Pacific plate, a large tectonic plate which mostly consists of the oceanic crust underlying the Pacific Ocean but also incorporates the continental crust of California west of the San Andreas Fault. The volcanic rock underlying the islands was laid down in undersea eruptions between 19 and 15 million years ago.
The Channel Islands platform may have been exposed above sea level for a time after its initial formation, as a result of continuous tectonic uplift and volcanic activity. Still, it was quickly eroded below the water line and underwent sediment accumulation for the next 10–14 million years. Much of these sedimentary layers, composed primarily of sandstone, siltstone, and shale, document a prolonged history of mixed marine and terrestrial deposition. Formations such as the Vaqueros Sandstone, Rincon Claystone, and Monterey Shale were deposited during the early to middle Miocene, representing millions of years of both marine and terrestrial accumulations. During the same period, the ongoing collision of the Pacific plate and the adjacent North American plate caused the Channel Islands platform and adjacent mainland areas to rotate 90 degrees counterclockwise. Paleomagnetic evidence from rocks older than 16 millions years within the Western Transverse Ranges supports this rotation, which resulted in the present east–west orientation of the islands' ridges.
About 5 million years ago, the Channel Islands and the onshore east–west ranges, such as the Santa Monica Mountains, were uplifted as a result of tectonic forces from the collision of the northward-moving Baja California peninsula—attached to the Pacific plate—with the North American plate. Compression of the rocks lifted the islands above sea level in a process of folding and faulting that continues today.
Since the uplift began, the extent of the islands has varied with sea levels. During ice ages, when the water line was hundreds of feet lower than today, more land was exposed, and several islands were effectively joined into a single large island. Conversely, less of the land was exposed when sea levels were higher, and shorelines formed at higher levels. Evidence for ancient shorelines at higher sea levels is visible today as marine terraces along the islands' slopes. Undersea exploration has found evidence of lower shorelines below today's sea level.

History

Separated from the California mainland throughout recent geological history, the Channel Islands provide the earliest evidence for human seafaring in the Americas. The northern Channel Islands are now known to have been settled by maritime Paleo-Indian peoples at least 13,000 years ago.
The Arlington Springs Man was discovered in 1960 at Arlington Springs on Santa Rosa Island. The remains were dated to 13,000 years BP.
The Tuqan Man was discovered on San Miguel Island in 2005. His remains were exposed by beach erosion and were preserved by University of Oregon archeologists. His age was determined to be about 10,000 years.
Archeological sites on the island provide a unique and invaluable record of human interaction with Channel Island marine and terrestrial ecosystems from the late Pleistocene to historic times. The Anacapa Island Archeological District is a historic district that was listed on the National Register of Historic Places in 1979.

Indigenous peoples

Historically, the northern islands were occupied by the Chumash, while the southern islands were occupied by the Tongva.
The earliest known Chumash village site is on Santa Rosa Island. It belongs to the period around 7,500 BP. The Chumash people lived in large villages or towns with up to 1,000 residents. Chumash villages typically contained houses and sweat lodges and occasionally had menstrual houses, cemeteries, sacred spaces, and structures for food storage and preparation. The Chumash people were leaders in the creation of their villages, they had a sociopolitical organization that allowed their villages to be so well preserved and created great social space and village community that lasted even into an excavation of their villages. Soon after, the population density on the islands began to rise. A significant increase in fish and marine mammal exploitation has been observed. The Tongva people used many marine artifacts in their daily lives, such as shells. They used shells to create beads, and while this was not part of their dietary practices, it was a vital part of their economy. They used these shell beads to trade to obtain more food from the mainland that they could not cultivate on the island.
Around 2,500 BP, there was a significant evolution in technology and increasing reliance on fishing. The circular shell fishhooks were increasingly used. Mortars and pestles were manufactured on San Miguel Island for trade with the mainland. The middens in San Miguel Island showed some of the earliest known fishing hooks and specialized tools for processing seafood. Archaeologists on site CA-SMI-608 found various tools made from chipped stone, bone tools, and beads.
A new type of boat created by the Chumash known as tomol and by the Tongva as te'aats, appeared on the islands around 1,500 BP. The boat had become a critical part of Chumash and Tongva culture by 650 AD. The tomol boats were highly sophisticated boats that were able to transport multiple families across the islands which were valuable to the culture of the Chumash people. The boats were made from tule which made the boats very buoyant and unsinkable.

Modern history

The Nicoleño

The Nicoleño was a Uto-Aztecan Native American people group living on San Nicolas Island in California. The population was "left devastated by a massacre in 1811 by sea otter hunters". The group's last surviving member was named Juana Maria, born before 1811 and died in 1853. Juana Maria, better known to history as the "Lone Woman of San Nicolas Island", lived alone on San Nicolas Island from 1835 until her removal from the island in early September 1853, when men discovered her inside a hut made of whalebones and brush. Arrived on California's mainland, Juana Maria's fondness for green corn, vegetables, and fresh fruit caused severe attacks of dysentery. In her weakness, she fell from Nidever's porch and injured her spine. On Oct. 18, 1853, only seven weeks after arriving on the mainland, she died of dysentery in Garey, California, at age 43. Before she died, Father Sanchez baptized and christened her with the Spanish name Juana Maria. She was buried in an unmarked grave on the Nidever family plot at the Santa Barbara Mission cemetery.
Aleut hunters visited the islands to hunt otters in the early 1800s. The Aleuts purportedly clashed with the native Chumash, killing many over trading disputes. Aleut interactions with the natives were detailed in Scott O'Dell's novel Island of the Blue Dolphins which described the indigenous peoples living on the island.
The Chumash and Tongva were removed from the islands in the early 19th century and taken to Spanish missions and pueblos on the adjacent mainland. The Channel Islands were then used primarily for ranching and fishing for a century. Several of the islands were used by whalers in the 1930s to hunt for sperm whales. This had significant impacts on island ecosystems, including the local extinction of sea otters, bald eagles, and other established species. For example, the decline in the local otter population led to the population growth of their prey, the black abalone. As a result, the Channel Islands became an essential stop in the 1850s for Chinese-American fishermen who harvested the abalone and exported them to Hong Kong.