The Baja California peninsula (Spanish: Península de Baja California, lit. 'Lower California peninsula') is a peninsula in northwestern Mexico. It separates the Gulf of California from the Pacific Ocean. The peninsula extends from Mexicali, Baja California, in the north to Cabo San Lucas, Baja California Sur, in the south.
With a length of 1,247 km (775 miles), its width ranges from 40 km (25 miles) at its narrowest to 320 km (200 miles) at its widest point and has approximately 3,000 km (1,900 miles) of coastline and approximately 65 islands. The total area of the Baja California peninsula is 143,390 km2 (55,360 sq mi).
The peninsula is separated from mainland Mexico by the Gulf of California and the Colorado River. There are four main desert areas on the peninsula: the San Felipe Desert, the Central Coast Desert, the Vizcaíno Desert, and the Magdalena Plain Desert.
The name of California existed as a myth among European explorers before it was discovered. The earliest known mention of the idea of California was in the 1510 romance novel Las Sergas de Esplandián by Spanish author Garci Rodríguez de Montalvo. The book described the Island of California as being west of the Indies, "very close to the side of the Terrestrial Paradise; and it is peopled by black women, without any man among them, for they live in the manner of Amazons".[1]
The Baja peninsula was originally believed by the first Spanish sea explorers to be an island, and acquired the name California, after the mythical paradise. Following Hernán Cortés's conquest of Mexico, the search for the fabled Strait of Anián connecting the Atlantic to the Pacific helped motivate him to send several expeditions to the west coast of New Spain in the 1530s and early 1540s. In 1539, explorer Francisco de Ulloa proved that Baja California was a peninsula rather than an island,[2] and named the water separating it from the mainland the "Vermillion Sea" (sometimes referred to as the "Red Sea"). The Spaniards gave the name Las Californias to the peninsula and lands to the north, including both Baja California and Alta California, the region that became parts of the present-day U.S. states of California, Nevada, Utah, Arizona, and parts of Colorado and Wyoming.[citation needed] Over time the name "Sea of Cortez" replaced Vermillion Sea, and today the term "Gulf of California" is used by some.[3]
Although cartographers such as Abraham Ortelius showed the Baja as an extensive peninsula in his Theatrum Orbis Terrarum, published in Antwerpen in 1589, and on the map Maris Pacifici from 1589, in the first half of the 17th century the idea of California as an island spread again; this persisted well into the 18th century, and was included in many erroneous maps that did not have the knowledge of the Spanish sailors about the Pacific coast of North America.[4] It is believed to have originated with Carmelite friar Antonio Ascension, who around 1620 drew a map of California depicting it as an island, supposedly on a misconception of reports by Spanish navigators Juan de Fuca and Martin d'Aquilar.[5] A copy of this map was sent to Spain and was seized by the Dutch on its way and then reproduced in the Netherlands, and eventually found its way to Henry Briggs in London who widely disseminated this misinformation. The first printed map showing California as an island was published by Briggs in 1622 (this map was also included in Hakluytus Posthumus by Samuel Purchas, 1625), where it was written that it was sometimes supposed to be a peninsula, but had since been shown by the Dutch to be an island. The idea was warmly accepted by cartographers and presented even in c. 1720 on Carte Nouveelle de la Mer du Sud, published in Amsterdam by Andries and Hendrik de Leth.[6] Garcia and Jorge opined in 2023 that a reason for such a mistake could have originated in the secret in which the Spaniards held their cartography from other European powers' eyes.[7]
The final blow to the notion of California as an island was struck by an influential map created by Italian Jesuit priest Eusebio Kino during his mission in the Pimería Alta. It was titled Paso por tierra a la California y sus confinantes nuevas Naciones y Misiones nuevas de la Compañía de JHS [Jesús] en la América Septentrional ("Overland Passage to California and its Contiguous New Nations and New Missions of the Society of Jesus in Northern America").[8] Originally, in 1695, it depicted California as a peninsula but based on the presence of blue abalone shells (most likely Haliotis fulgens) from the Pacific coast in the Pimería Alta, the information from natives, and his own travels and sightings, Eusebio Kino redrew the map in 1701.[9] The map was printed in 1707 in Hamburg and Leipzig and became one of the best-known maps of northern New Spain. A notable colleague of Eusebio Kino who accompanied him on one of his major travels (in 1694) and acted as the intermediary in the publication of this map and dissemination of Kino's knowledge in Europe was Carniolan priest Marcus Antonius Kappus.[10]
The province of the Californias was united until 1804, in the Spanish colonial Viceroyalty of New Spain, when it was divided into Alta (upper) and Baja (lower) California.
The two Californias division was kept after Mexican independence in 1821. The Spanish Baja California Province became Mexican Baja California Territory, and remained a separate territory until 1836. In 1836, the Siete Leyes constitutional reforms reunited both Californias in the Departamento de las Californias. After 1848, the Baja California peninsula again became a Mexican territory when Alta California was ceded to the United States (see 1854 map).
In 1931, Baja California Territory was divided into northern and southern territories. In 1952, the "Territory of Baja California Norte" became the 29th State of Mexico as Baja California. In 1974, the "Territory of Baja California Sur" became the 31st state as Baja California Sur.
The northern part is the state of Baja California. It is sometimes informally referred to as Baja California Norte, to distinguish it from both the Baja California peninsula and the adjacent state Baja California Sur. The citizens of Baja California are named bajacalifornianos ("Lower Californians" in English). Mexicali is the capital.
The southern part, below 28° north, is the state of Baja California Sur. The citizens of Baja California Sur are named sudcalifornianos ("South Californians" in English). La Paz is its capital.
The Baja California peninsula was once a part of the North American Plate, the tectonic plate of which mainland Mexico remains a part. About 12 to 15 million years ago the East Pacific Rise began cutting into the margin of the North American Plate, initiating the separation of the peninsula from it. Spreading within the Gulf of California consists of short oblique rifts or ridge segments connected by long northwest trending transform faults,[14] which together comprise the Gulf of California Rift Zone. The north end of the rift zone is located in the Brawley seismic zone in the Salton Sea basin between the Imperial Fault and the San Andreas Fault.[14] The Baja California peninsula is now part of the Pacific Plate and is moving with it away from the East Pacific Rise in a north northwestward direction.
Along the coast north of Santa Rosalia, Baja California Sur is a prominent volcanic activity area.
Volcanoes of the peninsula and adjacent islands include:[15]
Researchers from Scripps Institution of Oceanography have found a 2,000-year-old layer of non-decomposed roots, or peat, up to 4 metres (13 ft) under the desert mangroves. The peat layer acts like a sponge for stored atmospheric carbon, a record of sea-level-rise is also recorded in the peat layer.
The desert mangroves restricted to rocky inlets on the rugged coast of Baja California have been growing over their own root remains over thousands of years to compensate for sea-level rise, accumulating a thick layer of peat below their roots. However, mangroves in flat coastal floodplains have accumulated a thinner peat layer.[16]
