Luzon Volcanic Arc

The Luzon Volcanic Arc is a chain of volcanoes in a north south line across the Luzon Strait from Taiwan to Luzon. The name Luzon Volcanic Arc was first proposed by Defant et al. to describe a series of Miocene to recent volcanoes due to eastward subduction along the Manila Trench for approximately 1,200 km from the Coastal Range in Taiwan south to southern Mindoro in the Philippines. They presented representative geochemistry of a number of volcanoes along the arc and were able to show five distinct geochemical domains within the arc (Mindoro, Bataan, Northern Luzon, Babuyan, and Taiwan). The geochemistry of the segments verified that the volcanoes are all subduction related (e.g., strong Nb anomalies and calc-alkaline characteristics). Isotopes and trace elements allowed them to show unique geochemical characteristics in the north. They proposed that the geochemical variations northward (Babuyan segment) were due to the subduction of sediments derived from the erosion of continental crust from China and Taiwan.

Volcanic arc

A volcanic arc is a chain of volcanoes formed above a subducting plate, positioned in an arc shape as seen from above. Offshore volcanoes form islands, resulting in a volcanic island arc. Generally they result from the subduction of an oceanic tectonic plate under another tectonic plate, and often parallel an oceanic trench. The oceanic plate is saturated with water, and volatiles such as water drastically lower the melting point of the mantle. As the oceanic plate is subducted, it is subjected to greater and greater pressures with increasing depth. This pressure squeezes water out of the plate and introduces it to the mantle. Here the mantle melts and forms magma at depth under the overriding plate. The magma ascends to form an arc of volcanoes parallel to the subduction zone.

These should not be confused with hotspot volcanic chains, where volcanoes often form one after another in the middle of a tectonic plate, as the plate moves over the hotspot, and so the volcanoes progress in age from one end of the chain to the other. The Hawaiian Islands form a typical hotspot chain; the older islands (tens of millions of years) to the northwest are smaller and more lush than the recently created (400,000 years ago) Hawaii island itself, which is more rocky. Hot spot volcanoes are also known as "Intra-plate" volcanoes and the islands they create are known as Volcanic Ocean Islands. Volcanic arcs do not generally exhibit such a simple age pattern.

Luzon

Luzon /luːˈzɒn/ is the largest and most populous island in the Philippines and the 15th largest in the world. Located in the northern region of the archipelago, it is the economic and political center of the nation, being home to the country's capital city, Manila, as well as Quezon City, the country's most populous. With a population of 48 million as of 2010, it is the fourth most populous island in the world, containing about 53% of the Philippines' total population.

Luzon may also refer to one of the three primary island groups in the country. As such, it includes the Luzon mainland, the Batanes and Babuyan groups of islands to the north, Polillo Islands to the east, and the outlying islands of Catanduanes, Marinduque, Masbate, Romblon, Mindoro, and Palawan, among others, to the south.

Etymology

The name Luzon is thought to derive from the Tagalog word lusong, which is a large wooden mortar used in dehusking rice.

History

Luzon (disambiguation)

Luzon is the largest island in the Philippines. Luzon may also refer to:

Places

In the military

Buildings

People

See also