Central Basin Spreading Center (CBSC), formerly Central Basin Fault, is a seafloor

spreading center Seafloor spreading, or seafloor spread, is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. History of study Earlier theories by Alfred Wegener ...

of the West Philippine Basin. It is a long, NW-SE-trending structure that is considered to have been the spreading center of the West Philippine Basin (WPB) from the

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

to the

middle Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but t ...

. It is a remnant spreading center, meaning that it is no longer active. However, it still displays many of the features that are characteristic of spreading centers, such as a

rift valley A rift valley is a linear shaped lowland between several highlands or mountain ranges produced by the action of a geologic rift. Rifts are formed as a result of the pulling apart of the lithosphere due to extensional tectonics. The linear ...

, axial ridges, and abyssal hills. The CBSC is divided into two segments: the eastern segment and the western segment. The eastern segment is characterized by slow-spreading features, such as a deep rift valley and nodal basins. The western segment is characterized by fast-spreading features, such as overlapping spreading centers and volcanic axial ridges. The CBSC is also associated with a number of other features, including oceanic plateaus and

seamount chains A seamount is a large submarine landform that rises from the ocean floor without reaching the water surface (sea level), and thus is not an island, islet, or cliff-rock. Seamounts are typically formed from extinct volcanoes that rise abruptly a ...

. These features suggest that the CBSC formed in a complex tectonic environment, possibly involving a

mantle plume A mantle plume is a proposed mechanism of convection within the Earth's mantle, hypothesized to explain anomalous volcanism. Because the plume head partially melts on reaching shallow depths, a plume is often invoked as the cause of volcanic ho ...

. The study of the CBSC provides important insights into the formation and evolution of marginal basins. Marginal basins are small ocean basins that are formed on the margins of continents or island arcs. The CBSC is a good example of a marginal basin that formed through

seafloor spreading Seafloor spreading, or seafloor spread, is a process that occurs at mid-ocean ridges, where new oceanic crust is formed through volcanic activity and then gradually moves away from the ridge. History of study Earlier theories by Alfred Wegener ...

References

Oceanography {{philippines-stub