[1] 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 to the middle Oligocene.
However, it still displays many of the features that are characteristic of spreading centers, such as a rift valley, axial ridges, and abyssal hills.
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.
These features suggest that the CBSC formed in a complex tectonic environment, possibly involving a mantle plume.