It typically occurs at triple junctions, though often one arm becomes a failed rift, as happened with the Red Sea and the Niger River.  Debate continues over whether this process is driven by active or passive upwelling, but bands of alternatingly polarized ferromagnetic deposits confirmed its existence. Proposed by Harry Hess in the 1960s, it is now believed to be caused by convection currents in the upper mantle. Notably occurring at the East Pacific Rise and the Mid-A
It typically occurs at triple junctions, though often one arm becomes a failed rift, as happened with the Red Sea and the Niger River.  Debate continues over whether this process is driven by active or passive upwelling, but bands of alternatingly polarized ferromagnetic deposits confirmed its existence. Proposed by Harry Hess in the 1960s, it is now believed to be caused by convection currents in the upper mantle. Notably occurring at the East Pacific Rise and the Mid-Atlantic Ridge, FTP name this geological process in which oceanic crust is created, the mechanism that drives plate tectonics.
It typically occurs at triple junctions, though often one arm becomes a failed rift, as happened with the Red Sea and the Niger River.  
Seafloor Spreading