[1] Aulacogens are a part of plate tectonics where oceanic and continental crust is continuously being created, destroyed, and rearranged on the Earth’s surface.
[2] The term aulacogen is derived from Greek aulax 'furrow' and was suggested by the Soviet geologist Nikolay Shatsky in 1946.
[3][4] A triple junction is the point where three tectonic plates meet; the boundaries of these plates are characterized by divergence, causing a rift zone or spreading center; a transform fault; or convergence causing subduction or uplift of crust and forming mountains.
The failed arm of a triple junction can be either a transform fault that has been flooded with magma, or more commonly, an inactive rift zone.
The final inversion stage takes place when tectonic stress on the aulacogen changes from tensional to compressional forming horsts.