An aulacogen is a failed arm of a triple junction of a plate tectonics rift system. Influenza A virus subtype H5N1 triple junction beneath a continental plate initiates a 3 agency breakup of the continental plate. As the continental break-up develops i of the 3 spreading ridges typically fails or stops spreading. The resulting failed rift is called an aulacogen in addition to becomes a filled graben organisation inside the continent.
The term “aulacogen” is derived from the Greek aulax (furrow) in addition to was suggested past times the Soviet geologist Nicholas Shatski inwards 1946.
The crust inwards an aulacogen percentage remains weakened past times previous rifting action in addition to hence seismic action and, occasionally, volcanic action may re-occur afterwards from fourth dimension to time. As aulacogens stay places of weakness, given the appropriate conditions, they tin reactivate into active rift valleys again, every moment had happened to the Ottawa-Bonnechere Graben inwards Ontario in addition to Quebec, Canada, an ancient aulacogen that reactivated during the breakup of Pangaea.
The Mississippi embayment alongside the associated New Madrid Seismic Zone is an event of an ancient aulacogen that dates dorsum to the breakup of the ancient continent, Rodinia. This ancient rift was the site of extreme earthquakes inwards the early on 19th century inwards the region. The Southern Oklahoma Aulacogen, exposed inwards the Wichita Mountains, is an Eocambrian rift organisation formed every moment a production of intracontinetal rifting during the breakup of Pannotia. The Rio Grande Rift is about other example. Located on the Southwestern European margin (offshore Portugal) is about other abandoned rift, the Lusitanian Basin, that evolved at the same fourth dimension every moment the Canadian Grand Banks region, where the Hibernia Oil Field is located.
Abandoned rift basins that convey been uplifted in addition to exposed onshore, similar the Lusitanian Basin, are of import analogues of deep-sea basins located on conjugated margins of ancient rift axes.