1. This rifting continued until sea-floor spreading began 83 Ma. 2. Around 150 Ma sea-floor spreading propagated northward into the southern segment. 3. The existence of oceans is critical to sea-floor spreading and subduction. 4. Around 110-85 Ma, there was worldwide oscillatory increases in ocean floor spreading rates. 5. It seems an inevitable conclusion that sea-floor spreading could have occurred during the earliest history of Mars, 6. Various estimates date the propagation of sea-floor spreading in this segment to the period 120 96 Ma. 7. Convection currents in the sub-lithospheric mantle are the driving mechanisms that caused sea floor spreading to occur. 8. A rift valley, caused by sea-floor spreading , runs adjacent and parallel to the Knipovich Ridge. 9. This worldwide regression marks the slowing of sea-floor spreading and bounds the Gulfian Series in a sequence boundary. 10. The collision caused an extrusion of Indochina relative to South China, which resulted in crustal extension and sea floor spreading .
