Continental margins and Ocean-Continent Transitions of the Gulf of Aden: how Africa and Arabia broke up?

摘要: Fundamental characters of rifted-margins are commonly related to the large-scale processes during rifting, but variations at the scale of 10-20 kilometers segments can be equally significant. The presence or absence of magmatism during continental rifting appears to control the subsequent geometry and duration of continental breakup within discrete rift sectors. Here we show, from new geophysical and geological observations in the Gulf of Aden, that rift sectors between transforms have a large internal variability attributed usually to large-scale processes: over short distances (~ 10 kilometers), the OCT evolves from a narrow magmatic transition (few kms to 15km wide) to wider zones (~ 50km) where continental mantle is probably exhumed. We suggest that this small-scale variability is caused (1) by the long-offset Fracture Zones, which can enhance magma production on its young side,(2) by channeled flow of …