Structure of the Bransfield Strait Crust

Data on the high heat flow, active volcanism, and extensional folding, in combination with modeling of the gravity and magnetic anomalies and earthquake focal mechanisms, indicate that the Bransfield strait floor represents a zone of lithosphere extension forming in the Antarctic Peninsula. The most important structural element of the strait floor is the neovolcanic zone near the South Shetland Islands and the diapirism zone near the Antarctic Peninsula. The discussed stages of rifting of the Bransfield floor reflect the propagating of the American-Antarctic Ridge into the continental lithosphere of the Antarctic Peninsula. The propagating causes thrusting of the South Shetland Island arc onto the peripheral part of the relict Phoenix plate, which is accompanied by the seismicity in the South Shetland trench.