Tuesday, 28 August 2007
2.PS-65

The passive subduction of the Phoenix plate remnant at the South Shetland trench

Bruno Della Vedova1, Flavio Accaino2, Filomena M. Loreto2, and Umberta Tinivella2. (1) Dept. of Civil and Environmental Engeneering, University of Trieste, Via Valerio 10, Trieste, I-34127, Italy, (2) Istituto Nazionale di Oceanografia e Geofisica Sperimentale - OGS, Borgo Grotta Gigante 42/c, Sgonico,Trieste, I-34010, Italy

We present multibeam bathymetry, Chirp profiles and seismic data acquired in the South Shetland Trench during the Antarctic summer 2003-2004 (R/V OGS-Explora cruise), to study the differential passive subduction of the Phoenix Plate remnant, subdivided into three main segments by the “D” and “E” Fracture Zones. The investigated area (160 x 60 km) includes parts of the trench, incoming oceanic plate and outer front of the Antarctic Peninsula accretionary prism. The integrated dataset displays an interesting faults pattern deforming the seafloor and oceanic crust with variable orientation, controlled by the slab pull down and by the fracture zones which act as effective mechanical discontinuities. The differential mechanical coupling across the Hero, Shackleton, “E” and “D” Fracture Zones influences the regional stress field distribution and the sinking of the oceanic segments, during passive subduction and roll-back.

[Manuscript]

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