GNGTS 2016 - Atti del 35° Convegno Nazionale

510 GNGTS 2016 S essione 3.1 Three study areas have been considered in this paper (Fig. 1a): 1) oceanic and transitional crust of the South Scotia Sea (SSS), where the seismic profiles IT95-167 and IT-154 cross respectively the Dove Basin and the Ona Basin-Ona High; 2) the South Shetland Trench (SST), where the seismic profile IT90-A44 crosses the slope in NW-SE orientation; 3) the continental crust of the Victoria Land Basin (VLB) crossed by the seismic profiles IT90AR-63S and IT90AR-64S. We show the seismic characteristics of the recognized BSRs and analyze their relationships with the geological setting of the studied zones, through re-processing of seismic data and new analysis with seismic attributes, AVO (Amplitude Variation with Offset) and P/ S wave reflectivity analysis. Analysis of seismic data. The seismic profiles that cross the recognized BSRs have been re- processed, in order to extract all the useful information about seismic wave velocity, amplitude, phase, frequency, and burial depth. These parameters allow to perform a qualitative analysis and a BSR characterization. We adopt a processing flow made up of preliminary interpretation, improved velocity analysis, post stack depth migration, seismic attribute and AVO analysis. Study area 1 - South Scotia Sea. The nature of the BSR recognized in the Dove Basin has been ascribed to a fossil diagenetic origin, due to its seismic characteristics (no polarity inversion, velocity increasing) and burial depth between 600 and 700 m (Mocnik et al. , 2015). Fig. 1 – a) location of the study areas: SSS-South Scotia Sea, SST-South Schetland Trench, VLB-Victoria Land Basin; b) portion of seismic profile IT-154 crossing the Ona Basin-Ona High (location in c), where the red line represents the interval velocity trend through the observed BSR; d) pre stack depth migration where the arrows depict the continuity toward SW of sedimentary reflectors even through the BSR, while toward NE the BSR seems to coincide with an unconformity.