Sediment transport patterns on the Estremadura Spur continental shelf: Insights from grain-size trend analysis

• Dispersion patters due to oceanographic drivers are in general agreement with GSTA.
• Transport vector field computed by GSTA is disturbed by rocky outcrops barriers.
• Sampling resolution is crucial for characteristic distance and transport vectors.
• Spatial resolution higher than characteristic distance required for GSTA solution.

Grain-size trend analysis (GSTA) was used to infer sediment transport patterns on Estremadura Spur continental shelf. Sediment transport patterns were defined using the Gao and Collins (1992) method applied on an extensive collection of superficial sediment samples collected from 14 to 706 m water depths and using a characteristic distance based on geostatistical analysis. Results are in relatively good agreement with known oceanographic drivers for the external shelf (internal waves, and upwelling) and measured near-bottom currents. At the mid and inner shelf computed sediment transport vectors yielded less coherent patterns probably related with low sampling density in relation to surficial sedimentary deposit dimensions and the presence of rocky outcrops.