Statistical analysis of the structural trends in the Galician Margin and their relationship with the Cenozoic evolution of the northwestern sector of the Iberian Margin

Abstract

Statistical methods of crust surface analysis based on Digital Terrain Models (DTM) and applied to structural elements have become a useful tool in tectonic studies. This paper presents a DTM morphostructural analysis of the Galicia Margin and the Iberian and Biscay abyssal plains, which has identified about 5,800 lineaments. The highest number of lineaments are located in the Charcot and Coruña Highs, in the western sector of the Galicia Bank, in the marginal platforms zone and in the Galicia northern margin. The lineaments analysis shows that they have two dominant directions, E-W and NE-SW. In addition, two other relative maxima of NW-SE and N-S directions have been determined. The cumulative total length of the identified lineaments exceeds 45,000 km. The statistical parameters have a length mode of around 5,000 m, a length average of about 7,800 m and a log-normal distribution of the length frequency. The orientations determined from the analysis of the lineaments are a reflection of the crustal scale fault systems established from gravimetric and magnetic anomalies and multi-channel seismic profiles. These faults developed in the Galicia Margin during the Variscan and Alpine orogenies and were reactivated under the recent stress field.