Archaeologia Polona, vol. 53: 2015, 547-588 PL ISSN 0066-5924 Role of potential feld derivatives in delineating buried archaeological ruins Akram M. Aziz a , El-Arabi H. Shendi b and Mohamed Abd El-Maksoud c KEY-WORDS: total magnetic feld, potential derivatives, tilt derivatives, analytical signal amplitude, total horizontal derivative, generalized derivative a Geology Department, Port Said University, Port Said, Egypt b Geology Department, Suez Canal University, Ismailia, Egypt c Supreme Council of Antiquities of Egypt, Cairo, Egypt Potential feld derivative techniques are intensively used in various geophysical large-scale investigations. Te current work applies some of these techniques to small-scale high-resolution surveys commonly conducted in archaeological prospection and environmental investigations. Te techniques include: spatial orthogonal derivatives, analytical signal amplitude (ASA) (Nabighian 1972; Roest et al. 1992), total horizontal derivative (THDR) (Cordell and Grauch 1985; Phillips 2000), tilt angle derivative (TDR) (Miller and Singh 1994; Wijns et al. 2005), total horizontal derivative of TDR (TDR-THDR) (Verduzco et al. 2004), horizontal tilt angle (TDX) (Cooper and Cowan 2006), tilt angle of total horizontal derivative (TAHDR) (Ferreira et al. 2010; Cheyney 2012; Jacques et al. 2014), and generalized derivative operator (GDO) (Cooper and Cowan 2011). A high-density total feld magnetic survey was conducted at an ancient Egyptian archaeologi- cal site located in northeastern Sinai. Te region is part of the old delta of the river Nile (Aziz et al. 2013). Te chosen site was proposed by feld archaeologists, aiming to delineate the eastern extension of the buried southern wall of Tjarou citadel (Abd El-Maksoud and Valbelle 2005). Te citadel was erected mainly of mud brick, resulting in a low magnetic susceptibility contrast between the buried wall and the surrounding fll (Shendi and Aziz 2010). A proton precession magnetometer was used to measure the total magnetic feld. Te instru- ment is also equipped with two sensors to measure the vertical gradient of the magnetic feld. Tree squared grids, covering an area of 20 m by 60 m, were laid out. Te shortest side of the surveyed grids was parallel to the course of the wall: N800 E. Traverses were surveyed perpen- dicularly to the wall azimuth, and were spaced 0.5 m apart. Measurements were recorded every Processing and visualisation of data Archaeologia Polona, vol. 53: 2015, pp. 547-550