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The geotectonic setting and emplacement style of ophiolites are very significant for an understanding of the geological evolution of any region. In this context, it is essential to know the true tectonic relationship between ophiolites and adjacent units as accurately as possible. This study focuses on the Balkan sector, where Mesozoic convergence/collision processes left behind several NNW–SSE stretching ophiolite belts. The easternmost belt, known as the East Vardar Zone (EVZ), differs from other Balkan ophiolites (i.e. West Vardar) in having pronounced supra-subduction affinity as well as in lacking large peridotitic masses, metamorphic sole assemblages, and clear evidence of a westward obduction. This study was aimed at unraveling the true structural position of the EVZ ophiolites and the surrounding units. We applied 2D modeling of gravity and magnetic data and pseudo 3D modeling of the two largest exposures of the East Vardar Zone (EVZ) ophiolites. The methodology included: qualitative (remote sensing and field observation data as well as mathematical transformations of geophysical data), and quantitative analysis (2D modeling of both, aeromagnetic and gravity data along six cross-sections and the creation of pseudo 3D models). The obtained results invariably suggested that the EVZ ophiolites are dipping to the east beneath the Serbo-Macedonian Massif (SMM). The buried ophiolite bodies display steep contacts in shallow levels, but the contacts become much less steep with depth. The models are considered robust for the first 2–3 km, however, there are indications that the EVZ ophiolites exist at much greater depths, as well. Our geophysical–geological model implies that the mode of emplacement of the EVZ ophiolites was related to accretion/underthrusting and it was strikingly different from the emplacement of the other Balkan ophiolites that were uniformly obducted toward the west. This scenario is supported by the independent evidence provided by mantle xenolith studies and studies of lamproitic lavas, which indicated that at least parts of the mantle underneath the Tethyan Mesozoic suture are compositionally more similar to oceanic supra-subduction mantle.

The purpose of this paper is the development of a new Bouguer anomaly map for the broader Adriatic Sea area to be used as geo-scientific tool which will answer questions mainly regarding the deep and intermediate depth structure of the Adriatic and its surrounding areas. As a first step, a consistent, high-resolution and accuracy free-air gravity anomaly database is created using all the available terrestrial and satellite altimetry data sources. The least-squares collocation (LSC) method is employed to validate the different gravity data sets through an appropriate covariance analysis and following the remove–compute–restore procedure (RCR) for the detailed study of the gravity spectrum. The finally generated gravity database has a resolution of a 0.0333° (∼3.2 km) in both latitude and longitude, while its external and internal accuracy is estimated to about ±5 mGal and ±0.5 mGal, respectively. Based on the derived free-air gravity database a new Bouguer gravity anomaly database is determined at the same resolution for the wider region of the Adriatic Sea. Comparison with existing results confirms the reliability of the new Bouguer map for the study area, mainly due to the combination of both land and sea data. The derived Bouguer anomaly map can support different kind of geophysical investigations of both local and regional structure of the study region. As an example three density models are constructed along selected cross sections extracted from the Bouguer anomaly database, in order to obtain structural information for the crustal–upper mantle structure of the region and draw relevant conclusions. The obtained results show that the Bouguer map can provide important information for the lower-crustal/upper-mantle depth range but also helps to constrain the 2D geometry of the shallow geological units, in very good agreement with the observed surface geology and the current understanding of the geotectonic setting of the area.