Paleomagnetism of the Western Vardar ophiolitic unit: indication for Oligocene–Miocene remagnetization

This integrated paleomagnetic and mineralogical study investigates the Late Jurassic ophiolites of the Western Vardar Zone in Serbia. The Western Vardar ophiolitic unit constitutes a prominent 100–150 km wide belt of obducted ophiolites representing the former Vardar-Meliata Ocean, a northwestern branch of the Neotethys. 
From the Western Vardar ophiolite belt, oriented cores were collected from 18 localities representing different lithologies, including serpentinized peridotites, diabases, gabbros, amphibolites, and eclogites.
The laboratory analysis included standard demagnetization processes, as well as the investigation of the magnetic properties and mineralogical composition of the sampled rocks. In serpentinized peridotites, possible correlations between the degree of serpentinization and the magnetic susceptibility, as well as the natural remanent magnetization (NRM) were examined.
Magnetic mineralogical analyses suggest that magnetite is the dominant ferromagnetic mineral in the studied rocks, with minor to intermediate amounts of ferritchromite in serpentinites, and titanomagnetite in diabases and some serpentinites. The grain size of the magnetite varies between the pseudo-single domain and multidomain ranges. In the serpentinized peridotites (serpentinization degree: 40–90%), magnetite formed during the serpentinization, and can preserve the magnetization acquired at the time of this process.
Well-defined paleomagnetic directions were obtained for 12 localities and can be divided into two groups. In one group, the directions cluster close to the present-day magnetic field, suggesting a very recent remagnetization. The other group shows an approximately 30° clockwise rotation, which is consistent with previously observed Oligocene–Miocene results from the wider area. The similar directions obtained on both serpentinites and diabases, together with the derived paleolatitude from the overall mean direction from the ophiolites, raise the possibility of remagnetization during the late Paleogene–Neogene.
This study is supported by the bilateral project between Serbia and Hungary with reference numbers of 2023-1.2.4-TÉT-2023-00088 and 001908878 2025 13440 003 000 000 001 02 003.