Bagirova A.A.

Ministry of Sciences and Education of the Republic of Azerbaijan,“Institute of Geology” Public Legal Entity (PLE), Azerbaijan 119, H. Javid Ave., Baku, AZ1073: arzu-bagirova2013@yandex.ru

DOI: 10.35714/ggistrat20260200028

Summary. This article presents the results of investigations of the Mesozoic (Triassic) sedimentary deposits in the Nakhchivan Autonomous Republic, focusing on the horizontal movements of the Earth's crust and approaches to resolving related tectonic problems. Paleomagnetic investigations were carried out on the Akhura and Tananam stratigraphic sections, where Triassic sedimentary rocks were studied in detail. Based on the paleomagnetic data, the kinematic parameters of tectonic blocks and their horizontal displacements were determined. Similar results were obtained from the characterization of lithological components: clays and fine-grained sandstones exhibit the highest magnetic stability, coarse-grained rocks display metastable magnetic behavior, whereas coarse-grained sandstones, dolomites, and related lithologies are characterized by unstable magnetic properties.

During the magnetic cleaning (demagnetization) process, the stable components of remanent magnetization were isolated. On average, their directions coincide with the magnetization directions determined by the fold test. The investigated sections exhibit a regular alternation of rocks with normal and reversed magnetic polarity. Following thermal and stepwise demagnetization, rocks with both normal and reversed magnetization from the Akhura and Tananam sections yielded the same characteristic magnetization direction. This demonstrates the synchronicity of the natural remanent magnetization (Jn) and confirms the absence of the secondary magnetization components after demagnetization.

The objectives of this study were to investigate the paleomagnetic properties of the Triassic sedimentary rocks exposed within the Nakhchivan Autonomous Republic; to determine the position of the Earth's northern geomagnetic pole during the Triassic; to evaluate the horizontal displacements and rotational parameters of tectonic blocks; and to reconstruct the regional geological evolution and paleotectonic development based on paleomagnetic evidence.

The significance of the present paleomagnetic investigation lies in the fact that paleomagnetic methods provide the only quantitative approach for reconstructing paleotectonic settings and assessing the relative rotations of different geological structures.

This study represents the first comprehensive paleomagnetic investigation conducted in the Nakhchivan region (39.5°N, 45.3°E), in which paleomagnetic directions of the Triassic sedimentary rocks were determined using complete demagnetization procedures and Principal Component Analysis (PCA). Nevertheless, the results obtained from the Nakhchivan region are in close agreement with previously published paleomagnetic data from neighboring regions and stratigraphically equivalent Triassic sections, confirming the regional consistency and reliability of the obtained paleomagnetic dataset.

Keywords: Magnetic susceptibility, stratigraphic division, geological-geophysical analysis, Tananam sections, Trias epoch

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