The Urmia-Dakhtar region, a focal point of significant geological interest, has been extensively studied due to its complex tectonic settings and unique magmatic history. Previous research in this area has primarily focused on the dynamics of subduction processes and the resulting magmatic activities (Agard et al., 2011; Moghadam et al., 2022). Notably, studies have highlighted the region’s role in the convergence of the Arabian and Eurasian plates, which has shaped its geological structure through intense orogenic activities (Agard et al., 2011). The presence of ophiolites and volcanic arcs in this region provides critical evidence for the subduction and subsequent collisional processes, offering insights into the deeper mantle dynamics and crustal evolution (Moghadam and Stern, 2011; Moghadam et al., 2022). These geological features not only highlight the region’s crucial role in tectonic research but also provide essential insights into continental growth and crustal dynamics. This understanding is enhanced by seismic profiles that have been extensively employed to explore the upper crustal structure of the Iranian plateau (Mohammadi et al., 2014; Irandoust et al., 2022). These seismic investigations are vital for unraveling the complex interactions between tectonic activities and crustal structures, thereby deepening our comprehension of the region’s geodynamic behavior and its broader geological implications. Furthermore, the investigation of seismic activities and their correlation with structural geology in this area has helped delineate fault zones and assess seismic hazards, making it an invaluable site for studying earthquake genesis and mitigation (Jackson, 1992; Derakhshani and Eslami, 2011; Rashidi et al., 2023a).

The study of fault interactions and tectonic processes often involves the examination of analog models to better understand geological phenomena. A simple test involving the pinching of a cylindrical part between scissors provides valuable insights into the behaviour of geological structures subjected to oblique shortening (Figure 1). In Iran, the Alborz and Zagros mountain ranges represent two distinct pincer segments (Ghanbarian et al., 2021; Mehrabi et al., 2021; Ghanbarian and Derakhshani, 2022; Rashidi and Derakhshani, 2022; Kamali et al., 2023; Mohammadi Nia et al., 2023), while the central continental crust can be considered analogous to the center column. In central Iran, intriguing fault processes resembling horst and graben systems are observed, where abandoned regions exhibit similar behaviours to the Lut block, undergoing predominantly east-west processes (Rashidi et al., 2019; Rashidi et al., 2021).

Further investigations reveal the presence of extraterrestrial blocks, such as Shotory and Tabas, along with Posht-Badam, Dasht Bayyaz-Bardsir, and Yazd blocks (Ezati et al., 2022a; 2022b; Rashidi et al., 2023b). These blocks demonstrate an east-west stretching pattern influenced by diagonal stresses in the south-north direction (Figure 1). Moreover, the scissors-cylinder test indicates that closing the scissors at an angle of 135° induces rotation of the cylinder. Drawing a parallel, the continental crust of Central Iran exhibits similar behaviour, possibly forming coloured melange due to intercontinental rifts associated with strike-slip faults and pull-apart systems around the region.

To gain a comprehensive understanding of these geological phenomena, the current study focuses on the Urumieh-Dokhtar pluto-volcanics and ophiolites located within the Qom-Zefreh and Nayin-Baft fault regions. Detailed investigations of petrogenetic and structural geology are conducted to develop new models on the formation and evolution of these features.

The integration of these findings provides valuable insights into the complex tectonic processes and fault interactions occurring in the Qom-Zefreh-Nayin-Dehsheir-Baft region. Understanding the genesis of ophiolites and pluto-volcanics within the context of pull-apart basin structures and dextral fault stairs can significantly contribute to our broader knowledge of geological evolution in Central Iran.

The presence of strike-slip faults and adjacent rhomboidal structures, along with volcanic activities aligned with these strike-slip faults, indicates a shear-tension tectonic system. This system facilitates the ascent of magma tongues from deeper parts by creating pull-aparts in the crust. On the other hand, the observation of ophiolitic rocks alongside rhomboid structures, the formation of a complete ophiolite sequence in the Dehshir regions, and the presence of pillow lava magma near the Dehshir-Baft fault and south of Nayin suggest active traction in these areas. Therefore, the tensile activities in a shear system, starting from the late Cretaceous during the convergence of the Arabian and Central Iranian plates, should be considered.

Such behaviors during the convergence of the plates and the creation of tension zones can be explained and justified by diagonal convergence and, subsequently, diagonal subduction. Moreover, due to this diagonal subduction, the subducting pillar, under diagonal stress, fractures and subducts under itself, forming a duplex of the oceanic slab. This process later leads to magmatism, such as the Tholuieta Arctic Islands type, in this location. Also, the emplacement of magma in the Oligo-Miocene occurred in the same fault areas and along the Urumieh-Dokhtar belt with oblique subduction as a result of the fracture and dextral strike-slip displacement along the edge of the Iranian plate corresponding to the magmatic belt’s zone resulting from subduction.

Therefore, the fracture of the subduction edge since the late Cretaceous, while a large part of the Central Iranian plate was still deep in the sea, and the metamorphism of Cretaceous units near ancient diabase dykes and pillow lavas, can be considered a reflection of the onset of rifting in the Upper Cretaceous and the metamorphism of skarn formation and strip meta-cherts. This has led to the creation of deeper basins in sea areas and, consequently, the formation of pull-aparts and the presence of pillow lava magma in these areas. In the current location of the Urumieh-Dokhtar magmatism belt, which was the site of an ancient fracture on the edge of the Central Iran plate during subduction, the increasing convergence of the plates due to diagonal subduction caused further displacements in this fractured edge. As a result, the extensional basin deepened, the sediments of the ophiolitic sequence became complete and mature, and this process of convergence continued until the pressure reduced the amount of displacement, breaking the corresponding tension basin and creating smaller basins with fault-formed sides. These faults were created due to the fracturing of the larger tensile basin and the creation of a smaller basin.

Finally, with the continued convergence of the plates and diagonal subduction, magmatism resulting from the subduction began to rise from the same ancient fracture of the plate edge and through the resulting fractures, creating the Urumieh-Dokhtar magmatism belt. Given the presence of various types of alkaline and calc-alkaline magmatism, it can be stated that the intrusion of magmatism resulting from subduction and traction occurred simultaneously. Additionally, considering the obliqueness of the subduction, the presence of adakitic magmatism originating from deeper depths can be attributed to the fracture of the subducting column or shrinkage in the slab. As a result, the presence of two types of magmatic rocks and an ophiolitic sequence in the vicinity, demarcated by faults and the transformation of ophiolites, indicates that the ophiolitic sequence predated the magmatism in the extensional basins, which later evolved due to the placement of magma within the fractures and its diagonal pressure and preceding faults. In fact, the presence of ophiolites and subsequent magma tongues resulting from subduction can be attributed to the creation of a pull-apart in the ocean floor and the formation of an oceanic rift, which, following the retreat of the sea, transformed the former rift into a stretching basin for magma emergence. The result of subduction is shown schematically in Figure 10.

In this study, we investigated the presence of magma types in an area in the vicinity of ophiolites of oblique and Iceland arc types, along with the presence of adakite and its consequences in the Urmia-Dakhtar region. Our findings highlight the deep melting depth required to form adakite magmas, originating from the melting point of the oceanic crust of the mantle wedge. As a result, the ascent of magma leads to contamination of the mantle. It is worth noting that we observed that the ophiolitic fabric in the Kashan Nain Dashir region is intricately linked with the volcanic arc.

The model developed by revealed a diverse range of magma types, including Tolutia, Toluieta Arctic Islands, Sub-Alkaline, Alkaline, and Calc-Alkaline, spanning from the late Cretaceous to the Tertiary period. These magmas exhibited distances varying from hundreds of meters to 20 km, indicating the complex tectonic regime in the region, far more intricate than a simplistic model suggests.

We propose a shear-tectonic system as a suitable model to explain the local dislocations caused by slip movements and the deformation of tensile stones in conjunction with subduction. The influence of subduction and pressure systems resulting from the collision between the Arabian plate and Iran induces a rightward movement in the Urumieh-Dokhtar axis, featuring a set of faults extending from the southeast to the northwest, spanning from Tabriz to Minab.

Our investigation further suggests an ancient transformation fracture located beneath the continental crust, which underwent its own displacement and gave rise to multiple magmas due to stretching motions and the creation of tensile stacks over various periods. Subsequent to the collision, volcanic activities ensued, leading to the formation of plavo-alkanic rocks during the Eocene to Oligocene period.

Notably, colored compounds observed in the east of the northern part and the western part of the southern part of the high-rise stack indicate that this arrangement occurred during the formation of a stretch stack in the Upper Cretaceous.

Furthermore, the crustal structure underwent deformation under tensile stretch and eventually formed the present-day duplex of oceanic plates. This duplex structure serves as a source of tholeiite magma for Arctic islands and necessitates the supply of calc-alkaline magma following the continental collision.

In conclusion, our comprehensive investigation presents an innovative understanding of the Urumieh-Dokhtar region’s geological complexities, shedding light on the formation of Adakit magma, the interplay of tectonic forces, and the volcanic processes shaping the area’s geological history. These findings provide valuable insights into the complex geological processes and contribute to a deeper understanding of the region’s dynamic tectonic evolution.