Discovering Earth's Challenge: Insights of Out-of-Sequence Thrusts in Alpine-Himalayan Orogenic Belt

The Zagros orogenic belt is a component of the active Arabia-Eurasia collision zone in the Middle Eastern segment of the Alpine-Himalayan system, and it is one of the world's youngest seismically active continental collision zones. The Zagros region, which is one of the most seismically active continental collision zones in Zagros orogenic belt, provides an excellent case study for understanding tectonic processes and their consequences for geological development and seismic hazard assessment. This work presents an overview of the geological significance of the Zagros orogenic belt, with a focus on its function in larger context of the Arabia-Eurasia collision. It investigates the dynamic interaction of tectonic forces that have sculpted the landscape, from the first convergence of the Arabian and Eurasian plates to current deformation and seismic activity. 

Furthermore,  significance of continuing scientific efforts to understand the complexity of the Zagros orogenic region and its implications for seismic risk mitigation and natural resource exploration. Out-of-Sequence thrusts in the Eastern Alps' frontal zone (Levi et al., 2021). Out-of-Sequence thrusting in the Karwendel mountains of the western Northern Calcareous Alp (Kilian and Ortner, 2019). Besides, Out-of-sequence reactivation of older in-sequence thrusts is difficult to quantify. In Vienna Basin area, out of sequence Thrust adjusted to around 2 km at the Early Karpatian (approximately 16.5 Ma). The well Kirchdorf-1 drill explores that Molasse rocks that are exposed in tectonic windows caused by out-of-sequence thrusting at a depth of approximately 800 m above the basal thrust at the Alpine-Carpathian junction (Beidinger and Decker 2014). In-depth examination of the geological significance of the Zagros orogenic belt, focusing on its role within the broader context of the Arabia-Eurasia collision. Mukherjee (2015) docuemented OOS thrust displacement  along the length Himalayan Arc.

Through a detailed analysis of tectonic processes and their consequences for geological development and seismic hazard assessment, this study offers insights into the dynamic evolution of the region. From the initial convergence of the Arabian and Eurasian plates to the ongoing deformation and seismic activity, the landscape of the Zagros orogenic belt bears the imprint of complex tectonic interactions. Furthermore, this study highlights understanding the complexity of the Zagros orogenic region and its implications for seismic risk mitigation and natural resource exploration in neighbouring mountain ranges such as the Eastern Alps and the Northern Calcareous Alps.

References:

• Levi, et al. (2021). Out-of-Sequence thrusts in the Eastern Alps' frontal zone.
• Kilian and Ortner (2019). Out-of-Sequence thrusting in the Karwendel mountains of the western Northern Calcareous Alps.
• Mukherjee,S., (2015).  A reivew of Out-of-sequence thrust in Himalaya
• Beidinger and Decker (2014). Out-of-sequence thrusting in Vienna Basin: Kirchdorf-1 drill.