Influence of the caprock on the growth dynamics of salt diapirs (southern Iran)

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The Zagros fold and thrust belt (ZFTB) in southeastern Iran offers unique surface exposures of salt diapirs that can be directly studied in the field and by remote sensing methods over multiple scales. These structures reveal mobilized salt together with its overlying solid residuum (caprock) that reflect reactivation of several kilometer-high, columnar salt diapirs by the compressional tectonic stresses. A major aim of this bi-lateral proposal is the deeper understanding of the mechanical properties of caprock and influence of the caprock properties on the morphotectonics of the diapiric extrusions and the kinematic evolution of salt diapirs in general. The present proposal addresses the internal structure and growth dynamics of salt diapirs in the ZFTB by integrating geological field work, geochronological, geodetical and gravimetric survey datasets and geophysical data resources of the National Iranian Oil Company. Scaled analogue modelling with strain quantification system will be employed for simulating the deformation dynamics of the caprock sequences above the salt diapir extrusions. Our proposed research will improve our knowledge on: 1) the origin and composition of the caprock, 2) the deformation behaviour of the caprocks with different physical properties and their reaction on far-field and local strain, 3) the influence of caprock on short-term and long-term extrusion dynamics of underlying salt, and 4) the impact of the tectonic strain of the surrounding overburden on caprock deformation. We propose a novel and interdisciplinary approach by combining results from petrological and structural field mapping, space-geodetic measurements, geochronology, analogue modelling into a stratigraphic-geological framework model. The added value of the joint proposal lies in the multi-proxy integration of salt and caprock composition studies, measurements of active vertical surface motion with the structural mapping, geophysical measurements and modelling. Field work and data integration will be carried out jointly throughout the project. Our collaboration fosters training of early career scientists, female geoscientists, and enhances the intercultural academic exchange between German, Czech, Swiss and Iranian partners. An improved understanding of the caprock’s influence on salt dynamics will help to better understand salt dynamics in general, in particular for those systems of economic value that are not directly accessible elsewhere.