InSAR surface deformation and numeric modeling unravel an active salt diapir in southern Romania

Iuliana Armaş,Vlad Constantin Manea,Marina Manea,Mihaela Gheorghe

doi:10.1038/s41598-021-91517-4

Iuliana Armaş, Vlad Constantin Manea + Show 2 more

Open Access

https://doi.org/10.1038/s41598-021-91517-4

Copy DOI

Abstract

Salt diapirism is often associated with potential hydrocarbon energy resources, and detecting active diapirs can strongly affect the prospect to discover new gas and oilfields. Here we use InSAR techniques as a proxy to evaluate surface deformation in the Diapiric Fold Zone located in the East Carpathians Bend. Significant surface uplift (~ 5 mm/year) is identified in a relatively small region not previously known for the presence of an actively rising salt diapir. Using high-resolution two-dimensional thermomechanical numerical simulations of salt diapirs intrusions, we show that that the observed surface deformation can be induced by a relatively small salt diapir (1–2 km in diameter) rising from an initial salt layer located at < 7 km depth. We constrain the salt diapir viscosity by comparing the InSAR surface deformation pattern with results from numerical simulations and our best fitting model is obtained for a salt viscosity of 1 × 1017 Pa s. The best fitting model reveals the presence of a relatively small salt diapir that has not pierced yet the entire sedimentary layer and is located just 1–2 km below the surface.

Highlights

For more than a century and a half, salt tectonics represented a key research topic closely related with the formation and evolution of major hydrocarbon provinces
The present study region is limited to a small part within the Diapiric Fold Zone (DFZ) where we evaluate spatial–temporal variations in deformation using InSAR, extending this research to other areas would be an interesting research topic to pursue in the future
Using InSAR techniques, we can estimate the magnitude of surface uplift without a detailed knowledge of actual subsurface geology and tectonic processes both of which vary from region to region

Summary

Introduction

For more than a century and a half, salt tectonics represented a key research topic closely related with the formation and evolution of major hydrocarbon provinces. Numerical investigations started to employ innovative schemes based on viscoplastic rheology which allows to study large nonlinear deformations, which are not specific for salt d iapirism[26,27,28,29,30] Despite their limitations, numerical and analogue modeling proved to be a powerful tool in understanding salt diapir formation and evolution in the context of sedimentary basin tectonics[4,27,30,31]. This study shows that the combination between InSAR and numerical modeling technique represents a powerful and cost-effective tool for preliminary identification and space–time tectonic evolution investigation of unknown active salt diapirs

Methods

Results

Conclusion