Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Structural analysis of the East Band-e-Lengeh anticline (Southeast of Zagros) based on subsurface data and seismic line interpretation

Document Type : Original Research Paper

Authors
Zahra Mollaali 1
, Seyyed Ahmad Alavi 1
Mohsen Ehteshami Moeinabadi 1
Seyyed Farajollah Mirhashemi 2
1 Department of Sedimentary Basins and Petroleum, Faculty of Earth Sciences, Shahid Beheshti University, Tehran, Iran
2 Department of Exploratory Geology, Exploration Directorate, National Iranian Oil Company, Tehran, Iran
10.22071/gsj.2025.500479.2176
Abstract
This study investigates the geometry and folding pattern of the East Band-e-Lengeh anticline, located in the Coastal Fars subzone, using 5 structural cross-sections and one longitudinal section derived from seismic line data, geological maps, and exploratory well data. The analysis reveals that the anticline is an almost symmetric fold with an overall elliptical to box-shaped geometry. Based on structural studies and interpretation of seismic lines, the southern limb of the East Band-e-Lengeh structure is affected by a reverse fault originating from the Dashtak formation. According to calculations using the excess area method, the folds detach at a depth of approximately 11 km, indicating that the deformation mechanism of the sedimentary cover in this anticline is a faulted detachment fold. Tectonic thickening of evaporites in the Dashtak formation (Middle Triassic) occasionally forms a detached horizon within the sedimentary cover, altering the geometry of Mesozoic and Cenozoic formations compared to the reservoir horizon of the Dehram group (Permo-Triassic) and causing axial shift. A UGC map of this horizon has been generated to explore the saddle-shaped relationship between the central segment of the anticline and its eastern segment and evaluate the exploration target horizon (Dehram group). Based on cross-section balancing using the bed-length conservation method, the shortening of the anticline is estimated at approximately 4%.
Keywords
Band-e-Lengeh anticline
Faulted detachment fold
Coastal Fars
Dehram group
Seismic Lines
UGC Map

Subjects

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Scientific Quarterly Journal of Geosciences
Volume 35, Issue 2 - Serial Number 136
Summer 2025, vol. 35, Issue 2, Serial no. 136
Spring 2025
Pages 101-122