Spatial differences of Quaternary deformation and intensity of tectonic activity are assessed through a detailed quantitative geomorphic study of the fault-generated mountain fronts and alluvial/fluvial systems around the Maharlou Lake Basin in the Zagros Fold-Thrust Belt of Iran. The Maharlou Lake Basin is defined as an approximately northwest-southeast trending, linear, topographic depression located in the central Zagros Mountains of Iran. The lake is located in a tectonically active area delineated by the Ghareh and Maharlou faults. Combined geomorphic and morphometric data reveal differences between the Ghareh and Maharlou mountain front faults indicating different levels of tectonic activity along each mountain front. Geomorphic indices show a relatively high degree of tectonic activity along the Ghareh Mountain Front in the southwest, in contrast with less tectonic activity along the Ahmadi Mountain Front northeast of the lake which is consistent with field evidence and seismotectonic data for the study area. A ramp valley tectonic setting is proposed to explain the tectonosedimentary evolution of the lake.

AbstractKinematic analysis of mélange fabrics provides critical information concerning tectonic processes and evaluation of the kinematics of ancient relative plate motion. Systematic kinematic analysis of deformed structures within a tectonic mélange exposed along the Zagros Suture Zone elucidates that this zone is an ancient transpressional boundary. The mélange is composed of a greywacke and mudstone matrix surrounding various lenses, blocks and ribbons of radiolarian chert, limestone, sandstone, pillow lava, tuff, serpentinite, shale and marl. The deformation fabrics of the mélange suggest that the mélange units were tectonically accreted at shallow levels within a subduction complex, resulting in layer-parallel extension and shearing along a NW–SE-trending suture that juxtaposes the Afro-Arabian continent to the south and the Central Iranian microcontinents to the north. The tectonic mélange is characterized by subhorizontal layer-parallel extension and subsequent heterogeneous non-coaxial shear resulting in alternating asymmetric and layer-parallel extensional fabrics such as P–Y fabrics and boudinaged layers. Kinematic data suggest that the mélange formed during oblique subduction of the Neo-Tethys oceanic lithosphere in Late Cretaceous time. Kinematic shear sense indicators reveal that the slip direction (N9°E to N14°E) during accretion-related deformations reflects the relative plate motion between the Afro-Arabian continent and Central Iranian microcontinents during Late Cretaceous to Miocene times.

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Fractures within a reservoir play an influential role in the porosity and permeability, therefore affect the fluid flow. By analyzing properties of fractures, such as fracture height, density and mutually spacing and compare them with different tectonic locations and different lithologies, one could gain insight in the mechanical behavior of a rock mass, when distorted by tectonic forces. The velocity deviation log (VDL) can be used for determination of effective porosity. The result indicated that there is a high fractures density in the Asmari Formation which shows high correlation with VDL. They are mainly strike N75E, S75W direction and are chiefly observed in the upper Asmari zones. Fractures and vuggy have been also observed in the well. Image log showed a range of bedding dip from 53-89 degree with strike N55W, S55E in the well indicating of reverse limb in the field. Image log show tow set fracture which azimuth 347 for discontinuous fracture and 220 with strike N55W, S55E for continuous fracture. Main type of lithology determined by petrophysical log showed that dolomite is dominant constituent. Induced fractures and breakouts haven't seen observed in this well. After correlating image logs with VDL and lithology, zones with dominant pure dolomite presented higher aperture rather zones with dolomite and anhydrite. Fracture density is more affected by bed thickness to mineralogy. Zones with negative deviation velocity have high fracture density or high fracture aperture.

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