Seismic Activity and Fractal Geometry of Kareh Bas Fault System in Zagros, South of Iran

Kareh Bas is one the transverse fault systems in Zagros fold-thrust belt. Kareh Bas Transcurrent Fault System with a total length of 200 Km is situated about 80 Km east of the Borazjan segment (a part of Kazerun fault zone) and 40 Km west of Shiraz. It is a nearly N-S trending right-lateral linked strike-slip fault system, and several anticlinal axes have been displaced by it. Strike separation (109 Km) of Mountain Front Fault/Flexure (MFF) of Zagros is the most important function of Kareh Bas Transcurrent Fault System. According to fractal analysis (Box-counting method) on space image maps (1:50,000) prepared from Spot data, fault related surface ruptures have non-linear patterns and fault segments have nearly plane form fractal dimensions;specially at north and south terminations. It means that, the north and south terminations of Kareh Bas Transcurrent Fault System are active (earthquake fault segments) and latter case is more active, because it is coinciding on Zagros mountain front faults (MFF).

Fault Movement Potentials in the Tehran-Semnan Region (North Iran)

The major Quaternary faults in the Tehran-Semnan region can be classified based on their strikes into three sets: northeast-southwest, northwest-southeast and east-west. In this paper, we use a model to evaluate fault movement potential (FMP). Their theoretical model is based on the relationship between fault geometrical characteristics and regional tectonic stress field. The results show that The Mosha, Emam Zadeh Davood and Pourlcan-Vardij fault zones have high FMP (0.9 or 90%) and the Parchin fault zone has very low FMP (0.0 - 0.1) in the area.

The Biggest Salt-Tongue Canopy of Central Iran

One of the most interesting salt structures is salt-tongue canopy. The Central Iran basin has a few salt provinces and in this paper, morphotectonic concept of the salt-tongue canopy on the west of Garmsar city has been investigated. In this study, field data coupling with the salt tectonic-related factors to provide a position for salt rocks in the west Garmsar. Firstly, various geological factors such as faults, folds and roads were extracted and compiled. This is because the factors mentioned above play important role in the instability of the region. The results of this study showed that the salt extrusion from the Lower Red formation is severe. Further, it is evident that the shortening of main structures has had a great impact on it whilst the salt movements have occurred within Garmsar Syncline. Finally, the paper concluded that the salt-tongue canopy in the region has increased the rates of salt extrusion.

Tectonic Geomorphology of Iran’s Salt Structures

Iran has a various salt structures that their tectonic geomorphology is subject of this paper. Geologic situation of salt structures in Iran have determinate. According to age and geological setting of salt deposits that revealed by tectonic geomorphology methods, salt structure provinces of the Central and Southern Iran have been distinguished. Also, critical concepts of salt diapirism in the Southern Iran and Central Iran salt basins have explained. Therefore, Central Iran’s salt diapirs have triggered by tectonic forces, but salt diapirism in the Southern Iran has triggered by halokinesis, then it has effected by tectonic forces, especially in Zagros fold and thrust belt.

Microbiostratigraphy of the Sediments of Talezang Formation in Ghalebi Section (Southwest Lorestan, Iran)

In the present paper, Talezang Formation, located in southwest of Khoramabad, is studied. Ghalebi section (200 m thickness) contains gray limestones with cherty nodules and sandy limestone isoclinally overlies Amiran Formation (gray shale and limestone). It is underlain concordantly and discontinuously by Kashkan Formation. 160 samples are surveyed (examined) from the section;28 genera and 4 species of benthonic foraminifera and 6 genera and 2 species of algae are identified. Due to similarity between identified benthonic foraminifera and Miscellanea-Kathina Assemblage Zone, the age of Talezang Formation can be assumed late Paleocene (Thanetian).

A Review on Fossil Findings of Central Iran’s Permo-Triassic Deposits

In this research, a review was done on Permo-Triassic deposits in Central Iran including Abadeh, Hambast, and Elika formations. Following an overview about the circumstances of Central Iran Basin during Permotriassic time interval, the respective formations are introduced, and then, history of paleontology studies on these deposits will be depicted. Through analysis and comparison of previous studies, the following ages were estimated for the aforementioned formations: Early Dzhulfian for Abadeh Formation, Late Dzhulfian-Dorashamian for Hambast Formation, and Early Triassic (Scythian) for Elika Formation. Also, Permotriassic boundary in Central Iran is continuous, bearing the proposed sedimentation and fossil content. It is noteworthy that due to volcanic events at the boundary of these deposits in Central Iran, one might infer that occurrence of the aforementioned activities has been among the major causes of the respective extinction.