Hydrocarbon Trap and Folding Style of the Pishvar Anticline, Sub-Coastal Fars, Zagros

The Pishvar anticline with Northwest-Southeast trend is located in the Sub-Coastal Fars area. This anticline with 80 Km length and 5 - 7 Km width is located in western part of the Lar area. The Pishvar anticline has two closures that are separated together by smooth down-warp. The oldest units that have outcropped on the surfaces are Asmari and Jahrom Formations. The most faults that observed on the Pishvar anticline are Normal fault. In the study area, the Razak and Hendurabi faults are main faults. These faults are strike slip with sinistral displacement. This anticline has greater dip in Northern flank compared to Southern flank. In this research, the main aim is folding style analysis, based on Description of fold geometry for indicate hydrocarbon trap structure in the Pishvar anticline. Description of fold geometry is important because they allow comparisons within and between folds and pattern-recognition in addition to occurrence and distribution of fold systems. We used Tectonics FP and Global Mapper Software for prepared some data in our study. In addition, we used the common classification of folds for our research. Based on results, the folding pattern of this anticline has indicated the fold style has different type in different parts of the Pishvar anticline. According to fold style variation and deformation analysis from B-B’ to C-C’ parts of the study anticline, it seems that the location of the Razak sinistral strike slip fault has existed in this parts. Fold style change can show this case. In addition, fold style variation and deformation analysis from E-E’ to F-F’ parts of this anticline has been affected of the secondary fault that is related to the Razak sinistral strike slip fault. We introduced this fault for first time. Finally, Based on results in this research, in western part there is little probability for access to hydrocarbon trap in upper horizons, unless the exploratory drilling continues to the deeper horizons.

Structural Style in the Zagros Fold-Thrust Belt: The Gavbast Anticline, Coastal Fars

The Gavbast anticline is located in the Coastal Fars area of the Zagros folded belt, with north-south trend. The study anticline is restricted to the Bavush and Paskhand anticlines from North, the Gezzeh and Dehnow anticlines from South, the Varavi anticline from West and Nakh anticline from East (Figure 1). Description of fold geometry is important because they allow comparisons within and between folds and pattern-recognition in addition to occurrence and distribution of fold systems. The main goal of this paper is to define folding style of the Gavbast anticline and define structural features affected on them in the study area. In this research, we used the Tectonics FP software, Global Mapper software and geological maps and reports of Iranian National Oil Company. In addition, we used common classification of fold for indicating of folding mechanism of the Tabnak anticlinal structure. In the Gavbast anticline, fold style elements in all parts of this anticline have been calculated and analyzed for indicating of folding style mechanism. The results of this method have been shown the folding geometry changes accurately. The Gavbast anticline is gentle in structural sections D-D' and G-G' to K-K'. The anticline is an open fold in the L-L' section. Also fold type in the E-E' and F-F' sections of the Gavbast anticline is steeply inclined sub-horizontal. These sections are located between the Razak (western part) and Hendurabi fault (eastern part). It seems that E-E' and F-F' parts in the Gavbast anticline have been suffered most deformation affected by the Razak and Hendurabi faults. At the end of, it seems that, the Razak and Hendurabi faults have major effects on folding style. This structure is a very good sample for effect of strike slip faults on the folding geometry and for this reason;the Gavbast anticline is considered a special structural style in the Zagros fold-thrust Belt.