فهرست مطالب سید حسن حجازی

The Vazhnan Formation in the Shahreza-Abadeh belt, apparently extending from latest Carboniferous to Asselian, consists of conglomerate, limestone, sandstone and shale, which is correlative to the Dorud Formation of the Alborz Mountains and the Zaladou Formation of Central Iran. This work is presenting some results on revision of the lithostratigraphy of the Vazhnan Formation in the Tang-e-Darchaleh section (northeast of the Shahreza town). Introduction of this interval in the Banarizeh section (north of the Abadeh town) and correlation of the Vazhnan Formation in the sections understudied are other purposes. Based on the results of this study, Vazhnan Formation in the Tang-e- Darchaleh (as the type section) and Banarizeh (as the reference section) section is distinguished with the distinct eroded surface at the base and rests disconformably on the sandstones of Late Carboniferous, corresponding to the Sardar Formation. The upper part of this interval is disconformably overlain by the Surmaq Formation (late Early–Middle Permian) in the Banarizeh section. Field investigations revealed that the contact between the Vazhnan and Surmaq Formations in the Tang-e-Darchaleh section is faulted. The vertical and lateral changes of the lithofacies in the Vazhnan Formation indicate the depositional system which is evolved from a distal into a homoclinal ramp setting.

The khas-e Tarash cave is one of the caves of the Isfahan region that can considers as a Geo-touristic area. This cave is a limestone cave and based on speleology is located in vadose area. This cave is located near khas-e Tarash village, about 55 Km away from the city of Isfahan. Studying formation of cave is very important in speleological studies. Tectonic is the main factor of khas-e Tarash cave forming. Its architecture is based on backup process which caused widening, cutting of rock blocks and gaps that redound to form the passages and halls. According to the cave classifications, this cave is an irregular fissure network cave.

The Aghajari Formation, known also as Upper Fars, extends throughout the Folded Zagros and its thickness in the type section is about 2966 m. To determine the sedimentary environment of this formation according to the lithofacies and architectural elements, a section, with a thickness of 2266 m, was measured in SW of Sarvestan in Fars Province. In this section, 17 lithofacies and 6 architectural elements were identified. The lithofacies were divided into two groups: a major group and a minor group. The major group consists of coarse-grained (Gh, Gp, Gt, Gcm, Gmg), medium-grained (Sh, Sp, St, Sl, Sm, Sr, Ss) and fine-grained (Fm, Fl, Fsm) lithofacies and the minor group consists of evaporate and mixed carbonate-terrigenous lithofacies. The identified architectural elements are CH, GB, SB, LA, SG and FF. According to the evidences due to lithofacies analyses and architectural elements and their incorporation, The Aghajari Formation in the studied section was divided into three parts. The sedimentary environments of the above-mentioned deposits, from top to the bottom, are gravelly meandering river, sandy-gravelly meandering river and ephemeral sandy meandering river. The most important sedimentary structures are horizontal bedding, cross bedding, load-cast, imbrications, graded bedding, turbulence traces, scour and fill and ball and pillow structures. Using some of these structures, the palaeocurrent direction in the studied area is measured as NW-SE during sedimentation. These data can be used in the interpretation of the basin and reconstruction of the palaeogeography in the local and regional scale.

The Givetian-Frasnian sandstones in the Kuh-e-Tizi section (25 km NE Kerman), unconformably overlie the Upper Cambrian Kuhbanan and underlie the Lower Carboniferous Hutk Formations respectively, in southeastern Central Iran. Petrographical data show that these sandstones are well-sorted, sub-angular to rounded quartzarenite. Diagenetic features include physical and chemical compactions (straight, concavo-convex, sutured grain contacts and pressure solution of quartz grain), reduction of the pore space through rearrangements and cementation (mostly silica, as quartz overgrowth). The provenance and tectonic setting of these sandstones have been interpreted using integrated petrographic and geochemical data. Petrographic analysis using standard methods revealed that mono and poly-crystalline quartz grains have been derived from plutonic rocks of an interior cratonic setting. Trace element analyses and their ratios used for provenance studies (Th/Sc and La/Sc) are similar to sediments derived from weathering of mostly felsic rocks. Values representing chemical index of alteration (CIA) and the plagioclase index of alteration (PIA) range from 44.24 to 83.43, with an average of 69.96, and from 42.98 to 92.56, with an average of 75.8, respectively. However, most samples have values greater than 60, suggesting moderate to high weathering in the source area or during transportation prior to find deposition. Major and trace element concentrations indicated a depositional setting in a passive continental margin.