RESEARCH JOURNAL OF UNIVERSITY OF ISFAHAN "SCIENCE"
Year:2003 | Volume:18 | Issue:2|Papers Count:9

Sampling from the Cenomanian rocks in Kerman province (Sekonj - Gloosalar) has been made in several different sections. A detailed study of benthic foraminifera indicated that dominant benthic foraminifera belong to 7 different genera including Nezzazatinella picardi, Pseudolituonella reicheli, Cuneolina pavonia, Dicyclina schlumbergeri, Orbitolina spp., Dictyoconus arabicus, and Iraqia simplex.Based on dominant benthic foraminifera, three different assemblages have been recognized. The assemblages are controlled mainly by paleoecological and biological changes.  

The subject of the Zagros basement has been discussed for a long time; but the Zagros basement rotation and its movement from Minab to Qatar-Kazerun faults has been discussed only in few papers without any attention to its details. The main objective of this paper is calculation of real distribution of linear movement in the basement from Minab to Qatar-Kazerun faults. Since any correct and basic model of the region structures should be based on real data, therefore at first, we proved the basement rotation by studying the whole existing features. Then the rate of rotational movement for Saudi of Arabia plate, based on geometrical movement theories and calculated velocities of the opening and displacement in the Red sea and Gulf of Aden was measured. Finally, by adding the vectors of displacement and rotational movement of basement, the distribution of linear movement for different points of basement was determined.  

Plant remains, mainly occurring as leaves from strata of Hojdek Formation, exposed near th Dasht-e-Khak village, along the Zarand - Kuhbanan road are identified and described briefly. They include 6 genera as Ptilophyllum, Sagenoptris, Cladophlebis, Pterophyllum, Nilssonia and Pagiophyllum. The ecology of tlora is discussed as well. Plant remains confirm the age of Middle Jurassic for the Hojdek Formation in this area.  

The genus of Ripidiorhynchus belongs to Rhynchonellida order, and its type species is the genus of Ripidiorhynchus livonicus (von Buch, 1834). The genus has twenty four species, and these species are distributed in different regions of the world such as: Iran, Afghanistan, Germany, Spain, USA, England, Northern Africa, Azerbaijan, Belgium, Tadjikestan, Turkey, Pamir, Czechoslovakia, Russia, France, Caucasus, Kazakhistan, Kirgizia, Poland and Ural, Tiana-Chan and Timan mountains. The age of Ripidiorhynchus in these regions is Early Frasnian - Middle Famennian. This genus in Iran has five species: Ripidiorhynchus barroisi, Ripidiorhynchus elburznsis, Ripidiorhynchus kermanensis, Ripidiorhynchus kotalensis, and Ripidiorhynchus minutissimus. These species have been found in Central Iran (Esfahan, Soh, Anarak, Kerman, Ozbak-Kuh) and Alborz (Central-Eastern Alborz) regions in Jeirud, Khoshyeilagh and Bahram Formations. The age of these species is Middle-Late Frasnian. Consequently, Ripidiorhynchus genus may be used as stratigraphic tool in a global scale, due to its relatively long-range age. In Iran, however, the genus can be used as a valuable stratigraphic tool, because of its short-range age and wild spread.  

In order to determine the microfacies and sedimentary environment of the Sarvak Formation, one stratigraphic column in SW of Semirom (Landaran Anticline) was sampled and studied. In the studied area the Sarvak Formation is a thick carbonate succession which deposited in Cenomanian-Turonian. Facies analysis and petrographic studies led to recognition of 7 microfacies of the open marine, shoal, barrier, lagoon and tidal flat sub-environments. The absence of slump, turbidite currents and reef indicate that the carbonate platform of the Sarvak Formation is a homoclinal ramp. Presence of shell fragments of rudist and peloids indicate a photozoan assemblage which formed under a tropical condition.  

Cretaceous deposits crop out in Abadeh, Eqlid and Bavanat in various parts of Sanandaj-Sirjan zone.For the purpose of stratigraphic study of Cretaceous rocks in this zone, three stratigraphic sections were studied and measured. These sections are located in south of Bavanat as well as south and north of Eqlid. Stratigraphic and paleontology observations indicate the Barremian-Aptian age for the deposits of the area studied. North Eqlid sedimentary rocks have Urgonian fades the same as of central Iran but South of Eqlid and Bavanat deposits are similar to SW. Iran (Zagros). Cretaceous deposits in Sanandaj-Sirjan formed on carbonate plateform composed of four sub-environments including open marine, bar, lagoon and tidal flat.  

The studied area is 30 Kilometers from western Abarkuh and near the south-east Abadeh between Yazd and Fars province. Permian sedimentary rocks in this area have about 1200m thickness covered by Triassic rocks. These eleven sedimentary microfacies are recognized through studying these rocks. These eleven microfacies occurred in four groups including open marine, bar, lagoon, and tidal flat and each of these microfacies owns the characteristics of one of them. Sea level changes caused these microfacies and accommodation changes produced a sequence with 7 sedimentary cycles (3-order).  

The Devonian rocks are exposed in Chah-Riseh which is 55 Kilometers from northeast of Isfahan. These rocks, with 590m. thickness are composed of sandstones, shales, dolomites, and calcareous marl. Based on field studies and 200 thin section, three clastic and thirteen carbonate microfacies were recognized. These microfacies are deposited in tidalflat, lagoon, bar and open marine sub-environment of an epicontinental sea. Vertical changes in microfacies and their depth change diagram showed that upper Devonian rocks in this area were composed of meter scale parasequences. They generally showed million years-scale transgressive.  

The late stage phases of Shirkuh batolite granitization have caused the various hydrothermal alterations and Fe-Cu sulphide mineralization in post Cretaceus. The mother rocks which have undergone alterations are arkosic sands tones and conglomerates that belong to Sangestan formation. Oxidation of such sulphides in supergen environments has released acidic solutions with copper. These solutions are responsible for acid-sulphate alteration. Also the apatites from arkosic rocks are leached by these solutions. Finally turquoise is formed due to phosphatization of alunites or the interaction of necessary components that exist in such solutions as veinlets or grains.