List of Articles
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Open Access Article
1 - Biostratigraphy of the Campanian-Maastrichtian deposits of the Gurpi Formation in Chenar anticline, Lorestan Zone and comparison with adjacent areas
Iraj Maghfori-Moghaddam ندا افروزهIn this research, biostratigraphic studies of the Gurpi Formation were carried out at the Chenareh section (Lorestan Zone). The thickness of Gurpi Formation at the studied section is 140 m and consists of limestobe, marly limestone and marl. The Gurpi Formation conforma MoreIn this research, biostratigraphic studies of the Gurpi Formation were carried out at the Chenareh section (Lorestan Zone). The thickness of Gurpi Formation at the studied section is 140 m and consists of limestobe, marly limestone and marl. The Gurpi Formation conformablely (with significant lithological changes) underlies the white limestones of the Ilam Formation and is covered by the sandstone of the Amiran Formation. On the basis of the recognized planktonic foraminifera, 7 biozone were reported as follows: Globotruncanita elevata Partial range Zone (Early Campanian), Globotruncana ventricosa Interval Zone (Middle to Late Campanian), Radotruncana calcarata Total Range Zone (Late Campanian), Globotruncanella havanensis Partial Range Zone (Late Campanian), Globotruncana aegyptiaca Interval Zone (Late Campanian), Gansserina gansseri Interval Zone (Late Campanian-Early Masstrichtian), Contusotruncana contusa Interval Zone (Late Masstrichtian). In the studied section, the Seymareh and Imam Hassan sections are not observed, unlike other sections in the Lorestan basin. The thickness of this formation in Chenareh anticline is much less than other sections in the adjacent areas. Manuscript profile -
Open Access Article
2 - بررسی خصوصیات فیزیکی و شیمیایی سیال کانه¬دار در رخدادهای سلستیت کمربند چین خورده-تراستی زاگرس؛ با استفاده از مطالعات ریزدماسنجی
مدینه ساعد Alireza Zarasvandi اکبر حیدری -
Open Access Article
3 - Physiochemical characteristics of oOre-bearing fluids for celestite occurrence in the Zagros fold-thrust belt: using microthermometry studies
رضوانه حمیدی Hojjat Ollah Safari مهاسا روستاییOilgocene-Miocene celestite occurrences are observed across the carbonate-evaporite formations of Asmari and Gachsaran in the Zagros fold - thrust belt. The aim of this research is the study of fluid inclusions in our celestite deposits (Tortab, Tarak, Likak and Babamoh MoreOilgocene-Miocene celestite occurrences are observed across the carbonate-evaporite formations of Asmari and Gachsaran in the Zagros fold - thrust belt. The aim of this research is the study of fluid inclusions in our celestite deposits (Tortab, Tarak, Likak and Babamohamad) to reveal the nature of ore-forming fluids. Abundant structures including: geodic and vein-like structures as open-space filling along with replacement textures like mosaic and vein-like in a carbonate matrix are present. Moreover, celestite, calcite, gypsum and anhydrite are observed as the major minerals in this deposits. Based on petrographic studies, 5 groups of fluid inclusions were recognised, which are categorized as: Liquid mono phase (L), vapour mono phase (V), liquid-rich two phase (LV), vapor-rich two phase (VL) and multi-phase fluids (LVS). The results obtained from the study of microthermometry data show 134.3 to 291.8°C as homogenisation temperatures and salinities of 2.5-18.17 wt%, NaCl equ, all are involved in forming celestite. Based on the results of microthermometry data, it can be deduced that formation mechanism of celestite is resulted from reaction between fluid and rocks of the area. Moreover, tectonic activities such as uplift and diagenesis of beds along with dissolution of minerals have caused release of strontium in the fluids responsible for ore-forming. This has generally undertaken by two fluids of meteoric and brine origins over different stages of ore-formation, replacing anhydrite with strontium at high temperatures during late- diagenetic and epigenetic processes. Manuscript profile -
Open Access Article
4 - Geology, mineralization and genesis of the Madabad celestite deposit, south Zanjan
مهسا نوری Hossein Kouhestani قاسم نباتیان میرعلی اصغر مختاری افشین زهدیRock units in the Madabad celestite deposit are composed of medium to thick-bedded and massive limestone interlayered with marly limestone and marl units of the Qom Formation (lower Miocene). Mineralization occurs as lens-shaped orebody, hosted by limestone units of mem MoreRock units in the Madabad celestite deposit are composed of medium to thick-bedded and massive limestone interlayered with marly limestone and marl units of the Qom Formation (lower Miocene). Mineralization occurs as lens-shaped orebody, hosted by limestone units of member of the Qom Formation usually crosscutting bedding of the host rocks. Three stages of mineralization occurred in the Madabad deposit. The first stage is characterized by calcite formation during syn-depositional to syn-diagenesis processes. The second stage is related to hydrothermal processes that are distinguished by formation of fine-grained and sugary crystals of massive stage-1 celestite, vein-veinlets of coarse-grained stage-2 celestite along with minor strontianite and barite, coarse-grained euhedral crystals of stage-3 celestite with vug infilling texture, and finally late-stage quartz and calcite vein-veinlets. Stage three includes supergene processes. Hydrothermal alteration includes dolomitization, calcitization and silicification. Celestite along with minor strontianite and barite are ore minerals, and calcite, dolomite, quartz and iron oxides-hydroxides are gangue minerals at Madabad. The ore minerals show vein-veinlets, vug infilling, brecciated and cataclastic textures. Microthermometric measurements of two-phase liquid-rich fluid inclusions hosted in celestite II indicate that salinities values range from 6 to 18 wt.% NaCl equiv. (avg. 10.6 wt.% NaCl equiv.). These inclusions have homogenization temperatures range from 248 to 365 °C, with an average of 278 °C. These data indicate a minimum trapping depth of 510 m for the Madabad deposit. Sr was originated from evaporate units within the marly parts of the Qom Formation and volcanic units of the Karaj Formation. Characteristics of the Madabad deposit are similar to epigenetic replacement celestite deposits. Manuscript profile -
Open Access Article
5 - Basic steps in determining the provenance of terrestrial sedimentary sequences, with examples from central and north west of Iran
عبدالحسین امینیBy stating the fundamental differences between terrestrial and detrital facies, this paper emphasizes on the limitations of provenance studies in terrestrial facies. Considering the presence of coarse-, medium- and fine-grained facies in most of terrestrial sedimentary MoreBy stating the fundamental differences between terrestrial and detrital facies, this paper emphasizes on the limitations of provenance studies in terrestrial facies. Considering the presence of coarse-, medium- and fine-grained facies in most of terrestrial sedimentary sequences, the differences in textural and mineralogical characteristics, their study methods and possible differences in the provenance of these facies, the basic and necessary steps in studying these facies for determining the sedimentary provenance was investigated. In explaining these steps, some examples from terrestrial formations of Central Iran (Upper Red Formation) and north west of Iran (Zivar Formation) are presented. The role of diagenesis, structural deformation and paleogeography in the provenance study and their importance in this type of studies are explained. Finally, it is discussed how to proof the accuracy of the interpretations for the studied sedimentary sequences. Manuscript profile -
Open Access Article
6 - The Iranian Plateau at the end of the Quaternary: new synthesis of geological, archaeological and historical data
Hamid Nazari Elahe Najar Jean franscois Ritz Mohammad Ali Shokri aram fathian fereidon Rezaei Alireza Rahim Hasan Fazali nashli Khalil Baharfirouzi hamed vahdatinasab alireza shahidi mahdi borzooii Elnaz AghaaliVia combining the geological, geochronological data with archaeological and historical data synthesis, it is shown that the northern part of the central plateau of Iran corresponded to a large lake, at the very end of the Pleistocene-early Holocene period.The morphologi MoreVia combining the geological, geochronological data with archaeological and historical data synthesis, it is shown that the northern part of the central plateau of Iran corresponded to a large lake, at the very end of the Pleistocene-early Holocene period.The morphological and stratigraphic markers of this ancient lake are still visible in some areas of the central plateau of Iran, especially in the Kavir desert, the Qom-Aran desert and the region of Masileh.The Paleo shorelines located at altitude of ~1100 m found in many places around the current Great Kavir depression is one of the most important signs that confirms the existence of an integrated lake, especially during the younger Dryas.Our geochronological data suggest that between the beginning of the Holocene (~11.5 ka) and 8 ka, the lake level gradually decreased by 250 m, to reach the altitude of 850 m.It is suggested that the cause of this lowering is the evaporation due to warmer and drier climate. According to absolute archaeological dating, the northern part of the Central Plateau has been inhabited by human communities for 50,000 years. From early Holocene; the first sedentary communities around 9,000 years ago provided the structure of rural communities in this part of Iran. From an environmental point of view, part of the water resources of these ancient settlements originated from the mountains of southern Alborz. Based on the newly found evidence of the present article, it can be assumed that in the current location of the Great Central Desert in the ancient world, freshwater lake or lakes provided suitable habitat, rich in biological resources, for prehistoric inhabitants. Manuscript profile