Number 38 Volume 10

Open Access Article

1 - Cruziana ichnofacies from Nayband Formation (Late Triassic) in the Parvadeh section, Southwest Tabas, East central Iran
Nasrollah Abbassi Mohammad ghavidel Morteza Yosefi Navid Navidi Izad

Nayband Formation is composed of sandstone, coal bearing shales, siltstone, and fossiliferous limestone in the southwest Tabas section, east central Iran. In this section, it is 1410 m in thickness and Late Triassic in age. A divers trace fossils have been found in the More

Nayband Formation is composed of sandstone, coal bearing shales, siltstone, and fossiliferous limestone in the southwest Tabas section, east central Iran. In this section, it is 1410 m in thickness and Late Triassic in age. A divers trace fossils have been found in the middle parts of sequence as 400-600 m. These trace fossils include Lockeia isp., Palaeophycus tubularis, Palaeophycus striatus, Planolites beverleyensis, Rhizocorallium isp., Rosselia isp., and cf. Treptichnus isp. This ichnoassemblage is attributable to Cruziana ichnofacies with presence of Lockeia isp., Rhizocorallium isp., and, Rosselia isp. This part of Nayband Formation was deposited in low energy conditions below fair-weather wave base. Manuscript profile

Open Access Article

2 - Introduction of Mari Copper Deposit as a Stratabound Manto-Type Copper Deposit in Tarom Zone, Northwest of Iran
Mehadi Moradi Sajad Maghfori Mohsen Moayyed Vahid Faridasl

Similar to other deposits of this type in the world, three major stages could be considered for mineralization in Mari copper deposit. The Mari Copper deposit is located in the northwest of Iran and Tarom metallogenic zone in the north of Zanjan. The ore-body is strata- More

Similar to other deposits of this type in the world, three major stages could be considered for mineralization in Mari copper deposit. The Mari Copper deposit is located in the northwest of Iran and Tarom metallogenic zone in the north of Zanjan. The ore-body is strata-bound and hosted by the Eocene mega-porphyritic andesites. The major copper sulfides are bornite, chalcocite, and chalcopyrite associated mainly with pyrite that represent open-space filling, disseminated, vein-veinlet, and replacement textures. The volcanic rocks of the study area mostly represent intermediate to acidic composition with high potassium shoshonitic magmatic series related to intra-arc rift environments. Wall rock alterations include carbonatization, chloritization, epidotization, and sericitization. The abundances of Cu and Ag in fresh mega-porphyritic andesite are up to 3200 and 216 ppm respectively. Based on the main characteristics of Mari ore body such as tectonic setting, host rock, strata-bound form, mineralogy, metal content, and wall rock alterations and comparison of these features with Manto - type copper deposits, Mari Cu deposit can be introduced as a Manto -type Cu deposit in NW Iran. The first stage includes submarine volcanic activity and eruption of mega-porphyritic andesitic lava associated with regional propylitic alteration. In the second stage, the early diagenesis and the activity of sulfate-reducing micro-organisms resulted in the generation of pyrite in the form of open-space filling and disseminated in the mega-porphyritic andesite. Finally, in the third stage, increasing of the thickness of sediments, basin subsidence, and burial diagenesis accompanied with the entry of metal-rich fluids into the reduced host rock, caused the replacement of the first stage pyrites by copper sulfides and mineralization in the Mari deposit. Manuscript profile

Open Access Article

3 - The Effect of uplift rate on geomorphic indices: insight to Misho Complex NW Iran
Mehdi Behyari Mohammad Mohajjal Mohsen Moayyed Mahnaz Rezaeiyan

The Misho Mountain is a prominent topographic feature in the North-West of Iran. This mountain is bounded with series of major active faults. Spatial array of these faults caused an uplift in the study area, and exposure of Kahar Formation in the core of the mountain. T More

The Misho Mountain is a prominent topographic feature in the North-West of Iran. This mountain is bounded with series of major active faults. Spatial array of these faults caused an uplift in the study area, and exposure of Kahar Formation in the core of the mountain. The active deformation affected topographic feature and changed the uplift rate. In this research we tried to quantify variation of uplift rate by using geomorphic indices and thermochronometry data. The analysis of stream length gradient, mountain front morphology, valley shape, and basin morphology indicated that uplift rate decreased from North to South and West to East. Hypsometric integral, which was calculated for the northern and southern flanks of Misho Mountain, also shows mature stage for the Southern flank, but in the Northern Misho tectonic activity increased and consequent;y show unstable state. Comparing between maximum and minimum swath profile in the west, central and east Misho indicated that in the west Misho the min and max swath profile indicate greater difference and show rapid uplift in the west Misho. Thermochronologic data show that rapid exhumation commenced by 21-22 Ma (Miocene), and an uplift rate of 0.16 to 0.24 Km/Ma was estimated. We propose that the range might be exhumed diachronously along strike and the magnitude of exhumation decreases to the ESE. This result is supported by structural and stratighraphy of study area. Manuscript profile

Open Access Article

4 - Mineral chemistry and P-T estimation of formation of garnetschist Mount Argon (west of Angoran Mine)
Moazzen Izadyar

The Mount Argon garnet schists contain mineral assemblages of quartz, feldspar, mica and garnet. The chemical composition of, plagioclase, biotite, muscovite and garnet in the studied sample shows that plagioclases are albite-rich, white mica flakes are rich in muscovit More

The Mount Argon garnet schists contain mineral assemblages of quartz, feldspar, mica and garnet. The chemical composition of, plagioclase, biotite, muscovite and garnet in the studied sample shows that plagioclases are albite-rich, white mica flakes are rich in muscovite end-member, phlogopite-annite is the dominant constituent in biotite and chemical composition of the analysed garnets shows that they are almandine and spessartine-rich. Maximum and minimum pressure and temperature of the studied rocks were estimated by using common calculation methods. The minimum and maximum temperature of metamorphism was calculated using Mg-Fe exchange between garnet and biotite. Considering a nominal pressure of 4 kbar, the highest calculated temperature was 615C and the lowest temperature was 380C. These were 644C and 392C for pressure of 8 kbar respectively. Also using multi-equilibria calculations, temperature of 800C and pressure of 9kbar were obtained for the peak of the metamorphism and temperature of 450C and pressure of 7kbar was calculated for the lower part of the metamorphism. . Two phases of metamorphism and deformation affected these rocks. The second deformation was associated with the peak of metamorphism. A decrease in temperature about 351°C with reduced pressure of about 2 Kbars is observed in the metapelitic rocks. Manuscript profile

Open Access Article

5 - Robustness of fuzzy c-mean method for delineation of hydrochemical facies distribution of groundwater in Varamin Plain
Mohammad Nakhaei Mehdi Talkhabi Meysam Vadiati

In this paper, classification of a large hydrochemical data set from Varamin plain is done by using fuzzy c-means (FCM) and hierarchical cluster analysis (HCA) clustering techniques. Then its application to hydrochemical facies delineation is discussed. Groundwater samp More

In this paper, classification of a large hydrochemical data set from Varamin plain is done by using fuzzy c-means (FCM) and hierarchical cluster analysis (HCA) clustering techniques. Then its application to hydrochemical facies delineation is discussed. Groundwater samples were grouped into three classes according to the optimum number of the classes and fuzziness exponent by using the fuzzy c-mean. The data set includes 90 deep and moderate deep well samples from groundwater data set and 9 hydrochemical variables were used. Results from both FCM and HCA clustering produced cluster centers that can be used to identify the physical and chemical processes creating the variations in the water chemistries. The optimum cluster in FCM method determined by optimization function, but in HCA method by trial and error. The FCM method is potentially useful in establishing hydrochemical facies distribution and may provide a better tool than HCA for clustering large data sets when overlapping or continuous clusters exist. Plotting the cluster membership value contours on a map demonstrated the existence of three spatially continuous, well-defined clusters of groundwater samples. The results showed that the FCM method is more sound for investigating threshold data rather than HCA method (that represents sharp and abrupt variations). Manuscript profile

Open Access Article

6 - Geochemical and Tectonomagmatic analysis of dibasic dikes and basaltic lavas in the Noorabad ophiolite (North-West Lorestan)
Ahmad Ahmadi Khalaji mehrdad kiani Zahra Kamali Hadi Shafaei Moghadam asadollah kordnaeij

The Noorabad ophiolite is a part of Eastern Mediterranean-Zagros-Oman Tethyan ophiolites, cropping out in south-southwest of the Main Zagros Thrust fault. In this sequence of the ophiolite rocks, diabase dikes and basaltic lavas are widespread. The chemical composition More

The Noorabad ophiolite is a part of Eastern Mediterranean-Zagros-Oman Tethyan ophiolites, cropping out in south-southwest of the Main Zagros Thrust fault. In this sequence of the ophiolite rocks, diabase dikes and basaltic lavas are widespread. The chemical composition of these rocks comprise sub-alkaline basalts, andesitic basalt and andesite. According to normalized REE diagrams to the chondrite and trace elements normalized to the primitive mantle, these rocks show calc-alkaline series, the enrichment of LREE and LILE and depletion of HFSE elements. The characteristics of these ophiolites are similar to other exposed Tethyan ophiolites along Bitlis-Zagros suture zone, and their formation is associated with supra-subduction zones. Manuscript profile

Open Access Article

7 - Determination of parental melt nature and evolutions of volcanic rocks in Sarchah geological map area (southern Khorasan) based on isotopic data
Esmaeil Allahpour Mansor VosoghiAbedini Seyed Mohamad Pourmoafi

The 1/100000 geological map of Sarchah area in southern Khorasan province lies at 59˚,30′ to 60˚east longitude and 33˚to 33˚,30′ north latitude. The plain is covered by a wide spectrum of volcanic rocks with a compositional diversity from basic to acidic. In this More

The 1/100000 geological map of Sarchah area in southern Khorasan province lies at 59˚,30′ to 60˚east longitude and 33˚to 33˚,30′ north latitude. The plain is covered by a wide spectrum of volcanic rocks with a compositional diversity from basic to acidic. In this research he parental melt's nature and evolutions via isotopic studies and measurements were studied t. Isotopic correlation plots of 143Nd/144Nd versus 87Sr/86Sr (Zindler and Hart, 1986) showed that extrusive igneous rocks found in this area were originated from those parts of mantle affected by subducted lithospheric slab or metasomatized by crustal substances. As a result, it is necessary to consider the role of parameters such as crustal mingling in dasitic-rhyolitic rocks formation Rhyolitic rocks are significantly affected by crustal materials. These rocks are characterized by higher levels of 87Sr/86Sr and lower levels of 143Nd/1444Nd. Manuscript profile

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