فهرست مطالب حامد زندمقدم

The geochemical separation pattern and environmental behavior of rare earth elements (ΣREE) have been investigated in 5 different sedimentary systems related to the Dar-e-Allo copper mine. For this purpose, the total concentration and sequential patterns of ΣREE elements were determined using multi-acid digestion and mBCR (Modified Community Bureau of Reference, European Commission) selective extraction method. The normalization patterns of the total concentration of ΣREE are drawn based on the average North American Shale Composition (NASC) and Upper Continental Crust (UCC). General trends of concentration changes in the five sedimentary systems are very similar to each other, and the concentration of LREEs is higher than that HREEs, just a sample taken from under the rock dump that contains sulfide-leached elements shows a pattern different from other samples and standard patterns. Opposite of the changes in the concentration of ΣREEs, more enrichment is seen in HREEs compared to LREEs. This pattern of enrichment changes is consistent with the higher tendency of HREEs than LREEs for mobility during weathering and oxidation. The geochemical separation patterns of ΣREEs in natural sediment and samples containing iron and manganese oxides are mainly dominated by the residual fraction. Surprisingly, considering the different conditions of formation and stability in the samples taken from the waterways leading to the mine, evaporite deposits and sediments washed from the rock dump, the separation pattern of ΣREEs is controlled mainly with two parts soluble in Acid and reducible fraction. According to the enrichment trends, the trend of mobility and bioavailability from LREEs to HREEs increases with an upward slope. These results show that speciation, geochemical separation pattern and environmental behavior for ΣREEs without considering key environmental factors lead to a lack of understanding or even misinterpretation. The results of this study can be used as a reference in organizing the mine development and environmental planning of the Dar-e-Allo copper mine.

The Pliocene-Quaternary sediments of the southern plain of Rafsanjan (west of Kerman province), have a variety of sedimentary copper minerals which can be used as gemstones and suitable for minerals/rocks colledctioners. The most important copper identified minerals include malachite, azurite, atacamite and paratacamite. Copper mineralization in this sequence is observed in three forms: cement (in conglomerates), nodules (in sandstones and tuffaceous mudstones), and alternating parallel to cross-laminations with calcite (travertines). The first two groups have only a decorative value, but the third group has the potential for jewelry making and is therefore presented as a gemstone. The leaching of copper from porphyry copper deposits in the upstream area (related to the Dehj-Sardouyeh belt) followed by the enrichment and deposition of copper in the young deposits downstream is considered the most probable model for the copper mineralization in the studied deposits. These deposits are called as exotic copper deposits.

The present study has been performed to evaluate the prospective effects of activity mining on the mineralogy of sediments in the Dar-e-Allo copper mine, south of Kerman. Sediments affected by Dar-e-Allo mine are divided into six sedimentary groups including: natural background sediments, sediments of waterways leading to the mine, sediments of the Sarmashk River, sediments under the waste rock dump, sediments containing secondary phases, Fe-Mg oxy-hydroxide sediments, and evaporative sediments. Mineralogical studies of sediments as an indicator to evaluate the environmental effects of mining are classified into five main groups including primary and unaltered, carbonate, clay, sulfate and oxide minerals. Sediments in the operational area of the Dar-e-Allo copper mine are associated with extreme mineralogical diversity. The sulphide minerals are the most important source of acid mine drainage and secondary minerals such as gypsum, starkeyite, copiapite, magnesiocopiapite and natrojarosite are the most important temporary reserves of potentially toxic elements (PTEs) and H+ ions. The dissolution of the mentioned minerals, especially during the initial flushing events in the wet season, cause a sharp increase in the acidity and concentration of PTEs in the surface runoff.

This represents paleoenvironmental significance of echinoderms with emphasize on Miocene echinoids. Clypeasteroids, are one of the most typical echinoids which are very useful in interpretation of Oligocene and Miocene marine paleoenvironmental conditions. Based on different functional morphologies of clypeasteroid tests, sedimentary fabric (clusters, density and orientation of tests to the bedding surface) of echinoids in deposits (carbonates, sandstones and conglomerates) and taphonomic evidences on clypeasteroid tests, the following details can be evaluated: 1- type of substrates, 2- water energy and hydrodynamic conditions, 3- transportation and reworking, 4- events such as tempestites and winnowing, 5- availability and diversity of different nutrient sources and sedimentary grains and 6- sediment loading after final deposition of sediments and during diagenesis.

The hosted-rocks of the Pb-Zn ore deposits in two mines of Karavangah and Dehno (north of Kuhbanan) contain carbonate rocks of the Shotori Formation (Middle Triassic).The identified carbonate facies consists of limestone and dolomite, but ore bodies mainly occurred in dolomite facies. Petrographic studies show that the dolomites can be divided into four classes including fine crystalline, medium crystalline, coarse crystalline and saddle dolomites. Geochemical data (major and trace elements) of dolomites have almost similar characteristics and show a noticeable enrichment of lead and zinc. Also, significant enrichment and similar trend are observed in the REE of hosted-rock samples. Therefore, due to similarity between geochemical characteristics of the hosted-rocks, it seems that magnesium source for dolomitization was mainly seawater, but the influence of ore fluids is significant on the formation of coarse crystalline dolomites.

Nebkhas are one of the aeolian dunes that play an important role in wind erosion by stabilizing sediments around plants. Due to the depression of northern Shahdad plain (eastern Kerman), the sever wind impact, high rate of sediment supply and the presence of desert plants, nebkhas have expanded. In this study in order to achieve the formation of nebkha in the Shahdad plain, sedimentological parameters and the effect of vegetation on nebkha geomorphology have been investigated. Due to the expansion of the study area and the different geomorphology of the nebkha, 30 nebkha were sampled along with sediments between them. the analysis of these sediments shows that nebkha sediments are often fine sand sizes that are well-sorted and rounded. However, sediments between nebkha often have a range between gravel (pebble) and fine silt which are subdivided into either surface and sub-surface sediments (depth greater than 2 centimeters). Surface sediments are often coarse grains (granule to coarse sand) and have relatively well roundness and sorting. Field investigations and analyses have shown that genus and plant species are important in the geomorphology of nebkhas in the Shahdad plain but the effect of vegetation on the sedimentary parameters is insignificant. This is due to the fact that the three types of vegetation identified (Tamarix stricta, Seditzia rosmarinus, Prosopis farcta), the highest levels of nebkha is for Tamarix stricta but the sedimentary parameters with different vegetation are not significantly different.

This study led to identify 30 species and 16 genera of eight different plant macrofossils orders including Equisetales, Cycadales, Bennettitales, Coniferales, Peltaspermales, Ginkgoales, Corystospermales, and Filicales at the Deh-Shiykh section, north of Kerman. According to stratigraphic ranges of the index taxa such as Otozamites furoni, Nilssoniopteris mosafolia, Nilssonia tenuicaulis, Anomozamites major, Coniopteris hymenophylloides, Nilssonia bozorga and Elatides thomasii the age of early Middle Jurassic (Bajocian–Bathonian) is assigned to the Deh-Shiykh section. Middle Jurassic ichno fossils of the Hojedk Formation in the Deh-Sheikh section have been studied for the first time. The study also led to the determination of terrestrial ichno fossils including eight ichno species, belonging to four ichnogenera such as Planolithes, Rhizoliths, Taenidium and Thalassinoides. They have been found alongside the stems of Equisetals. Combination of the results of ichno fossil studies with plant fossils help us to identify the palaeoenvironment. These plant fossils are generally indicator of humid conditions. Moreover, the identified ichnofossils in accordance with the sedimentological studies, represent deltaic environments influenced by the river systems and channels. This is the first study of the combination of three studies of paleontology (Plant macrofossils), sedimentology and ichnology in east central Iran. The results have contributed to the accurate understanding of the paleoenvironment of fossiliferous horizons of the Hojedk Formation.

This research is a part of the studies of sedimentology and stratigraphy of deposits associated with the Devonian located in Central Iran, which is known as the Padeha Formation (Lower-Middle Devonian age). In this research, the Padeha Formation in north of Tabas (Ozbak-Kuh) and Yazd (Doruneh) blocks were selected and studied. These succession is measured in Ozbak-Kuh, 492 meters, which is often composed of siliciclastic, dolomitic and evaporite rocks, while in the Doruneh section, this formation consists of 310 meters of siliciclastic, calcareous and dolomitic rocks. The aim of this study is to focus on the petrography and geochemistry aspects for provenance studies.

Twenty one sandstone samples from Ozbak-Kuh and fifteen sandstone samples from Doruneh section were selectedand studied with Polarized microscope. In each thin section, about 300 points were counted using the Gazzi-Dickinson method. According to the point counting, the major and accessory components of this sandstones are identified and quartz, feldspar and rock fragments modes are utilized for naming the sandstones according to the Folk classification (Folk, 1980). 16 samples of medium grain sandstones with the lowest amount of carbonate cement were selected for geochemical analysis (ICP-MS method).

Petrographic studies of sandstone in Ozbak-Kuh section are mainly indicative of quartzarenite and sublitharenite (subchertarenite) petrofacies, however, quartzarenite and subarkose petrofacies have been identified in the Doruneh section. Compared to the Upper Continental Crust (UCC) (Taylor & McLennan, 1985), sandstones of the Padeha Formation in the Ozbak-Kuh section are somewhat enriched in some elements, such as zirconium and hafnium, but in the Doruneh section, zirconium and hafnium are slightly depleted compared to the Upper Continental Crust. All sandstone samples in both sections are strongly depleted compared to UCC. In both the Ozbak-Kuh and Doruneh sections, vanadium, cobalt, nickel and scandium exhibit much depletion compared to the UCC.

Geochemical diagram of Zr/Sc against Th/Sc (McLennan et al., 1993), along with plotting the data of Padeha Formation on this diagram shows that the samples of Doruneh section are plotted near the UCC. This shows that Padeha Formation sandstones in the Doruneh section are derived from intermediate to acidic igneous rocks, and recycling have not been affected. But the Ozbak-Kuh samples often reflect the granitic parent rock, which is located in the range of recycling. Additionally, the La/Sc versus Co/Th (Gu et al., 2002) is also a confirmation of the felsic to granitic parent rocks for Padeha Formation in both sections. For determination of tectonic setting, in this reseach, triangular diagrams based on trace elements (Bhatia, 1985) have been used. According to these diagrams, Ozbak-Kuh samples, mostly plotted in the passive continental margin field and Doruneh section sandstones are plotted in passive and active continental margin fields. The present study, using the results of petrography and geochemistry and the paleogeographic investigations, shows that the deposits of the Lower-Middle Devonian Padeha Formation can be formed in the transition between the transformations of rifted margin to passive continental margin of Paleo-tethys.

For study of different types of stromatolites, their modes of growth and their relation to sequence stratigraphy within the Derinjal Formation, three stratigraphic sections at Dahuieh, Gatkueih and Gazueih in SE and E of Zarand (NW Kerman), were measured and sampled with thickness of 160, 140 and 130 meter, respectively. Modes of sediment accretion, trapping and binding of sedimentary grains, together with the morphology of stromatolites and microbial mats in the Late Cambrian are analyzed, in order to show the interaction between the growth patterns, morphology and facies association. Based on morphologic study and modes of growth, 4 main groups of stromatolity including stratiform stromatolite, single and lateral accretion, domed stromatolites, Columnar stromatolites and Coniform stromatolites were identified. Growth environmental analysis shows that these sediments have been deposited in tidal environment. Relation between sea level changes and stromatolite types show that stratiform stromatolite is consistent with early TST and late HST, and domed, columnar and coniform stromatolies have been observed in late TST and early HST.

For identification and differentiation of different types of dolomites of the Padeha Formation, three stratigraphic sections in the northern and southern Tabas Block, with the maximum amount of dolomite, were selected and sampled. Based on petrographic evidence and geochemical data, three types of dolomite were identified, including primary (PD), replacement (RD) and vein and pore filling (VD) dolomites. The PD dolomites are fine-grained, anhedral with fenestral fabric and have sedimentary structures such as planar lamination, mud cracks, stromatolite and teepee structures, as well as dark and dark-red luminescence. The RD dolomite is mainly replaced the matrix and fossil fragments and observed as subhedral with orange to red luminescence. The VD dolomite is often coarse-grained and euhedral and according to the intensity of luminescence, six petrotypes were identified in this type of dolomite. The PD and RD dolomites indicate a similar range of geochemical data that reflects they formed in similar conditions. Based on oxygen isotopes, these dolomites formed at temperatures of 44 °C and 59 °C, respectively. Therefore, marine and very shallow burial model is the most probable model for the formation of PD and RD dolomites. The VD dolomite has the lightest oxygen isotope values, therefore on this basis, this type of dolomite is formed at 82 °C. Moreover, the study of fluid inclusions in these dolomites shows an average temperature of 83 ° C. The VD dolomite has likely formed in deep burial conditions and burial dolomitization model is proposed for this type of dolomite.

The 50 meters thick Top Quartzite sediments in Kerman area is laid between siliciclastic red beds of the Dahu Formation and carbonate deposits of the Kuhbanan Formation. Three stratigraphy sections were measured at Gazuieh, Katkuieh and Dahuieh in eastern Zarand for analysis of depositional environment. Field and petrographic studies led to identification of a conglomerate petrofacies and three sandstone petrofacies (chert arenite, quartz arenite, sublitharenite) with high textural and compositional maturity. Lithofacies analysis resulted in recognition of three coarse grain (Gcm, Gms, Gt), seven medium grain (Sp, St, Sh, Sl, Sr, Sm, Se), one fine grain (Fl) and three intermediate sand-mud lithofacies (Sr(Fl), Sr/Fl, Fl(Sr)). Structural and textural evidences as well as predominant bimodal paleo-currents in most facies show that these sediments have been deposited in the tidal flat environment. The coarse, medium and fine grain sediments are deposited in tidal channels, intertidal flats, supratidal flats, respectively. We hope represented data in the study improve the basin analysis and paleogeographical reconstruction of Cambrian sedimentation.

Two stratigrphic sections from Dahu Formation (Early Cambrian), at Gezuieh and Dahuieh (type section) in E and SE Zarand, NW Kerman, with thickness of 227 and 240 meters respectively, were measured. These data have been used for interpretation of provenance of these siliciclastic sediments. Lithofacies, architectural elements and petrofacies analysis show that Dahu Formation has been deposited in meandering river system when the river was flowing from south toward the north. Provenance studies and depositional history, using petrography frameworks characteristics, paleocurrent analysis and tectonic setting (using the triangle diagram Qt-F-L and Qm-F-Lt), show that the sediments of Dahu Formation may have been derived from alkali granite related to Pan-African orogeny from Saudia Arabian train. These sediments may have been deposited as post rift sediments in Kerman region. We hope that this information can be used for paleogeographical reconstruction of the Early Cambrian time in local and regional scales.