فهرست مطالب

Iranian Journal of Earth Sciences
Volume:15 Issue: 1, Jan 2023

  • تاریخ انتشار: 1401/11/08
  • تعداد عناوین: 6
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  • Hossein Moinevaziri, Hossein Azizi * Pages 1-9

    The skarn type mineralization has long been accepted as an interaction of magma and the host carbonate rocks. Most researchers have considered the iron deposits in the northern Sanandaj Sirjan zone (Kurdistan area) as skarn-type mineralization which has been generated during the injection of the granitoid bodies into the host carbonate. The calculation of normative minerals from the mixed composition of granite and host dolomite shows that normal reactions cannot produce a large volume of Fe or Mn mineralization in northwest Iran as skarn deposits. One of the iron deposits which is known as the Saheb skarn deposit, 33 km east of Saqqez, NW Iran was selected for this study. The normative minerals from this deposit were calculated for a mixed composition based on 100 grams of Saheb granite and 50 grams of host dolomite. The results show the iron oxides don’t extend into the last stages of magma crystallization to provide the Fe-Mn mineralization in the host rocks. Occasionally, in the contacts of plutons, various types of mineralization appear, however, they are not the result of a magma and carbonate interaction. They are probably the results of the hydrothermal fluids in the late stages of magma crystallization. The magma fluids and fossil water in the host rocks that were heated during the magma injection, leaching the Fe-Mn from the granitoid bodies and surrounding rocks. As follows, Fe-Mn-rich fluids move towards fractures and caves, finally precipitating as ore deposits into the host rocks. The skarnization phenomenon causes the reduction of volume due to the release of CO2 gas and also the crystallization of relatively dense minerals such as garnet. This process, make a partiality space for the precipitation of Fe-Mn-rich hydrothermal fluids. Our findings show that skarnization only makes space for the precipitation of the Fe from the hydrothermal fluids.

    Keywords: Hydrothermal Fluids, Iron ore deposits, magma reaction, Sanandaj Sirjan zone
  • Fouzia Hizir, Abderrezak Krika *, Farès Kessasra, Fouad Krika Pages 10-20
    This study is to investigate the physico-chemical parameters and trace metal’s concentrations (Cd, Pb, Cu, and Zn) in water and surficial sediments (0-5 cm) samples in the Kebir-Rhumel Wadi, north-eastern Algeria. Trace metal concentrations was determined using flame atomic absorption spectroscopy. The mean values of the physico-chemical parameters of the Wadi water samples are consistently above than thresholds of the Algerian standard. The comprehensive pollution index (CPI) varied from 1.46 to 3.90, indicating that the Wadi water was classified from polluted to seriously polluted. The eutrophication index (EIs) were above the unity, signifying that the eutrophication is serious, except for sites S1, S7, and S8. Metals was not detected in water samples. However, the metallic concentrations in the sediment were higher than background levels. The average geo-accumulation index (Igeo) revealed an order of trace metal contamination of the Kebir-Rhumel Wadi sediments: Pb>Cd>Zn>Cu. The contamination factor (CFs) of studied metals indicated a highly contaminated nature of sediments, whereas the Cd values indicated moderate contamination, considerable contamination with Pb and low contamination with Cu and Zn. The pollution load index (PLIs) were above the unity (1), displaying an advanced decline of the sediment’s quality. Potential ecological risk index of trace metals were changed as follows: Cd>Pb>Cu>Zn. Cadmium was of highly potential ecological risk to the ecological environment and prominently contribute to potential toxicity response.
    Keywords: Water, sediments, Pollution indices, Kebir-Rhumel Wadi, Algeria
  • Kaltoum Belhassan *, Ashok Vaseashta, Mohammed Abdelbaset Hessane, Hafizullah Rasouli, Mohammed KA Kaabar, Emad Kamil Hussein, Muhammad Adnan Pages 21-33
    Mikkes River Basin is located in the north-center of the Kingdom of Morocco (North-West of Africa). It comprises of three different zones which represent diversified geologies and which shelter a phreatic and confined aquifer in Saïs plain and a shallow aquifer in El Hajeb Ifrane Tabular. This research aims to highlight the potential impact of drought on Mikkes River flow through climate indexes including rainfall, temperature and evapotranspiration during the period 1968-2009. Monitoring the evolution of rainfall, temperatures and evapotranspiration in the Mikkes basin during the period 1968-2009 shows that rainfall decreases, temperature and evapotranspiration increase from South to North of the basin (spatial drought). Also, these climatic indicators highlight a decrease in rainfall, increase in temperatures and evapotranspiration after 1980 (temporal drought). Flow deficit of Mikkes River between the period 1968-1979 and 1980-2009 is around 76%. This high River flow may due to the drought which the region has experienced since 1980 and also to the overexploitation of groundwater resources to satisfy water demands. The Mikkes basin is suffering severe depletion of groundwater piezometric levels, especially in the confined aquifer.
    Keywords: Mikkes River, Morocco, drought, rainfall, temperature, Flow, piezometric level
  • Bahman Javadian, Seyed Ahmad Babazadeh *, Ali Solgi, Burzu Asghari Pirbaluti Pages 34-43
    In this research, the biostratigraphy, microfacies, and depositional environment of carbonate sediments of the Jahrum Formation will be investigated based on microscopic textures and the distribution of benthic foraminifera. The Jahrum Formation was measured from Kuh-e-Hamze Ali in the Chaharmahal Bakhtiari province (Zagros Basin, Iran). The biostratigraphic analysis of this formation has led to the detection of three biozones in this area. These biozones consist of Somalina subzone, Nummulites–Alveolina assemblage subzone, and Nummulites fabianii- Nummulites striatus assemblage subzone which assigned to Middle and Late Eocene. The Nummulites fabianii- Nummulites striatus assemblage subzone is represented for the first time in the studied area. Nine microfacies are identified based on their fossil content (mainly foraminifera) and sedimentary textures. They consist of Dolostone, Mudstone with quartz, Bioclast- miliolids wackestone/packstone, Praerhapydionina -miliolid wackestone, Alveolina -Nummulites-Orbitolites wackestone/packstone, Bioclast–miliolid-Rotalia wackestone/packstone, Bioclast-lump packstone/grainstone, Interaclast-bioclast-Alveolina wackestone/grainstone, and Bioclast-Nummulites wackestone/packstone. These facies were deposited in four major depositional environments from a tidal flat, lagoon, shoal, and open marine environmental settings. The depositional environment of the Jahrum Formation is interpreted as a carbonate ramp.
    Keywords: Biostratigraphy, microfacies, Jahrum Formation, Eocene, West of Iran
  • Saeed Saadat *, Maliheh Zafarimoghadam, Aliasghar Ariaee Pages 44-53
    Khunik gold prospecting area is located in the eastern part of Lut block, eastern Iran. Main rock units are andesite, agglomerate, latite, dacitic lava, rhyodacite, volcanic breccia and conglomerate. Geological and geochemical evidences indicate low to medium sulfide gold mineralization. Mining activates accumulate heavy metals in soil and water that are associated with harmful effects on human health. The object of this research is to evaluate the concentration of heavy metals in soil and groundwater resources and assess the effects of the mineralization zone. All investigated metals in soil samples are below world concentration except arsenic, antimony, and iron. Based on the assessment of pollution, high enrichment of silver, medium to high enrichment of antimony, arsenic, lead, and selenium in some samples were detected. The high correlation of silver, gold, and arsenic is due to the sulfide mineralization of gold in the Khunik area. Chemical analysis of water samples comparing International Standards confirms that water resources in this area have been polluted by heavy metals and it is not drinkable. MI and HPI values denote the dangerous pollution of groundwater, which has been described as serious in most sites.
    Keywords: Heavy metals, Pollution indices, Groundwater, soil, Lut block
  • Tooba Jalali Nezhad, Hamid Reza Masoumi *, Mohammadsadegh Dehghanian, Jamal Tarrah Pages 54-65
    This study investigates the concentration, potential of toxicity, and source rocks of seven toxic elements (As, Cd, Cu, Cr, Pb, Zn, and Ni) in the sediments of four salt domes on the north of Hormuz Strait (Hormuz, Pol, Gachin and Angouran). In this regard, to determine the origin of toxic elements in the sediments of salt dome waterways, field studies, sediment sampling, and mass spectrometry elemental analysis were performed. Moreover, the enrichment factor and index of geo-accumulation were calculated. Agglomerative hierarchical clustering was also performed to determine the carriers and adsorbents of the elements. The results showed that sediments of the study area have the potential for toxicity of As, Cd, and Pb. In contrast, the contingence ‎intoxication by Cu, Cr, Zn, and Ni is minimal in the sediments around the salt domes of the Hormuz strait area. Based on the concentration of elements in the sediments, determined their probable source rocks. The minerals of the sulfate salts, Fe-oxides/sulfides, and volcanic rocks of the Hormuz Series are the major sources of As and Pb, and mafic/ultramafic minerals of the volcanic rocks are sources of Cu, Zn, and Ni. Neogene carbonate rocks are also a source of cadmium.
    Keywords: Enrichment factor, geo-accumulation index, Hormuz strait, Salt dome sediments, Toxic Elements