List of articles (by subject) Economic Geology
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Open Access Article
1 - Origin and development of Skarn-Forming fluids from the Band-e-Narges Skarn Iron ore, Central Iran
Maliheh Nazari Mohammad Lotfi Nematallah Rashidnejad omran Nima NezafatiThe Band-e-Narges magnetite deposit is located in central part of Urumieh–Dokhtar Magmatic Arc (UDMA). Wide I-type calk-alkaline and alkalin magmatic activity in the Koh-e- Latif region has been reported due to Eocene intrusive processes in UDMA. The iron ores are MoreThe Band-e-Narges magnetite deposit is located in central part of Urumieh–Dokhtar Magmatic Arc (UDMA). Wide I-type calk-alkaline and alkalin magmatic activity in the Koh-e- Latif region has been reported due to Eocene intrusive processes in UDMA. The iron ores are hosted by Cretaceous limestone intruded by granite and granodiorite units. Genetic model of this deposit was determined using petrological, stable isotope, fluid inclusion and mineralographical data. Five stages of paragenesis were observed in terms of mineralization in this area: prograde stage, retrograde stage, sulfide-quartz stage, carbonate stage and oxidation stage. According to mineralogy and geochemistry studies, formation of the skarn has resulted from a hydrothermal fluid changing carbonate units to hydrosilicate minerals. The ore minerals showed magnetite features with slight chalcopyrite and pyrite. The δ34S values ranged from +3.31 to +6.29 for the early retrograde stage pyrite and from +5.51 to +7.1 for that of late retrograde stage pyrite + anhydrite pairs. All the δ34S values of pyrite and anhydrite + pyrite were positive with a magmatic sulfur origin in these deposits. Fluid inclusions were observed according to petrographic and microthermometric inclusions within garnet, quartz, and calcite minerals at various stages. Due to high temperature (414 -448 ºC ) and middle salinity (up to 13.186 wt% NaCl) of fluid inclusions in prograde skarn-stage (garnet), the fluid inclusions showed a composition related to magmatic fluids following reaction with calcareous wall rock and fluid inclusions were trapped at pressures of 400 -500 bars, corresponding to depths of 1.5 -2 km in prograde stage. Fluid inclusions in quartz had moderate temperatures (152-303 ºC) and low salinity (7.9-11.3 wt% NaCl) indicating quartz-sulfide stage and late retrograde stage. The presence of fluid inclusions with moderate homogenization temperature (303 ºC) suggested that reboiling has occurred under hydrostatic pressure of 150-250 bars, equivalent to a depth of 1 -1.5 km in the late retrograde skarn and quartz-sulfide stages. Fluid inclusions in calcite had moderate temperatures (160 -287ºC) and low –to- high salinities (0.406-23wt% NaCl). A greater number of the fluid inclusions in the Band-e-Narges deposit had salinity (0.4-23.74 wt% NaCl) and homogenization temperatures (152-448 ºC) showing them as a moderate-high temperature and low–to-high salinity type of deposit. A decline in temperature and variation in salinity documented for the Band-e-Narges deposit would cause a notable decrease in Fe solubility and ore precipitation. Fluid compositions indicated that ore-forming fluid had a high fO2 value and rich Fe concentration in the early stage, while having relatively lower fO2 value and poor Fe concentration in the retrograde and sulfide stages. The data obtained from geology, mineralogy, geochemistry, salinities, and homogenization temperatures of the fluid inclusion populations at the Band-e-Narges iron deposit followed a model of boiling as a result of decrease in pressure, mixing, and cooling. Manuscript profile -
Open Access Article
2 - Integration of geological and geophysical studies in order to mineral exploration at the Zaveh mineralization area, NE Iran
Azadeh Malekzadeh Shafaroudi Bahareh Boroziniat Mohammad Reza Haidarian ShahriThe copper deposit of Zaveh lies in the SE of the city of Torbat-e-Heydarieh and in middle of the Khaf-Kashmar-Bardaskan Magmatic Belt (KKBMB) in the Khorasan-e-Razavi Province. The lithology of the area consist of Jurassic and Cretaceous sedimentary rocks and Eocene vo MoreThe copper deposit of Zaveh lies in the SE of the city of Torbat-e-Heydarieh and in middle of the Khaf-Kashmar-Bardaskan Magmatic Belt (KKBMB) in the Khorasan-e-Razavi Province. The lithology of the area consist of Jurassic and Cretaceous sedimentary rocks and Eocene volcanic units. Ore-formation is controlled by fault activity, representing vein-veinlet style E-W trending, formed within a conglomerate rich in quartz. Primary minerals are chalcopyrite, pyrite and arsenopyrite and secondary minerals contain malachite, azurite chalcocite, bornite, covellite, Cu sulphates, wad (Mn hydroxide), haematite, goethite, jarosite, limonite and (to a lesser extent) chrysocolla. The predominant alteration is silification which is associated with vein ore-formation. The volcanic units host propylitic, sericite, carbonate and silicification alterations. The ore-formation itself represents anomalies of Cu (2.1 % max), As (>1%), Sb (~105 gr/T), Pb (4371 gr/T) and Zn (1.1% max). Induced polarization and electrical resistivity (IP/RS) surveys unveil that the most chargeability anomaly corresponds to center of ore-forming vein and fault zone.The chargeability anomaly extends and amplifies with depth. The most amount of specific electrical resistance has been observed in the quartz-rich conglomerate. Interpretation of IP/RS data reveals that the chargeable source is extending in deeper beds (presumably sulphid ore-formation) which needs to be verified by boring operation. Geophysical surveys are significantly commensurate with field observations, ore-forming and geochemical data. Utilization Geophysical methods in different style of ore-deposits and interpretation of obtained information by means of geological, ore-forming and geochemistry data is considered to be a big step towards subterranean exploration and deposits modeling. Manuscript profile -
Open Access Article
3 - Economic geology of the carbonate rocks from Mesozoic Alpurai group, Peshawar basin, Pakistan
Muhammad Anjum Muhammad Ishfaq Sibghat Ullah Muhammad Yaseen Liaqat Ali Jaroslav Prsek Gohar RehmanThis study aims at evaluating the utilization of carbonate rocks from the Bampokha (Nikanai Ghar Formation) and Sawaldher (Kashala Formation) areas in different industries. Two varieties from the Nikanai Ghar Formation, known under the trade names as Super-white and Sun MoreThis study aims at evaluating the utilization of carbonate rocks from the Bampokha (Nikanai Ghar Formation) and Sawaldher (Kashala Formation) areas in different industries. Two varieties from the Nikanai Ghar Formation, known under the trade names as Super-white and Sunny-grey, are selected for petrographic and geochemical analysis to evaluate these as a source of calcite (CaCO3), in chemical industries. Petrographically, both the varieties from Bampokha area, are calcitic marbles that exhibit heteroblastic mosaic texture. Geochemical data coupled with X-ray diffraction and petrographic analysis confirms that the Super-white variety is very high purity marble and hence meets the specifications for different chemical industries such as iron and steel industry, glass manufacturing, flue gas desulphurization, soda ash manufacturing and water purification and effluent treatment. In contrast, the high silica (4.1 wt.%) and low calcite contents (<95 wt.%), render the Sunny-grey unsuitable for chemical industries. The rock from Sawaldher quarry, exhibiting an interlocking mosaic pattern, is calcitic marble. Minor amounts of quartz, muscovite and opaque minerals also occur. Comparing the physico-mechanical properties of the aggregate from Sawaldher marble with time-honoured international standards suggests its suitability in concrete work with ordinary portland cement and asphalt. The concrete mix, designed for Class D2 concrete, has an average 28-days compressive strength value of 518 kg/cm2 and thus well above the minimum targeted strength of 425 kg/cm2 for the mentioned class, and hence further endorses that the aggregate can produce strong concretes. This study also suggests the utilization of the studied carbonate resources on industrial scale. Manuscript profile -
Open Access Article
4 - The evaluation of Khyber limestone in Pakistan for using as road aggregate based on geotechnical properties
Naveed Rehman Syed Haroon Ali Zahid Ullah Muhammad Kashif Muhammad Arslan Abid Atif Saleem Amjad Ali Muhammad YaseenKhyber Formation of Paleozoic age, has been studied here to access its physiochemical and mechanical characteristics. There has been several studies on the sedimentology of the Khyber limestone, however, much more detailed study is required to understand it aggregate po MoreKhyber Formation of Paleozoic age, has been studied here to access its physiochemical and mechanical characteristics. There has been several studies on the sedimentology of the Khyber limestone, however, much more detailed study is required to understand it aggregate potential in desired resolution and precision. It is achieved by understanding the rock types, microscopic textures and physical/ mechanical properties. The Khyber Formation is widely exposed in eastern and central parts of district Khyber, Khyber Pakhtunkhwa (KP) Province, Pakistan. It is a thick bedded hard limestone unit. The carbonates in the Khyber Formation are dominated by calcite, with dolomite, and other accessory minerals as minor component. The mechanical and physical properties of aggregates like specific gravity (2.69), water absorption (0.80%), soundness (2.34%), Los Angeles abrasion value (23.60%), aggregate crushing value (12.18%), aggregate impact value (12.76%) flaky index (10.15%), elongation index (13.02%), California bearing ratio (90.35%), coating and stripping values (96.32%), Schmidt rebound attains (34.23) and compressive strength (38.58Mpa) are according to the available standards. The petrographic analyses of samples of Khyber Formation and energy dispersive X-Rays analysis (EDX) illustrate that it dominantly consists of calcite (88-92%) with small to trace assemblage of dolomite (2-8%), ungraded quartz (1-3%) and ores (1-2%). The chemical and petrographic examinations show that the limestone units of the Khyber Formation are inoffensive in terms of Alkali Silica Reaction (ASR) and Alkali Carbonate Reaction (ACR). These characteristics of the limestone units demonstrating that these deposits are potential aggregate for large-scale projects in the KP Province (Pakistan) and region. Manuscript profile -
Open Access Article
5 - Assessment of excavability classification in a Limestone Quarry: A case study from Bayburt, Turkey
Gökhan Külekçi Alaaddin Vural Şener AliyazıcıoğluExcavability is a measure of material which can be excavated with classical excavation equipment. Studies to decide the rock excavability characteristics contribute to the suitability of engineering projects. In this study, a limestone quarry (in Bayburt, Turkey) was an MoreExcavability is a measure of material which can be excavated with classical excavation equipment. Studies to decide the rock excavability characteristics contribute to the suitability of engineering projects. In this study, a limestone quarry (in Bayburt, Turkey) was analysed with excavability classification systems and appropriate systems were determined. To accomplish this aim, point load index and Schmidt hardness tests were practiced and changed to uniaxial compressive strength tests. After that, findings were categorized with classification systems in excavation and matched against practices from field. In this study, rock mass was addressed as “pre-explosion”, “hard ripping” and “hammer and blasting” in accordance with distinctive classification systems. All determined as rock mass should be blasted for loosening then dug with hydraulic breakers. This practice is totally compatible with in-site excavations fulfilled. According to study results, the most suitable parameters to decide surface excavational classification are load strength index, geological strength index and the degree of rock mass weathering. Manuscript profile -
Open Access Article
6 - Is skarnization the cause of mineralization? a case study, Sanandaj Sirjan zone, west Iran
Hossein Moinevaziri Hossein AziziThe 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 d MoreThe 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. Manuscript profile -
Open Access Article
7 - An interpretation of Airborne Magnetic data to characterize Nickel-Copper mineralization over Mpemba Hill, Blantyre Malawi
Joshua Chisambi Tiyamike HaundiThe present study seeks to characterize Ni-Cu mineralization at Mpemba hill in Blantyre, southern Malawi by using aeromagnetic and drill hole data. The area has been under-explored for this im-portant economic commodity and as such not much is known regarding its minera MoreThe present study seeks to characterize Ni-Cu mineralization at Mpemba hill in Blantyre, southern Malawi by using aeromagnetic and drill hole data. The area has been under-explored for this im-portant economic commodity and as such not much is known regarding its mineralization poten-tial. The minimal curvature gridding technique was utilised to grid the aeromagnetic data, and a grid cell size of 50 m was employed. The Ni-Cu host lithologies are characterized by high mag-netism, and are mostly ultramafic rocks. Drilling results indicates that the mineralization starts at depths from 50m and remains open. The area is associated with disseminated and blebby type of mineralization and the mineralization is associated with high magnetic signatures in ultramafic meta pyroxenite bodies yielding high base metal values. Euler model depths analysis of the mag-netic sources is deep, lies at 3.2 km depth and the shallower magnetic bodies lie between 100 m and 1km. The depth estimates show that the mineralization is near surface and goes deep, so fur-ther exploration should not be limited to shallow depth. The ultramafic rocks are potential sites for Ni-Cu mineralization in the area and Mpemba hill has a huge potential to find economic min-eralization suitable for mining. Manuscript profile