Economic Geology
Rahimzadeh Bahman; M. Movahednia
Abstract
The Kamyaran manganese is located in the 20 km from NW of Kamyaran and south of Kurdistan province. In geological structure map these Mn-deposite are outcrops in Zagros and northern Sanandaj-Sirjan collision zone and close to Zagros ophiolites. In this area, Mn-mineralization occurs as regular lenses ...
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The Kamyaran manganese is located in the 20 km from NW of Kamyaran and south of Kurdistan province. In geological structure map these Mn-deposite are outcrops in Zagros and northern Sanandaj-Sirjan collision zone and close to Zagros ophiolites. In this area, Mn-mineralization occurs as regular lenses and interlayers with radiolarian cherts within the Eocene radiolarite and shale. The present work has been done based on field geology, mineralogy and geochemistry characterization. Study of Mineralogy and texturally Kamyaran Mn-ores show two stage mineralization including Braunite and Okhotskite were formed singenetic and pyrolusite was formed diagenetic. The high rate of Si and rhadiolarite fossils in Mn-bearing cherts suggest that the Kamyaran Mn-deposit was formed in deep oceanic area. The Variable content of Mn/Fe and high rate of detector element such as Ba and Sr revel the hydrothermal source for mineralization. Despite, Existence rhadiolarite fossils, sub-bedding deposits and some geochemical characterization suggest the sedimentary origin for Kamyaran Mn-deposit.
Petrology
Rahimzadeh Bahman
Abstract
Scoria cones are one of the main parts of East of Kurdistan volcanoes. Olivine, Pyroxene, Plagioclase and Biotite are main phonocrystals with Amygdaloidal-glassy matrix. This paper was studied processes of bubbles nucleation and grow during the eruption of scoria's unite using the Bubble Size Distribution ...
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Scoria cones are one of the main parts of East of Kurdistan volcanoes. Olivine, Pyroxene, Plagioclase and Biotite are main phonocrystals with Amygdaloidal-glassy matrix. This paper was studied processes of bubbles nucleation and grow during the eruption of scoria's unite using the Bubble Size Distribution (BSD) method including study of population density, bubbles volume, 3D modeling, nucleation and bubble growth. For selected sample from different cone, in total was measured 3623 bubbles and drawn that bubbles volumes calculated from 40 to 85 percent. Using the 2D bubbles shape renovated 3D bubbles schematic shape and compared together. Most population for four samples bubbles shapes are near to sphere and for other four samples are ellipsoid. Longest ellipsoid bubbles shape has 1:3.2:8 diagonals ratio that it’s flat ellipsoid. The longest diameter (L) is perpendicular to the surface and parallel to lower pressure dictated on magma and bubbles could be growth more than other sides. Presence of 2-5 peaks in frequency distribution versus bubble size diagram, suggesting unimodal, polymodal, exponential and power low events for bubbles generation in the east of Kurdistan Scoria's. Nucleation density increased from first to lasts generation but bubbles growth reduced. Recur of bubble forming in macroscopic samples, microscopy, SEM and nucleation and grow model suggested fractal model.
Rahimzadeh Bahman; F. Masoudi; S. M. Fatemi Aghda; T. Parhizkar; A. Pour Khorshidi
Abstract
In the north of Abyek - Qazvinmain road, various volcanic units contain olivine basalt, basalt, andesitic basalt, dacite, andesite and their associated tuffs with Eocene to Quaternary age are exposed. In order to examine geochemical and petrographic features effect on pozzolan activity, five samples ...
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In the north of Abyek - Qazvinmain road, various volcanic units contain olivine basalt, basalt, andesitic basalt, dacite, andesite and their associated tuffs with Eocene to Quaternary age are exposed. In order to examine geochemical and petrographic features effect on pozzolan activity, five samples of different rocks in the area crushed and analysed by thermogravimetric method in Housing and BuildingResearchCenter. Unweathered glassy tuff s with 26.83% pozzolanic activity ranked as good quality pozzolan. Relatively weathered tuffs and dacite present pozzolanic activities in the range of 21 to 24 % and are medium quality pozzolan. Lithic tuffs with 19.70% pozzolanic activity are in the weak quality pozzolan category. Generally, tuffs and dacits with no alteration and glass in their matrix are suitable alternatives to use as pozzolane in mix cement and lithic bearing tuffs with weathering are poor in pozzolanic features and are not recommended to be used in cement composition.
