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Showing 3 results for Sandstone

Somayeh Salehinasab, Farajoallah Fardoost, Afsaneh Soltani,
Volume 27, Issue 3 (10-2019)
Abstract

Band-e-Ghichy copper deposit is located in the northern margin of the Central Iran structural zone, about 120 km south of Shahrood and 70 km south east of Torud. Copper mineralization occurred in the rock units including sandstone, conglomerate and siltstone with the Oligocene age. Mineralization has occurred in the form of stratiform (syngenetic), stratabound (epigenetic) and supergen (the surface processes). The minerals forming the deposit include sulfide (chalcocite, covellite, bornite, chalcopyrite and pyrite) and carbonate (malachite and azurite) minerals. The main mineralization forms in the reduction zone as well as in the red formations and is controlled by permeability, the content of organic materials and sulfides in the host rock. Due to the expansion of Eocene andesitic lavas in the adjacent area of the deposit and the presence of volcanic fragments containing copper-bearing minerals in host conglomerate units, it can be concluded that the source of copper in the region is attributed to volcanic units. Based on geochemical studies, sandstone of the region have a felsic to intermediate source rocks and the copper element in the base metals has the highest production coefficient (4 to 8 weight percent) and shows the highest correlation with silver. According to the basic characteristics of Band-e-Ghichy copper deposit such as host rock, mineralogy, structure and texture, companion elements, depositional environment and important mineralization factors, this deposit can be considered as a copper deposit with a sedimentary host and red bed type.
Khan Chuban, Abedini, Aliyari, Calagari, Faridazad,
Volume 28, Issue 3 (10-2020)
Abstract

The sedimentary copper mineralization of the Sorkheh area is located about 20 km northwest of Marand, East-Azarbaidjan Province, northwest Iran. The most important lithologic units in this area include sandstones and red-color shales, with the Late Miocene age, that are intruded by lamprophyric dike. The copper mineralization in the study area occurred as stratiform laminations and disseminations hosted by sandstones and shales and as open-space filling textures within lamprophyric dike. The ore mineralization in the sandstones consists of chalcopyrite, bornite, chalcocite, tetrahedrite, covellite, native copper, and cuprite. This study showed that mineralization is associated with weathering and leaching of the lamprophyric dike. Also, deposition of copper in sandstone units can be related to trapping of organic matters. Activity of the hydrothermal fluids,  presence of abundant organic matters, function of diagenetic processes, existance of the geochemical barriers (organic matter and silicification), and the active tectonic in the area played crucial roles in this ore mineralization.
Abolfazl Jamshidipour, Dr. Mohammad Khanehbad,
Volume 31, Issue 4 (12-2023)
Abstract

The Sibzar Formation (Middle Devonian) is located about 30 Km east of Neyshabur city and is composed of lower dolostone with intercalations of sandstone, middle basaltic sill, and upper dolostone to limy dolostone, with a thickness of 334 m. The sandstone intercalations of this formation have fine to sometimes medium-grained quartz, with low values of feldspar, and rock fragment. According to petrography studies, sandstones of the Sibzar Formation were mostly quartzarenite and subarkose, however some samples plotted on litharenite. From the perspective of geochemical studies, the most abundant major oxides in these sandstones are SiO2 and Al2O3 with an average concentration of 77.8 and 8.3 (wt%), respectively. According to the ratios of SiO2/Al2O3 and Na2O/K2O and other amounts of major oxides and trace elements, such as CaO, Fe2O3, TiO2, Zr, and V, these sandstones have medium to high values of quartz; therefore have a quartzose sedimentary provenance, and are located in an intracratonic basin on the passive continental margin. Source rocks of these sandstones are intermediate to felsic igneous rock and have been affected by moderate to extreme degrees of chemical weathering. According to the evidence, the source of siliciclastic sediments for Sibzar Formation sandstones may have been Arabian and African plates.

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