نویسندگان
1 دانشیار زمین شناسی- دانشکده زمین شناسی - پردیس علوم- دانشگاه تهران- تهران
2 دانشیار، گروه محیطزیست، دانشکده منابع طبیعی، دانشگاه گیلان، گیلان
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
The Upper Red Formation, in the stratigraphic column, overlies the Qom Formation and is itself overlain by the Hezar Dareh Formation. Its lithological composition consists of thick-bedded red sequences of shale, siltstone, marl, mudstone, sandstone, and layers of gypsum accompanied by salt, with numerous outcrops distributed along the Tehran-Qom highway corridor. Marls are predominantly classified into two categories: marine and continental; the marine type contains a higher proportion of calcium carbonate, whereas the continental type exhibits a greater clay mineral content.The characteristics of the marls and bricks produced were examined through XRF and XRD analyses, as well as sandstone petrography, following Pettijohn’s classification scheme. Geochemical investigations indicate that the studied sandstones originated from intermediate to felsic igneous rocks formed within active continental margin tectonic settings. The principal non-clay minerals identified in the marls of this region mainly include quartz, calcite, and dolomite, while the clay minerals comprise montmorillonite, mixed-layer illite-muscovite clays, and chlorite. Atterberg limit tests on marl samples demonstrate that the studied marls possess plasticity limits and plasticity indices conducive to brick manufacturing. The iron oxide (hematite or magnetite) is responsible for the color and strength of the bricks. The water absorption of the manufactured bricks meets Iran’s national standards for internal-use bricks, with suitable calcium oxide content and compressive strength. Overall, the marls from the studied area have potential for lightweight brick production, provided that appropriate measures are taken to improve the quality of raw materials.
کلیدواژهها [English]
)