عنوان مقاله [English]
نویسندگان [English]چکیده [English]
In this reaserch, the sandstones belong to the middle parts of the Upper Red Formation in the Hamzelou region, 70 Km NW of Zanjan, has been studied based on sedimentology and elemental geochemistary. The Upper Red Formation in the Hamzelou region has a 945 m thickness and is divided into four parts. These parts from button to top of the formation consist of the alteration of evaporite units and green-marl with interbedded of the gypsum (300 m); the alternation of red-marl with the layers of red and grey-sandstone and micro-conglomerate (355 m); the alternation of red and green-marl with interbedded of the grey and red-sandstone (150 m); the alternation of green-grey marls with interbedded of the layers of gypsum (140 m). These sandstones contain different types of the rock fragmensts such as sedimentary, metamorphic and minor amount of volcanic, monocrystalline quartz with straight extinction and finally feldspar manily orthoclase types with a less frequency. Carbonate cements and matrix are also visible between the grains. These sandstones represent manily a feldspathic-litharenite and litharenite composition with submature to mature in terms of textural maturity. The micro-conglomerate layers are similar in composition to sandstones and classified as an extra-formational conglomerate, ortho-conglomerate and polymictic conglomerate. The tectonic setting of these sandstones is related to collision and recycled orogenic. Also, according to the obtained data in this research, the source rocks of these sandstones are intermediate to felsic igneous rocks, which were influenced by semi-arid climates duirng the deposition.