نشریه رخساره های رسوبی
سال چهاردهم شماره 2 (پیاپی 27، پاییز و زمستان 1400)

Toryan area is located in the Central Iranian zone, about 120 km northwest of Zanjan. In this area, the exposed rock units belong to the Upper Red Formation (URF). The thickness of the URF at Toryan is 1010 m, and consist of four main parts. These parts, from bottom to top, consist of: 1-alternation of gypsiferous (locally salt) green marls (300 m), 2-alternation of red marls and grey to red sandstones (275 m), 3-alternation of red and green marls intercalated with sandstone (210 m), and 4-green marls with interbedded green siltstones (225 m). Based on microscopic studies, average particle size of sandstones in the Toryan area is about 0.2 mm. These sandstones also display poor orientation, poor to moderate sorting, and mainly are angular to semi-angular. Based on component types and results of point counting, the studied sandstones contains 16% quartz (included mono and poly-crystalline with both straight and wavy extinction), different types of rock fragments (sedimentary, metamorphic and volcanic) and 10% feldspar (mainly ortoz). According to Folk (1980) classification, it can be stated that the studied sandstones are litharenite to feldspathic litharenite with calcite and evaporitic cements. Based on the main components and the results of petrographic, major and minor elements geochemical analyses, the tectonic setting of these sandstones is related to foreland and collision basins. These data represent an intermediate to felsic source rock for these sandstones, which were affected by semi-arid to arid climate.

In order to paleobathymetry of the Farokhi Formation at type section, have been studied based on planktonic foraminifera. The thickness of this formation is 251 meters and was composed of limestone, marl, and limey marl with fossils limestone. The lower and upper contacts of studied formation with Haftoman and Choopanan formations are respectively conformed and disconform. Based on this research were realized 28 planktonic foraminifera species belonging to 9 genera. Comparing planktonic assemblages recovered from the formation with those biogeographical provinces indicate a close similarity with those of Tethyan provinces. Also, based on a statistical analysis of foraminifera assemblages, it has been proposed that Farokhi Formation was deposited at Middle-Outer Neritic open marine environment. In the Early Campanian Sea level is low and at the Middle-Late Campanian is high. At Campanian-Maastrichtian transition sea level is low and at the Maastrichtian stage is high. Finally based on a statistical analysis of %P, M3 and Van der Zwaan et al. (1990) depth equation was display Farokhi Formation was deposited at 75-meter depth.

The Asmari Formation is an important part of Cenozoic (Oligocene-Miocene) deposits in southwestern Iran (Zagros Basin). This Formation is known as one of the most important reservoir formations in Iran. The purpose of this study is to study the Asmari Formation in the Karanj oil field in southwestern Iran, 115 km southeast of Ahvaz and 40 km east of Ramhormoz. In this study, based on the study of microscopic thin sections (including 161 thin sections of drilling cores) prepared from 225 m of underground cutting sequences of one of the wells of Karanj oil field, microfacies and depositional environment of the Asmari Formation, were fully investigated, and 10 microfacies were identified and interpreted. The depositional environment of this Formation can be classified into three sub-environments: inner ramp, middle ramp and outer ramp. The Asmari Formation in the one of wells of the Karanj oil field deposited on a carbonate ramp.

In this research biostratigraphy of Baghamshah Formation based on calcareous nannofossills in the kalshaneh section was investigated. This section is located in northwest of Tabas. Baghamshah Formation in this section with 505 m thickness mainly consists of green- gray marl, very thin bedded shale with intercalation of fine sandstone and brown limestone abundant of brachiopodae and pelecypodae fragments and gerrn marl with interbedded of nodular limestone. Lower boundry with Parvadeh Formation is comformable and upper boundry with Kamar-e- Mehdi Formation is also marked. The study of nannofossils has been led to the identification of 44 species and belonging to 22 genera. According to stratigraphy distribution of calcareous nannofossils, CC3-CC5 biozones of Sissingh (1977) were determined. Nannofossil biozones indicate lateValanginian- late Haterivian age for the Baghamshah Formation in the Kalshaneh section.

In this study, biostratigraphy of Gurpi Formation in Assaluyeh section was performed based on the scattering pattern of calcareous nannofossils and a comparison was made with the stratigraphic sections of Kuh-e Harm and Pazanan. In the Harm section, the Gurpi Formation with a thickness of 153 m is mainly consists of marl and intercalations of clay limestone, in the Assaluyeh section with a thickness of 76 m consists of marl, shale and argillaceous limestone, as well as in the Pazanan section with 55 m thickness mainly consists of marl. As a result, ten bio-zones of calcareous nannofossils Lucianorhabdus cayeuxii Zone (CC16 / UC12), Calculites obscurus Zone (CC17/ UC13), Aspidolithus parcus Zone (CC18/ UC14TP), Calculites ovalis Zone (CC19), Ceratolithoides aculeus Zone (CC20/-UC15bTP), Quadrum sissinghii Zone (CC21/ UC15cTP), Quadrum trifidum Zone (CC22/ UC15dTP-UC15eTP), Tranolithus phacelosus Zone (CC23/ UC15eTP-UC16-UC17), Reinhardtites levis Zone (CC24/UC18), Arkhangelskiella cymbiformis Zone (CC25/UC19- UC20a,bTP) of Sissingh (1977) and Burnett (1998) zonations were detected. Based on the identified bio-zones, the age of Gurpi Formation is proposed in Assaluyeh section from late Santonian to early late Maastrichtian, as well as at the Kuh-e Harm and Pazanan is early Campanian to early late Maastrichtian. Also, because the absence of CC26, the Gurpi and Pabdeh Formation boundaries are fossil discontinuous in all three sections.

The is studied already of the Sachun Formation around the Shiraz (Interiorl Fars zone) in the southwest of Zagros basin has been studied in terms of biostratigraphy, the paleoenvironment (based on stratigraphic data of feraminifers) and sequence stratigraphy. Two biozones of framinifiers were determined in three sections (Tang-e- khiyare, Dariyan and Kohenjan). The age range of Sachun Formation in the studied sections is from Lower Paleocene to Lower Eocene.The Sachun Formation in the studied area is conformably overlaid on the Pabdeh Formation and underlaid the Jahrum Formation. Qorban member as carbonates sequence in the Sachun Formation, with the accumulation of more fossils and prominent outcrops deposited in a bioclactic barrier, can be distinguished from other units of the Sachun Formation. Based on observations and laboratory study, eight microfacies were identified in four sedimentary environments. The sequence of the Sachun Formation was deposited in a carbonate-clastic platform. Comparison of paleoecologic and paleoenvironment of both three studied sections represent Qorban member of Kuhenjan section was deposited in shallow water and high energy environment proportion of Dariyan section. Actually, fossil diversity is more recognized in oligotrophic and mesotrophic environments of Dariyan section whereas fossil diversity ismore than Qorban member of Kuhenjan section. The Sachun Formation is deposited in a shallow water. The Sachun Formation of the studied sections as Paleocene-Eocene age consists of two third-order sequences.

Karst water sources in many areas can be used as a main source of fresh water to supply water to residents and the chemical and stable isotopes technique can be can used for understanding of karstic aquifers. Sarpol-e-zahab area is located in Kermanshah province, west of Iran. Alluvial deposit and Asmary formation cover the most outcrops in this area (Mohammadzadeh et al., 2016) and has an important karst water resources (Mohammadzadeh and amiri, 2019). The concentrations of inorganic and organic carbon (DIC and DOC) and variations of δ13C values can be investigated to determine carbon sources in water resources. In this research, the seasonal and spatial variations of dissolved carbon concentration and values of carbon isotope in water resources of Sarpol-e-zahab region have been evaluated. 

 In order to evaluate the origin of dissolved carbon (DIC and DOC), samples were collected in two wet (January 2014) and dry (September 2015) seasons from surface and groundwater resources and field parameters were measured at the time of sampling. For measuring DIC and DOC concentration and variation of δ13CDIC, all water samples were collected in colored glasses 40 cc and were sent to the G.G Hatch Stable isotope laboratory at the university of Ottawa and Environmental isotope laboratory at Waterloo university, Canada, for DIC, DOC and 13C isotope analysis. 

The mean DIC concentrations in wet and dry seasons were 71/9 and 80/9 mg/l ppmC, respectively. By increasing the DOC concentration (with average of 0/3 mg/l), the δ13CDIC values were depleted. The average values of isotopic composition of carbon (δ13CDIC) in water samples was about -11/7‰ and -11/3‰ in wet and dry season, respectively. Among the water samples, Gandab spring has high DIC concentration and due to presence of organic matter of hydrocarbon origin has depleted carbon isotope than other samples. Glodare sample has high amounts of DOC due to entry of organic detergent from upstream bath. Some samples have depleted isotopic composition due to agricultural activities and the use of pesticides. High PCO2 values (with average 10-1/8 and 10 -1/6 atm in wet and dry seasons, respectively), which is more than atmosphere CO2 pressure (10 -3/5 atm), indicate weathering and dissolution of carbonates occur by soil CO2 in study area. By increasing PCO2, the DIC concentrations were increased, however, the δ13CDIC values were depleted that can be caused by the decomposition of organic matter and root respiration of plants. 

The results indicated that the main origin of dissolved carbon in the water samples of the Sarpol-e-zahab area is due to dissolution of carbonate rocks (lithology) and partially of it comes from organic matter and soil CO2.

The tectonic depression Urmia Lake in the northwest of Iran is receiving a lot of erosional sediments of the geological structures and waste materials of the industrial, mining and agricultural activities. Fifteen surface samples including sandy and muddy sand sediments of the studied area have selected and analyzed by ICP. Based on average values of heavy metal concentration the ranking of intensity of heavy metal pollution of the studied area sediments is as follows: Al> Fe> Mn> Ba> Cr> Ni> Zn> Cu> Co. The concentrations of Ni, Mn and Cr are much higher than Consensus-based PEC (probable effect concentration) and Iran Standard (especially in south and southwest sites of the lake) that display very high probability of the harmful biological and environmental effects of heavy metal in these sites. the mean concentration EF in the studied sites displays industrial and mining effects in enrichment of the heaviest metals especially Ni, Cr and Cu (moderate to moderately severe enrichment) in the south and southwest transects and Cu (moderately severe) in the Jabal transect. the mean contamination factor value display considerable enrichment for Ni, Cr and Cu and partly for Mn especially in south and southwest transects. The modified degree of contamination for all of transects with the exception of the Jabal Kendy site in the southwest lake that have moderate contamination, displays low contamination. Geoaccumulation index for all of transects displays no to moderate enrichment. In general, concentration of the toxic metals of the studied sediments displays low biological hazard (except for Cu and Ni).