نشریه زمین شناسی محیط زیست
پیاپی 14 (بهار 1390)

Southeast Tabriz, Sahand volcanic rocks with Plio-Quaternery age located in the northwest part of Central Iran. These rocks are mainly composed of pyroclastics (tuff and ignimberite) and lava flows (rhyolite, rhyodacite, dacite and andesite) that unconformably cover the Miocene sedimentary formations. The major constituent minerals include plagioclase and hornblende which is surrounded by a matrix of fine grained and glassy.Their texture are porphyritic. Heterogenous mineralogy, field and textural evidences such as sieve texture in plagioclase, resorption rims in crystals, oscillatory zoning in plagioclase, high normative quartz and rounded enclaves suggest that the primary magma undergone magmatic evolution including fractional crystallization, fractionation, contamination and magma mixing during ascending. There are mineralogical as well as geochemical evidences that AFC-type processes were involved in the evolution of the Sahand volcanic rocks. The chemistry of the felsic- intermediate volcanic rocks indicates that the parent magmas are medium-K calc-alkaline and metaluminous in nature. The volcanic rocks display highly fractionated REE patterns, with no negative Eu anomaly. Their geotectonic environment is post-collision and continental margin arcs.

Baft coloured mélange with approximate area 617 km2, is located along Baft and Shahr-e-Babak major faults in south of Kerman province. Field and microscopic studies on peridotites, chromitites and related dunites in this area indicate that they are formed in mantle environment. Because peridotites in this mélange have been deeply altered (serpentinized), primary minerals such as olivine and pyroxene have been changed into secondary minerals, spinels are only resistant primary minerals against alteration in these rocks that has been survived in completely serpentinized rocks. In this study, chemical compositions of spinel's unaltered cores have been used for the petrogenesis and tectonic setting of the studied peridotites and chromitites. Based on evidences, the studied lithologies can be divided into two groups. The first group is peridotites include harzburgite, dunite and lherzolite that belong to Alpian type peridotites and the harzburgites, probably resulted from 15-20 percent partial melting of a fertile lhrzolitic mantle. Second groups are chromitites for which a magmatic genesis could be assumed. The studied chromitites are podiform and their parental magma is boninite. The chromites with average Cr2O3=62.8% and Cr#=0.83 are classified as Cr-rich chromitites or as the first grade type chromites in the world. Cr# and Mg# values indicate that the studied chromitites have been crystallized from boninite magmas, probably in suprasubduction zone setting in a back arc environment.

The reconstruction of the Caspian Sea water level fluctuations in the Quaternary period is the main objectives of this research. Thus, with the study of biofacies on 254 cores samples associate to exploration wells (Mazandaran 1 and Gorgan 3 - A) and 150 sediment samples which have been collected from depths of 10 to 800 meters from the sea bed of the Caspian Sea bioindicators and sedimentary indexes were identified. The results of studies of the Quaternary sediments showed that gastropod species are the most important biological evidence for the reconstruction of sea level changing of the Caspian Sea. Also there are alternatively fluctuations in this region that were affected by global climatology impact.

Asmari Formation (oligo-Miocene) is the most important reservoir unit in south west of Iran oil Fields. The Rag-e-Safid oil field is one of them. This field is located in Dezful Embayment. In several studies, there are still some uncertainty about microfacieses and depositional environment of the Asmari formation in Rag-e-safid oil field. There for according to petrographical study of thin sections supplied of cores and cutting samples (2138 thin sections with 7 wells) and comparison of associated constituent facieses with standard microfacies types of carbonate ramps of Flugel (Flugel, 2004) and facies belts of Buxton and Pedley (Buxton and Pedley, 1989), 13 carbonate microfacieses and 2 non carbonate microfacieses is investigated. The microfacieses are in five group facieses (depositional sub environment) that consist of open marine (group O), shoal or bar (group B), lagoon (group L), intertidal (group I) and supratidal (group S). The sub environment ascribed to a carbonate platform ramp.

The studied area is located in the north of Nahavand’s Firozan, Sanandaj-Sirjan geological zone. The Cretaceous dacite, andesite, quartz-andesite and tuff are dominated rocks in the area.Granite and granodiorite intrusive rocks have been intruded to this complex. The geochemical analysis shows anomalies of Au, Ag, As, Sb, Fe, Pb and Zn. The heavy minerals are magnetite, hematite, limonite, martite, oligist, pyrite, oxidized pyrite, galena, sphalerite, native copper, azurite, barite, pyrolusite, ilmenite, rutile, anataz and leucoxene that they are principally affiliated with anomalous zones. Also, 18 sample from mineralized zone show that noticeable geochemical anomaly for Au, Ag, Cu, Pb, Zn and Fe. Finally, field study, mineralography, stream sediments and heavy minerals analysis show that anomalous zone in western part of the area.

Kazerun covers one of the most precious and beautiful natural regions of Fars Province. Parishan Conservative, part ofwhich is on the east of Kazerun, is located in Kouhmareh, Nodan and Gerearea. Parishan Lake is also called Famour. This comes from the name of the spring which is the Lakes main source of water. The scenery during spring and fall is very attractive, and the green and flower fields around the lake and presence of wild birds make a very astonishing natural resort. This lake has been registered as an international pond in Ramsar Convention (1971) and as a conservative region in the classification of regions. In this article, a brief study of the animals and plants specifications of Parishan Lake before fire and also the effective factors on its destruction are presented. At the end, there is report on the current conditions of the lake after the fire. The Methodology includes documentary as well as field study.

Kish coralline Island is the most important ones in Persian Gulf and form of carbonate biochemical deposits. Kish Island is located 18 km of Iranian main land and part of folded Zagross. Island’s rocks made from Pleistocene Khark limestone. In this research introduce of foraminifera have done in 2 parts: surface and core samples. In surface studies of Foraminifera, 7 genera and 33 species were identified that most abundance of them is Ammonia beccarii. But in core samples studies of Foraminifera, 5 genera and 2 species were identified. According to core samples studies any foraminifera with agglutinate test didn’t identify.

Every year, due to the penetration of cyclone and different air masses and also local conditions, the resulting flood phenomena causes extreme damage to the natural and economical resources. Sometimes, due to the flood waves or high density of residual materials, hydrometric stations are damaged and consequently the recorded data do not match to real data. Considering the lack of hydrometrical stations in most of the small watersheds, determination of runoff and maximum flood discharge requires a suitable method to estimate runoff and peak flow which to be used in flood and erosion control management plans. In this study empirical CN method is used. In this study, a principle of work method is applying of statistical data ( statistics year of climatology stations Robate, Ghare bil, Cheshmekhan, Hagholkhaje, Dasht, Dashte shad, tangrah,Ghojmaz,Til abad, pishkamar, Galikesh and station hydrometric Tnagrah). Spatial data analysis and also using of satellite images for gaining CN map in SCS model with GIS, in the next stage recognized applying the SCS equation, CN map and precipitation layer which zones have the potential for creating of similar runoff. In this study, also due to assessment curve number CN choice several flood danger that the results shows the high correlation between curve number calculated and curve number observed and also resulted that use of weight model in curve number calculate provided to consider all of effective factors in runoff existing and at the result attain reliable estimate of runoff resulting the rainfall