JOURNAL OF SCIENCES (ISLAMIC AZAD UNIVERSITY)
Year:2003 | Volume:13 | Issue:49|Papers Count:8

Trace elements were analyzed in streambed-sediment samples collected from 35 sites in Khorram Ahad River Watershed. Sites sampled represented agricultural, mining, mixed and Urban/recreation land-uses and background conditions.The elements of cadmium, selenium and zinc were detected in streambed-sediment samples collected at all sites. Because of toxicant effects, these trace elements are known as pollution indexes. Zinc and cadmium concentration in streambed-sediments are highest at mining land use sites in the Khorram Abad watershed. Selenium concentration in streambed-sediments is highest at agricultural land-use sites in this province. The concentration of trace elements in streamhed-sediments generally increased as particle size decreased.

Through the median part of Khoshumi mountains, the Mesozoic granitic rocks have intruded the Precambrian metamorphics of Chapedony Complex. In this way, numerous dykes intruded the igneous and metamorphic rocks. Some of the dykes are metamorphic and belong to Precambrian age. And some of them have not been metamorphosed.The non-metamorphosed dykes are more abundant, their basic to intermediate types include dolerite, and andesitic basalt and trachyandesite. Acidic non-metamorphosed dykes are of rhyolite and dacite in composition. Acidic dykes indicate to cale-alkaline type composition, and hasic to intermediate dykes are associated with alkaline type in series. Basic to intermediate dykes are possibly generated from the mantle flow and localized through the local rifts, whereas acidic dykes sourced from the upper crust.

Development of normal faults is caused by extension regimes that have spread in many parts of crust specially in continental rifting and oceanic ridges. Furthermore, normal faults may develop in an pecial condition in some areas under the compression regimes (mainly folds, thrusts and reverse faults are produced in this situation). Compression process may cause.folding and uplifting. Uplifting can produce surface tension forces and then the normal faults could form. Normal faults are formed clearly due to accumulation hige sedimentary materials in the northern and south parts of Makran region (south margin of Jazmourian and Makran coastral area). The procedure under wich the normal faults in the coastal area form differs to those in the south margin of Jazmourian. The absolute movement uplifting of the footwall in the reverse faults in the margin of Jazmourian causes their appearance as relatively normal faults.Whereas, the development normal faults in the Makran coast is affected by surface tension forces, induced by the uplift and absolute movement of hanging wall of reverse faults. So that uplifted parts under the effect of gravitional unstability produces normal faults. Also the accumulation of faults dip toward south and vertical extension fractures (hoo) are in agreement with this subject.

The studies area is situated in the south of Chaharmahal Va Bakhtiari between the eastern longtitude of 50°, 28° to 51°, 13° and north lattiude of 31°, 20° and 31°, 38°.The only existing geological map of the region is the map of Boroujen with a scale of 1:250,000, prepared by Ministry of Oil that with regard to the scale of the map, the studied region with brief geological information is observable on it. Therefore preparing the map of the above said region with geological interpretations and stratigraphic details seemed necessary. This region is divided by Bagh Heyran fault into two eastern and western zones. The eastern part is situated on high Zagross zone and its sediments date back to Paleozoic and Mesozoic eras. The significant characteristic of this zone is plenitude of faults and shattered structures. Sediments of this zone equals structure of Barote, Zygone, Lalone and Milia. In addition, carbonate sediments dating back to Jurassic and cretaceous periods are also discernible. The faults of this zone, in the south of Bagh Heyran village have a N-340 direction and in the north and north-west of the ahove mentioned village they show an east-west direction. The western zone that includes the main part of the studied zone contains sediments from the third and fourth eras. Main structures constituting this zone include: 1.Eocene sediments which are mainly calcareous and are sometimes converted to dolomite lime and dolomite. 2. Oligocene sediments which are mainly calcareous, Marne lime and occasionally chille. 3. Formation asmari inducing limestones and marne limestones. 4. Fars group that in the inferior section includes conglomera and in the upper part comprises chalk contatining marnes. silts tone and sandstone.5. Bakhtiari formations including conglomera and sandstone. 6. Sediments of the fourth era that in this zone are observable in the form of terraces, young alluviums and alluvial fans. The faults of this zone have north-west-south-east, north-east-south-west and north-south directions. At the end the geological map of the region with all details and guides was prepared that it is hoped to be used in development projects.

Groundwater discharge is one of the main components of the streamflow in dry periods.Therefore the recharge quantities of groundwater aquifers connected to ZAYANDEH-ROUD catchment was determined on base of an analytical groundwater model named "Rorabaugh's method", Since in this method is necessary to plot the groundwater discharge recession curves, the base flow master recession curve was plotted both manually and automatically for 15 Iranian calendar years from 1360-1361 to 1374-1375 water year. Then the recharge values were computed manually and automatically by "RORA" software, but in regarding to nonentity of error accurance in automatical method, the result of these methods is more reliable.

The studied area is located in south-eastern Iran with a measurement about 510 Km2. The Igneous nicks of this area belong to teriary. The oldest part is eocene volcanic and pyroclastic rocks, as andesite-basalt, andesite, lathite andesite, dactie, acidic to intermediate tuffs and ignimbrite. A batholitic body intruded in the volcanic rocks in miocene. This batholite is composed of diorite and granithoidic (tonalite, granodiorite porphyry" granodiorite porphyry granitc porphyry and granophyre) rocks. According to field observation, geochemical and tectonomagmatic studies, there are two different magmatic episode as volcanism and plutonium. In this area differentiation of calk - alkline pyroxene and plagioclase is the main reason of evolution for the calcalkine volcanic rocks. There was a dioritic magma in the miocene which a small part of it intruded in the volcanic rocks directly. The differentiation of pyroxene, plagioclasc and titonomagnetite minerals changed the composition of the magma. Then different granitoidic rocks were formed in respect to composition and the depth of magma. The granitioidic rocks are I type and belong to (VAG) group. According to their spider diagrams they are very similar to Lima granite in Peru, which is a continental margine granite.

Nowadays,- geomorphologic studies constitute the principle and foundations of studies of natural resources. In this study, our attempt was made to recognize, segregate and reveal the units and main geomorphologic phenomena of the southern Chahar-Mahal Va Bakhtiari. Such units includes: 1. Mountains, 2. Hills and high grounds (stoney hills and high grounds and alluvial hills and high grounds) 3. Alluvial Plains Mountains of the studied area, high with rather sharp precipice peaks, very steep slopes and narrow and mainly V-shaped valleys. Main factors involved in erosion of uneven nesses of this unit climate (type of precipitalations, intensity of rainfalls and temperature range), topography, type of formation and surface run off were studied. In this unit, all types of physical, chemical and biological erosions are discernable and landslip, debris and landslide are part of the mass movements on the mountain slopes of this region. Bakhtiyari conglomerate formations, sand stones and marns of fars group have formed stoney hill knolls of the studied region. in this unit peaks of hillknolls are round and circular and pnltile of the slopes are mostly convexed. Also effects of physical destruction and chemical decomposition are clearly evident in this unit. Alluvial hill knolls in clay and marn formations are seen in the north west of the region. Water erosion in different ways has played a significant role in modification of the uneven nesses of this region. Creep, solifluxion, landslide and narrow creeks are amongst the phenomena exiting in this region. Alluvial Slope plains present in the under studied region include Alloni and Jamal plains. The Alloni is amongst the plains rised as a result of pressure suhsidences at the foot of Dena fault. The most interesting phenomenon found in Jamal plain is God-Jamal which, infect, is a small closed basin with its topographic slope towards the center from which the surface waters do not got out. The central plain in the under studied region is located in an alluvial strata formed from the sedimentary deposits of the two rivers of Khanmirza from the north east and Chelehkhaneh from the southeast. In this plain rill, and sheet erosion the surface and thalluses on steep slopes are clearly seen. Main morphologic forms in this region include riverine deposits, alluvial terraces, lake deposits, sources and alluvial fans studies in this research.