JOURNAL OF SEDIMENT AND SEDIMENTARY ROCK
Year:2009 | Volume:2 | Issue:5|Papers Count:8

Gadvan Formation (Late Barremian to Early Aptian) consists of three members in Kuzeh Kuh section. These members include Lower Gadvan (shale and marl with thin limestone), Khalij limestone and Upper Gadvan (shale and marl with thin limestone). Gadvan Formation is 58 meters thick at Kuzeh Kuh section. Gadvan Formation is unconformably overlain by Fahlian Formation and conformably overlain by Darian Formation. Field and microscopic investigations of Lower and Upper Gadvan show that these members include shallow open marine benthic foraminifera, shale and marls with planktonic foraminifera and turbidite related to deeper part of this basin. Massive limestone facies of Khalij Member show that these sediments were deposited in lagoon and shallow marine environments. Gadvan Formation sediments were deposited in a carbonate shelf platform. The comparison of relative change curve of the studied facies with global sea level change shows that Gadvan Formation facies changing in investigated area corresponds to Arabian platform pattern.

12 samples were selected from the top of Che-Jam windblown sands. Grain sizes of these samples were analyzed at sedimentary lab, which were between 1  - 5Æ. Cumulative and frequency diagrams were plotted for each sample. The means of grain sizes were between 2Æ and 2.59Æ.The sand grains were well sorted to very well sorted. The skewness was positive except in 3 samples. Kurtoses were Mesokurtic to very leptokurtic. The comparison between Moment and Graphic methods showed that they were very similar but sorting was slightly different. The titration test represents samples which include 15% to 39.5% carbonate minerals. The sphericity and roundness of 200 quartz grains were studied and it was revealed that the grains with high and low sphericity were roughly equal. Mean Roundness of the two groups were subrounded.

Asmari Formation in Dareyan section with the thickness of 170 meters and in Runiz section with the thickness of 150 meters was studied and researched. The Formation is overlain and underlain with disconformable contacts, by Jahrum and Razak Formations, respectively. Accurate petrographic studies led to the recognition of 15 carbonate microfacies and 1 sandy facies which compromise 5 facies associations. They are peritidal, lagoon, protected, shoal and open marine. Based on these results, Asmari Formation deposited in different parts of a homoclinal carbonate ramp.

White mine located east of Vartoun village, north-east of Esfahan city. The region belongs to Uromia-Dokhtar belt zone. MorpHologic evidences imply that the travertine are Fissure- Ridge type and are related to the Quaternary age. Petrology and geochemistry evidences shows Fabric and texture characteristic of these sediments empHasize the active presence of micro organisms and biological activities with travertine sedimentation simultaneously. It shows special peloid's texture with micrite and estromatolite lamination. The presence of lamination in travertine is due to alternative seasonally/daily growth.. Most of this travertine is seen in the 1 to 2 kilometers of the active fault zones. With regard to the process of these faults, the generating agent of travertine is the local tension in fault regions.one special estromatolits facieses is existence in this mine. the geological evidences shows that these rocks occurred in a high geogradiant environment and due to the tectomagmatic activities circulation of magmatic and meteorite waters in depth and represented on surface by the faults and fractures in the form of hot springs causing the formations of travertine in springs and large faults trends.

The Dariyan Formation (Aptian) is one of the important hydrocarbon reservoir rocks of Khami Group in the south west of Iran. As exact evaluation of reservoir rocks is possible through of microfacies depositional environment and reservoir characterization analysis, by this way, the subsurface section (X1 well) of Dariyan Formation in Salman Oil Field, located in 144 kilometers from south of Lavan Island, Persian Gulf with the mentioned aims was considered and evaluated. Extended microscopic assessment of deposits of the Dariyan Formation in mentioned section led to recognition of four facies associations related to, open marine (A), bar (B), lagoon (C) and tidal flat (D) environment. The vertical changes survey and comparing it with modern and old depositional environments indicate that the facies of Dariyan Formation in the studied section have been deposited in a carbonate rimmed shelf. Assessment of porosity and permeability according to distribution of microfacies and drawing diagrams, describes that microfacies C1 realated to lagoon because of many fractures has the best reservoir quality in Dariyan Formation and from other most porosities in Dariyan Formation can point to intergranular and intercrystalline porosities.

Ziarat Formation in Khalkhal region is disconformably located on creataceours limes and is covered by acidic tuffs and andesite lithic unites of Eocene Age which is equal to the lower part of Karaj Formation and this is the indicator of a unit of Nummulitic limestone with the age of middle Eocene.The thickness of the studied section is 36 meter and its dominant lithology includes limestone, sandy limestone, nummulitic limestone and marl. According to field studies and microscopic sections, the identified microfacies belong to six environments, namely, tidal flat, lagoon, back bar, bioclassic bar, forebar and open marine. The sedimentation model of a shallow sea is in the epicontinental platform which has never found the conditions of a deep marine.This carbonate platform which is the type of homoclinal ramp is comparable withsouthern parts of Persian Gulf (Troutial Coast) in the present age environment.

In this research two sections of Sarvak Formation called Kareh-tavy and Zakiyan totally 585 m including 400 thin sections of upper Cenomanian sediment were selected. The major microfacies in the studied section include wackestone, packstone, grainstone, boundstone, floatstone and rudstone. These microfacies fall into four environment groups: open marine, bar, lagoon and tidal areas. The major elements of microfacies include bioclast, intraclast, extraclast and pleiod.Considering sequence stratigraphy studies, two 3rd-order sediment sequences (3rd class cycle) have been identified: sequence 1 (upper Albian to Lower Cenomanian) which is related to Lower Sarvak Farmation, and sequence 2 (Middle to Upper Cenomanian) which is related to middle and upper part of Sarvak Formation and include bar, lagoon, tidal flat facies.

The Oligo-Miocene Asmari Formation is one of the most important reservoir units of the Parsi Oil Field that is located in North Dezful Embayment in SW of Iran.This formation is laid over the shales of Pabdeh Formation concordantly and is overlaid concordantly by evaporates of Gachsaran Formation. Asmari Formation (with 419m thickness) is composed of anhydrite, carbonate rocks (limestone & dolomite) associated with thin shale interlayers.In this study lithofacies, microfacies, and their associated facies of studied formation have been investigated based on core samples and thin sections. Study of asmari formation led to recognition of 8 lithofacies and 18 microfacies that are related to open marine, barrier, shallow subtidal facies, reef, lagoon, supratidal and intertidal environments. The Correlation of mentioned micofacies with standard model of carbonate from ramp environment (Buxton & Pedley, 1989), show that Asmari Formation was deposited in a carbonate ramp which some local reef or patch reef.