Biostratigraphy,Microfacies,Sedimentary Environments and Sequence Stratigraphy of the Late Devonian-Carboniferous Deposits at the Anarak Section,Central Iran

The Late Devonian-early Carboniferous deposits of the Anarak section in northeastern Isfahan,Central Iran,evaluated based on conodont biostratigraphy,sedimentary environment and sequence stratigraphy.According to the field observations,five lithological units were identified.Investigating the conodont fauna of the Late Devonian-Carboniferous(Mississippian-Pennsylvanian)deposits of Bahram,Shishtu,and Qaleh(Sardar 1)formations in Anarak section led to the identification of 67 species of 18 conodont genera,and accordingly 22 conodont biozones were differentiated.The correlation of sea-level change curves,regarding to the conodont biofacies with the global sea-level curve,demonstrates the relative correlation in the mentioned times due to the shallow condition of the central Iran basin compared to the European and American basins.The microfacies analysis led to the identification of 12 microfacies related to the open sea,bioclastic barrier,lagoon and tidal flat sub-sedimentary environments in a homoclinal carbonate ramp environment.Based on sequence stratigraphy studies,three 3rd order sequences were identified.The first sequence,which is of the Late Devonian(upper part of the Bahram Formation,32.5 m),the second sequence(12.5 m)is the Late Devonian(uppermost part of the Bahram Formation),and the third sequence(68 m)is the early Carboniferous(the Shishtu I Formation).

Tectonic paleostress field and its impact on the geodynamic evolution of Central Iran, case study: the Shotori Mountain

The Shotori mountain range is located along the northern terminus of the Nayband fault on the eastern and western domains of the Tabas and Lut blocks,respectively.This range with NNW-SSE trending and approximately 120 km long includes a series of thrust faults approaching the right-lateral strike-slip Nayband fault.Since the Shotori range has experienced various geological events since the Triassic,our investigations suggest that the basement of the Central Iranian subcontinent of the Shotori range contains the early Triassic deep sedimentary with normal faults which confirms Triassic tensional tectonic stress regime in the region.After the middle Triassic,the mountain range has experienced thrust and strike-slip regimes.Therefore,in this study,we reconstruct the stress regimes for different geological periods using fault-slip data.The inversion of faultslip data reveals drastic temporal changes in the maximum stress regime(σ1)over the Triassic,Jurassic,Cretaceous,Paleogene,Neogen,and Quaternary.The reconstruction of the stress field based on the age and direction of fault movement reveals that the direction of the maximum horizontal stress axis(σ1)under a tensional stress regime was approximately N129°in the Early Triassic.This stress regime is the cause of thinning and subsidence of the Shotori sedimentary basin.During the middle Triassic,theσ1 direction was about N81°and the upper Triassic,theσ1 direction was almost N115°.The middle Triassic and upper Triassic stress states exhibited two distinct strike-slip and compressive stress regimes.This stress regime led to the uplift of the Shotori sedimentary basin.During the Jurassic,the direction of the maximum horizontal stress axis(σ1)was~NW-SE under a compressive stress regime.During the Triassic,theσ1 direction was~N-S.This stress regime led to the formation of the high topography of the Shotori Mountain Range.In the Late Cretaceous,the direction of the maximum horizontal stress axis(σ1)under the extensional stress regime was~NE-SW.This stress regime led to the uplift of the Paleogen Dacite in eastern Iran.During the Neogene,theσ1 direction was~N60°.The Quaternary tectonic regime is strike-slip and theσ1 direction is~N50°,consistent with the current convergence direction of the Arabia–Eurasia plates.Our paleostress analysis reveals four recognized stress in this area,which includes compressional,transtensional,transpressional,and strike-slip regimes.Our findings indicated that the crustal diversity of the tectonic regimes was responsible for the formation of various geological structures,such as folds,faults by different mechanisms,and the present-day configuration of the Shotori sedimentary basin.

Facies Analysis and Sequence Stratigraphy of Silurian Carbonate Ramps in the Turan(Kopeh-Dagh) and Central Iran Plates with Emphasis on Gondwana Tectonic Event

Two sections from the Silurian deposits in the Central Iran Micro and Turan Plates were measured and sampled. These deposits are mostly composed of submarine volcanic rocks, skeletal and non-skeletal limestone, shale and sandstone that were deposited in low to high energy conditions （from tidal flat to deep open marine）. According to gradual deepening trend, wide lateral distribution of facies as well as absence of resedimentation deposits, a depositional model of a homoclinal ramp was proposed for these deposits. Field observations and facies distribution indicate that, two depositional sequences were recognized in both sections. These sections show similarities in facies and depositional sequence during the Early Silurian in the area. Although there are some opinions and evidences that demonstrated Paleo-Tethys rifting phase started at the Late Ordovician-Early Silurian, similarities suggest that the Turan and Iran Plates were not completely detached tectonic block during this time, and that their depositional conditions were affected by global sea level changes and tectonic events.

Facies Analysis and Sequence Stratigraphy of the Qal'eh Dokhtar Formation(Middle-Upper Jurassic) in the West of Boshrouyeh, East Central Iran

The study area is located in the east Tabas Block in Central Iran. Facies analysis of the Qal＇eh Dokhtar Formation（middle Callovian to late Oxfordian） was carried out on two stratigraphic sections and applied to depositional environment and sequence stratigraphy interpretation. This formation conformably overlies and underlies the marly-silty Baghamshah and the calcareous Esfandiar formations, respectively. Lateral and vertical facies changes documents low-to high energy environments, including tidal-flat, beach to intertidal, lagoon, barrier, and open-marine. According to these facies associations and absence of resedimentation deposits a depositional model of a mixed carbonate-siliciclastic ramp was proposed for the Qal＇eh Dokhtar Formation. Seven third-order depositional sequences were identified in each two measured stratigraphic sections. Transgressive systems tracts（TSTs） show deepening upward trends, i.e. shallow water beach to intertidal and lagoonal facies, while highstand systems tracts（HST） show shallowing upward trends in which deep water facies are overlain by shallow water facies. All sequence boundaries（except at the base of the stratigraphic column） are of the no erosional（SB2） types. We conclude eustatic rather than tectonic factors played a dominant role in controlling carbonate depositional environments in the study area.

Above- and below-ground biomass and carbon stocks of different tree plantations in central Iran

In arid and semi-arid lands using industrial wastewater for irrigating tree plantations offers a great opportunity to fulfill the purpose of Clean Development Mechanism by sequestering carbon in living tissues as well as in soil. Selection of tree for plantation has a great effect on the goal achievements, especially when the managers deal with afforestation projects rather than reforestation projects. The objective of this study was to quantify the above- and below-ground biomass accumulation and carbon storages of the 17-year-old monoculture plantations of mulberry (Morus alba L.), black locust (Robinia pseudoacacia L.), Eldar pine (Pinus eldarica Medw.) and Arizona cypress (Cupressus arizonica Greene) planted in central Iran. To assess the potential carbon storage, we destructively measured individual above- and below-ground tree biomass and developed and scaled models at stand level. Furthermore, carbon content at three soil depths (0–15, 15–30, 30–45 cm), the litter and the understory were assessed in sample plots. The results showed that the total amount of carbon stored by Eldar pine (36.8 Mg/hm2) was higher than those stored by the trees in the other three plantations, which were 23.7, 10.0, and 9.6 Mg/hm2 for Arizona cypress, mulberry and black locust plantations, respectively. For all the species, the above-ground biomass accumulations were higher than those of the below-ground. The root mass fractions of the deciduous were larger than those of the coniferous. Accordingly, the results indicate that the potential carbon storages of the coniferous were higher than those of the deciduous in arid regions.

Wildfire events at the Triassic-Jurassic boundary of the Tabas Basin,Central Iran

This paper presents organic geochemical evidence pointing to the occurrence of wildfire events at the Triassic-Jurassic boundary in Central Iran.The studied outcrop section(the Kamarmacheh Kuh section)is comprised of the Upper Triassic Nayband Formation which passes conformably into the Lower Jurassic Ab-e-Haji Formation with no sharp boundary.Organic petrographical studies reveal a higher concentration of semi-fusinite macerals and microscopic charcoal at the boundary between studied formations.This observation can be an evidence for widespread wildfire events at the Triassic-Jurassic boundary of the studied area.Following these fires,vast areas of land were exposed for erosion and large volumes of clastic sediments were provided due to increased run-off.This agrees well with previous sedimentological and stratigraphical studies suggesting a major change in the depositional conditions from marine to non-marine at the Triassic-Jurassic boundary of the Tabas Basin.These findings can have important implications about paleo-depositional settings of the studied formations and the nature of the associated organic matter.

Geochemistry, Mineral Chemistry and Thermobarometry of Boneh-Shorou Amphibolites in Gelmandeh Massive (Saghand-Central Iran)

The Gelmandeh Massive is located in the Central part of Iranian Microcontinent. Amphibolitic rocks occupy the main portion of Gelmandeh complex, which consists of hornblendite, garnet amphibolites, and gneiss. Geochemical investigations indicate that the ratio of Eu/Eu* separates samples into two categories: first category with ratio of Eu/Eu* > 1 and the second with ratio of Eu/Eu* < 1, which the former indicates an enriched mantle origin while the latter points to crustal contamination. Generally, amphibolites can be differentiated into two separate series. First series is characterized with calc-alkaline to alkaline composition with enriched mantle origin, and the second one has calc-alkaline to tholeiitic nature and it is of continental type that underwent crustal contamination within subduction zone. The microprobe electron analysis shows that the amphiboles were a member of the calcic group and hastingsite-tschermakite series. Geo-barometric studied and mineral paragenesis show that the metamorphism is of Barovian type with PT condition upto 7 K bar and 580°C.

Economic Geology of the XIV Iron-Oxide Prospect, Bafq Mining District, Central Iran: A Preliminary Approach

This paper presents an overview about the XIV iron-oxide prospect which is located in the Bafq mining district, central Iran. The prospect and its host rocks were investigated by field observations together with mineralogical and geochemical studies. According to these investigations, the XIV prospect is similar to Kiruna-type iron deposits and demonstrates a magmatic source for the ore forming processes with a metasomatic overprinting.

Dolomitization Mechanism Based on Petrography and Geochemistry in the Shotori Formation (Middle Triassic), Central Iran

Middle Triassic carbonate sequences of Shotori Formation have a thickness of 70 m and are deposited Robat-e-Kalmard region of Tabas city in Central Iran basin. Gradationally and conformably overlying Sorkh shale Formation, Shotori Formation, mostly composed of medium to thick dolomites (50 m), interbeded with thin lime and sandstones, is disconformable by a laterite horizon at its upper boundary. This Formation mainly consists of fine-to-coarsely crystalline dolomites. According to petrographic (fabric and grain size) and geochemical (elemental analysis of Ca, Mg, Na, Sr, Fe, Mn) evidence, five various types of dolomites were recognized in Shotori Formation. This variety results from early and late diagenetic processes, triggering a change in dolomitizing fluids and thereby forming various dolomites. Geochemical studies have revealed that the dolomites of Shotori Formation have formed under meteoric diagenesis and reducing conditions. Various dolomitization mechanisms are proposed for various types of dolomites;that is to say, Sabkha model is considered for type 1 dolomite, mixing zone model for type 2 and 3 dolomites and burial model for type 4 and 5 dolomites.

Modelling the impact of climate change on rangeland forage production using a generalized regression neural network:a case study in Isfahan Province,Central Iran

Monitoring of rangeland forage production at specified spatial and temporal scales is necessary for grazing management and also for implementation of rehabilitation projects in rangelands. This study focused on the capability of a generalized regression neural network（GRNN） model combined with GIS techniques to explore the impact of climate change on rangeland forage production. Specifically, a dataset of 115 monitored records of forage production were collected from 16 rangeland sites during the period 1998–2007 in Isfahan Province, Central Iran. Neural network models were designed using the monitored forage production values and available environmental data（including climate and topography data）, and the performance of each network model was assessed using the mean estimation error（MEE）, model efficiency factor（MEF）, and correlation coefficient（r）. The best neural network model was then selected and further applied to predict the forage production of rangelands in the future（in 2030 and 2080） under A1 B climate change scenario using Hadley Centre coupled model. The present and future forage production maps were also produced. Rangeland forage production exhibited strong correlations with environmental factors, such as slope, elevation, aspect and annual temperature. The present forage production in the study area varied from 25.6 to 574.1 kg/hm^2. Under climate change scenario, the annual temperature was predicted to increase and the annual precipitation was predicted to decrease. The prediction maps of forage production in the future indicated that the area with low level of forage production（0–100 kg/hm^2） will increase while the areas with moderate, moderately high and high levels of forage production（≥100 kg/hm^2） will decrease both in 2030 and in 2080, which may be attributable to the increasing annual temperature and decreasing annual precipitation. It was predicted that forage production of rangelands will decrease in the next couple of decades, especially in the western and southern parts of Isfahan Province. These changes are more pronounced in elevations between 2200 and 2900 m. Therefore, rangeland managers have to cope with these changes by holistic management approaches through mitigation and human adaptations.

Tectonics and Mineralisation of Copper in the Ardestan-Kahang Area, Central Iran by Remote Sensing

The Ardestan-Kahang area is located in Urmieh-Dokhtar Magmatic Arc. This area is situated in Ardestan, Kouhpayeh, Kajan and Zefreh in 1:100,000 geological maps. In order to extract mineralization zones related to copper mineralization and accessories elements, and also identify Argillic, Prophylitic, Sericitic and Siliceous alteration with major and minor lineaments, various kinds of algorithms, band ratio and personal interpolation have been utilized. The applied methods for extracting alteration consist of LS-Fit (Least Square Fit), Matched Filtering (MF), Spectral Angle Mapper (SAM) and Spectral Feature Fitting (SFF), band ratio and visual interpretation. Comparing different outputs of utilized algorithms illustrates that the best algorithm for argillc alteration extraction are Matched Filtering (MF) and Spectral Feature Fitting (SFF), with visual interpretation, and for argillic alterations the visual interpretation with RGB: 468 that has seen pink-red color. For prophylitic alterations the utilized algorithms are Matched Filtering (MF). Lineaments have extracted with visual interpretation on satellite images and it is revealed that in areas where the fracture density is greater, conditions are more suitable for copper mineralization.

Neotectonics of Tabas Area, Central Iran by Index of Active Tectonics (IAT)

In this research, Tabas area, which is located in central Iran, was selected as the study area and three geomorphic indices were calculated for its structural fronts. Through averaging these three indices, we obtained index of active tectonics (IAT). The values of the index were divided into classes to define the degree of active tectonics. Therefore, relative tectonic activity was calculated and their values were classified and analyzed in two groups. Regions were identified as high and moderate levels. In analyzing data and combining them with tectonic setting, the results were often associated and justified with regional geology. Our results show that the highest value is located along Shoutori fault, which shows 2 class of relative tectonic activity (high level). Also, moderate values are located along Ereshk, Ezmeighan and Jamal faults (moderate level). According to these results, Shoutori fault is the most active fault in the study area and this situation is compatible with its position as a mountain front fault.

The Biggest Salt-Tongue Canopy of Central Iran

One of the most interesting salt structures is salt-tongue canopy. The Central Iran basin has a few salt provinces and in this paper, morphotectonic concept of the salt-tongue canopy on the west of Garmsar city has been investigated. In this study, field data coupling with the salt tectonic-related factors to provide a position for salt rocks in the west Garmsar. Firstly, various geological factors such as faults, folds and roads were extracted and compiled. This is because the factors mentioned above play important role in the instability of the region. The results of this study showed that the salt extrusion from the Lower Red formation is severe. Further, it is evident that the shortening of main structures has had a great impact on it whilst the salt movements have occurred within Garmsar Syncline. Finally, the paper concluded that the salt-tongue canopy in the region has increased the rates of salt extrusion.

Biozonation and Paleobathymetry on Foraminifera Upper Cretaceous Deposites of Central Iran Basins (Isfahan, Baharestan Section)

In this study Late Cretaceous stratum in central Iran, Baharestan section in Isfahan area, was evaluated by biozonation and paleobathymetry.?These sediments have 89 meters thick, and strata have been formed of marl and marl limestone. In order to indicate the ancient depth of Upper Cretaceous at this time, planktonic and benthic foraminifera were studied. The percentage of the total planktonic foraminifera to the whole sample of foraminifera after the removal of indwell benthic foraminifera (%P*) using the formula?D?=?e(3.58718 + (0.03534?×?%P*))?was identified and depth of 200 - 450 meters was achieved for them. In the present investigation, 30 planktonic species of 11 genus have been identified. The Upper Cretaceous deposit was divided to 6 biozones on the basis of planktonic foraminifera which are cosmopolitan and consist of: Biozone 1—Marginotruncana sigali-Dicarinella primitiva?partial range zone;?Biozone 2—Dicarinella concavata?interval zone;?Biozone 3—Dicarinella asymetrica?total range zone;Biozone 4—Globotruncanita elevata?partial range zone;Biozone 5—Globotruncana ventricosa?interval zone;Biozone 6—Radotruncana calcarata?interval zone.?Based on planktonic foraminifera, the Upper Cretaceous sediments in the study area are of the Turonian-Late Campanian ages.

A Review on Fossil Findings of Central Iran’s Permo-Triassic Deposits

In this research, a review was done on Permo-Triassic deposits in Central Iran including Abadeh, Hambast, and Elika formations. Following an overview about the circumstances of Central Iran Basin during Permotriassic time interval, the respective formations are introduced, and then, history of paleontology studies on these deposits will be depicted. Through analysis and comparison of previous studies, the following ages were estimated for the aforementioned formations: Early Dzhulfian for Abadeh Formation, Late Dzhulfian-Dorashamian for Hambast Formation, and Early Triassic (Scythian) for Elika Formation. Also, Permotriassic boundary in Central Iran is continuous, bearing the proposed sedimentation and fossil content. It is noteworthy that due to volcanic events at the boundary of these deposits in Central Iran, one might infer that occurrence of the aforementioned activities has been among the major causes of the respective extinction.

Non-Diapiric Salt Domes in the West Zanjan, Central Iran

The salt domes of the west Zanjan (Central Iran) are the most important structures in the study area. They have been formed by the uplifting and erosion together under low humidity and dry and warm climate condition. The salt rocks with near to 200 meters thickness are related to lower member of the Upper Red Formation (Early Miocene) that deposited in the inverted back arc basin. They have been formed in the Central Iran basin after the Arabian-Eurasian convergence. Based on filed works and preparation of geologic map, salt domes have been cropped out during regional uplifting and erosion along hinge zone of a longitudinal anticline. Also, there is no evidence for salt diapirism and so, they are different from some salt diapirs in the southwestern margin of Zanjan that is investigated by other researchers.

Fe-Ti Oxide Mineralization in the XV Intrusion,Bafq Mining District,Central Iran:Insights from Mineralogy,Mineral Chemistry and S Isotopic Data

The mafic-ultramafic intrusion in the XV anomaly area,contains magmatic Fe-Ti oxides±(p)ore,is located in the Bafq mining district in the Central Iran.It consists of cumulate and layered Fe-Ti-bearing gabbros and pyroxenites.The mineral assemblages include clinopyroxene,Fe-Ti oxides,plagioclase,amphibole,apatite and sulfides(pyrite and chalcopyrite).The Fe-Ti oxides mainly consist of magnetite-titanomagnetite and ilmenite,which occurred as disseminated,intergrowth,lamellae(trellis and sandwich textures)and inclusions.Magnetite in the gabbroic rocks is from the near end-member of Fe_(3)O_(4)(<1 wt.%TiO_(2))to titanomagnetite containing up to 8 wt.%TiO_(2)(about3.73 wt.%to 26.84 wt.%Ulvospinel(X_(Usp))).Magnetite in pyroxenite rocks is characterized with TiO_(2)range from 0.46 wt.%to 3.14 wt.%(X_(Usp)varied from 1.76 wt.%to 10.46 wt.%).The abundances of V_(2)O_(3)range from 0.03 wt.%to 1.29 wt.%and 0.24 wt.%to 1.00 wt.%for gabbro and pyroxenite,respectively.X_(Usp)contents of magnetite show insignificant correlations with Al_(2)O_(3)and MgO.The average XIlmin the ilmenite of gabbro is 92%,whereas it is 90.37%in the pyroxenite rocks.The MgO and V_(2)O_(3)contents show a slightly positive correlation with TiO_(2)in ilmenite.The composition of clinopyroxenes in gabbro and pyroxenite rocks fall in the diopside to augite field with Mg#ranging from 67 to 98 and 74 to 96,respectively.In both rock types,amphiboles are mainly pargasite and rarely actinolite.Plagioclase in pyroxenite rocks is clustered in the labradorite to andesine fields with a compositional ranges of An46-69and in gabboic rocks fall in two fields with compositional ranges of albite with An0.65-5.95and labradorite with An50-63.Theδ34S isotopic values cover a limited range from+3.15‰to+4.10‰V-CDT consistent with magmatic origin.Fe-Ti mineralization is formed in two stages,minor inclusions of Fe-Ti oxide minerals in the pyroxene and plagioclase crystallized in the early magmatic stage,whereas interstitial oxides formed by fractional crystallization processes that accumulated by gravitational settling in the later stage as intercumulus phase.Gravitational settling process is supported by the observation of decreasing the amount of Fe-Ti oxides from Fe-Ti oxide-rich pyroxenite to weak mineralized gabbro(base to top).The high contents of H2O,phosphorate and high initial Ti-Fe in parental magma are the crucial factors controlling the Fe-Ti oxides enrichment and mineralization.

On the occurrence of Neoplanorbulinella Matsumaru, 1976(Foraminifera) from the late Oligocene of Central Iran(Qom Formation):Palaeobiogeographic implications

The shallow marine carbonates of the upper Oligocene Qom Formation yielded several occurrences of the foraminiferan genus Neoplanorbulinella Matsumaru. Neoplanorbulinella saipanensis Matsumaru has so far been recorded from the late Eocene-early Miocene of Japan and late Oligocene of NE Italy whereas N. malatyaensis Gedik is only reported from the Oligocene from its type locality in the Malatya Basin, eastern Turkey. The new records reported here from the Qom Formation indicate that both species occur in the Dobaradar section, ca. 10 km south of the city of Qom in North-Central Iran. The palaeogeographic distribution of these two species therefore has to be extended as far as the palaeolongitude of current Central Iran.The accompanying larger benthic foraminifers, including Miogypsinoides complanatus(Schlumberger),M. formosensis Yabe and Hanzawa, Spiroclypeus margaritatus(Schlumberger), Operculina complanata(Defrance), and Risananeiza pustulosa Boukhary et al., indicate the upper Chattian SBZ 23 Zone. The coexistence of the N. saipanensis and N. malatyaensis points to suitable palaeobiogeographic conditions of Central Iran to host Western and Eastern Tethyan taxa.

Postmiogypsinella intermedia Sirel and Gedik 2011 from the upper Oligocene of Central Iran(Qom Formation):Paleogeography and paleoenvironmental implications

Postmiogypsinella intermedia Sirel and Gedik,2011 is reported for the first time from the shallow-marine limestones of the upper Chattian Qom Formation,Central Iran.This miogypsinid species has so far only been recorded from the upper Oligocene of Malatya(type locality)and Sivas(Central Anatolia)in eastern Turkey and from the upper Oligocene of the Prebetic Domain,SE Spain.The new record from Central Iran,paleobiogeographically located at the Eurasian margin of the Tethyan Seaway between the Western and Eastern Tethys realms,indicates that the paleogeographic distribution of this species has to be extended eastwards as far as Central Iran.This observation is not unexpected,since miogypsinid foraminifers with eccentric embryonic-nepionic apparatus(e.g.,Miogypsinella,Miogypsinoides,Miogypsina)are usually widely distributed.The accompanying larger benthic foraminifera,including Miogypsinoides complanatus(Schlumberger),Miogypsinoides formosensis Yabe and Hanzawa,Spiroclypeus margaritatus(Schlumberger),Operculina complanata(Defrance),and Risananeiza pustulosa Boukhary et al.,indicate the late Chattian age(corresponding to SBZ 23 Biozone).Postmiogypsinella intermedia is indicative of a shallow-marine middle ramp environment with oligotrophic conditions and inhabited the relatively deeper part of the photic zone.

Geochemical and Nd-Sr Isotopic Compositions of Hypabyssal Adakites in the Torud-Ahmad Abad Magmatic Belt,Northern Central Iran Zone:Analysis of Petrogenesis and Geodynamic Implications

Eocene intermediate to felsic subvolcanic rocks of the Torud-Ahmad Abad magmatic belt(TAMB),in the northern part of the Central Iran zone,are exposed between the Torud and Ahmad Abad regions in South-Southeast Shahrood.These igneous rocks include hypabyssal dacite,trachyte,andesite,trachy-andesite,and basaltic andesite;they are mainly composed of phenocrysts and microcrystalline groundmass of pyroxene,amphibole,and plagioclase,with minor biotite and titanomagnetite;they form domal structures(plugs and stocks),dikes,and sills that intruded into Neoproterozoic to cogenetic Eocene volcano-sedimentary sequences.Based on isotopic analysis of these intermediate to acidic rocks,initial ratios of^(143)Nd/^(144)Nd range from 0.512775 to 0.512893 and initial ratios of^(87)Sr/^(86)Sr range from 0.703746 to 0.705314,with quite positiveε_(Nd(i))values of+3.69 to+6.00.They are enriched in light rare earth elements and large ion lithophile elements and depleted in heavy rare earth elements and high-field strength elements,the SiO_(2) content is(52-62)wt.%,and Na_(2)O content>3 wt.%,Al_(2)O_(3) content>16 wt.%,Yb<1.8 ppm,and Y<18 ppm.These geological,geochemical,and Sr and Nd isotopic data are consistent with adakitic signatures originating by partial melting of the subducted Neo-Tethys oceanic slab(Sabzevar branch)and lithospheric suprasubduction zone mantle.The mantle signatures typifying the rapidly emplaced adakitic rocks(slab(high-silica adakite)and suprasubduction zone(low-silica adakite)melts)together with their locally voluminous extent are evidences that support a locally extensional geodynamic setting;and the evidence is consistent with an evolution to local transpression in the Late Eocene in this convergent margin are environment to rifting(basalts to adakites)towards submarine conditions in the Neogene.