Marginal Regime Research Articles

Balance-Sheet Netting in U.S. Treasury Markets and Central Clearing

In this paper, we provide a comprehensive investigation of the potential for expanded central clearing to reduce the costs of the supplementary leverage ratio (SLR) on Treasury market intermediation in both cash and repo markets. Combining a detailed analysis of the rules involved in calculating the SLR with a unique set of regulatory data, we conclude that expanding central clearing would have relatively limited effects on the level of SLRs. We do find intermediaries’ increase their balance sheet netting when their regulatory balance sheet costs are higher. Our data permits us to establish a number of empirical facts related to the noncentrally cleared bilateral (NCCB) repo segment, and to repo activity overall, at the bank holding company level. We find that sizeable amounts of bilaterally-cleared activity would not be nettable even if centrally cleared. We also find that a significant portion of activity is already nettable outside of central clearing because dealers are structuring their NCCB trades to net. While expanded central clearing could have other benefits, such as imposing a more uniform margin regime on Treasury market intermediation, the scope of its effects on reducing balance sheet costs associated with the leverage ratio is limited.

Investigation of Feasible and Marginal Operating Regimes of Electric Power Systems

The paper is devoted to the analysis of the feasibility domain of electric power systems. The problems of calculating feasible and marginal regimes of power systems, analyzing the geometry of the feasibility domain, and generating samples in this region are considered. Parallels are drawn with the works of B.T. Polyak on the analysis of the image of a quadratic map, modification of the Newton method and the development of methods for generating asymptotically uniform samples in areas with complex geometry. Particular attention is paid to Newton’s method with the transversality condition (TENR), its application for constructing a boundary oracle procedure and utilization for generating samples in the power system feasibility domain.

Nonparametric Bayesian Q-learning for optimization of dynamic treatment regimes in the presence of partial compliance.

Existing methods for estimation of dynamic treatment regimes are mostly limited to intention-to-treat analyses-which estimate the effect of randomization to a particular treatment regime without considering the compliance behavior of patients. In this article, we propose a novel nonparametric Bayesian Q-learning approach to construct optimal sequential treatment regimes that adjust for partial compliance. We consider the popular potential compliance framework, where some potential compliances are latent and need to be imputed. The key challenge is learning the joint distribution of the potential compliances, which we accomplish using a Dirichlet process mixture model. Our approach provides two kinds of treatment regimes: (1) conditional regimes that depend on the potential compliance values; and (2) marginal regimes where the potential compliances are marginalized. Extensive simulation studies highlight the usefulness of our method compared to intention-to-treat analyses. We apply our method to the Adaptive Treatment for Alcohol and Cocaine Dependence (ENGAGE) study , where the goal is to construct optimal treatment regimes to engage patients in therapy.

COUPLED EFFECT OF SOLID FRACTION AND INTERNAL ENERGY SOURCE ON CONVECTIVE HEAT TRANSPORT IN THREE-LAYERED AIR-POROUS-AIR DOMAIN: COMPARISON WITH DIFFERENT TWO-LAYERED DOMAINS

This paper studies convective heat transport driven by a uniform internal energy source coupled with the solid fraction in the partial air-saturated porous domains bounded by the top and bottom impermeable thermally conductive surfaces. The consideration of the coupled effect distinguishes our work from the papers of previous authors. We provide a comprehensive numerical study of internal convection and compare results of the linear stability analysis for three distinct domains. The first domain is air-porous-air (APA), where the heat-generating porous matrix is between the upper and lower air layers. In the second air-porous (AP) domain, the air layer overlays the porous medium. In the third porous-air (PA) domain, the air layer underlays the porous medium. The bimodal marginal stability curves and regime map with a demarcation line between the local and large-scale convective flows are obtained only for the APA and AP domains due to the division of each domain into the upper unstably stratified and lower stably stratified parts. The local convection cannot originate in the PA domain because the air layer belongs to the lower stably stratified part. A remarkable destabilizing effect of additional air layers has been revealed. For example, at the fixed solid fraction of 0.1, we achieve a 40-fold reduction of the critical Darcy-Rayleigh number in the APA domain by increasing the depth ratio from 0 to 0.5, and by 14 times in the AP domain and only by 3.5 times in the PA domain. The destabilizing effect enhances with increases in the solid fraction.

Keeping it Simple–Efficiency Costs of Fixed Margin Regimes in Transfer Pricing

Keeping it Simple–Efficiency Costs of Fixed Margin Regimes in Transfer Pricing

Gyrokinetic electrostatic turbulence close to marginality in the Wendelstein 7-X stellarator.

The transition from strong (fluidlike) to nearly marginal (Floquet-type) regimes of ion-temperature-gradient (ITG) driven turbulence is studied in the stellarator Wendelstein 7-X by means of numerical simulations. Close to marginality, extended (along magnetic field lines) linearly unstable modes are dominant, even in the presence of kinetic electrons, and provide a drive that results in finite turbulent transport. A total suppression of turbulence above the linear stability threshold of the ITG modes, commonly present in tokamaks and known as the "Dimits shift," is not observed. We show that this is mostly due to the peculiar radial structure of marginal turbulence, which is more localized than in the fluid case and therefore less likely to be stabilized by shearing flows.

Unified theory of tearing mode growth from linear to Rutherford regime in the presence of local equilibrium current gradients

Using the two-field reduced magneto-hydrodynamic (MHD) model, a new theory of tearing mode transition from linear to Rutherford regime in the presence of local equilibrium current gradient (LCG) effects is proposed. By containing the LCG term in the vorticity equation, I reproduce the modified Rutherford equation with saturation terms via a quasi-linear approach. Therefore, the LCG term in the vorticity equation is responsible for the saturation mechanism of the classical tearing mode. The unified formula of the tearing mode evolution from linear exponential growth to quasi-linear saturation is obtained if one contains the LCG and inertial terms in the vorticity equation simultaneously. Since LCG is essential for the linear growth rate of tearing mode in the marginal stable regime, the new theory is also valid when the mode close to marginality.

The Paleoproterozoic magmatic arc of Trivandrum Block, southern India: From Columbia to Gondwana

The southern part of Peninsular India is designated as the ‘Southern Granulite Terrane’ (SGT), the southern domain of which is composed of three Paleoproterozoic crustal segments – the Madras, Trivandrum and Nagercoil blocks. The Trivandrum block is mostly covered by metasupracrustals, termed as khondalites, representing granulite facies metapelites with the basement rocks occurring as NW-SE trending ribbon-like exposures and previously termed as massive charnockites. Here we investigate these basement rocks and identify that they are dominantly composed of charnockites (felsic) and enderbites (intermediate) corresponding to orthopyroxene bearing granulite facies granitoids, together with (meta) gabbro and diorite. We present petrologic, geochemical and zircon U-Pb-Hf and REE data on these rocks. The gabbros are mostly ferroan and calc-alkaline to calcic affinity with tholeiitic parentage. Their REE patterns are relatively flat and both REE and trace element plots indicate an E-MBORB source. The diorites are ferroan and tholeiitic with calcic to calc-alkaline nature and are slightly metaluminous The enderbite corresponds to granodioritic composition with ferroan signature and tholeiitic lineage. The charnockites are high silica granitoids with a transitional feature between magnesian and ferroan. Marked LREE enrichment and steep LREE to HREE slope, HFSE depletion, and other geochemical features suggest arc magmatic affinity in a subduction-related setting. Trace element discrimination plots also suggest subduction-related origin for all the rock types. Zircon U-Pb data show that the gabbro, charnockite and enderbite are broadly coeval with magma emplacement during the Paleoproterozoic at 1990–1962 Ma, and the dominantly positive εHf(t) values (up to + 7.0) indicate formation of new crust from juvenile magmas. The diorites represent a slightly younger phase of magmatism at 1808–1794 Ma involving crustal recycling as indicated by the negative εHf(t) values (-5.8 to −10.5). The construction of the Trivandrum block correlates with the timing of assembly of Columbia. Zircon U-Pb data also date the timing of metamorphism as 590–496 Ma, suggesting long-lived heat input and metamorphism, coinciding with Gondwana amalgamation. A compilation of the zircon U-Pb-Hf data from this block shows a major pulse of magmatism at ca. 2.1 to 1.9 Ga that involved building of new crust from juvenile magmatic sources. In contrast, the younger pulse which lasted up to 1.7 Ga dominantly involved the reworking of Paleoproterozoic as well as the vestiges of ancient Meso-Neoarchean crust. Thus, the Trivandrum Block records the gradual maturity of a subduction-related magmatic arc within a Paleoproterozoic convergent margin regime. The lithologic assemblages from the basement of Trivandrum block trace the history from the Paleoproterozoic Columbia to the late Neoproterozoic – Cambrian Gondwana supercontinents.

Toward achieving persistent behavior change in household water conservation

Achieving persistence in household behavior modification has been a central but elusive goal of environmental conservation attempts that rely on behavioral interventions. We implemented a habit change intervention, designed to achieve persistent change in household water conservation behavior in an affluent residential community in urban India. We found a 15 to 25% reduction in household water consumption in the absence of any volumetric pricing. Most importantly, the effects of our 5-wk intervention persisted for more than a year, after which marginal pricing was introduced. The treatment gap was not bridged even after a year under the marginal price regime.

Holocene Interactions Between Glacier Retreat, Sea Ice Formation, and Atlantic Water Advection at the Inner Northeast Greenland Continental Shelf

AbstractDuring the past four decades significant decrease in Arctic sea ice and a dramatic ice mass loss of the Greenland Ice Sheet (GIS) has been coincident with global warming and an increase in atmospheric CO2. In Northeast Greenland significant mass loss from the outlet glaciers Nioghalvfjerdsbræ (79NG) and Zachariæ Isstrøm (ZI) and intensive seasonal breakup of the local Norske Øer Ice Barrier (NØIB) have also been observed since 2000. In order to better understand the processes driving these modern changes, studies of paleoclimate records are important and of major societal relevance. A multiproxy study including organic‐biogeochemical and micropaleontological proxies was carried out on a marine sediment core recovered directly in front of 79NG. Data from Core PS100/270 evidenced a strong inflow of warm recirculating Atlantic Water across the Northeast Greenland shelf from the early Holocene between ~10 and 7.5 ka. An overall high in phytoplankton productivity occurred within a stable sea ice margin regime, accompanied by 79NG retreat most probably triggered by peak solar insolation and changes in the local ocean circulation. Enhanced basal melt of the underside of 79NG at ~7.5 ka then led to the total disintegration of the ice shelf. The released freshwater would have driven water column stratification and promoted the formation of the local landfast ice barrier, which is shown by lowered biomarker values and foraminifera abundances toward the end of the early Holocene. Near perennial sea ice conditions with short summers and 79NG retreat to the inner fjord then prevailed from ~7.5 to ~0.8 ka.

Violation of the viscosity/entropy bound in translationally invariant non-Fermi liquids

The shear viscosity is an important characterization of how a many-body system behaves like a fluid. We study the shear viscosity in a strongly interacting solvable model, consisting of coupled Sachdev-Ye-Kitaev (SYK) islands. As temperature is lowered, the model exhibits a crossover from an incoherent metal with local criticality to a marginal fermi liquid. We find that while the ratio of shear viscosity to entropy density in the marginal Fermi liquid regime satisfies a Kovtun-Son-Starinets (KSS) like bound, it can strongly violate the KSS bound in a robust temperature range of the incoherent metal regime, implying a nearly perfect fluidity of the coupled local critical SYK model. Furthermore, this model also provides the first translationally invariant example violating the KSS bound with known gauge-gravity correspondence.

Marginal Fermi Liquid in Twisted Bilayer Graphene.

Linear resistivity at low temperatures is a prominent feature of high-T_{c} superconductors which has also been found recently in twisted bilayer graphene. We show that due to an extended van Hove singularity (VHS), the T-linear resistivity can be obtained from a microscopic tight-binding model for filling factors close to the VHS. The linear behavior is shown to be related to the linear energy dependence of the electron quasiparticle decay rate which implies the low-energy logarithmic attenuation of the quasiparticle weight. These are distinctive features of a marginal Fermi liquid, which we also see reflected in the respective low-temperature logarithmic corrections of the heat capacity and the thermal conductivity, leading to the consequent violation of the Wiedemann-Franz law. We also show that there is a crossover at T∼6 K from the marginal Fermi liquid regime to a regime dominated by excitations on the Dirac cone right above the VHS that also yields a linear resistivity albeit with smaller slope, in agreement with experimental observations.

The Lazurnoe deposit in the Central Sikhote-Alin, Eastern Russia: Combined shoshonite-related porphyry Cu-Au-Mo and reduced intrusion-related Au mineralization in a post-subduction setting

The Lazurnoe porphyry Cu-Au-Mo deposit (>1Mt Cu-eq.) in the Mesozoic Central Sikhote-Alin orogenic belt (Eastern Russia) is located in an Early Cretaceous turbidite basin associated with a crustal-scale strike-slip fault zone, and was formed under the continental transform margin regime after the cessation of active subduction. The deposit is related to a magnetite-series, high-K calc-alkaline to shoshonitic, Early Cretaceous igneous suite that occurred in this tectonic setting, possibly due to asthenospheric mantle upwelling. The fertile magma was sourced from a subduction-modified mantle, under a low degree of partial melting, and was subjected to intense amphibole fractionation during its crystallization, the latter facilitating water and metal saturation. The parental igneous suite at Lazurnoe was coeval to ilmenite-series calc-alkaline igneous suites accompanied by reduced intrusion-related Au(±W) to W-Au deposits as well as to ilmenite-series, high-K calc-alkaline to shoshonitic suites accompanied by Sn-polymetallic mineralization.The deposit comprises magnetite-rich, quartz-K-feldspar to quartz-K-feldspar-biotite (potassic) alteration assemblages, containing bornite and chalcopyrite, which evolve to quartz-chlorite ± epidote ± amphibole (propylitic) assemblages, containing dominant pyrite with magnetite and chalcopyrite. Molybdenite-chalcopyrite-pyrite paragenesis dominates in quartz-sericite (phyllic) alteration assemblages that overprint and replace potassic and propylitic alteration. Potassic alteration assemblages formed from hot (~530–510 °C), high-salinity (45–48 wt% NaCl and 9–10 wt% CaCl2), sodic-calcic aqueous-chloride fluid. Gradual fluid cooling and dilution (from 29 to 31 wt% NaCl and 18–19 wt% CaCl2 through 24–25 wt% NaCl and 16–17 wt% CaCl2 to 12 ± 0.5 wt% NaCl and 12 ± 0.5 wt% CaCl2) is recorded for propylitic alteration assemblage. Another cycle of fluid exsolution from crystallizing magma can be suggested for phyllic alteration assemblages formed from a cooler (~390–310 °C), high-salinity (30–37 wt% NaCl and 5 ± 0.5 wt% CaCl2) aqueous-chloride fluid. The porphyry-style mineralization was overprinted by the late auriferous quartz-sulfide veins containing arsenopyrite, pyrrhotite and other sulfide minerals, together with native gold (locally > 100 g/t Au) and tellurides. These veins were formed from boiling aqueous-carbonic fluid that was characterized by elevated CO2 and CH4 contents, with subsequent separation of high-carbonic and aqueous-chloride phases, and the fluid cooling from ~390 to 250 °C. These veins can be related to another, more reduced, plutonic suite, which crystallized at a greater depth.

Modified propagation path and expanded coupling regime of lower hybrid fast wave by n∥-upshift via wave scattering in VEST

Experimental investigation of lower hybrid fast wave (LHFW) coupling and propagation is carried out by wave measurements utilizing magnetic probes in Versatile Experiment Spherical Torus. Coupling experiments are conducted in marginal (ne≥nconfluence) and prohibited (ne≫nconfluence) regimes for fast wave coupling. In the marginal regime of Ip = 25 kA, about two folds of n∥-upshift are observed. The propagation path of the fast wave is largely modified compared to that of full wave simulation, and more fast waves are detected inside the last-closed-flux surface despite the unsatisfied accessibility condition. Since spectral broadening is measured to be narrow and linearly proportional to coupled wave power with a high density fluctuation of about 20% in the frequency range (ω0/ωlh∼15), it is thought to be crucially correlated with wave scattering rather than parametric decay instabilities. Consequently, the spectral broadening implicates that n∥-upshift can take place via a wave scattering mechanism. In the prohibited regime of Ip = 100 kA, more enhanced coupling of up to 90% is observed with similar density fluctuation to that of the marginal regime, which is explained with intensified wave scattering due to the high dielectric constant of spherical torus plasmas. It is concluded that practical windows for propagation and coupling of LHFW are widened with the aid of n∥-upshift via wave scattering even though the accessibility condition is not satisfied right in front of the antenna.

Assessment of creep deformation and rupture behaviour of 304HCu austenitic stainless steel

Reduction in CO2 gas emission and decrease in fuel consumption can result in increase in efficiency of the thermal power plants. Increase in efficiency is directly linked to the steam temperature and pressure which requires materials having high creep strength. This resulted in development of Advanced Ultra Super Critical (AUSC) power plant which aims to increase efficiency to more than 45 % and significant decrease in CO2 emission. The 304HCu stainless steel is one of the candidate materials to be used in AUSC power plant. It contains around 3 wt. % of copper, certain amounts of niobium and nitrogen and increased carbon content for enhancing creep strength. Creep tests are conducted for 304HCu stainless steel at 923K, 973K and 1023K over a stress range of 100-240MPa. The creep curve exhibited shorter primary regimes followed by marginal secondary regimes and extended tertiary regime. The variation of steady state creep rate with applied stress exhibited Norton’s power law relationship (εs = Aσn). The value of n (stress exponent) decreased with increase in temperature but decrease was more pronounced at 923K. The product of steady state creep rate and rupture life obeyed Monkman-Grant relation. The contribution of tertiary creep was found to increase with temperature. Microstructural degradation in the form of coarsened precipitates, dislocation cell formation and deformation bands was the primary reason for increase in tertiary regime of creep curve and increase in the value of damage tolerance factor (λ). A mathematical model based on finite element analysis coupled with continuum damage mechanics has been used to predict the creep deformation and rupture life of 304HCu SS. The prediction of creep curve based on this model was found to be in good agreement with experimental results.

High-resolution stratigraphic forward modeling of a Quaternary carbonate margin: Controls and dynamic of the progradation

The relationships between the margin sedimentary regime and the platform progradation are studied using forward stratigraphic numerical simulations on the Leeward (Western) prograding margin of the Great Bahama Bank (GBB) during the Quaternary (1.7–0 Ma). The corresponding sedimentary regime in the slope and the platform is well known from the ODP leg 166 and Bahamas Drilling Project wells located along the “Western line” seismic transect. However the sedimentary regime on the margin is not well established: the coral reefal margin observed before between 1.7 and 0.8 Ma in the well Clino is not active anymore at present-day, and the Holocene sedimentary regime is geometrically unable to account alone for the progradation. This study is based on three 2D high-resolution forward stratigraphic numerical modeling experiments with the software DionisosFlow that include the platform, margin and slope domains on the “Western Line Section” in the same sedimentary models. The results are compared to the six sedimentary cores and to the present day bathymetry in order to identify the more realistic scenario. The three experiments test different models of carbonate sediment production and transport. Experiment 1 shows that the highstand shedding of the fine-grained uncemented platform production is unable to reproduce the progradation and the present-day profile. Experiments 2 and 3 incorporate cemented facies in the margin, with the best results obtained with the cemented marginal wedges produced in Experiment 2 during platform emersion. From these results a high-resolution interpretation of the margin seismic section is proposed. This study shows that the platform progradation can be decoupled from the highstand shedding of the fine-grained platform production. It is dependent on the accumulation in front of the steep margin of coarse or cemented material. Before 0.8 Ma this corresponds to the coral reef identified in Clino. The transition after 0.45 Ma to 100-kyr large eustatic cycles with total platform flooding created two distinct marginal regimes: (1) during platform flooding aggrading accumulation of non-skeletal sands, and (2) during platform emersion prograding cemented marginal wedges produced in-situ.

Translationally Invariant Non-Fermi-Liquid Metals with Critical Fermi Surfaces: Solvable Models

We construct examples of translationally invariant solvable models of strongly-correlated metals, composed of lattices of Sachdev-Ye-Kitaev dots with identical local interactions. These models display crossovers as a function of temperature into regimes with local quantum criticality and marginal-Fermi liquid behavior. In the marginal Fermi liquid regime, the dc resistivity increases linearly with temperature over a broad range of temperatures. By generalizing the form of interactions, we also construct examples of non-Fermi liquids with critical Fermi-surfaces. The self energy has a singular frequency dependence, but lacks momentum dependence, reminiscent of a dynamical mean field theory-like behavior but in dimensions $d<\infty$. In the low temperature and strong-coupling limit, a heavy Fermi liquid is formed. The critical Fermi-surface in the non-Fermi liquid regime gives rise to quantum oscillations in the magnetization as a function of an external magnetic field in the absence of quasiparticle excitations. We discuss the implications of these results for local quantum criticality and for fundamental bounds on relaxation rates. Drawing on the lessons from these models, we formulate conjectures on coarse grained descriptions of a class of intermediate scale non-fermi liquid behavior in generic correlated metals.

Simulation of Hindered Sedimentation of the Coarse Fraction of a Bidisperse Suspension in the Presence of Interfractional Coagulation

The peculiarities of the sedimentation of aggregates in a bidisperse (or two-fraction) suspension have been studied. A complete set of equations for the dynamics of an aggregate and suspension in the presence of the interfractional coagulation process and the hindering effect has been given. For the marginal Stokes and Newtonian regimes (corresponding to small and large Reynolds numbers), formulas have been obtained for the stationary sedimentation rate of aggregates, and their analysis has been performed. Some results of the numerical integration of the equations of motion of large particles in a suspension are have been. It has been established that the coagulation leads to an increase in the sedimentation rate of an aggregate and, on the contrary, the hindrance contributes to a decrease in the sedimentation rate. The nonmonotonic behavior of the sedimentation rate of aggregates as a function of the volume fraction of the dispersed phase is found.

Fluid evolution of Au-Cu zones in Um Balad area, North Eastern Desert of Egypt: Implications from mineral chemistry and fluid inclusions

Scanning electron microscope (SEM), Electron microprobe (EMPA) and fluid inclusion studies of the ore body, as well as geochemical analyses of country rocks were performed to determine the nature and characteristics of the mineralizing fluid responsible for Au-Cu deposits in Um Balad area, Northern Eastern Desert of Egypt. The Um Balad Au-Cu deposits are confined to well developed-quartz veins and veinlets cutting through the hosting country rocks. Petrographic and geochemical investigations of the hosting rocks distinguished between two main rock units; 1) metagabbro-diorite rocks with tholeiitic nature derived in island arc/continental margin tectonic regime, and 2) granodiorite rocks formed from calc-alkaline magma in continental margin regime. Wallrock alterations are represented by propylitic and argillic types. The mineralized quartz veins are striking in NE-SW direction and dipping between (35°–45°) in SE direction, other mineralized mafic dykes enriched with auriferous quartz veinlets are trending NE-SW and dipping 70°/SE. The main ore minerals are represented by gold, chalcopyrite, pyrite, sphalerite, malachite, covellite and goethite. While, geffroyite, cuprite, chrysocolla, pseudomalachite, britholite, wolframite, scheelite, hematite and rutile are detected as minor constituents. Fluid inclusions microthermometry and isochore calculations combined with chlorite geothermometry revealed that the Um Balad deposits were formed at temperature ranging from 305 °C to 325 °C and pressure between (100–500 bar). The mineralization had been developed in the shallow levels, beneath the water table at depth of 350–1760 m, rather than common mesothermal vein-type deposits in Egypt. Magmatic water have been suggested as the main source for the mineralized fluid. The transportation of the gold metal seems to be happen as bisulfide complexes in moderately acidic environment. The deposition was resulted from combination of changes in physico-chemical parameters, temperature and pressure plus the instability of the reduced sulfur complexes. A contamination with metamorphic and/or meteoric water was also proposed that has strong influence during the depositional process.

Petrogenesis and geochronology of Mishao peraluminous I-type granites, Shalair valley area, NE Iraq

The Shalair area, which is located in northeastern Iraq, is considered to be part of the northern Sanandaj-Sirjan Zone (SaSZ) and contains several granitoid bodies. One of these bodies, the Mishao porphyritic-granite (MG), was crystallized at 111.6 ± 2.4 Ma, based on its zircon U-Pb age. Its geochemical characteristics suggest that the MG rocks are calc-alkaline, peraluminous, I-type granites with microgranular mafic enclaves. They are enriched in SiO2, Na2O, Al2O3 and Zr and depleted in MgO, Fe2O3, Nb and Ti; in contrast, the enclave sample records lower SiO2 content and higher contents of MgO and Fe2O3. These rocks show an enrichment of LREE relative to HREE, and pronounced negative Eu anomalies implying feldspar fractionation. The isotopic and geochemical characteristics of the MG samples suggest that these rocks are evolved through fractional crystallization. In the La/Nb-Nb diagram and Sm/Nd ratios, the MG rocks and the enclave samples exhibit strong evidence for crustal contamination. The MG rocks record high initial 87Sr/86Sr (0.70625–0.70740) and low 143Nd/144Nd(i) (0.51235–0.51274) ratios. These Sr-Nd isotopic data, combined with the presence of high Th/U and Rb/Sr ratios and significant depletions of Nb, Ta and Ti, show a relation of these bodies to an active continental margin regime. Based on the age and geochemical data of the MG, this study presents new information about the occurrence of Middle Cretaceous magmatic activities, which are related to the active continental margins in the SaSZ that run parallel to the Zagros Fold-Thrust Belt.